Re: Car stereo output stage blown
- From: "dBc" <not_necessary@xxxxxxxxxx>
- Date: Sat, 26 Apr 2008 08:55:53 GMT
Greetings..
Just a crazy question but, WHY were you in there with a "logic
probe" in the first place?
Granted, after repairing HF, VHF and UHF radios for years in the
amateur service I realize the computerization of radios these
days, but I'm just curious.
Do you have electrical schematics for this unit? Ultimately a
service manual for this type of situation?
No?
Simple solution, IF you want to pay for correcting the issue -
back to the certified manufacturer repair depot. Otherwise, scrap
or shotgun guesswork (and associated expense) without schematics,
voltage levels, waveform diagrams and alignment procedures.
Cheers,
Mr. Mentor
"Meat Plow" <meat@xxxxxxxxxxxxxx> wrote in message
news:1qrd4q.p9q.19.1@xxxxxxxxxxxxxxx
| On Fri, 25 Apr 2008 15:32:05 -0700, JR North wrote:
|
| > Pyle PLRG23
| > I had the unit out, on the bench, troubleshooting no FM lock.
AM was
| > fine. I had power/ground connected to the plug, which also
carries the
| > speaker circuits. These are female connectors.The radio was
on, at min
| > volume. I did not have speakers connected. During initial
testing with a
| > logic probe in the tuner section, the radio shut off. I found
high
| > current draw in the power supply, and turned it off
immediately. On
| > checking, the radio would not power up, and drew 10A from the
supply. I
| > determined the monolithic stereo output chip (TDA-burn) was
dead short
| > to ground. The heatsink was quite hot.
| > Q:
| > Could the chip fry from no load connected? I'm certain I
didn't short it
| > at the plug, and wasn't even in the output stage with my
tests.
| > JR
|
| Getting my start in mobile audio some seeming centuries ago, I
would say
| yes it is possible. I was taught to always load the outputs
regardless.
| I feel for you. I've spent many hours righting accidental
wrongs and
| wrongs that in your case appeared secondary to the cause for
repair and
| weren't justified as billable.
.
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