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The radio on my '89 started to get staticky. Took it to the radio repair place and they said the output failed and I need a new one. They state that part hasn't been made in 20 years and they will attempt to find one, if possible.
. It is. He hooked it up to a diagnostic panel and it pegged one of the gauges. He said it was a short circuit. The one in my other ‘89 did the same thing and I sent it to a member here who used to repair them. He fixed it, no issue. But he’s disappeared.
An output is some sort of power transistor. Newer amps use a MOSFET chip output. With the introduction of the Monsoon amps in the 90's, the guy is probably correct that your part hasn't been around for a long time.
Should be a somewhat large black block with maybe 6 - 10 leads on it, mounted to a heat sink. Get a good up-close photo of it showing the part # on it, and a shot of the circuit board where the leads plug into it, both top and bottom. I'll see what I can find.
The wonderful thing about that sort of stuff is, it tends to be in ALOT of different products. It's not that hopeless.
Should be a somewhat large black block with maybe 6 - 10 leads on it, mounted to a heat sink. Get a good up-close photo of it showing the part # on it, and a shot of the circuit board where the leads plug into it, both top and bottom. I'll see what I can find.
The wonderful thing about that sort of stuff is, it tends to be in ALOT of different products. It's not that hopeless.
I will look around also. It's the output IC you are looking for, like Sofa described.
Should be a somewhat large black block with maybe 6 - 10 leads on it, mounted to a heat sink. Get a good up-close photo of it showing the part # on it, and a shot of the circuit board where the leads plug into it, both top and bottom. I'll see what I can find.
The wonderful thing about that sort of stuff is, it tends to be in ALOT of different products. It's not that hopeless.
Originally Posted by NoEmissions84TA
I will look around also. It's the output IC you are looking for, like Sofa described.
They still have the radio. He told me he'd try to find the part and repair it. If not he'd call. So, I can't take any pics at the moment.
If you guys think you might have that part, please let me know. Thanks in advance!
BTW, they had a bunch of AC Delco radios from the '80's and '90's on shelves. They told me that folks have been sending more and more of them in for repair, lately.
If the shop can't find the 'output IC' you need you can send me a picture of it (or the IC # such as DM165 or DM136 ) and I'll check to see if I have it.
I've got several good used DM165 (AKA "AMP") chips; when I replace bad capacitors on a head unit with bad speaker channels and the repair isn't successful ( because the DM165 chip on that side is dead or the board is bad ) I don't bother to replace the dead AMP chip,....... I remove the tested/good chip (usually the left ) and toss the AMP board in the trash.
Yup,..... the 25 or so AMP chips in that hardware drawer = about 25 or so dead radios that I've tossed !
If the shop can't find the 'output IC' you need you can send me a picture of it (or the IC # such as DM165 or DM136 ) and I'll check to see if I have it.
I've got several good used DM165 (AKA "AMP") chips; when I replace bad capacitors on a head unit with bad speaker channels and the repair isn't successful ( because the DM165 chip on that side is dead or the board is bad ) I don't bother to replace the dead AMP chip,....... I remove the tested/good chip (usually the left ) and toss the AMP board in the trash.
Yup,..... the 25 or so AMP chips in that hardware drawer = about 25 or so dead radios that I've tossed !
Thanks John. I'll give them a call Monday and see what's what.
I do not know if the E-Bay chip is the same chip.........I've only used originals. The used chips I've got are $14 each; 2@ $25, and 3@$30; Shipping is $4.
I do not know if the E-Bay chip is the same chip.........I've only used originals. The used chips I've got are $14 each; 2@ $25, and 3@$30; Shipping is $4.
Send me a PM if needed.
Thanks John, I'll let you know. I spoke to the tech today and he has a source that may still be able to get NOS.
So got the radio back, with 2 new DM165s. Plug it in and only the left side speakers work. I call the guy, he said they must be blown speakers, because he just tested it. I'm thinking, what? So plug in another unit and yes only the left side speakers work.
So got the radio back, with 2 new DM165s. Plug it in and only the left side speakers work. I call the guy, he said they must be blown speakers, because he just tested it. I'm thinking, what? So plug in another unit and yes only the left side speakers work.
What do you guys think?
I'm not comprehending.... you plugged in another radio to your car, and only the left side speakers worked? Or you put the returned radio into another car and only the left side speakers worked??
I'm not comprehending.... you plugged in another radio to your car, and only the left side speakers worked? Or you put the returned radio into another car and only the left side speakers worked??
Plugged in another unit into the same car and only the left side speakers worked, just like with the newly fixed one. I have never had a unit go bad simultaneously with two speakers going out.
I think your RIGHT side speakers are blown, or there is a problem in the right side speaker wiring.
Be careful, a short in the speaker wiring will blow your new output ICs.
For what it's worth: Whenever I've repaired a Delco 2000 radio that had AM/FM reception problem the 'bug' was on 1 of the large horizontally mounted circuit boards. Pretty sure it's the board on top of the radio that the antenna plugs into, but I normally swap the entire top 1/2 of the radio for simplicity sake; If I've got spare parts,..... I use them ! ( don't mind the circles this pic was meant for someone else. )
While my experience is limited ( about 200 repairs ) I have never had a reception problem trace back to the AMP board due to a bad AMP chip. I almost wrote this in my last post to this thread but I'm not a professional and the professional already gave you a definitive answer. He said you needed DM165s, so I just offered some spare Chips. If your radio originally had a reception problem and now it's got 2 dead speakers,................
**As I was writing this you posted an update, ( then the Queen needed my help for a few minutes ! )
1) Are you 100% SURE that the second radio you used is 100% functional ??? ( dead right side speakers is the #1 Delco radio problem I encounter. )
2) Have you tried to swap any speakers from Left to Right side yet ??
** Just saw NoEmissions84TAs' update and think I know what he's thinkin'......... rather than swapping speakers you can simply probe the speaker terminals/wires to check for voltage. You can probe any speaker terminal or wire; front, rear, positive or negative. Should have around 6 volts but could be from 5.6-to-6.4; all 8 speaker terminals should be about the same reading and the reading might change as the radio warms up. ( This radio has new right side Caps. )
Last edited by John in RI; 06-21-2020 at 11:59 AM.
**As I was writing this you posted an update, ( then the Queen needed my help for a few minutes ! )
1) Are you 100% SURE that the second radio you used is 100% functional ??? ( dead right side speakers is the #1 Delco radio problem I encounter. )
2) Have you tried to swap any speakers from Left to Right side yet ??
** Just saw NoEmissions84TAs' update and think I know what he's thinkin'......... rather than swapping speakers you can simply probe the speaker terminals/wires to check for voltage. You can probe any speaker terminal or wire; front, rear, positive or negative. Should have around 6 volts but could be from 5.6-to-6.4; all 8 speaker terminals should be about the same reading and the reading might change as the radio warms up. ( This radio has new right side Caps. )
I plugged in an Alpine unit I happened to have. I "assume" it's 100% functional. I may remove a Delco from one of the other cars and try as well.
Probe the speaker wire at the connector? Sorry, guys you'll have to forgive me, but my knowledge here is limited. Which connector is it? The blue or white one. And if low Ohms what does that mean? Replace speakers?
Also, how could everything go from functioning normally to having all of these components fail simultaneously?
Okay, I removed the Delco radio from my other '89 and plugged it in to this car and it's the same. So yes it's the speakers. The front right barely makes any sound, the rear right nothing. I'm convinced all of this audio carnage happened nearly simultaneously. My theory is one DM165 leaked and blew and took the speakers with it.
The radio guy says to come to his house this weekend so he can figure it out. It'll give me a chance to burn off some 2019 gas, too.
Just so you know,..... the DM165 is a chip; It's the Capacitors that leak electrolyte.
Sounds like it's time to shop around for some new speakers ! Glad to hear the radio tech is going to get the 'tunes' playing in your ride again for Ya'.
Just so you know,..... the DM165 is a chip; It's the Capacitors that leak electrolyte.
Sounds like it's time to shop around for some new speakers ! Glad to hear the radio tech is going to get the 'tunes' playing in your ride again for Ya'.
Any recommendations on speakers, John?
The irony is, that I almost never listen to the radio in this car, preferring the sound of the N10 exhaust.
Good to see he replaced the capacitors too,... should allow for a long life of good sound, you just never know when the originals are goin' to crap-out !
I know that finding good fronts can be a hassle, 4x6 and 10 OHM are not that common anymore & anything aftermarket with those specs will be good. When it comes to rears - IMO - what's most important is to get the right KIND of speaker. I'd advise against 3-way or 4-way ( because the produce too many "highs" ) and stick with the same type the factory installed; 6x9, 4-OHM, Duel-Cone. Here's what I wrote to another member that had bought 4-way speakers and didn't like the sound once they got installed.
Regardless of what else is done - If I were in your shoes - I'd return the rear speakers and find a good duel-cone speaker for the rear sail area. I did NOT check these things for mounting depth and fitment,... but here's a few speakers to give you an idea what I mean. ( The "Kicker" 6x9s seemed to have the lowest frequency response at 30HZ)
..... It's the Capacitors that leak electrolyte.......
Originally Posted by NoEmissions84TA
Hi NoEmissions84TA , I'm curious why you think John's statement is funny , when electrolytic capacitors fail leaking electrolyte is one common visual cue .
Here is an internet picture of the internal workings of an electrolytic capacitor .......
Failed caps leaking electrolyte,... see it all the time.
I've got to wonder were the 4th green capacitor came from,.... there are only 3 "shorty" Caps located under the heat sink in every radio. ( leaking Caps killed the CHIP on this AMP board.
Hi NoEmissions84TA , I'm curious why you think John's statement is funny , when electrolytic capacitors fail leaking electrolyte is one common visual cue .
Here is an internet picture of the internal workings of an electrolytic capacitor .......
Well, I am an electronics technician, but this is a new one on me - I have never seen the caps of this style actually leak.
Some really, really old caps - yes. So I stand corrected.
Well, I am an electronics technician, but this is a new one on me - I have never seen the caps of this style actually leak.
Some really, really old caps - yes. So I stand corrected.
Hi NoEmissions84TA , myself also , I have been into electronics restoration for over 50 years , I'm one of those old guys who keep the vacuum tube devices of the past functional in our modern times . I do cosmetic as well as electronic restoration and I'd like to show you a three section electrolytic capacitor that I rebuilt for my 14 tube 1947 Westinghouse radio (that has the modern FM band 88 to 108 MC) . When I've finished , the capacitor appears original but contains modern replacements in place of the dried out original internal structure .
So, let me ask you guys a question, since you guys are more knowledgeable on this than I? What do I have to gain from driving my car over to the radio guy's house for further diagnosis? I already know my right hand side speakers are gone. Or am I looking at this the wrong way?
I'd hold off on the visit,.... replace the speakers first and then take him up on his offer to re-check things for Ya' if there is still a problem after the new speakers get installed. Might save you a little time, he'll appreciate you taking the initiative, & it's 1 less thing on your - & his - priority 'to do' list.
So I stand corrected
Happens to me just about everyday Bro !!!
Pretty cool stuff there OrangeBird,...................... ! I'm very much an amateur when it comes to electronics, but learning more and more as time passes. Just finding 'stuff' of that vintage has gotta' be tough !
Hi Chazman , I'm sorry I can't verify whether those speakers will fit or not , but I did want to tell you this ;
John is right that you should replace the speakers and then try out your repaired radio , because very often when the output chip goes bad in audio equipment it destroys the speakers connected to it . The exact cause is that sometimes semiconductor devices fail open circuit , and sometimes they fail short circuited , and when they fail shorted they put straight DC to the coil of the speaker which is designed to only see an AC signal that varies with the changes of the sounds intended to be reproduced . The poor speaker's voice coil then quickly overheats and either goes open circuited itself or melts the coil form (attached to the speaker cone) to the magnet resulting in the reproduced sound being more akin to a buzzing gnat than any kinds of music we want to hear . All semiconductor devices are subject to such short circuits (such as the commonly seen "shorted diode" in the alternator fault ) and that's why high end audio amps have sensing circuits built into themselves to pull the power from the output chips in the event of a output chip short , saving the expensive speakers . Such an amp will typically have a "protection" light that will illuminate for a half second on power up , as the circuit checks for proper speaker/output chip impedance . Any resistance too low or high will trigger the circuit to not allow power to that chip .
And to John , believe it or not the parts for antique radios , with the exception of the transformers and RF coils , and still very available . The tubes , resistors and capacitors are no problem at all to get and I've got quite the stash of all those components . But when a radio has a bad coil or transformer , oftentimes the replacement has to come from a scrapped radio having the exact same circuit configuration , leading to decisions of which radios are restoration worthy VS which become parts donor sets .
Hi Chazman , I'm sorry I can't verify whether those speakers will fit or not , but I did want to tell you this ;
John is right that you should replace the speakers and then try out your repaired radio , because very often when the output chip goes bad in audio equipment it destroys the speakers connected to it . The exact cause is that sometimes semiconductor devices fail open circuit , and sometimes they fail short circuited , and when they fail shorted they put straight DC to the coil of the speaker which is designed to only see an AC signal that varies with the changes of the sounds intended to be reproduced . The poor speaker's voice coil then quickly overheats and either goes open circuited itself or melts the coil form (attached to the speaker cone) to the magnet resulting in the reproduced sound being more akin to a buzzing gnat than any kinds of music we want to hear . All semiconductor devices are subject to such short circuits (such as the commonly seen "shorted diode" in the alternator fault ) and that's why high end audio amps have sensing circuits built into themselves to pull the power from the output chips in the event of a output chip short , saving the expensive speakers . Such an amp will typically have a "protection" light that will illuminate for a half second on power up , as the circuit checks for proper speaker/output chip impedance . Any resistance too low or high will trigger the circuit to not allow power to that chip .
And to John , believe it or not the parts for antique radios , with the exception of the transformers and RF coils , and still very available . The tubes , resistors and capacitors are no problem at all to get and I've got quite the stash of all those components . But when a radio has a bad coil or transformer , oftentimes the replacement has to come from a scrapped radio having the exact same circuit configuration , leading to decisions of which radios are restoration worthy VS which become parts donor sets .
Yes I agree. I definitely feel all this damage came simultaneously. Everything was working perfectly - and then it wasn't.
I hope one of you guys can give me some guidance on these speakers. If they are correct, I'll order them.
The ones you posted might be from a Buick and are the same size & rated the same,... just not sure if the mounting holes are exact or the mounting depth.
The rear speakers you posted are not original; They will work, but 8 OHM is not original.
The GM PN I've got for the Thirdgen Camaro rear speaker is 16019120. You can see this speaker - and a bunch of other GM 4 OHM and 10 OHM rear 6x9's - in this thread: https://www.thirdgen.org/forums/car-...-speakers.html
05-29-2020, 03:24 PM
I will look around also. It's the output IC you are looking for, like Sofa described. 
Hi NoEmissions84TA , myself also , I have been into electronics restoration for over 50 years , I'm one of those old guys who keep the vacuum tube devices of the past functional in our modern times . I do cosmetic as well as electronic restoration and I'd like to show you a three section electrolytic capacitor that I rebuilt for my 14 tube 1947 Westinghouse radio (that has the modern FM band 88 to 108 MC) . When I've finished , the capacitor appears original but contains modern replacements in place of the dried out original internal structure . 
