RPO U69 AM/FM Radio Speaker Issue

[Dennis H.]

My 73 has RPO U69 AM/FM Radio (Mono) and the left speaker out of the blue decided to stop working. Worked a few months back, parked the car with battery disconnected went for a drive a few days ago and now only the right speaker works. RPO U69 consists of the radio, convector and two speakers.

From what I have researched the function of the convector is to serve as the final speaker drive amplifier and without it you get no audio output from the speaker. Can just the left side output of the convector fail or this a all or nothing type component?

Not looking forward to opening the dash up to troubleshoot this but at this point have no other options. Any tips on least intrusive way to troubleshoot and narrow it down to the failed component?

Thanks
Dennis

[Richard M.]

Re: RPO U69 AM/FM Radio Speaker Issue

Dennis, I'm not familiar with the convector wiring, but... Can you swap speaker connectors to see if the fault stays left or moves to the right?

Is the convector easy to get at?

Rich

[Richard M.]

Re: RPO U69 AM/FM Radio Speaker Issue

So I found this wiring diagram. The convector is likely ok as it's wired back to the radio, then from radio via 2 connectors to the speakers.

If the speakers are accessible, maybe swap them out.
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[Dennis H.]

Re: RPO U69 AM/FM Radio Speaker Issue

Thanks, my research points out that the mono convector is a single transistor component feeding both speakers, so I guess I have a bad radio or speaker.

[Richard M.]

Re: RPO U69 AM/FM Radio Speaker Issue

I poked around and found a photo online of a 73 AM/FM mono radio. The right connector(blu/grn/yel) goes to the convector, the left connector to the speakers. Black is common, a green to each side.

If you can get at that speaker connector, and feel adventurous, you could swap the 2 green terminals in it. Just mark which is which for later swap back.

Then reconnect to the speaker harness and retry. If the left works, right doesn't, its in the radio. If the same as before, either a bad speaker or speaker harness/connector/wiring fault. I read that the speakers are 10 ohms so be cautious if you're thinking of swapping one out with one off the shelf.

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[Edward J.]

Re: RPO U69 AM/FM Radio Speaker Issue

You could make a simple jumper harness also rather than swap the wires. I think it maybe a speaker issue.

[Joe L.]

Re: RPO U69 AM/FM Radio Speaker Issue

My 73 has RPO U69 AM/FM Radio (Mono) and the left speaker out of the blue decided to stop working. Worked a few months back, parked the car with battery disconnected went for a drive a few days ago and now only the right speaker works. RPO U69 consists of the radio, convector and two speakers.

From what I have researched the function of the convector is to serve as the final speaker drive amplifier and without it you get no audio output from the speaker. Can just the left side output of the convector fail or this a all or nothing type component?

Not looking forward to opening the dash up to troubleshoot this but at this point have no other options. Any tips on least intrusive way to troubleshoot and narrow it down to the failed component?

Thanks
Dennis

Dennis------


I'd say your first step should be to test the speakers as others have suggested. It does seem a little suspicious, though, since your problem seems to "alternate" between speakers.

If it is the speakers, it is important that they be replaced with 10 ohm units, although 8 ohm can usually be used without problems. The original speakers were GM #7312421. These were discontinued in July, 1983 and replaced by a succession of part numbers. The most recent one is still available under GM #15173233.

The main component of the convector is a large transistor. These used to be available from GM but are long-since GM-discontinued. I do not know of a current replacement but there may be one.

[Tom R.]

Re: RPO U69 AM/FM Radio Speaker Issue

If you find you need to look at speaker replacement, many options but a source late-model C3 owners are going to for both front and rear speakers is S&M Electro-Tech. They offer speakers for all Corvette years and the 8-10 ohm configuration. After an 8-track rebuild in my 78, I was cautioned to check speakers and found they were replaced and were 4 ohm speakers. Thus, replacing with speakers compatible with the 8-10 ohm system.

You probably could call and ask about that convector deal.

http://Home | S&M Electro-Tech (smelectrotech.com)

[Patrick H.]

Re: RPO U69 AM/FM Radio Speaker Issue

Of the cars that I've repaired over the years, it's the speaker first, everything else later.
Having your original speaker re-coned is inexpensive at about $25. I have done that, and I have installed the Electro-Tech speakers.
Both work.

[Tom R.]

Re: RPO U69 AM/FM Radio Speaker Issue

I have installed the Electro-Tech speakers.Both work.

I was disappointed when I got the Electro-Tech speakers and noted I would be unable to use the originai-style connectors. The spades will work, of course, When you installed did you just cut the connectors and wire in the spades?

[Patrick H.]

Re: RPO U69 AM/FM Radio Speaker Issue

I was disappointed when I got the Electro-Tech speakers and noted I would be unable to use the originai-style connectors. The spades will work, of course, When you installed did you just cut the connectors and wire in the spades?

I left the connectors on the original speakers, and bought the replacement speaker wires with connectors. I then cut that one to make it connect to the spades.

[Joe L.]

Re: RPO U69 AM/FM Radio Speaker Issue

I was disappointed when I got the Electro-Tech speakers and noted I would be unable to use the originai-style connectors. The spades will work, of course, When you installed did you just cut the connectors and wire in the spades?

Tom------


Don't the original speakers have pigtails that can be removed at the speaker and re-soldered to the replacement?

[Tom R.]

Re: RPO U69 AM/FM Radio Speaker Issue

So you had to replace the speaker harness and used the spades rather than hard wire the harness to the original speakers. my connector is a double and fits perfectly the original spade configuration on the speaker. If I could get a couple of those connectors that are single, it would work nicely with the replacement speakers...any source of those? Probably Lectric Limited.

[Owen L.]

Re: RPO U69 AM/FM Radio Speaker Issue

I used the Electro-tech speakers last summer, but I believe they are out of stock these days. My '72 uses a short bit of wire with a connector soldered to the speaker -- pigtails as Joe L. mentioned. I had to de-solder what the speakers came with and solder on the replacement LectricLimited pigtails so I could use the factory radio harness connections.

[Leonard M.]

Re: RPO U69 AM/FM Radio Speaker Issue

"Don't the original speakers have pigtails that can be removed at the speaker and re-soldered to the replacement?"
Yes.
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