Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 2,017
Default CRT vertical deflection -- bad solder joints?

On Monday, March 28, 2011 4:15:45 AM UTC-7, Mike Tomlinson wrote:
In article
s.com, Sean Hamilton writes

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television?


Yes, but it's more likely to be a bad cap.


Visual inspection is not enough. You need an ESR meter.


Maybe not; the ESR issues crop up mainly in high-performance
low voltage power supplies (like computers); the vertical
sweep circuit doesn't need a low-ESR capacitor. It will
take (and work well with) just about any capacitor with
adequate voltage rating and capacity.

The capacitor is inexpensive; just replace it with a new one,
don't bother with testing the old unit.
  #2   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"whit3rd" wrote in message
...
On Monday, March 28, 2011 4:15:45 AM UTC-7, Mike Tomlinson wrote:
In article
s.com, Sean Hamilton writes

Is it likely that bad solder joints would cause vertical foldover in a
mid-90s CRT television?


Yes, but it's more likely to be a bad cap.


Visual inspection is not enough. You need an ESR meter.


Maybe not; the ESR issues crop up mainly in high-performance
low voltage power supplies (like computers); the vertical
sweep circuit doesn't need a low-ESR capacitor. It will
take (and work well with) just about any capacitor with
adequate voltage rating and capacity.

The capacitor is inexpensive; just replace it with a new one,
don't bother with testing the old unit.


I think you are missing the point of what he was saying regarding ESR. This
parameter is a valid test of the 'goodness' of any electrolytic capacitor,
regardless of its ESR pedigree. Even 'normal' electrolytics have a
relatively low ESR when they are properly functional. As they fail, that
figure will increase, and that is readily spotted with an ESR meter. As to
the OP's actual problem, whilst bad joints in vertical output stages in CRT
televisions were common, this more often lead to initially intermittent, and
finally permanent frame collapse, than geometry problems like foldover,
which the OP said was the problem he had. My money would be 100% on it being
a bad cap, or possibly the feed resistor to the output IC having gone high.
This was also a relatively common problem on many chassis, and could cause a
severe foldover, usually at the bottom of the screen where the deflection
drive current needed to be at its highest.

Arfa

  #3   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,069
Default CRT vertical deflection -- bad solder joints?

In article , Arfa Daily
writes

I think you are missing the point of what he was saying regarding ESR.


I think so too )

My money would be 100% on it being
a bad cap


+1

--
Mike Tomlinson
  #4   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,833
Default CRT vertical deflection -- bad solder joints?

Hello? Instead of fussing over it, why not replace all the electrolytics "in
the vicinity" while the bad-looking solder joints are being re-done?

This is a common problem in servicing. As an EE, I want to know exactly why
something isn't working correctly. But I learned a long time ago that it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.


  #5   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,069
Default CRT vertical deflection -- bad solder joints?

In article , William Sommerwerck
writes

This is a common problem in servicing. As an EE, I want to know exactly why
something isn't working correctly. But I learned a long time ago that it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.


If you're fixing stuff regularly, particularly many of the same item,
it's worth diagnosing the problem so that in future you can say, "oh,
that model, that fault, it's C35", and replace that - saving time and
the cost of replacing components unnecessarily.

--
Mike Tomlinson


  #6   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"William Sommerwerck" wrote in message
...
Hello? Instead of fussing over it, why not replace all the electrolytics
"in
the vicinity" while the bad-looking solder joints are being re-done?

This is a common problem in servicing. As an EE, I want to know exactly
why
something isn't working correctly. But I learned a long time ago that it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.



Shotgunning is, IMHO, very bad practice, and often leads to the creation of
more problems than it fixes. I am actually quite surprised that you would
advocate doing this, William.

Arfa

  #7   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"Mike Tomlinson" wrote in message
...
In article , William Sommerwerck
writes

This is a common problem in servicing. As an EE, I want to know exactly
why
something isn't working correctly. But I learned a long time ago that it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.


If you're fixing stuff regularly, particularly many of the same item,
it's worth diagnosing the problem so that in future you can say, "oh,
that model, that fault, it's C35", and replace that - saving time and
the cost of replacing components unnecessarily.

--
Mike Tomlinson


Seconded ...

Arfa

  #8   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,833
Default CRT vertical deflection -- bad solder joints?

This is a common problem in servicing. As an EE, I want to know
exactly why something isn't working correctly. But I learned a long
time ago that it's more important to simply get the damned thing
fixed. If that means shotgunning likely components, so be it.


Shotgunning is, IMHO, very bad practice, and often leads to the
creation of more problems than it fixes. I am actually quite surprised
that you would advocate doing this, William.


I don't understand how shotgunning can /create/ problems, as long as the
replaced components are correct replacements. Unless you mean the customer
might get upset.

As an experienced service technician, you know that the cause of a given
problem is not always obvious, even after extensive troubleshooting. The
customer is paying for your time, often more than what the parts cost. Why
burn up the customer's money when replacing a half-dozen parts is likely to
fix the thing?


  #9   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 117
Default CRT vertical deflection -- bad solder joints?

"Arfa Daily" wrote in message
...


"William Sommerwerck" wrote in message
...
Hello? Instead of fussing over it, why not replace all the electrolytics
"in
the vicinity" while the bad-looking solder joints are being re-done?

This is a common problem in servicing. As an EE, I want to know exactly
why
something isn't working correctly. But I learned a long time ago that
it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.



Shotgunning is, IMHO, very bad practice, and often leads to the creation
of more problems than it fixes. I am actually quite surprised that you
would advocate doing this, William.

Arfa



I have seen sets (notably Toshiba and Mitsubishi) where shotgunning was
advisable in addition to replacing whichever single cap might have been
causing your issue.

Mark Z.

  #10   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 173
Default CRT vertical deflection -- bad solder joints?

On Wed, 30 Mar 2011 07:38:43 -0500, Mark Zacharias wrote:

"Arfa Daily" wrote in message
...


"William Sommerwerck" wrote in message
...
Hello? Instead of fussing over it, why not replace all the
electrolytics "in
the vicinity" while the bad-looking solder joints are being re-done?

This is a common problem in servicing. As an EE, I want to know
exactly why
something isn't working correctly. But I learned a long time ago that
it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.



Shotgunning is, IMHO, very bad practice, and often leads to the
creation of more problems than it fixes. I am actually quite surprised
that you would advocate doing this, William.

Arfa



I have seen sets (notably Toshiba and Mitsubishi) where shotgunning was
advisable in addition to replacing whichever single cap might have been
causing your issue.

Mark Z.


We used to call some of the factory repair 'kits' for certain Panasonic
sets "shotgun packs" because of the amount of components included.
Some of those even included parts not on the board that were to be
added on the solder side.



--
Live Fast Die Young, Leave A Pretty Corpse


  #11   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,069
Default CRT vertical deflection -- bad solder joints?

In article , William Sommerwerck
writes

But I learned a long time ago that it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.


Would you be happy for a car mechanic to shotgun a fault on your car,
with you paying for his time and all the parts he is unnecessarily
fitting?

--
Mike Tomlinson
  #12   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 173
Default CRT vertical deflection -- bad solder joints?

On Wed, 30 Mar 2011 16:31:15 +0100, Mike Tomlinson wrote:

In article , William Sommerwerck
writes

But I learned a long time ago that it's more important to simply get the
damned thing fixed. If that means shotgunning likely components, so be
it.


Would you be happy for a car mechanic to shotgun a fault on your car,
with you paying for his time and all the parts he is unnecessarily
fitting?


Isn't that an unfair comparison?



--
Live Fast Die Young, Leave A Pretty Corpse
  #13   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,833
Default CRT vertical deflection -- bad solder joints?

But I learned a long time ago that it's more important to simply
get the damned thing fixed. If that means shotgunning likely
components, so be it.


Would you be happy for a car mechanic to shotgun a fault on
your car, with you paying for his time and all the parts he is
unnecessarily fitting?


Yes, if an initial /conscientious/ troubleshoot didn't reveal the problem.
I'd rather pay for parts than time.

Of course, you can't draw an exact parallel between cars and electronic
equipment. It's easier to "see" what is wrong with mechanical devices, but
car parts tend to be more-expensive than electronic parts.


  #14   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 5,040
Default CRT vertical deflection -- bad solder joints?

In article ,
Mike Tomlinson wrote:


Would you be happy for a car mechanic to shotgun a fault on your car,
with you paying for his time and all the parts he is unnecessarily
fitting?


It's commonly done. Had a girlfriend a few years back who took her car
in because it was overheating. They called with the estimate (of many
hundreds of dollars,) saying they had determined that it needed a new
radiator, new water pump, new thermostat, and new hoses.

I went down there and asked them how they had determined the radiator
fault, and they claimed to have pressure tested it. A 15 second look
under the hood confirmed my suspicion that they had not.

I took the car and replaced the thermostat - $12 and 1/2 hour - and it
served her for several more years.

The shop in question is consistently voted winner of the annual
"Reader's Poll" in our local rag.

Oddly, I don't think they operate that way solely to cheat the customer
financially. I think they're more driven by not wanting any return
complaints. That's why the "Readers" like them -- "they fixed it right
the first time!!"

I drove around town for the next 3 months with a giant sign in my back
window:

"Richard's Auto: As Crooked As the Day is Long."

I got a lot of stories from people who saw the sign, about their own bad
experiences there.
  #15   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,833
Default CRT vertical deflection -- bad solder joints?

Would you be happy for a car mechanic to shotgun a fault on your
car, with you paying for his time and all the parts he is unnecessarily
fitting?


It's commonly done. Had a girlfriend a few years back who took her car
in because it was overheating. They called with the estimate (of many
hundreds of dollars), saying they had determined that it needed a new
radiator, new water pump, new thermostat, and new hoses.


I went down there and asked them how they had determined the radiator
fault, and they claimed to have pressure-tested it. A 15-second look
under the hood confirmed my suspicion that they had not.


I took the car and replaced the thermostat -- $12 and 1/2 hour -- and it
served her for several more years.


The shop in question is consistently voted winner of the annual
"Reader's Poll" in our local rag.


Oddly, I don't think they operate that way solely to cheat the customer
financially. I think they're more driven by not wanting any return
complaints. That's why the "Readers" like them -- "they fixed it right
the first time!!"


There's also the possibility that a comprehensive makes it possible to offer
a "lifetime" warranty on the repair.


I drove around town for the next 3 months with a giant sign in my back
window:
"Richard's Auto: As Crooked As the Day is Long."
I got a lot of stories from people who saw the sign, about their own bad
experiences there.


It goes without saying that if a service shop claims that lots of things
need fixing, it's probably not telling the truth.

Thirty years ago I worked part-time -- at $6/hour -- for Chestnut Hill Audio
in Philadelphia. The owner said to me "You're not as fast as the other
people I use -- but nothing you repair comes back."

I had a holy horror of callbacks. It costs the business money, and it makes
the business and the service tech look bad.

By the way, I never shotgunned anything I repaired there, because nothing
seemed to need it.




  #16   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"William Sommerwerck" wrote in message
...
This is a common problem in servicing. As an EE, I want to know
exactly why something isn't working correctly. But I learned a long
time ago that it's more important to simply get the damned thing
fixed. If that means shotgunning likely components, so be it.


Shotgunning is, IMHO, very bad practice, and often leads to the
creation of more problems than it fixes. I am actually quite surprised
that you would advocate doing this, William.


I don't understand how shotgunning can /create/ problems, as long as the
replaced components are correct replacements. Unless you mean the customer
might get upset.

As an experienced service technician, you know that the cause of a given
problem is not always obvious, even after extensive troubleshooting. The
customer is paying for your time, often more than what the parts cost. Why
burn up the customer's money when replacing a half-dozen parts is likely
to
fix the thing?



Every component that is replaced, increases the potential margin for error
by the person replacing it. I have had many items cross my bench over the
years, which have been 'elsewhere' first, and have seen wrong values fitted,
caps in backwards, diodes in backwards, damaged print and so on, amongst the
many components that have have obviously been shotgunned, as evidenced by
the flux all over their joints. I have also seen unsuitable substitutes
fitted, where technicians have had insufficient understanding of the
requirements of a circuit's design, and have just put in 'what came to hand'
in order to complete their shotgun.

Very occasionally, it is necessary to replace a block of components, when a
fault is particularly obscure, but I would never recommend it as an
acceptable procedure to anyone who wasn't hugely experienced in the field of
service work, and particularly in the case of a simple problem such as the
OP has with his TV's field scanning, and which would be easily diagnosed
with the use of appropriate test equipment.

Arfa

  #17   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"Mark Zacharias" wrote in message
eb.com...
"Arfa Daily" wrote in message
...


"William Sommerwerck" wrote in message
...
Hello? Instead of fussing over it, why not replace all the electrolytics
"in
the vicinity" while the bad-looking solder joints are being re-done?

This is a common problem in servicing. As an EE, I want to know exactly
why
something isn't working correctly. But I learned a long time ago that
it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.



Shotgunning is, IMHO, very bad practice, and often leads to the creation
of more problems than it fixes. I am actually quite surprised that you
would advocate doing this, William.

Arfa



I have seen sets (notably Toshiba and Mitsubishi) where shotgunning was
advisable in addition to replacing whichever single cap might have been
causing your issue.

Mark Z.


Occasionally, this is true, but only - for me at least - if the manufacturer
has recommended a block of components to be replaced, on the grounds that
some or all of the additional ones, may have been unacceptably stressed or
damaged, by the primary failure. In these cases, the manufacturer or his
spares agent usually supplies 'service kits' of all the necessary
components. Often the case with switch mode power supplies.

As in, for instance

http://www.ohmsupplies.co.uk/

Arfa

  #18   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"William Sommerwerck" wrote in message
...
But I learned a long time ago that it's more important to simply
get the damned thing fixed. If that means shotgunning likely
components, so be it.


Would you be happy for a car mechanic to shotgun a fault on
your car, with you paying for his time and all the parts he is
unnecessarily fitting?


Yes, if an initial /conscientious/ troubleshoot didn't reveal the problem.
I'd rather pay for parts than time.

Of course, you can't draw an exact parallel between cars and electronic
equipment. It's easier to "see" what is wrong with mechanical devices, but
car parts tend to be more-expensive than electronic parts.



I'm not at all sure you would say that if one of the incorrectly fitted
parts was the EMU, for example. This, and many of the expensive sensors on
engines nowadays, are usually 'bonded' parts, and once the box has been
opened, the supplier will not accept it back, which leaves you paying for
it, when it was not required. A while ago, I had just this problem with my
local garage, who replaced a cartload of parts and sensors on my engine, for
an idle problem that ultimately turned out to be due to a split in the PCV
hose. I argued with them long and hard about having to pay for parts that
had been shotgunned due to the fact that the guy doing the job had not
correctly diagnosed the problem. I eventually had to settle for a reduced
labour bill to offset the unnecessary parts cost, which they were determined
were staying on the engine, and that I was going to be paying for (at retail
price, just to make it worse)

Arfa

  #19   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 6,772
Default CRT vertical deflection -- bad solder joints?



"William Sommerwerck" wrote in message
...
Would you be happy for a car mechanic to shotgun a fault on your
car, with you paying for his time and all the parts he is unnecessarily
fitting?


It's commonly done. Had a girlfriend a few years back who took her car
in because it was overheating. They called with the estimate (of many
hundreds of dollars), saying they had determined that it needed a new
radiator, new water pump, new thermostat, and new hoses.


I went down there and asked them how they had determined the radiator
fault, and they claimed to have pressure-tested it. A 15-second look
under the hood confirmed my suspicion that they had not.


I took the car and replaced the thermostat -- $12 and 1/2 hour -- and it
served her for several more years.


The shop in question is consistently voted winner of the annual
"Reader's Poll" in our local rag.


Oddly, I don't think they operate that way solely to cheat the customer
financially. I think they're more driven by not wanting any return
complaints. That's why the "Readers" like them -- "they fixed it right
the first time!!"


There's also the possibility that a comprehensive makes it possible to
offer
a "lifetime" warranty on the repair.


I drove around town for the next 3 months with a giant sign in my back
window:
"Richard's Auto: As Crooked As the Day is Long."
I got a lot of stories from people who saw the sign, about their own bad
experiences there.


It goes without saying that if a service shop claims that lots of things
need fixing, it's probably not telling the truth.

Thirty years ago I worked part-time -- at $6/hour -- for Chestnut Hill
Audio
in Philadelphia. The owner said to me "You're not as fast as the other
people I use -- but nothing you repair comes back."

I had a holy horror of callbacks. It costs the business money, and it
makes
the business and the service tech look bad.

By the way, I never shotgunned anything I repaired there, because nothing
seemed to need it.



Which is precisely what I'm saying. Yes, there are some items - notably
switch mode power supplies - where it is often prudent, or even recommended
by the manufacturer, to replace a whole raft of parts, but for most general
repairs, the cause of the problem should be correctly diagnosed, and the
(usually) one faulty component replaced.

Arfa

  #20   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 3,833
Default CRT vertical deflection -- bad solder joints?

Every component that is replaced, increases the potential margin for error
by the person replacing it. I have had many items cross my bench over the
years, which have been 'elsewhere' first, and have seen wrong values

fitted,
caps in backwards, diodes in backwards, damaged print and so on, amongst

the
many components that have have obviously been shotgunned, as evidenced by
the flux all over their joints. I have also seen unsuitable substitutes
fitted, where technicians have had insufficient understanding of the
requirements of a circuit's design, and have just put in 'what came to

hand'
in order to complete their shotgun.


Yes, but you and I don't make such mistakes.




  #21   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 4,069
Default CRT vertical deflection -- bad solder joints?

In article , Meat Plow
writes

Isn't that an unfair comparison?


Tell me how. Not being argumentative, I'd be genuinely interested to
hear why you think it's unfair.

--
Mike Tomlinson
  #22   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 117
Default CRT vertical deflection -- bad solder joints?

"Mike Tomlinson" wrote in message
...
In article , William Sommerwerck
writes

But I learned a long time ago that it's
more important to simply get the damned thing fixed. If that means
shotgunning likely components, so be it.


Would you be happy for a car mechanic to shotgun a fault on your car,
with you paying for his time and all the parts he is unnecessarily
fitting?

--
Mike Tomlinson



If the parts are cheap with little or no additional labor, and done to
prevent a repeat failure in the near time frame, as is often the case with
TV's, then yes, I would be happy, and so are my customers.

Mark Z.

Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
CRT vertical deflection -- bad solder joints? Sean Hamilton Electronics Repair 11 March 29th 11 12:17 PM
CRT vertical deflection -- bad solder joints? whit3rd Electronics Repair 0 March 27th 11 10:10 PM
NO VERTICAL DEFLECTION [email protected] Electronics Repair 3 January 18th 06 11:34 PM
low ESR cap question & vertical deflection ... Mark D. Zacharias Electronics Repair 4 August 28th 05 12:33 AM
Sanyo with no vertical deflection L. Kotney Electronics Repair 1 July 1st 05 08:02 PM


All times are GMT +1. The time now is 01:38 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"