Delco Gold question - left side still dead after CDM repair - ZR-1 Net Registry Forums

Matt B · 03-06-2021

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 · 03-06-2021

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 · 03-07-2021

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 · 03-07-2021

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 · 03-07-2021

Quote:

Originally Posted by 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!!

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

Matt B · 03-08-2021

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 · 03-08-2021

Quote:

Originally Posted by 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?

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

Matt B · 03-08-2021

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 · 03-08-2021

Dr. Don is awesome!

rkreigh · 03-09-2021

you can also rob the nissan bose amps which are cheap

a bit more power too.

03-06-2021	#1
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 523	Delco Gold question - left side still dead after CDM repair 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! __________________ ZR-1 #638/1991

03-06-2021	#2
ram_g Join Date: Jun 2020 Location: Houston, TX Posts: 183	Re: Delco Gold question - left side still dead after CDM repair 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.

03-07-2021	#3
Paul Workman Join Date: Nov 2007 Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri Posts: 6,493	Re: Delco Gold question - left side still dead after CDM repair 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. __________________ Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry

03-07-2021	#4
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 523	Re: Delco Gold question - left side still dead after CDM repair 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!! __________________ ZR-1 #638/1991

03-08-2021	#6
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 523	Re: Delco Gold question - left side still dead after CDM repair 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? __________________ ZR-1 #638/1991

03-08-2021	#9
dredgeguy Join Date: Aug 2012 Location: Ellicott City, MD Posts: 1,671	Re: Delco Gold question - left side still dead after CDM repair Dr. Don is awesome! __________________ Charlie __________ Dredgeguy WAZOO Member 1992 Bright Red/Black ZR1 #246 Dana 4:10 gears Polished LT5 by Haibeck Polished Fikse FM5's with Michelin Pilot Sport 2 Stainless Works headers and cats with Corsa

03-09-2021	#10
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: Delco Gold question - left side still dead after CDM repair you can also rob the nissan bose amps which are cheap a bit more power too. __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)