Delco Gold question - left side still dead after CDM repair

[Matt B]

Hi all,

I just had my control head & CDM repaired and squeezed both back into the car today. Now the right side front and rear speaker work well. Both left side speakers are still stone dead.
I put a probe to the orange lead at the left front speaker connector (assuming this would be the power lead) and it reads 12.xV when radio is on.
So... Can I assume my speakers need a fix, too? Are there any other tests I can do to ensure all except the speakers is working correctly?

Before I sent both, control head and CDM, to have it fixed the system showed a similar behavior except that the right hand speakers were next to silent (but still made a very weak sound at max volume). Left side was already dead then.

Any hints are welcome. I read a lot about the Delco Gold and summarizing what I read I expect the left speakers to need some fresh capacitors. However before I send them to a repair shop I'd like to do all necessary tests - in case any further are needed ;)

Thanks!

[ram_g]

The speakers all have local amplifiers. These do go bad and need rebuilding. It is quite easy to swap a known good amp (from your right side) to a speaker on the left to test it. For that matter you could plug an entire right side speaker enclosure in on the left to test that.

[Paul Workman]

A simple (shade tree) test of a (car) speaker is to clamp a couple alligator clip wires to the speaker terminals and hold the other end of a clip wire against one of the terminals of a 1.5V battery while "scratching" the end of the other clip wire across the other end of the battery. You should get a "scratching sound". That indicates the speaker is probably OK.
Then you can repeat the test, this time moving to the audio input to the audio amp input terminals while the amp is powered and connected to the speaker(s). If you also get a scratching sound from the speakers, the amp/speakers may be good and the issue stems from the receiver output

For what that's worth!

P.

[Matt B]

Thanks both! I unplugged both left speakers today and measured incoming current and signal at the connectors. Both work. Then I plugged both enclosures to the right rear connector (which works perfectly well). No sound... So they're both defect. I will ship them for repair tomorrow. Can't wait to hear to full Delco Gold sound!!

[secondchance]

Thanks both! I unplugged both left speakers today and measured incoming current and signal at the connectors. Both work. Then I plugged both enclosures to the right rear connector (which works perfectly well). No sound... So they're both defect. I will ship them for repair tomorrow. Can't wait to hear to full Delco Gold sound!!

Or, if you want I have working Bose amps, front and rear, out of my 94 for sale. $35 rack plus shipping.

[Matt B]

Thanks for the offer, but first I'd try to have mine fixed. Any recommendation for who can do this? I found Bose Central and here in the forum "Dr Don". However in the latter case I can't open his website - maybe because I'm in Germany, maybe because he's out of business?

[secondchance]

Thanks for the offer, but first I'd try to have mine fixed. Any recommendation for who can do this? I found Bose Central and here in the forum "Dr Don". However in the latter case I can't open his website - maybe because I'm in Germany, maybe because he's out of business?

Try below link. It opened fine for me just now.
https://www.doctordons.com/corvetteradios.htm

[Matt B]

Ah, way better :). Thanks! The other linke I found reported a server error but maybe was outdated. Thanks to our just awesome local data protection and cookie laws many US websites are not reachable from here so I suspected that to be yet another case...

[dredgeguy]

Dr. Don is awesome!

[rkreigh]

you can also rob the nissan bose amps which are cheap


a bit more power too.

[secondchance]

Same era Cadillac amps plug right in and are 100w.

[Z51JEFF]

Do all 4,not just the defective ones.

[Matt B]

Right, that's the idea. Front ones seem to be good to be overhauled and I have an opportunity to have it carefully done over here.
Rear has to be replaced, as left one has severe circuit damage from electrolyte and right one seems to be not a Corvette amp at all.
However as I sit in Germany I have only very limited opportunities to grab a set of Nissan, Cadillac or other amps. These cars a very uncommon here. No way to find any of them them or even parts on wrecking yards. So I'm thinking about buying a matching pair from either Dr. Don or Bose Central. Both seem to have good reputation whereas Bose Central seems slightly more budget friendly. Not sure yet which way to go with the rears.
Anyway I will replace/fix all for, that's for sure.