bad solder joints -- threat or menace?

[William Sommerwerck]

I believe we recently had a discussion about an unsoldered ribbon cable that
had managed to make "acceptable" contact for many years, until...

I just had two "bad soldering" experiences that might be of interest.

Case 1: Both of my JVC XP-A1000 hall synthesizers had leaking power-supply
caps. About two years ago I replaced the caps in one of them. Then, six months
back, I replaced them in the other.

The second started having problems with oddball noises in the rear channels,
including some that sounded like idle noise. They came and went. I finally
ripped into the unit, and unsoldered my suspicious-looking joint on the
negative side of one of the caps. The pad came loose! I used a piece of heavy
solid wire to restore the connection. Et viola, the noise stopped.

Case 2: I hadn't used my Fosgate Tate II 101A SQ decoder in some years, and
tested it for a project I'd planned. The decoding was all shook up. This
looked bad, because the custom Exar chips used for logic control are no longer
made. In fact, they went out of production before the initial product run of
the Fosgate unit was completed, 30 years ago!

One of the designers told me how to confirm that the logic chips were okay.
They were (big sigh of relief). This left the phase-shift networks, which have
1% caps that can (supposedly) drift. Not only are the caps expensive and hard
to obtain, but unsoldering them runs the risk of destroying the foil.

The designer urged me to test the circuit's behavior (with a 'scope) before
unsoldering. This really required a schematic -- but harman\kardon had
destroyed all the schematics when it bought Fosgate! So I had no choice but to
trace it out, starting with a close-up photo of the foil side.

Some of the solder joints didn't look so hot. I resoldered them. Need I go
further? The unit is now working correctly.


"We already know the answers -- we just haven't asked the right questions."
-- Edwin Land

 

On Saturday, April 5, 2014 7:22:12 PM UTC-4, William Sommerwerck wrote:

I believe we recently had a discussion about an unsoldered ribbon cable that

had managed to make "acceptable" contact for many years, until...



I just had two "bad soldering" experiences that might be of interest.



Case 1: Both of my JVC XP-A1000 hall synthesizers had leaking power-supply

caps. About two years ago I replaced the caps in one of them. Then, six months

back, I replaced them in the other.



The second started having problems with oddball noises in the rear channels,

including some that sounded like idle noise. They came and went. I finally

ripped into the unit, and unsoldered my suspicious-looking joint on the

negative side of one of the caps. The pad came loose! I used a piece of heavy

solid wire to restore the connection. Et viola, the noise stopped.



Case 2: I hadn't used my Fosgate Tate II 101A SQ decoder in some years, and

tested it for a project I'd planned. The decoding was all shook up. This

looked bad, because the custom Exar chips used for logic control are no longer

made. In fact, they went out of production before the initial product run of

the Fosgate unit was completed, 30 years ago!



One of the designers told me how to confirm that the logic chips were okay.

They were (big sigh of relief). This left the phase-shift networks, which have

1% caps that can (supposedly) drift. Not only are the caps expensive and hard

to obtain, but unsoldering them runs the risk of destroying the foil.



The designer urged me to test the circuit's behavior (with a 'scope) before

unsoldering. This really required a schematic -- but harman\kardon had

destroyed all the schematics when it bought Fosgate! So I had no choice but to

trace it out, starting with a close-up photo of the foil side.



Some of the solder joints didn't look so hot. I resoldered them. Need I go

further? The unit is now working correctly.





"We already know the answers -- we just haven't asked the right questions."

-- Edwin Land

I've repaired many intermittent units over the years by "wholesale" re soldering anything that looked suspicious. I may not have found the problem but I fixed the unit. Lenny

 

[John Robertson]

On 04/05/2014 4:22 PM, William Sommerwerck wrote:

I believe we recently had a discussion about an unsoldered ribbon cable
that had managed to make "acceptable" contact for many years, until...

I just had two "bad soldering" experiences that might be of interest.

Case 1: Both of my JVC XP-A1000 hall synthesizers had leaking
power-supply caps. About two years ago I replaced the caps in one of
them. Then, six months back, I replaced them in the other.

The second started having problems with oddball noises in the rear
channels, including some that sounded like idle noise. They came and
went. I finally ripped into the unit, and unsoldered my
suspicious-looking joint on the negative side of one of the caps. The
pad came loose! I used a piece of heavy solid wire to restore the
connection. Et viola, the noise stopped.

Case 2: I hadn't used my Fosgate Tate II 101A SQ decoder in some years,
and tested it for a project I'd planned. The decoding was all shook up.
This looked bad, because the custom Exar chips used for logic control
are no longer made. In fact, they went out of production before the
initial product run of the Fosgate unit was completed, 30 years ago!

One of the designers told me how to confirm that the logic chips were
okay. They were (big sigh of relief). This left the phase-shift
networks, which have 1% caps that can (supposedly) drift. Not only are
the caps expensive and hard to obtain, but unsoldering them runs the
risk of destroying the foil.

The designer urged me to test the circuit's behavior (with a 'scope)
before unsoldering. This really required a schematic -- but
harman\kardon had destroyed all the schematics when it bought Fosgate!
So I had no choice but to trace it out, starting with a close-up photo
of the foil side.

Some of the solder joints didn't look so hot. I resoldered them. Need I
go further? The unit is now working correctly.


"We already know the answers -- we just haven't asked the right questions."
-- Edwin Land

Touching up questionable solder joints is the norm for me too, prior to
digging deeper into many devices...

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Trevor Wilson]

On 6/04/2014 9:22 AM, William Sommerwerck wrote:

I believe we recently had a discussion about an unsoldered ribbon cable
that had managed to make "acceptable" contact for many years, until...

I just had two "bad soldering" experiences that might be of interest.

Case 1: Both of my JVC XP-A1000 hall synthesizers had leaking
power-supply caps. About two years ago I replaced the caps in one of
them. Then, six months back, I replaced them in the other.

The second started having problems with oddball noises in the rear
channels, including some that sounded like idle noise. They came and
went. I finally ripped into the unit, and unsoldered my
suspicious-looking joint on the negative side of one of the caps. The
pad came loose! I used a piece of heavy solid wire to restore the
connection. Et viola, the noise stopped.

Case 2: I hadn't used my Fosgate Tate II 101A SQ decoder in some years,
and tested it for a project I'd planned. The decoding was all shook up.
This looked bad, because the custom Exar chips used for logic control
are no longer made. In fact, they went out of production before the
initial product run of the Fosgate unit was completed, 30 years ago!

One of the designers told me how to confirm that the logic chips were
okay. They were (big sigh of relief). This left the phase-shift
networks, which have 1% caps that can (supposedly) drift. Not only are
the caps expensive and hard to obtain, but unsoldering them runs the
risk of destroying the foil.

The designer urged me to test the circuit's behavior (with a 'scope)
before unsoldering. This really required a schematic -- but
harman\kardon had destroyed all the schematics when it bought Fosgate!
So I had no choice but to trace it out, starting with a close-up photo
of the foil side.

Some of the solder joints didn't look so hot. I resoldered them. Need I
go further? The unit is now working correctly.

**A lifetime ago, I was service manager for Marantz Australia (ca. 1975
~ 1980). One of my favourite Marantz amps was the 1070. Nice size, sound
quality, price and power, but most of all, incredibly reliable. The
damned things hardly ever broke down. The confidential data from
Superscope was that they exhibited a 0.5% failure rate within the (3
year) warranty period. Very impressive. Anyway, one landed on my bench.
The customer complained of a slight buzz in both channels. I fired it up
and immediately noted severe asymmetry at high(ish) power levels. I
pulled the base plate off and spotted a wire that someone had poorly
soldered to one of the main filter caps.


--
Trevor Wilson www.rageaudio.com.au

 

[RosemontCrest]

On 4/5/2014 4:22 PM, William Sommerwerck wrote:

Some of the solder joints didn't look so hot. I resoldered them. Need I
go further? The unit is now working correctly.

Well, I'm not sure about your instance, but several years ago I repaired
a 1986 Montgomery Ward TV simply by touching up all the suspicious
solder joints that I found in the tuner section. It's been working fine
ever since.

Good luck.

 

[William Sommerwerck]

wrote in message news:67f08ac5-58e4-431e-9e7c-152ab4b6a513@googlegroups.com...

I've repaired many intermittent units over the years by
"wholesale" re soldering anything that looked suspicious.
I may not have found the problem but I fixed the unit.

That might not be intellectually satisfying, but it's what you have to do to
keep the customer happy and your company in business.

 

[William Sommerwerck]

"Trevor Wilson" wrote in message news:bqc2vtFfiu4U1@mid.individual.net...

A lifetime ago, I was service manager for Marantz Australia (ca. 1975 ~
1980). One of my favourite Marantz amps was the 1070. Nice size,
sound quality, price and power, but most of all, incredibly reliable. The
damned things hardly ever broke down. The confidential data from
Superscope was that they exhibited a 0.5% failure rate within the (3
year) warranty period. Very impressive. Anyway, one landed on my bench.
The customer complained of a slight buzz in both channels. I fired it up
and immediately noted severe asymmetry at high(ish) power levels. I
pulled the base plate off and spotted a wire that someone had poorly
soldered to one of the main filter caps.

My problem exactly!

Would that all equipment were that reliable. The rep of one of the leading
high-end audio manufacturers told me that the company had trouble getting
reliable solder joints. He didn't explain the nature of the problem.

I was told the Fosgate unit was hand-soldered, apparently because Jim Fosgate
didn't trust wave soldering. Hand soldering has the advantage of visual
inspection as each joint is soldered.

 

[Cydrome Leader]

captainvideo462009@gmail.com wrote:

On Saturday, April 5, 2014 7:22:12 PM UTC-4, William Sommerwerck wrote:
I believe we recently had a discussion about an unsoldered ribbon cable that

had managed to make "acceptable" contact for many years, until...



I just had two "bad soldering" experiences that might be of interest.



Case 1: Both of my JVC XP-A1000 hall synthesizers had leaking power-supply

caps. About two years ago I replaced the caps in one of them. Then, six months

back, I replaced them in the other.



The second started having problems with oddball noises in the rear channels,

including some that sounded like idle noise. They came and went. I finally

ripped into the unit, and unsoldered my suspicious-looking joint on the

negative side of one of the caps. The pad came loose! I used a piece of heavy

solid wire to restore the connection. Et viola, the noise stopped.



Case 2: I hadn't used my Fosgate Tate II 101A SQ decoder in some years, and

tested it for a project I'd planned. The decoding was all shook up. This

looked bad, because the custom Exar chips used for logic control are no longer

made. In fact, they went out of production before the initial product run of

the Fosgate unit was completed, 30 years ago!



One of the designers told me how to confirm that the logic chips were okay.

They were (big sigh of relief). This left the phase-shift networks, which have

1% caps that can (supposedly) drift. Not only are the caps expensive and hard

to obtain, but unsoldering them runs the risk of destroying the foil.



The designer urged me to test the circuit's behavior (with a 'scope) before

unsoldering. This really required a schematic -- but harman\kardon had

destroyed all the schematics when it bought Fosgate! So I had no choice but to

trace it out, starting with a close-up photo of the foil side.



Some of the solder joints didn't look so hot. I resoldered them. Need I go

further? The unit is now working correctly.





"We already know the answers -- we just haven't asked the right questions."

-- Edwin Land

I've repaired many intermittent units over the years by "wholesale" re soldering anything that looked suspicious. I may not have found the problem but I fixed the unit. Lenny

same here. Once a board is in position for inspection, you might as well
just solder anything that looks suspect. I'm pretty picky about solder
joints and have send back many new boards for projects as they were just
just garbage, and if you fix what they didn't do at the factory the
warranty is then void.

 

[John Robertson]

On 04/06/2014 8:36 PM, Cydrome Leader wrote:

captainvideo462009@gmail.com wrote:
On Saturday, April 5, 2014 7:22:12 PM UTC-4, William Sommerwerck wrote:
I believe we recently had a discussion about an unsoldered ribbon cable that

had managed to make "acceptable" contact for many years, until...



I just had two "bad soldering" experiences that might be of interest.



Case 1: Both of my JVC XP-A1000 hall synthesizers had leaking power-supply

caps. About two years ago I replaced the caps in one of them. Then, six months

back, I replaced them in the other.



The second started having problems with oddball noises in the rear channels,

including some that sounded like idle noise. They came and went. I finally

ripped into the unit, and unsoldered my suspicious-looking joint on the

negative side of one of the caps. The pad came loose! I used a piece of heavy

solid wire to restore the connection. Et viola, the noise stopped.



Case 2: I hadn't used my Fosgate Tate II 101A SQ decoder in some years, and

tested it for a project I'd planned. The decoding was all shook up. This

looked bad, because the custom Exar chips used for logic control are no longer

made. In fact, they went out of production before the initial product run of

the Fosgate unit was completed, 30 years ago!



One of the designers told me how to confirm that the logic chips were okay.

They were (big sigh of relief). This left the phase-shift networks, which have

1% caps that can (supposedly) drift. Not only are the caps expensive and hard

to obtain, but unsoldering them runs the risk of destroying the foil.



The designer urged me to test the circuit's behavior (with a 'scope) before

unsoldering. This really required a schematic -- but harman\kardon had

destroyed all the schematics when it bought Fosgate! So I had no choice but to

trace it out, starting with a close-up photo of the foil side.



Some of the solder joints didn't look so hot. I resoldered them. Need I go

further? The unit is now working correctly.





"We already know the answers -- we just haven't asked the right questions."

-- Edwin Land

I've repaired many intermittent units over the years by "wholesale" re soldering anything that looked suspicious. I may not have found the problem but I fixed the unit. Lenny

same here. Once a board is in position for inspection, you might as well
just solder anything that looks suspect. I'm pretty picky about solder
joints and have send back many new boards for projects as they were just
just garbage, and if you fix what they didn't do at the factory the
warranty is then void.

Not to menion equipement that used single sided circuit boards. Common
in the 70s and 80s, but pretty rare now. However I still see a lot of
that in our servicing of older gear. B&W Vector monitors in late 70s
video games commonly were SSCBs and the pin connectors crack at the
solder joint...

John :-#)#

--
(Please post followups or tech inquiries to the newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."