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Radio problems


DH Comet

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The radio in my 88 coupe does not seem to show the classic popping or crackling noises that I read about on the forum, due to the "infamous green capacitors"; rather, when it is turned on the antenna goes up and you can hear a faint unknown radio station, but the radio will not settle on a station, it just keeps scanning, and the sound of the mysterious radio station continues unchanged. I have checked the antenna connections, as it seems that a lack of an antenna connection would be the most likely problem, but as far as I can see, both ends of the antenna cable are secure. Is this a known problem? Any ideas?

Thanks

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I guess I should first ask if this is an FM only issue, or if it is doing it on AM as well.

That said, if doing it only on FM I doubt a bad antenna connection. Unless you are in a very rural area that lacks ANY strong FM signals, it should find something it can lock onto even with no antenna. Sounds like a failure of the synthesized tuner of some sort. The fact that it won't lock in, but apparently is sending audio from one station (albeit faintly) could be a problem in the PLL circuit among other things, but my expertise in RF circuits is rather limited so I would really be making a guess at it. These types of issues require a tech that knows tuners to repair. Being an all electronic IC based tuner of proprietary design (by Delco for GM) makes it even rougher as sourcing replacements for custom IC's is not easy.

As cheaply as these radio modules can be had now from a salvage yard or one of the vendors here, I would get a working pull and then recap it to eliminate (or prevent) the popping sounds. Could send it to M&R for repair, but might be better off just buying one of their already refurb'd units if you are not inclined to do your own capacitor replacement.

Another thing, replacing the green capacitors only addresses the amplifier section. Age is taking it's toll on the tuner stage as well, and I notice the RIM module in my 88 introduces some intermittent static/popping even on strong local FM stations that I suspect is due to component drift in the tuning circuits. That is about another 20 small capacitors to replace (among other things) and then a tuner alignment is really needed. My point being that after 25 years we are at the point where the whole module needs refurbing, not just the caps in the amplifier circuit which is only half of the module.

KDirk

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The "mystery" station only comes in on AM, and it doesn't change whatever the radio is tuned to on AM. There is nothing but static on FM. The cassette player is a basket case, just eats tapes. Maybe I'll try a trip to the u-pull, but I don't know how many early 90's Regals there are out there.

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DH-

A radio module from a 88/89 Reatta or Riviera will definately work. If you happen across a Olds Toronado or Trofeo from 88-91 that has the touchscreen computer instead of the conventional radio head unit, it will also have a remote radio module that will work buried in the center console. From there, there are many other Buick, Olds and Cadillac models in the late 80's to early 90's range that have modules that will work, but not all have identical features. Some lack the EQ and get regular bass/treble controls, others (Cadillac) have no inboard amplfier as they were part of a Bose system that used outboard amp modules at each speaker.

If you have a decent size U-pick yard nearby, there almost has to be something there that will work.

KDirk

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95 regal and probably a few years prior, grand prix (not sure of the years and have only seen one), some of the cadillacs around 95 and older, early 90s full sized blazers and surburbans, and there is a vette out there with a one. Sorry for being vauge it has been a while sense I was fooling around with them. Also as mentioned before, if you want the EQ the radio you get must have the EQ. If not you will only have bass and treble tone controls. (I honestly think the non eq versions sound better)

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Ronnie,

I made a typo regarding the Toronado/Trofeo - should be model years 1989-1992. 1988 did not have the touchscreen (VIC) option, and all were made with a conventional radio head unit. The VIC was an available option from 1989-1992, though only a small percentage apparently had this feature. Nonetheless, the radio module used in the cars that were so equipped is identical to that used in the Reatta for 88-89.

The 86/87 Riviera could also be added, though I am not 100% sure if these had support for the remote cassette deck found in 88/89 models. They may also have lacked the graphic equalized function, and had bass/treble controls instead. It may be worth adding in your article that non-eq radios will work fine as the CRT system is programmed to recognize and will adapt it's displayed controls to 3 known variants. These are: amplified with EQ, amplified with conventional tone control (bass/treble) and Bose non-amplified which have no balance control (left/right), but do have a fader (front/rear) function. Of course, the latter would also require an external amp to be installed.

Beyond those already mentioned, I am not able to say with certainty which years/models have radio modules that will work. Daniel covered some of the potential candidates.

KDirk

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Okay, I've been the rounds of the u-pick yards in the area, and aside from one questionable looking unit from a '90 Chev pickup (that they wanted $80 for!)

I've got nothing. I phoned Precision Radio in San Antonio and he'll fix it up for $60, so I sent it down there. While I was pulling my radio I discovered that it has been repaired before, looks like a long time ago, and while they were opening up the console they broke it; the top part has been held down with big globs of glue. Every car has hidden history, I suppose. August is a positive month: radio fixed (possibly) and the driver's seat suede will be replaced later in the month. Ever upward!

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Maybe not a cheesehead, but I will tell you Kdirk is a great junker. He stayed focused on what parts he wanted/needed and didn't look at cars that wouldn't have parts he needed.

We were out there just over 4 hours and he grabbed Cadillac parts for his brothers car as well as his own. He also grabbed some Trofero parts that he wantted for a project and of course MAF sensor/throttle body, alternators, coil packs, etc..

It was a fun visit, and made junkin more fun.

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Heh,

Well I could call myself a cheese head since I love cheese (I know this is not the definition Ronnie was referring to of course). Wish I'd taken the time to stop at one of the Cheese Chalet I saw on billboard on my way into Wisconsin on Friday, but was on a tight schedule. I did see the world's largest Culver's (restaurant for those unfamiliar).

I did have a very productive trip at the salvage yard with Dave as my most gracious host. Didn't grab any radio modules as I have a few spares on hand already, but did get a lot of good stuff for a stupidly cheap amount of money.

KDirk

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Even I was surprised at Kevin got and how little he paid. I try to rationalize it by thinking that they buy these cars for the steel, motors, trannys, starters, alternators, etc. The interior trim pieces, and electrical items are bothersome to them, therefore the price is cheap.

I just wish I would have started junkin a couple years earlier then I did. Altough as Gibsons has steel/salvage drop sites around the state and bring all the cars here, I may have a few more years of good junkin.

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