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88-89 Radio


padgett

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Just replaced my module and all of the snaps, crackes, and pops are now gone. Was the first FM radio (I collect high-end Zeniths) I ever experienced with all of that noise.

Must admit that have had the replacement for quite a while, just hadn't gotten around to opening console before.

Not difficult as long as you use care. Pull clip from shift knob and remove. Pop four tangs from shift indicator plate (two from back corners, two from sides about even with space between park and reverse in indicator. Remove connector from bottom after lifing a few inches.

Remove four screwa - two Torx T-15 at front of opening revealed by removing plate, two philips at rear of ash tray opening (undercover).

Lift just far enough to remove connector on bottom of cigarette lighter and bulb. Remove five (believe 7/32" nut driver) screws (don't miss the one in center) from tin surround under window and power mirror switches. Switches then drop out bottom. Remove console plate.

Radio is under black splash cover on driver's side about even with window switches - will see four connectors clustered on one end and antenna wire at rear. Remove these then unscrew two plastic nuts (these are expandable inserts so whole piece pulls out once screw is loosened enough). Remove plastic spash shield.

Aside: electonics under a console are not a good idea but imagine designers had no choice. Spill anything on console and will drip in worst possible place. Had a '58 T-bird with the radio speaker in the console. Didn't last long.

Once splash shield is removed, radio is visible and just lifts out except for one thing - there is a connector on the bottom with not a whole lot of slack in the wire to be removed first. Are actually two sockets with a large number of pins but only one is used and only two wires in it. These appear to be for the serial data line.

R&R is then easy.

On the replacement, I left the splash shield off but made a new cover to divert spilled Pepsi (cables routed through old one and may need to go in again).

Radio now sounds as it should - will dissect original and check the green .01ufs that seem to be problematic.

Interestingly the FSM (both 88 and 89) is confusing in this area - makes it look as if the entire console needs to be removed. Not true, the top console cover gives necessary access just be careful of the sharp screw points on both sides.

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Right: have heard about the little green capacitors that were rejects from a cancelled military program but how do you get to them ? Have found screws requiring 1/4" & 3/16" nutdriver and T-10 torx but the heatsink does not seem to be removable and the circuit boad is soldered to the chassis.

Would appreciate knowing what must be removed & in what order to get to the little green thingies.

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Just heat the two metal case tabs and bend them away from the circuit board.

There are two boards. One is the receiver and the other is the control memory interface / amplifier.

The heat sink should come off easily after removing the four screws revealing the two amplifier chips. Depending on the year, the screws may be hex or torx. If you have a dead channel, one of these 2 amplifier chips is probably bad. If you have a memmory programming problem one of the large chips may be the culprit.

I used Radio Shack pn# 272-996 to replace the bad little green capacitors. The replacements are non-polorized so thay can be installed in either direction without fear of destroying them. They are physically larger than the originals, but they will fit by laying them down horizontally. Put all six in before cutting the leads or soldering because space is tight and you will have to manuver them to get them all to fit. Take caution to not cause a short circuit by allowing dissimilar leads to touch. You may want to use sleeving on the leads. Use a magnifying glass to inspect your work for solder bridges or other possible shorts.

If you want better reception, now would be the time to upgrade by replacing your IF ceramic filters with 150 khz ones. http://www.geocities.com/toddemslie/betterfmselectivity.htm

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Wow; the depth of knowledge here always amazes me. Would love to try this tweak.

sahein, you may be one of the few people who can answer the following question. <span style="font-style: italic">Can a CD player be hardwired to the "radio" and used without the RF adaptor?</span>

Thanks and keep up the good work.

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Not certain that I would want to narrow the bandwidth though I can see that someone living in the northeast with dense channels (stations every click) might. In central Florida the separation between stations is sufficient that I have no problem with selectivity.

The problem described is one of nearby channel rejection. FM always will select the strongest station, rejecting others. So if you are listening to aa weak station and a nearby one is 200 khz off (next click), your radio may reject the one you want and try to lock on the nearby one.

Note that the article is specifically for FM-DXers - people who try to log distant stations.

Now if I made a lot of long trips and wanted to maximise the time on each station or if I was experiencing a lot of station switching (the 1967 Delco AM-FM Stereos were really bad and would make a loud "click" when switching). the mod might make sense.

For me, I think I'll just replace the caps. Thanks for the Rat Shack part numbers. While I do not really care for them having run the real electronics stores (Allied, Lafayette) out of business here, they can be usefull for small stuff.

Going through some old schematics I found an interesting reference to a p/n 16068799 "compact disk interface board" that was used on 1987 2000 series Delco radios to interface both a compact disk and a cassette player. Have no idea if it could be adapted to a Reatta but the input lines look the same as the casettes...

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There are three ways to wire in a CD. RF is the easy one and with a good modulator directly connected to the antenna lead can be as good as the radio.

For better you have two (well three but the third is stupid) choices - switch out the radio but use the internal amplifier. This would require some rewiring of the radio but the radio already has an audio input for the cellular telephone (may be mono - anyone know ?) option.

Otherwise you could tap onto the cassette audio inputs but would have to tell the radio to switch to the cassette.

Else you could just switch out the radio and switch in the CD on the speaker & power lines. This would require a separate amplifier for the CD.

Or you could just have a completley separate system for the CD including speakers but this is what I would consider kindof dumb.

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