Car radio stopped working

[eccerr0r]

Re: Car radio stopped working

You mean, test the COBs, nevermind identifying them? :-p

Once again, flying blind...

[stj]

Re: Car radio stopped working

not the cobs, i think i know what atleast one is anyway.
test the transistors and diodes

[eccerr0r]

Re: Car radio stopped working

The vast majority of the active elements are in the COBs including the mixer, RF/IF amplifiers, and most importantly the VCO... external transistors and diodes are fairly few and far in between.

And the shield is being annoying...grr. Need better tools...

[stj]

Re: Car radio stopped working

i like to take shields off by heating them with the hot air rather than going for the solder joints

[eccerr0r]

Re: Car radio stopped working

hmm...probably lost cause to repair this at this point taking into the possibility of a COB die bond failure as well. Wonder where I can get a car radio cheap...or even free... as long as it receives am and fm broadcast bands... local boneyard wants $15 though there's a chance to find a really nice one that I'll never use the features of...

[stj]

Re: Car radio stopped working

15?
you can get a chinese DIN std car FM radio/mp3 player with 4 channel output for not much more than 20!

probably because they dont waste money with a tape or cd deck nobody gives a shit about.
not sure about AM though.

[redwire]

Re: Car radio stopped working

The hassle with another make of radio is the wiring harness- you have to figure out the car's wiring and then make an adapter. I soldered onto the car's wiring because the radio plugs/connectors are all proprietary and useless for anything else.
Sometimes the same radio was used in a few models and you might find one cheaper or less on a car getting stripped.

[eccerr0r]

Re: Car radio stopped working

Yeah, the $15 was intended to either get something that's a perfect match or something that has the exact mounting and wiring kit - from the boneyard if I find the exact car. The $20 CCR would still require a mounting kit, so total cost is higher.

But the nice thing is that the boneyard doesn't distinguish am-fm-cassette to perhaps something with video and composite input... if I am lucky to find one...

[eccerr0r]

Re: Car radio stopped working

Well after finding the pinout, here we go, shield removed...

... nothing interesting here unfortunately.

[stj]

Re: Car radio stopped working

you can check the diode and tants

[eccerr0r]

Re: Car radio stopped working

Well... It happened.

A few months ago I had the radio teetering on a stack of other crap, and it tipped over. Smashed the volume control and bent the shaft. Unrecoverable failure. Probably parts salvage at this point - maybe a VFD and a rotary encoder, maybe some other stuff.

And then today... I was able to locate another TEMIC module in a donor radio of similar vintage... Radio is almost identical except a few years newer. But unfortunately it uses a different volume control, rats. This donor radio had a blown left front channel and the tape player was jammed. Not to mention it doesn't physically fit as it was designed for another vehicle from the same parent company ... which does mean it plugged straight into the car harness.

Grr. Should have kept the old radio in a less likely place that would stack smash.

Well. I ended up tracing the blown left channel and found a bad resistor. Stuck a jumper resistor across it and...yep that was it, now all four outputs pass power to their speaker (I was almost tempted to swap the front/rear outputs to use the good output to drive the front speaker but having all four outputs working is better.) Tape player looks beyond repair but don't really care too much about it, could always broadcast.

Now I just need to make it "fit". Probably need to cut off the OEM "ears" so it would slide in (and slide out... need to figure out a way to make sure that doesn't happen.)

Oh well, who would have thought I'd running across another module...and it's all moot now, though I can hear broadcast radio once more on all speakers again (had another jury rigged radio in there but could only drive 2 speakers with it and didn't have a clock...that annoyed me.)

[sam_sam_sam]

Re: Car radio stopped working

eccerrOr

I have the same tendency to make do with what you have and try to fix something that you really like and become attached to and if you can fix it or trying to find something that is very similar to what you already have and hope that it works correctly with out having to fix the replacement device

[eccerr0r]

Re: Car radio stopped working

Price was right at least ($0 discard), else I don't think I would have bothered. No frills radio. Just too bad the old deck has a working tape player but can't port it over ("new" one has a jammed robotic eject mechanism. "old" one had a human powered eject mechanism, not to mention face plate placements are different.) I completely disconnected the tape mechanism in the "new" mechanism as it makes noises as it fails to eject every power up.

I had another radio installed for the time being, also has a robotic and busted tape mechanism, but I gave it up because I had no clock in the car. This "new" mechanism had a clock at least.

("new" radio, like the original, is 22WPC using bridged drive using two TDA1557Q AFAIK, 4 channels/speakers (stereo with front/rear fader), and the TEMIC is a fairly good FM receiver. AM (different module) is acceptable, not as great as FM reception IMHO but not horrible. The interim radio was a crappy single-ended output, probably 10WPC or so, not sure.)

[eccerr0r]

Re: Car radio stopped working

Technically speaking I wonder if I should have gone the route of jury rigging another volume control into the old radio... it's one of those coaxial pots which has a balance control. The dual pot nature of the volume control (see Dannyx's problem) makes me give up on it, getting a custom pot is more expensive than what it's worth even if I just hardwire the balance to be in the middle, rarely do i need to muck with that.

Funny, I was so mad that the front left channel was bad prior to debugging and fixing it. I have four speakers in my car, the two front speakers I put in (new then) coaxials with better frequency response; the rears I left the OEM sh1tty 5¼" "full range" speakers that have no treble. If the rears didn't work I wouldn't have minded too much. Alas this now is of course better with all channels working, and the rears are just good for "LFE".

Dang I don't know if I'm simply jury rigging too much. Or just trying to be cheeeeap...

[stj]

Re: Car radio stopped working

balance is only used to diagnose speaker problems.
just hardwire it with fixed resistors and fit a regular pot for the volume.

[eccerr0r]

Re: Car radio stopped working

or rather ganged dual pot that is ... stereo is a b17ch even without the coaxial balance pot (triple pot? with power switch... *sigh*)

[stj]

Re: Car radio stopped working

you dont need a power switch, thats what the ignition barrel is for

[petehall347]

Re: Car radio stopped working

you dont need a power switch, thats what the ignition barrel is for

i have never touched the power switch on mine .

[eccerr0r]

Re: Car radio stopped working

still solving the easy problems. Now suggest a solution to the two hard problems: ganged stereo volume control and getting it all to fit in limited space...

[petehall347]

Re: Car radio stopped working

steering wheel with controls fitted .