But hey, that's how you learn. I have a resistor that completely broke off
the circuit board in a guitar amp that I have. I located exactly where it
came off but it was loose in the chassis. Here's the dumb question. Does
it matter which way it goes back in or does a resistor work the same in
either direction?

Tia. JJ

No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke off
the circuit board in a guitar amp that I have. I located exactly where it
came off but it was loose in the chassis. Here's the dumb question. Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

Thanks John for the help. I'm almost positive it came loose from bouncing
in my trailer. I did a gig in Houston recently and the roads there are the
pits, and my trailer is only a single axle so it takes a beating.. I'm
surprised it didn't happen a long time ago.

On Tue, 24 Apr 2007 20:09:41 -0400, John Popelish
Gave us:

No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke off
the circuit board in a guitar amp that I have. I located exactly where it
came off but it was loose in the chassis. Here's the dumb question. Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.


Or the result of a very poor design.

"SuperM" SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGala xy.org wrote in
message ...
On Tue, 24 Apr 2007 20:09:41 -0400, John Popelish
Gave us:

No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.


Or the result of a very poor design.

Or lead-free solder - that would be a very plausible cause of components
falling out. Don't laugh, it does actually happen!

"
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.


Or the result of a very poor design.

Or lead-free solder - that would be a very plausible cause of components
falling out. Don't laugh, it does actually happen!


Not when you solder it right in the first place....

"TT_Man" wrote in message
...

"
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke off
the circuit board in a guitar amp that I have. I located exactly
where it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.


Or the result of a very poor design.

Or lead-free solder - that would be a very plausible cause of components
falling out. Don't laugh, it does actually happen!


Not when you solder it right in the first place....


It seems some manufacturers are only just getting on top of that one.

"No Clue" wrote in message
...

"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke
off
the circuit board in a guitar amp that I have. I located exactly
where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

Thanks John for the help. I'm almost positive it came loose from bouncing
in my trailer. I did a gig in Houston recently and the roads there are
the
pits, and my trailer is only a single axle so it takes a beating.. I'm
surprised it didn't happen a long time ago.


Well I was hoping it would be that easy...but it wasn't. After soldering
the resistor back in, it's still DOA. I'm still getting power but no signal
to the speaker. The amp also has an output for headphones and I'm getting a
signal there. I'm also hitting about every soldering joint I can see that
looks a bit weak but still nothing.

"No Clue" wrote in message
...

"No Clue" wrote in message
...

"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke
off
the circuit board in a guitar amp that I have. I located exactly
where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

Thanks John for the help. I'm almost positive it came loose from
bouncing
in my trailer. I did a gig in Houston recently and the roads there are
the
pits, and my trailer is only a single axle so it takes a beating.. I'm
surprised it didn't happen a long time ago.


Well I was hoping it would be that easy...but it wasn't. After soldering
the resistor back in, it's still DOA. I'm still getting power but no
signal
to the speaker. The amp also has an output for headphones and I'm getting
a
signal there. I'm also hitting about every soldering joint I can see that
looks a bit weak but still nothing.


Headphone jacks are notorious for faulty spring contact, some makes are
worse than others, if the contacts are not inside a molded socket body
they're usually easy to inspect and ensure the break contact makes when the
jack is removed and if necessary bend slightly to make the contact make
again. The molded body types can be a bit fiddly and might be easier to just
replace.

good question...better safe than sorry...either way is fine
"No Clue" wrote in message
...
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where it
came off but it was loose in the chassis. Here's the dumb question. Does
it matter which way it goes back in or does a resistor work the same in
either direction?

Tia. JJ

"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

That's exactly what's happening. After resoldering the resistor and getting
nothing, it popped off again. So I resoldered and still nothing. I decided
to touch the resistor and it was too hot to touch. Where would you suggest
to look next?

No Clue wrote:
"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same in
either direction?
They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

That's exactly what's happening. After resoldering the resistor and getting
nothing, it popped off again. So I resoldered and still nothing. I decided
to touch the resistor and it was too hot to touch. Where would you suggest
to look next?

I'm afraid, that without the schematic of the amp (or a good
close look at it) I could only make very low value guesses.
Have you got a good digital camera to take close up
pictures of both sides of the board it fell off of? If so,
you may post them as attachments, here. Maybe somebody will
get a clue.

"John Popelish" wrote in message
. ..
No Clue wrote:
"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke
off
the circuit board in a guitar amp that I have. I located exactly
where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?
They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

That's exactly what's happening. After resoldering the resistor and
getting
nothing, it popped off again. So I resoldered and still nothing. I
decided
to touch the resistor and it was too hot to touch. Where would you
suggest
to look next?

I'm afraid, that without the schematic of the amp (or a good
close look at it) I could only make very low value guesses.
Have you got a good digital camera to take close up
pictures of both sides of the board it fell off of? If so,
you may post them as attachments, here. Maybe somebody will
get a clue.

I'll do that. Thanks.

"John Popelish" wrote in message
. ..
No Clue wrote:
"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke
off
the circuit board in a guitar amp that I have. I located exactly
where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?
They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

That's exactly what's happening. After resoldering the resistor and
getting
nothing, it popped off again. So I resoldered and still nothing. I
decided
to touch the resistor and it was too hot to touch. Where would you
suggest
to look next?

I'm afraid, that without the schematic of the amp (or a good
close look at it) I could only make very low value guesses.
Have you got a good digital camera to take close up
pictures of both sides of the board it fell off of? If so,
you may post them as attachments, here. Maybe somebody will
get a clue.

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp. I've
circled the resistor in yellow, and red dots on back of circuit board where
it connects.

"No Clue" wrote in message
...

"John Popelish" wrote in message
. ..
No Clue wrote:
"John Popelish" wrote in message
. ..
No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke
off
the circuit board in a guitar amp that I have. I located exactly
where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?
They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.

That's exactly what's happening. After resoldering the resistor and
getting
nothing, it popped off again. So I resoldered and still nothing. I
decided
to touch the resistor and it was too hot to touch. Where would you
suggest
to look next?

I'm afraid, that without the schematic of the amp (or a good
close look at it) I could only make very low value guesses.
Have you got a good digital camera to take close up
pictures of both sides of the board it fell off of? If so,
you may post them as attachments, here. Maybe somebody will
get a clue.

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp.
I've
circled the resistor in yellow, and red dots on back of circuit board
where
it connects.



I've got all the pics saved as tiff files and can enlarge them for a closer
look if needed. Any help would be greatly appreciated. Thanks. JJ

No Clue wrote:

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp. I've
circled the resistor in yellow, and red dots on back of circuit board where
it connects.

Is it possible for you to read any part number on the small
black rectangular block a half inch from the resistor, that
has 9 pins in a row? The resistor seems to be connected to
it and the black 24 VDC relay block.

"John Popelish" wrote in message
...
No Clue wrote:

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp.
I've
circled the resistor in yellow, and red dots on back of circuit board
where
it connects.

Is it possible for you to read any part number on the small
black rectangular block a half inch from the resistor, that
has 9 pins in a row? The resistor seems to be connected to
it and the black 24 VDC relay block.


The numbers on the side of that block are a large (T), then TA7317P - 4E.
The 4E is a lot smaller than the rest of the numbers. I marked the pic with
a red arrow to make sure we're talking of the same block.

No Clue wrote:
"John Popelish" wrote in message
...
No Clue wrote:

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp.
I've
circled the resistor in yellow, and red dots on back of circuit board
where
it connects.
Is it possible for you to read any part number on the small
black rectangular block a half inch from the resistor, that
has 9 pins in a row? The resistor seems to be connected to
it and the black 24 VDC relay block.


The numbers on the side of that block are a large (T), then TA7317P - 4E.
The 4E is a lot smaller than the rest of the numbers. I marked the pic with
a red arrow to make sure we're talking of the same block.

You got it. That number (TA7371) allowed me to Google for
the data sheet.

Hit "download data sheet on:
http://www.datasheets.org.uk/search....317&sType=part

It looks like this resistor is approximately the same one
that connects pin 6 to the relay coil on page 3 of the data
sheet (500 ohm 3 watt). The value may be different, because
the supply voltage is different. It uses up all the extra
supply voltage that exceeds that needed to operate the 24
volt relay. The relay coil may have partially shorted out,
causing extra power to be dumped into this resistor.

The voltage between pin 6 and pin 4 should be either about
1.2 volts (when it is turning the relay is on during
operation) or the full supply voltage (when the protection
relay is off for a while at start up, to prevent a big
speaker thump). This is the output voltage speced on page 1
to be typically 1 volt and not more than 2.

Can you measure the voltage across the resistor and provide
its color code (looks like orange, something, black gold),
so we can figure out whether its (and thus, the relay coil)
current is reasonable?

"John Popelish" wrote in message
news
No Clue wrote:
"John Popelish" wrote in message
...
No Clue wrote:

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp.
I've
circled the resistor in yellow, and red dots on back of circuit board
where
it connects.
Is it possible for you to read any part number on the small
black rectangular block a half inch from the resistor, that
has 9 pins in a row? The resistor seems to be connected to
it and the black 24 VDC relay block.


The numbers on the side of that block are a large (T), then TA7317P -
4E.
The 4E is a lot smaller than the rest of the numbers. I marked the pic
with
a red arrow to make sure we're talking of the same block.

You got it. That number (TA7371) allowed me to Google for
the data sheet.

Hit "download data sheet on:
http://www.datasheets.org.uk/search....317&sType=part

It looks like this resistor is approximately the same one
that connects pin 6 to the relay coil on page 3 of the data
sheet (500 ohm 3 watt). The value may be different, because
the supply voltage is different. It uses up all the extra
supply voltage that exceeds that needed to operate the 24
volt relay. The relay coil may have partially shorted out,
causing extra power to be dumped into this resistor.

The voltage between pin 6 and pin 4 should be either about
1.2 volts (when it is turning the relay is on during
operation) or the full supply voltage (when the protection
relay is off for a while at start up, to prevent a big
speaker thump). This is the output voltage speced on page 1
to be typically 1 volt and not more than 2.

Can you measure the voltage across the resistor and provide
its color code (looks like orange, something, black gold),
so we can figure out whether its (and thus, the relay coil)
current is reasonable?

Thank you for all your help with this. I don't know if I'm reading my meter
right or not since all I've ever used it for is continuity testing and
checking 9 volt batteries, but what I'm seeing is about 42 volts across the
resistor. Does that sound right? Across pin 4 and 6, I'm getting about 48
volts. As for the resistor, it's so faded out, my best guess would have to
be orange, yellow or possible orange again, black, gold.

No Clue wrote:
"John Popelish" wrote in message
news
No Clue wrote:
"John Popelish" wrote in message
...
No Clue wrote:

Here's some pics of the inside. It's a Yamaha G100-112III guitar amp.
I've
circled the resistor in yellow, and red dots on back of circuit board
where
it connects.
Is it possible for you to read any part number on the small
black rectangular block a half inch from the resistor, that
has 9 pins in a row? The resistor seems to be connected to
it and the black 24 VDC relay block.

The numbers on the side of that block are a large (T), then TA7317P -
4E.
The 4E is a lot smaller than the rest of the numbers. I marked the pic
with
a red arrow to make sure we're talking of the same block.
You got it. That number (TA7371) allowed me to Google for
the data sheet.

Hit "download data sheet on:
http://www.datasheets.org.uk/search....317&sType=part

It looks like this resistor is approximately the same one
that connects pin 6 to the relay coil on page 3 of the data
sheet (500 ohm 3 watt). The value may be different, because
the supply voltage is different. It uses up all the extra
supply voltage that exceeds that needed to operate the 24
volt relay. The relay coil may have partially shorted out,
causing extra power to be dumped into this resistor.

The voltage between pin 6 and pin 4 should be either about
1.2 volts (when it is turning the relay is on during
operation) or the full supply voltage (when the protection
relay is off for a while at start up, to prevent a big
speaker thump). This is the output voltage speced on page 1
to be typically 1 volt and not more than 2.

Can you measure the voltage across the resistor and provide
its color code (looks like orange, something, black gold),
so we can figure out whether its (and thus, the relay coil)
current is reasonable?

Thank you for all your help with this. I don't know if I'm reading my meter
right or not since all I've ever used it for is continuity testing and
checking 9 volt batteries, but what I'm seeing is about 42 volts across the
resistor. Does that sound right? Across pin 4 and 6, I'm getting about 48
volts. As for the resistor, it's so faded out, my best guess would have to
be orange, yellow or possible orange again, black, gold.

The standard 5% (that is what the gold means) values that
begin with orange and end with black are orange orange black
(33 ohms) orange blue black (36 ohms) and orange white black
(39 ohms). That 24 volt relay probably should draw much
less than 100 mA, when 24 volts is connected across it.
That means that the resistor should have much less than 100
mA going through it and that current would drop less than 4
volts. If the black used to be brown, then those resistance
possibilities would be 330, 360 and 390 ohms, and the
voltage drop would be 10 times bigger, and these seem more
likely.

Something is wrong with your volt readings, since the
voltage between pins 4 and 6 and the voltage across the ends
of the resistor should be equal to or less than the total
power supply voltage (pin 4 to the other end of the relay
coil). I expect that total to be less than 0 volts.

There should be a diode connected across the relay coil
(black cylinder with a stripe around one end), and that may
have shorted, putting an extra 24 volts across the resistor.
If you replace it, make sure you put the new one in with
the stripe at the same end. Any 1N400X (with X being
1,2,3,4,5,6,7) would work. If your meter has a range
labeled with a diode symbol, you can remove the diode and
check it with that range. One way, it would read off scale
(blank) and the other way, 6 hundred something (the forward
voltage drop in millivolts). If it is bad, it will read
near zero and the same in either direction. This failure
would not only explain the overheated resistor, but the
relay not pulling in and connecting the speaker to the
amplifier.

If the diode is good, before you solder it back in, check
the relay coil resistance (between the two holes where you
removed the diode). It should probably measure around 600 ohms.

"ian field" wrote in message
...

"SuperM" SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGala xy.org wrote
in message ...
On Tue, 24 Apr 2007 20:09:41 -0400, John Popelish
Gave us:

No Clue wrote:
But hey, that's how you learn. I have a resistor that completely broke
off
the circuit board in a guitar amp that I have. I located exactly where
it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.


Or the result of a very poor design.

Or lead-free solder - that would be a very plausible cause of components
falling out. Don't laugh, it does actually happen!


Worked on a piece of equipment one time where the owner had replaced some
parts. He installed the parts with Liquid Solder.or is that Plastic Solder.
Anyway when I stuck my iron to the joints they smelled like buring plastic.

Jimmie

"Jimmie D" wrote in message
...

Worked on a piece of equipment one time where the owner had replaced some
parts. He installed the parts with Liquid Solder.or is that Plastic
Solder. Anyway when I stuck my iron to the joints they smelled like buring
plastic.

That's happened many times in the past. Kitsets were prone to such
'assembly'.

"Jimmie D" wrote in message
...

"ian field" wrote in message
...

"SuperM" SuperM@ssiveBlackHoleAtTheCenterOfTheMilkyWayGala xy.org wrote
in message ...
On Tue, 24 Apr 2007 20:09:41 -0400, John Popelish
Gave us:

No Clue wrote:
But hey, that's how you learn. I have a resistor that completely
broke off
the circuit board in a guitar amp that I have. I located exactly
where it
came off but it was loose in the chassis. Here's the dumb question.
Does
it matter which way it goes back in or does a resistor work the same
in
either direction?

They work the same in either direction. The important thing
to know is why this resistor came lose. It may have
overheated enough to unsolder itself, and that is a symptom
of some other problem that may need repair.


Or the result of a very poor design.

Or lead-free solder - that would be a very plausible cause of components
falling out. Don't laugh, it does actually happen!


Worked on a piece of equipment one time where the owner had replaced some
parts. He installed the parts with Liquid Solder.or is that Plastic
Solder. Anyway when I stuck my iron to the joints they smelled like buring
plastic.

Jimmie


Years ago I saw a documentary about the early home computer industry one
company supplied the computers also as home construction kits, some guy from
that company recalled an instance someone returned a perfectly neatly
constructed kit to customer services because it didn't work - with all the
chips stuck in with Airfix glue!