Consumer electronics "war stories"

[Mark Zacharias]

Things that are second nature to us now were "learning experiences" back
then, yes?

At my first job as a tech, about the second piece I ever worked on was a
Pioneer SX-828.

Yup - the infamous "blue Sanyo cap" scenario.

Except I had never heard of that and had no tech support or even a more
experienced tech along side me.

I was totally on my own, as I usually was during the first 15 or 20 years of
my career.

Symptom: one channel gone, just a low hiss. Preamp issue.

Tracing signal - got it, don't got it, and so on.

In the tone amp, DC voltage low at collector of one transistor.

1.5uF Sanyo coupling cap to base was leaky, driving that stage into
saturation.

Felt really good about that one.


Mark Z.

 

On Saturday, December 5, 2015 at 2:44:26 PM UTC-5, Jon Elson wrote in rec.crafts.metalworking:

OK, we got one of those fancy energy-saving washing machines. After a few
years, it started having trouble filling with water. I replaced the
solenoid valve assembly twice over about 6 months, and then started
invetigating deeper. The control board had a micro and about a dozen
electeromechanical relays on it. The one for the cold water valve
eventually developed contacts burned so bad that I was able to diagnose it.
I replaced it with a solid state relay, and all has been good for several
years. I gues the cold water valve gets cycled the most often, so that
relay got burned up first. No problem yet with any of the others.

Yeah, obviously a current relay or just that kind of an interface or something. Tell 'em about it, so they can buy you a whole new one.

You can't get anything if you stay silent. (I learned that the hard way)

 

[amdx]

On 12/5/2015 6:52 AM, Mark Zacharias wrote:

Things that are second nature to us now were "learning experiences" back
then, yes?

At my first job as a tech, about the second piece I ever worked on was a
Pioneer SX-828.

Yup - the infamous "blue Sanyo cap" scenario.

Except I had never heard of that and had no tech support or even a more
experienced tech along side me.

I was totally on my own, as I usually was during the first 15 or 20
years of my career.

Symptom: one channel gone, just a low hiss. Preamp issue.

Tracing signal - got it, don't got it, and so on.

In the tone amp, DC voltage low at collector of one transistor.

1.5uF Sanyo coupling cap to base was leaky, driving that stage into
saturation.

Felt really good about that one.


Mark Z.

I had an SX-828, bought it sometime in the early 70s.
Been so many years, I don't recall the problem, but
I tossed it about two years ago, just too much stuff.

Mikek

 

[Mark Zacharias]

Here's one.

Onkyo cassette deck, circa 1986. Perhaps a TA-630 or some such.

Played just fine in PLAY mode.

In REC mode only, the auto-stop would trigger at random times.

Partially open bridge rectifier. One of those little black round ones. In
PLAY mode the voltages held up, but in REC mode the additional load of the
bias oscillator dropped the voltage enough to cause the problem.

Ripple waveform was definitive. Showed 1/2 wave pattern where it should have
been full-wave.


Mark Z.

 

[Chuck]

On Sat, 5 Dec 2015 14:34:50 -0600, "Mark Zacharias"
<mark_zacharias@sbcglobal.net> wrote:

Here's one.

Onkyo cassette deck, circa 1986. Perhaps a TA-630 or some such.

Played just fine in PLAY mode.

In REC mode only, the auto-stop would trigger at random times.

Partially open bridge rectifier. One of those little black round ones. In
PLAY mode the voltages held up, but in REC mode the additional load of the
bias oscillator dropped the voltage enough to cause the problem.

Ripple waveform was definitive. Showed 1/2 wave pattern where it should have
been full-wave.


Mark Z.

These bridge rectifiers also caused weird problems in Onkyo receivers
of the 1980s.

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[Chuck]

On Fri, 4 Dec 2015 07:13:43 -0800 (PST), makolber@yahoo.com wrote:

One of my favorite stories is from electronics lab in college.

We had to build a small two stage transistor audio amp in the lab with parts from the stock room, onto a protoboard like breadboard.

My lab partners and I were experienced hams and got ours working in no time , no problems.

The PHD proffesor called me over to help him troubleshoot another groups that they could not get to work.

The design had a 10uf cap between the two stages.

I looked at the other groups breadboard and immediatly saw a tiny ceramic cap with a 10 printed on it between the two stages.

I pointed to the cap and said, that doesn't look right.

Got an A in that lab.

=========================

Oh another one.

I worked for a company that made CATV settop boxes.
I wandered into the lab where a group of young engineers were stuck troubleshooting a new box design. The picture was black and white and they could not figure out why there was no color. Looking into the box I saw a crystal marked 3.579545.

On a total whim, I put my fingers on the crystal.

The picture immediatly snapped into color!!!!

I was amazed myself but didn't let it show....I just cooly said, there is your problem and walked away.



And lastly, in the same vein
you will all enjoy this story

http://www.rfcafe.com/references/popular-electronics/me-technician-you-engineer-february-1963-popular-electronics.htm

Have fun

Mark







Mark...
====================

For a very short time in the 1980s, Kenwood manufactured amplifiers
with wrong value resistors at various locations. The first one was a
bear because I had never seen a Japanese company make that kind of
mistake.

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[Chuck]

On Fri, 4 Dec 2015 14:28:24 -0600, amdx <nojunk@knology.net> wrote:

On 12/3/2015 6:34 AM, Mark Zacharias wrote:
OK, so it appears there is very little to discuss on this group in areas
like repairing audio components, amps, receivers, power supplies, etc
these days.

I "tune in" here almost daily and rarely find anything of interest to me.

Maybe we could share some "war stories" of cool repairs we have done in
the past.

Re-live some past glories?

The first time you traced down a bad reset line for a microprocessor?

That integrated amp that blew a channel about once a year until you
caught that bias diode occasionally opening up?

Sansui 5000A's? (yuck)

Crappy Euro caps in Tandberg tape decks?

Those times you sweated whether you could even get this thing put back
together?

Any more recent successs stories to brag about?

C'mon, don't we all enjoy patting ourselves on the back, really?


Mark Z.

In the late 80s early 90's I worked on VCR's. The Fisher FVH 906,
had a tuner that went defective, no schematic, a replacement part only.
That's ok under warranty, but after that, the part cost was to high to
get a repair ok. So one day, I decided to see if I could find out what
the cause of the failure was. I started spraying parts with freeze mist
and found when I hit a 1uf 35V cap the picture came back. I made a lot
of repairs, replacing that same cap on a whole bunch of tuners.
I'd do the same thing every time, dribble 2 or 3 drops of freeze mist
on the cap and the picture came in.

I had a customer bring in a remote for repair, it checked out fine.
He took it home and called saying it didn't work. I talked to him a bit
and found he had just install new CFL lights. I suggested he shield that
light and try it. It worked, I had just read about that in a trade
magazine two days previous.
Mikek

I got in early on the VCR curve, they were expensive, commanding high
service rates, then when prices dropped we had a high volume of repairs,
rode it down until the price was close to $200, then I moved to Florida.
A year later the tech that took my place said he came in a couple days
a week to repair the few that came in. I repaired a little over 11,000
vcr's in ten years, it was a good time.

In a similar vein to your remote story, we sold an $1800 Tandberg
cassette deck that came to the shop over and over again for not
responding to the transport keys. In the shop it always worked
perfectly. I decided to go to the customer's house after work to see
what the problem was. At his house, the keys didn't work. I spotted
a light dimmer on the wall. Turning it off and the deck worked
perfectly.

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[Jeff Liebermann]

On Thu, 3 Dec 2015 06:34:55 -0600, "Mark Zacharias"
<mark_zacharias@sbcglobal.net> wrote:

Any more recent successs stories to brag about?
C'mon, don't we all enjoy patting ourselves on the back, really?
Mark Z.

I haven't bothered to write anything new, but in 1994, I scribbled
this list for Wired Magazine, which never bothered to print it or pay
me:
<http://members.cruzio.com/~jeffl/nooze/support.txt>
I'm not sure I could call these success stories, but since I got paid
for most of the repairs, I guess it qualifies as successful.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Phil Allison]

Chuck wrote:

In a similar vein to your remote story, we sold an $1800 Tandberg
cassette deck that came to the shop over and over again for not
responding to the transport keys. In the shop it always worked
perfectly. I decided to go to the customer's house after work to see
what the problem was. At his house, the keys didn't work. I spotted
a light dimmer on the wall. Turning it off and the deck worked
perfectly.

** Need more explanation for that one.


..... Phil

 

[M Philbrook]

In article <1449310629.173856@news.evonet.be>, c4urs11@domain.hidden
says...

On Thu, 03 Dec 2015 06:34:55 -0600, Mark Zacharias wrote:

Maybe we could share some "war stories" of cool repairs we have done
in the past.

Somewhere in the eighties we installed a custom-built control system in
a 24/7 assembly line for SIL ceramic hybrid circuits.
Subcontractor of subcontractor job.

One night I was called in for an unexpected stop.
Inside the plant I was 'greeted' by the crowd of tech support people and
blaming managers gathered around our equipment.
On my way to the control system I came across one of the typical mushroom
emergency stops along the production line.
By habit I twisted the knob and felt the release spring.
I worked my way to the control panel and engaged the start.
Within seconds the crowd silenced and fled the scene: the line was up.

We were never again called in.

And what was the charge for that?

$1 for resetting the switch and $9,999.00 for knowing which one?

Jamie

 

[M Philbrook]

In article <nsl66bdu96kpnnu4lapfpgmoor5h862hs6@4ax.com>, ch@dejanews.net
says...

In a similar vein to your remote story, we sold an $1800 Tandberg
cassette deck that came to the shop over and over again for not
responding to the transport keys. In the shop it always worked
perfectly. I decided to go to the customer's house after work to see
what the problem was. At his house, the keys didn't work. I spotted
a light dimmer on the wall. Turning it off and the deck worked
perfectly.

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While I was in a neighborhood visiting a nice looking girl, a friend of
hers ask if I could go over to their place and see why their portable
color TV near the door had messed up colors they could not remove.

I really didn't want to go and told them it would be a minimum of $20
bucks just to walk in, they accepted.

So I walked in and didn't even bother to turn the TV on. I reached up
on top of the TV set and removed the 9x6 Triaxal Speaker with a large
magnet on it, sitting there for what ever reason, I have no idea why.

I held my hand out for the money! They asked aren't you going to even
turn it on? I said, you can do that, they did and could not believe what
they saw. I took the money and said, have a good day now..

Jamie

 

[Bruce Esquibel]

amdx <nojunk@knology.net> wrote:

I had an SX-828, bought it sometime in the early 70s.
Been so many years, I don't recall the problem, but
I tossed it about two years ago, just too much stuff.

Heh, anyone else reading this, before you toss it, check ebay for the
completed listings on both working and non-working audio stuff from the
70's and 80's, it's nuts.

Even if that 828 was broke, it seems to fetch $100-$150 and the working ones
$200 on up.

Some of the top of the line ones from back then (pio sx-1980, sansui 5500 i
think) in the thousands. This isn't the old tube stuff like Fisher and
Marantz, just the popular solid state crap from the 70's and 80's.

The power amps and speakers don't follow but anything with receivers and
turntables from that period, you probably can make back what you paid for it
new, and then some.

-bruce
bje@ripco.com

 

You can get them cheaper if you get lucky. Some of those three day auctions on eBay n shit. But there is quite a number of people who appreciate that old stuff. Like me, I see no reason my amplifier needs wifi. I knew we were going downhill when I saw an amp with an RJ-45. And to me, this new stuff mostly sounds like shit.

And I don't like the idea of 12 balsa wood speakers the quality of a 1966 table radio and one woofer. Stereo was invented because we got two ears. I might even tolerate quad, but 7.1 ? Nope. I have a hard enough time understanding the words in stereo and on TV I usually switch it to mono.

Anyway, the prices of some of this stuff are outrageous. A Marantz like my old one, $700. Look up the price of a Marantz 2385. A Pioneer SX-1980. (not sure but I think that was the most powerful receiver ever built) Recently a turntable went for $55,000. What's more I talked to my buddy and mentioned that and he told me they go higher, up into six figures.

And now, down in Sydney, Australia, Elton John was spotted in a record store buying albums. The guy can afford anything he wants but he wants a record player. (and logically, records of course)

There is quite the renewed interest in vinyl these days. Even youngins. Guys on AK for example talking about how they just got their teenager a turntable and an old vintage system. Sometimes for their college dorm if that is where they live, other times wherever.

In fact right now we are setting up something of a lab for this stuff. Distortion tester, standards to calibrate everything for power output measurements, and more to come. The idea here is to be sure the stuff is working right because when it is 40 years old it can have insidious problems that only distort a little and won't be noticed right away. And when you get them running really right, that old 1970s shit blows most of the new shit away.

Don't get me wrong, there is a high end still but if you think about 1979 dollars and a receiver is $400, how much would that be today ? Well, it IS. The same relative level of quality easily costs four times the money. What you get for $400 is like what you got for $79 back then, although THAT quality is a bit better.

Just not that much. Not enough for me.

I don't use it, but I got a Pioneer SX-850. No lid, no bottom, glass in front broke, tuning shaft bent. Power suppl.y board was broke in three places, needed work on that, one channel of the power amp and the preamp as well ! It works. It is a rag. It is filthy but everything works.

Not for sale.

 

Well I guess it is my turn.

NAP bigscreen no sound - vertical control IC.

Everything runs off the data and clock lines. This IC does the "S" correction and things like that pertaining to linearity. It is of course bus addressed. The one line, data or clock, doesn't matter, was clamping the signal down to like 2 volts. Leaky. That meant the data from the EPROM was not read when the unit got initialized so it did not know which sound system it had and never upped that.

Sony 32" loses green and blue - adjust vertical height.

This was an interesting comedy of failure mode. Apparently when they came out with AKB a had to be done to the CRT aperture grill frame. It reflected too much. The CRT had just been replaced. The way I figure it they used a dud from a non-AKB set. When the pulses feeding the cathodes to detect the current got to the frame they reflected like all hell and told the circuit there was too much green, and then blue as the circuit drifted a bit and brought the lines over the metal. I found this out with the scope. I mean, there is no green but it is getting alot of green feedback. WTF !

And THEN, to adjust the vertical you use a service menu. Guess what color the numbers and letters are in that menu. They were not red but if you left the set on for a while all you had was red.

I got some good ones about cars too.

 

I almost want to say it was a fault, but it may have been the design. Really, when you talk old stuff, some things just did not exist back then. Things that cause more interference.

When working on older equipment, much older, I had to learn not to expect too much.

In that case with the Tandberg I would have gotten some line filtering. they make those all put together units you can put right at the AC input, light enough so you can cut the cord even and just glue them about anywhere, just make sure they are as close to the AC inlet as possible.

To figure it all out we woukld need the print for that Tandberg. I remember working on one R2R deck that had no microprocessor. It was all gates and comparators and all that. I think it was a 9200 ??? So that one probably would have been alright, no keyboard scanning or any of that, just a bunch of switches and flipflops and gates. and then the solenoid and relay drivers, oh and the current drivers for the eddy current motors.

Simple, I liked it. I fixed it. It got sold. It got damaged in shipping. We got fucked. I wish I would have kept it but really, I have no tapes.

 

[Chuck]

On Sat, 5 Dec 2015 18:52:34 -0800 (PST), Phil Allison
<pallison49@gmail.com> wrote:

Chuck wrote:



In a similar vein to your remote story, we sold an $1800 Tandberg
cassette deck that came to the shop over and over again for not
responding to the transport keys. In the shop it always worked
perfectly. I decided to go to the customer's house after work to see
what the problem was. At his house, the keys didn't work. I spotted
a light dimmer on the wall. Turning it off and the deck worked
perfectly.


** Need more explanation for that one.


.... Phil

The light dimmer was putting an enormous amount of hash on the mains;
somehow it was getting into the microprocessor circuitry. I had seen
this before on much cheaper items so I had a hunch that this was the
problem.

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[Phil Allison]

Chuck wrote:

The light dimmer was putting an enormous amount of hash on the mains;
somehow it was getting into the microprocessor circuitry. I had seen
this before on much cheaper items so I had a hunch that this was the
problem.

** Wall dimmers put large voltage spikes on the wiring going to the lamp/s concerned - two spikes per cycle at up to the peak AC voltage. This radiates as buzzing noise across the audio and also AM radio bands.

Well shielded, low impedance gear is not affected but anything high impedance and not well shielded picks it up. Electric guitars and some keyboards are particularly susceptible.

Seems your Tandberg was too and that is piss poor design.


..... Phil

 

[Mike Tomlinson]

En el artículo <vtm66b5hsssqq9u6s1fde1vo8t87vve09b@4ax.com>, Jeff
Liebermann <jeffl@cruzio.com> escribió:

><http://members.cruzio.com/~jeffl/nooze/support.txt>

Good fun. Thanks for posting that.

Number 10 reminded me of this:

https://en.wikipedia.org/wiki/Lp0_on_fire

My first-ever call out to a Unix system was to this very message.

--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")

 

[whit3rd]

On Sunday, December 6, 2015 at 5:24:04 PM UTC-8, Phil Allison wrote:

The light dimmer was putting an enormous amount of hash on the mains;
somehow it was getting into the microprocessor circuitry.

** Wall dimmers put large voltage spikes on the wiring...

Well shielded, low impedance gear is not affected but anything high impedance and not well shielded picks it up.

There's another possibility: knob/tube wiring puts those spikes on distant
HOT and NEUTRAL wires (not a close-spaced pair). So, there can be significant
magnetic induction, and that can mess up low impedance circuitry. It used
to be seen a lot in CRT television pictures as deflection jitter.

You have to worry about low impedance, too (balanced pair helps).

 

[Cydrome Leader]

Chuck <ch@dejanews.net> wrote:

On Thu, 3 Dec 2015 06:34:55 -0600, "Mark Zacharias"
mark_zacharias@sbcglobal.net> wrote:

OK, so it appears there is very little to discuss on this group in areas
like repairing audio components, amps, receivers, power supplies, etc these
days.

I "tune in" here almost daily and rarely find anything of interest to me.

Maybe we could share some "war stories" of cool repairs we have done in the
past.

Re-live some past glories?

The first time you traced down a bad reset line for a microprocessor?

That integrated amp that blew a channel about once a year until you caught
that bias diode occasionally opening up?

Sansui 5000A's? (yuck)

Crappy Euro caps in Tandberg tape decks?

Those times you sweated whether you could even get this thing put back
together?

Any more recent successs stories to brag about?

C'mon, don't we all enjoy patting ourselves on the back, really?


Mark Z.
The receiver tech was flummoxed by one of those large 1970s Pioneer
receivers. It had a problem none of us had seen before and we were a
high volume audio chain. There was slight audio distortion on both
channels, only on FM. We all worked commission only so I was the only
one to volunteer to help him out. To cut to the chase, the receiver
had an over designed mute circuit that was 3 or 4 stages deep, At the
deepest stage there was one of the Sanyo electrolytics that became a
common failure item many years later which was slightly leaky.

I've got another one. In the early 80s there were these 19" Hitachi
tvs that ghosted. It looked exactly like a bad delay line. By that
time I ran the TV service department for the same company. We had
just switched over to the big box store concept and I was inundated
with broken tvs. Out of desperation, I switched out the CRT and the
ghosting disappeared. We sold 1000s of these sets and I saw the
problem 3 more times.

And another. Kenwood sold these Funai made cd changers that never
worked properly. All of them would come back with skipping or not
playing discs problems. Kenwood came out with 3 or 4 mods, none which
worked. Sometimes they would work for months before they came back.
Somehow I found out if the mechanism retaining springs were stretched
so the mechanism didn't sag at all, the problem disappeared. Called
up Kenwood and they put out a mod kit that included strong springs
which also didn't allow any downward movement of the mechanism.

Was that the type with the CD cartridge, like a trunked automotive unit?
Those things were all such garbage.