[Matt J. McCullar]

Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

[Jerry G.]

I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======



On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

[[email protected]]

On Dec 7, 9:28 pm, "Jerry G." wrote:
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.

Jerry G.
======

On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:



Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar- Hide quoted text -

- Show quoted text -

Thats exactly why it is of the utmost importance to wear safety
googles and other protective gear when attemping such a dangerous
task. I usually drink first.
Rick

[Smitty Two]

In article
,
"Jerry G." wrote:

I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======


Professionals - in any profession - are injured and killed, too. Let the
service tech who hasn't had an electrolytic capacitor explode, please
stand up... being an amateur is no reason to leave things alone.

[[email protected]]

Gotta side with the amateurs on this one. I am by no means a tech. I
have made mistakes while repairing things. You fix the mistake and
move on. If you wanted a safe hobby, you would have taken up golf.
Nothing safer than little white projectiles flying all over a field
with drunk guys yelling fore. I think anyone whos been in this hobby
for more than a year has probably had a decent shock before. Lord
knows I have. But it doesn't affect me any. But it doesn't affect
me any. The trick is to know when I a project is above your head and
send it off if you cant handle it. If you don't think the hobby is
dangerous, I know of someone who was moving a large game and if fell
striking him on the head. He later developed neurological problems
that was diagnosed as Lou Gerhigs disease. That is if I overheard
everything correctly. Just about everything about these games can
cause death. Whether its electrocution, fire, or being crushed by an
HS-5 dynamo. But we do it cause we love it. And we try to better our
skills by gradually taking on smaller projects until we are ready for
larger ones. If you get right down to it, no tech was born a tech.
They learned it somewhere whether its MIT, ITT or the TSHK(the school
of hard knocks.) Just my 2cents.

[gamefixer]

On Dec 7, 8:28 pm, "Jerry G." wrote:
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.

Jerry G.
======

On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:



Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar- Hide quoted text -

- Show quoted text -

Nah, practice makes perfect. Your going to have to try REALLY hard to
kill your self with a monitor. FWIW, Matt's a veteran in this group
and in the field. We all make mistakes...

Matt (a different one)

[Dave Plowman (News)]

In article ,
Matt J. McCullar wrote:
The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of
capacitors or other electronic parts: make sure you can read ALL the
numbers and letters on them!!!

There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by the
size difference between all the new ones?

--
*Acupuncture is a jab well done*

Dave Plowman London SW
To e-mail, change noise into sound.

[carneyke]

On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

I always change a part or two and did the next part. Sometimes test
the unit after changing one or two parts, checking for problems caused
by new part. I don't like pulling too many parts without checking
work performed, it depends on job.

[wc3p]

On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

Thanks for sharing the story, Matt!

I won't tell you to spend gobs of money paying someone else to make
the mistakes for you, since they're only human too. It is a wise man
(person) who listens to someone's story and logs the wisdom in their
own skull , then hears the little voice repeating that story in their
ear at the right time.

Bob WC3P

[Jeff[_5_]]

On Dec 7, 10:57 pm, wrote:
On Dec 7, 9:28 pm, "Jerry G." wrote:



I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.

Jerry G.
======

On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:

Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It sailed
past my ear and landed about three feet away! It was a small one, a 10 uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right value
of capacitance, and I'd installed it correctly. My mistake was the voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically a
rubberized version of hot glue. This white gunk had hardened all over one
side of this cap, and it had masked something critical: one digit. That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar- Hide quoted text -

- Show quoted text -

Thats exactly why it is of the utmost importance to wear safety
googles and other protective gear when attemping such a dangerous
task. I usually drink first.
Rick

Heavily and without prejudice.

[Jay]

I disagree, that example can happen to ANYONE, professionals and amateurs
alike. I wouldn't doubt it happens to professionals more often because of
pure cockiness. An amateur is more likely to take necessary precautions and
check the work over and over.

I for one, if I have the tools or equipment to do so will do anything myself
rather than have a professional do it. (not without doing a little research
first of course) Diagnosing a problem is a different story.

"Jerry G." wrote in message
...
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======



On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each
location,
its reference designation, and the value and voltage of each capacitor.
All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my
list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It
sailed
past my ear and landed about three feet away! It was a small one, a 10
uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right
value
of capacitance, and I'd installed it correctly. My mistake was the
voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically
a
rubberized version of hot glue. This white gunk had hardened all over
one
side of this cap, and it had masked something critical: one digit.
That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of
capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

[PeterD]

On Sat, 08 Dec 2007 02:45:31 GMT, "Matt J. McCullar"
wrote:

Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each location,
its reference designation, and the value and voltage of each capacitor. All
the original caps went into a zip-lock bag.


You are kidding right? And you are trying to offer advice?

First bit of advice to you: Replace ONE AT A TIME...
Second bit of advice to you: Check, then double check that yuo have
the right part, in the right way.

[Matt J. McCullar]

There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by the
size difference between all the new ones?


Indeed it was. Fortunately, the silk screening on the circuit board is what
gave me the clue. After the fact it said that the original cap was
physically much larger than the replacement I had installed. Sometimes
newer drop-in replacment caps are smaller than the originals, but not by
THAT much!

And thanks for the backup, everybody. Everybody makes mistakes, no matter
how many years you've got under your belt. And electricity, like steam and
the ocean, does not respect an idiot; it's waiting for you to make a
mistake. You gotta have respect for it or it'll kill you.

So learn from the mistakes of others as well as your own and don't be shy
about passing on what you've learned. It just might help someone else in
the future.

[n cook]

Matt J. McCullar wrote in message
t...

There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by the
size difference between all the new ones?


Indeed it was. Fortunately, the silk screening on the circuit board is
what
gave me the clue. After the fact it said that the original cap was
physically much larger than the replacement I had installed. Sometimes
newer drop-in replacment caps are smaller than the originals, but not by
THAT much!

And thanks for the backup, everybody. Everybody makes mistakes, no matter
how many years you've got under your belt. And electricity, like steam
and
the ocean, does not respect an idiot; it's waiting for you to make a
mistake. You gotta have respect for it or it'll kill you.

So learn from the mistakes of others as well as your own and don't be shy
about passing on what you've learned. It just might help someone else in
the future.





It would help if there was a standard, some mark + , some mark - and some
mark with arrows consisting of a line of negative signs leading to the other
side

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

[Morse]

"Jerry G." wrote in message
...
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======


Hmmm, here's a little story-

After several attempted and failed warranty repairs on my cooker to fix the
same fault, and all by different engineers, my son leant on the metalwork
and got a shock. I did a quick test with a multimeter from chassis to a
nearby earth point and, guess what- no earth.

I removed the small access panel on the back of the cooker where the mains
feed enters, and discovered that the internal earth leads had been
disconnected from ther terminal block and taped together. The mains lead had
also had its earth disconnected from the block and had a small length of
thin, solid core red wire taped to it which went nowhere.

One tech who came out said he'd 'done something to the wiring' to try and
eliminate the fault (the clock and oven randomly go off) so it's likely he
is responsible for this, but the worrying thing is that all the techs have
signed the paperwork saying that the appliance had been tested for safety.
The first rule of checking for electrical safety is surely checking the
earth- it took me literally 5 seconds so why did they all miss this? The
engineer who called today said it was disgraceful and he would be 'having a
quiet word' with the engineer who did it, but I had to suppress the urge to
point out that *he* was happy enough to sign it off as safe without checking
it, pots and kettles spring to mind.

So, no offence, but qualified techs can and do not only screw up but are
capable of potentially homicidal recklessness. Some individuals are
competent, some are not, regardless of qualifications. I have no formal
qualifications but I would *never* have done something like this, the
importance of a good earth on metal kitchen appliances is blatantly obvious
and cannot be overstated. Had I not have had an electronic background, the
missing earth may well have gone unnoticed and the shock may have been
dismissed as static. The consequences don't bear thinking about.

Morse

[Ken Layton]

Common sense dictates that you change one capaitor at a time. You
should also verify polarity and value of the capacitor you're
replacing and the new one too. Remember that monitor manufacturers
sometimes have incorrectly marked the polarity on the chassis too
(Hantarex I'm pointing directly at you).

[clifto]

Ken Layton wrote:
Common sense dictates that you change one capaitor at a time.

Anyone who's ever built a kit of any complexity can see the value of doing
all the unsoldering and cleaning at once, followed by doing all the parts
insertion and clipping at once, followed by doing all the soldering at
once.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

[Jay]

The problem Matt ran into was misreading a value on a cap .It can be made
whether you do all the caps at once or one at a time. Matt took all the
necessary precautions needed to avert any wrong installations of the caps by
noting each caps place, value and polarity rather than rely on the circuit
markings (to me, that shows some experience there) Though it is more time
consuming and there is more chance of a mistake, I see no problem with
removing all the caps at once so long as those steps are taken.

"William" wrote in message
...

"Matt J. McCullar" wrote in message
et...
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each
location,
its reference designation, and the value and voltage of each capacitor.
All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my
list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It
sailed
past my ear and landed about three feet away! It was a small one, a 10
uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right
value
of capacitance, and I'd installed it correctly. My mistake was the
voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically
a
rubberized version of hot glue. This white gunk had hardened all over
one
side of this cap, and it had masked something critical: one digit.
That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of
capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar




I never remove ALL the caps at one time. I do it one at a time and verify
voltage and polarity of the old cap first before installing the new
one....sometimes the markings on the circuit board are wrong.

[Tim O]

On Fri, 7 Dec 2007 19:28:02 -0800 (PST), "Jerry G."
wrote:

I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======

Thats my brother in laws attitude, and he gets screwed on everything.
From basic house maintenance, working on cars, right down to paying
someone to fix his computer problems.

He doesn't have to worry about fixing games because he can't afford
them after paying everyone else.

[Dave Plowman (News)]

In article ,
clifto wrote:
Ken Layton wrote:
Common sense dictates that you change one capaitor at a time.

Anyone who's ever built a kit of any complexity can see the value of
doing all the unsoldering and cleaning at once, followed by doing all
the parts insertion and clipping at once, followed by doing all the
soldering at once.

That's a prime way to miss out soldering things. It may be the way a
factory makes things but no use for home construction. Start with the
things least effected by heat - resistors etc - and end with the
semiconductors.

Perhaps your method clarifies why you talk about unsoldering when building
a kit. ;-)

--
*One tequila, two tequila, three tequila, floor.

Dave Plowman London SW
To e-mail, change noise into sound.

[Mickey Johnson]

Anyone who's ever built a kit of any complexity can see the value of
doing all the unsoldering and cleaning at once, followed by doing all
the parts insertion and clipping at once, followed by doing all the
soldering at once.


I sure would like to know what the value in the above plan is. That is
absolutely the worst way to approach a monitor cap kit. Do the job one cap
at a time and the values on the caps and silkscreening will all make sense
and it will be apparent if there is an error with either the silkscreening
or value of the item being replaced.

[gamefixer]

On Dec 8, 1:46 pm, "Dave Plowman (News)" wrote:
In article ,
clifto wrote:

Ken Layton wrote:
Common sense dictates that you change one capaitor at a time.
Anyone who's ever built a kit of any complexity can see the value of
doing all the unsoldering and cleaning at once, followed by doing all
the parts insertion and clipping at once, followed by doing all the
soldering at once.

That's a prime way to miss out soldering things. It may be the way a
factory makes things but no use for home construction. Start with the
things least effected by heat - resistors etc - and end with the
semiconductors.

Perhaps your method clarifies why you talk about unsoldering when building
a kit. ;-)

--
*One tequila, two tequila, three tequila, floor.

Dave Plowman London SW
To e-mail, change noise into sound.

I dunno about that. From the way Ken describes his work he and I do
cap kits in pretty close the same way. I change one cap at a time but
solder them all at the same time. Have yet to miss one in 20+
years....

Matt

[Scott Caldwell]

Matt, I absolutely agree with you. Anyone whom has done any repairs
at all has made mistakes. Live, learn, move on and above all, respect
electricity!

Scott C.

Matt J. McCullar wrote:
There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by the
size difference between all the new ones?


Indeed it was. Fortunately, the silk screening on the circuit board is what
gave me the clue. After the fact it said that the original cap was
physically much larger than the replacement I had installed. Sometimes
newer drop-in replacment caps are smaller than the originals, but not by
THAT much!

And thanks for the backup, everybody. Everybody makes mistakes, no matter
how many years you've got under your belt. And electricity, like steam and
the ocean, does not respect an idiot; it's waiting for you to make a
mistake. You gotta have respect for it or it'll kill you.

So learn from the mistakes of others as well as your own and don't be shy
about passing on what you've learned. It just might help someone else in
the future.

[clifto]

Dave Plowman (News) wrote:
clifto wrote:
Ken Layton wrote:
Common sense dictates that you change one capaitor at a time.

Anyone who's ever built a kit of any complexity can see the value of
doing all the unsoldering and cleaning at once, followed by doing all
the parts insertion and clipping at once, followed by doing all the
soldering at once.

That's a prime way to miss out soldering things. It may be the way a
factory makes things but no use for home construction. Start with the
things least effected by heat - resistors etc - and end with the
semiconductors.

Parts count X 2 = number of joints for the job described. Sanity check
afterwards: parts count X 2 = number of joints to deflux.

Perhaps your method clarifies why you talk about unsoldering when building
a kit. ;-)

Preparation, you big silly. With a kit I always check the boards, use steel
wool or whatever as necessary, check for obvious damage (hold it up to a
light to look for cracks), etc.

--
Dec. 6 (Bloomberg) -- Government officials and activists flying to Bali,
Indonesia, for the United Nations meeting on climate change will cause
as much pollution as 20,000 cars in a year.

[James Sweet]

There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by the
size difference between all the new ones?


We're talking about 25-30 year old monitors, I fix a lot of these, the new
caps are usually far smaller physically than the old ones, plenty of modern
250V caps are smaller even than the old 50V caps.

[James Sweet]

"Jay" wrote in message
. ..
I disagree, that example can happen to ANYONE, professionals and amateurs
alike. I wouldn't doubt it happens to professionals more often because of
pure cockiness. An amateur is more likely to take necessary precautions and
check the work over and over.

I for one, if I have the tools or equipment to do so will do anything
myself rather than have a professional do it. (not without doing a little
research first of course) Diagnosing a problem is a different story.



Not to point any fingers, but there's a few "professionals" around here who
seem to have forgotten that everyone started out as an amatuer at one point
or another. I wasn't born knowing anything about electronics, and I've never
been formally taught, I've picked it all up on my own through doing it.

[James Sweet]

"N Cook" wrote in message
...
Matt J. McCullar wrote in message
t...

There's usually a big difference in size between a 50 and 250 working
voltage one. And if replacing the lot it should have been obvious by
the
size difference between all the new ones?


Indeed it was. Fortunately, the silk screening on the circuit board is
what
gave me the clue. After the fact it said that the original cap was
physically much larger than the replacement I had installed. Sometimes
newer drop-in replacment caps are smaller than the originals, but not by
THAT much!

And thanks for the backup, everybody. Everybody makes mistakes, no
matter
how many years you've got under your belt. And electricity, like steam
and
the ocean, does not respect an idiot; it's waiting for you to make a
mistake. You gotta have respect for it or it'll kill you.

So learn from the mistakes of others as well as your own and don't be shy
about passing on what you've learned. It just might help someone else in
the future.





It would help if there was a standard, some mark + , some mark - and some
mark with arrows consisting of a line of negative signs leading to the
other
side



There are on a lot of things. The really fun one is the G07 chassis, they
made zillions of them, one of the caps has the polarity silkscreen wrong on
one side of the board, thankfully it's right on the other side, but then how
do you know which one is right? Pays to make a mental note when you pull the
part out.

[James Sweet]

I sure would like to know what the value in the above plan is. That is
absolutely the worst way to approach a monitor cap kit. Do the job one
cap at a time and the values on the caps and silkscreening will all make
sense and it will be apparent if there is an error with either the
silkscreening or value of the item being replaced.


You must have a lot of free time, or not so many monitors. When you've got
half a dozen monitor chassis' stacked on the bench, any tricks to speed up
the process are worthwhile. I tend to go for an assembly line approach, and
change groups of 4 or 5 caps at a time on each board. Pull them all, put in
all the new ones, solder them all, clip, then repeat with the next group and
mark off the checklist as I go.

[Vaxx]

All it proves is he is human like the rest of us. As long as you don't make
the same mistake, you have learnt something/

[mark krawczuk[_2_]]

hi, i`ve know properly trained service people in public and THE MILITARY
who have made much worse mistakes than that, mistakes my friends 14 yo son
wouldnt even make.

"Jerry G." wrote in message
...
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======



On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each
location,
its reference designation, and the value and voltage of each capacitor.
All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my
list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It
sailed
past my ear and landed about three feet away! It was a small one, a 10
uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right
value
of capacitance, and I'd installed it correctly. My mistake was the
voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically
a
rubberized version of hot glue. This white gunk had hardened all over
one
side of this cap, and it had masked something critical: one digit.
That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of
capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

[mark krawczuk[_2_]]

hi, also , so overnight people become fully trained techs ?? i bet u
$1000 that , they got interested in electronics , and made stuff ups as
USUAL when starting any hobby .
just because u might be a tech , does not mean YOU DO NOT MAKE STUFF UPS.


you learn from experiance .

and people CAN DO THE WORK THEMSELVES and have saved a few dollars.
thats why we have fully trained techs because people start of with
electronics as a hobby and make screw ups..
, and think , hey , what makes this tick , ???if i do,,,,,,,, etc..




"Jerry G." wrote in message
...
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.


Jerry G.
======



On Dec 7, 9:45 pm, "Matt J. McCullar" wrote:
Something I learned the hard way...

I was replacing a bunch of electrolytic capacitors in a video monitor. I
removed the originals all at once, taking careful notes about each
location,
its reference designation, and the value and voltage of each capacitor.
All
the original caps went into a zip-lock bag.

Then I got a fresh batch of new capacitors, tested each one first, and
installed them in one go. I carefully checked off each capacitor on my
list
as I went. (Another tip: I colorize the top of each new electrolytic
capacitor with a red magic marker so I can readily see if I've missed
something later.)

This was about 30 capacitors. It's very easy to put one in backwards, as
you well know. I was very, very careful.

I apply power, and...

BOOM! One cap literally got blown completely out of the monitor! It
sailed
past my ear and landed about three feet away! It was a small one, a 10
uF,
50 volt job, but it learned how to fly that day.

Well, poop. I quickly removed power and found the location of the fried
capacitor. I checked my notes again. Something in my gut told me to
re-double-check. I went back through the bag of original capacitors and
checked off each cap's value and voltage rating.

Now, here's the golden moment: I found my mistake. I had the right
value
of capacitance, and I'd installed it correctly. My mistake was the
voltage
rating. I had installed a 50-volt capacitor, which is what the original
capacitor was rated for. But... The original capacitor had some white
rubbery gunk on it; that had been applied on the circuit board at the
factory to keep parts and wiring from moving around much. It's basically
a
rubberized version of hot glue. This white gunk had hardened all over
one
side of this cap, and it had masked something critical: one digit.
That's
all, just one digit. I removed the gunk.

The original capacitor was rated for 250 volts, not 50! No wonder the
replacement cap exploded.

So, keep this in mind the next time you're replacing a bunch of
capacitors
or other electronic parts: make sure you can read ALL the numbers and
letters on them!!!

Matt J. McCullar

[mark krawczuk[_2_]]

i see jerry g hasent replied....

****.



"Vaxx" wrote in message
u...
All it proves is he is human like the rest of us. As long as you don't
make the same mistake, you have learnt something/

[Don Bowey]

On 3/9/08 3:33 PM, in article ,
"mark krawczuk" wrote:

i see jerry g hasent replied....

****.



"Vaxx" wrote in message
u...
All it proves is he is human like the rest of us. As long as you don't
make the same mistake, you have learnt something/




There wasn't anything meaningful to which he might have "replied."

Besides seeming rude, you are a top-posting ****, which can be overlooked
only if one is not a rude ****.

[Clams Canino]

"mark krawczuk" wrote in message
...


"Jerry G." wrote in message
...
I don't know your service experience, but you gave a simple example of
why professional service people warn people who don't have the proper
training and experience to give their service work out to qualified
services to have their repairs done.

The other good reason they warn them is to stay in business.

I know of cases where people have had injury from a terrible electric
shock, of cases where people had fires, and who were injured from
exploding parts that have not been correctly replaced.

But... For some reason many people think they can do the work
themselves, thinking that they will save a few dollars.

Fact is that anyone can make a stupid mistake, or in the case of the OP a
very legitimate error. In my 30 year involvement with Ham Radio I know
personally of a few guys that became instantly deceased by coming across the
B+ supply of a final amplifier circuit that they designed, built, and used
for years and years before they screwed up. Many of the tube type amps run
4-8kv at 1-2 amps DC. Even forgetting to discharge the filter caps can kill
you deader than dead. IMHO anyone working on this stuff needs to remain
paranoid of safety errors. In the case of the OP, a good schematic would
have shown the 250v cap and avoided the error.

-W

[Grauwulf]

I firmly believe that if you don't make mistakes, you never actually
learn anything.

I'm not a pro, just an experienced amateur, and how I approach a cap
kit depends on the chassis. For G07's and K4900 and K7000, I generally
change the caps in groups because I've done so many of them. Most
other monitors I just do one at a time to make sure I don't miss
anything.

James

[Pat D.]

I have worked on chassis that have had the incorrect value of caps
installed. (Which is why they weren't working in the first place).
Honest to God, they must have had something like a 220 uf @ 160v cap in
place where a 22uf@50v belonged. The person that worked on it before
must have just stuck whatever cap they had sitting on the bench in
whatever spot was open.

So, moral of the story...always use a cap list. Many times these have
been updated with new values anyway to fix issues with particular types
of chassis. The jamma fix for the G07 comes to mind. FWIW, I desolder
a cap, stick a new one in and move on. Then I solder all the legs and
clip all the legs. Then I look at the complete bottom of the chassis
with a magnifying lamp to look for suspect soldering from previous
repairs or solder splotches.

Yes, Matt knows what he is doing. I would like to repeat one of my
rules I have posted before. Never do a cap kit when drunk. You're just
going to have to do it again.

Pat D.

[boardjunkie]

On Mar 9, 6:50*pm, "Clams Canino" wrote:
Fact is that anyone can make a stupid mistake, or in the case of the OP a
very legitimate error. In my 30 year involvement with Ham Radio I know
personally of a few guys that became instantly deceased by coming across the
B+ supply of a final amplifier circuit that they designed, built, and used
for years and years before they screwed up. Many of the tube type amps run
4-8kv at 1-2 amps DC. Even forgetting to discharge the filter caps can kill
you deader than dead. *

That ain't no ****.....serious current at that voltage. Actually I'd
think it to be a little more current for large x-mitter tubes. I pay
the bills working on music equipment and a lot of that is tube guitar
amps. A 500v electrolytic installed reverse polarity makes a serious
racket and a huge mess (along with a rank stench) when they vent. My
general rule is check polarity after replacement, then again before
power up. I've never put one in backwards, but I've had 'em go postal
on the bench due to excessive leakage current.....should've been
monitoring the temp since they were 20+ yr old caps. I did have an amp
come in once with someone else's cap job already done and a bias
filter cap in backwards. How that didn't go ka-blooey I'll never know.


IMHO anyone working on this stuff needs to remain
paranoid of safety errors. *In the case of the OP, a good schematic would
have shown the 250v cap and avoided the error.

Actually he should have pulled off the glue-gunk to verify what came
out. Going by a list and checking them off as they were replaced
should've raised a red flag.

[Clams Canino]

"Pat D." wrote in message
news:IobBj.1821$yD3.280@trnddc05...

I would like to repeat one of my
rules I have posted before. Never do a cap kit when drunk. You're just
going to have to do it again.


Ummmm, It's prolly safe to say that one should never do anything more
technical than tying your soes when drunk.

-W

[Dave Martindale]

"Pat D." writes:
I have worked on chassis that have had the incorrect value of caps
installed. (Which is why they weren't working in the first place).
Honest to God, they must have had something like a 220 uf @ 160v cap in
place where a 22uf@50v belonged. The person that worked on it before
must have just stuck whatever cap they had sitting on the bench in
whatever spot was open.

I've also seen a board that was marked wrong from the manufacturer.

Once upon a time, there was a PDP-11 that ran Unix, about 1975. DEC
core memory was expensive, so we had a box of some third-party memory,
maybe Dataram. It interfaced to the Unibus via an assembly that
pretended to be a Unibus jumper between adjacent backplanes, so it
didn't take any slots of its own.

One day, we had it apart, and I noticed there was a little tanalum
capacitor that was clearly dead. I figured I might as well fix it,
replacing it with another tantalum of the correct capacitance and equal
or higher voltage rating, carefully orienting it according to the "+"
marking screened on the circuit board. Put it all back together and
turned on the power, and there was the smoke and smell of a fried
tantalum.

So I looked at it again, and traced circuit foils from the plus and
minus supply pins on the Unibus connector. (This was a 5 V bypass cap,
so it connected directly to the power supply pins). Sure enough, the
"+" in the silkscreened marking was adjacent to the *negative* lead of
the capacitor. I installed another cap "backwards" relative to the
marking, and it was fine for the rest of the life of the machine.

Dave