dr bob

Power jumper is there OK. If the power goes out whenever the engine goes past 3k, it should be easy to trace back to see where it doesn't drop out.

jwbeck17

That's great to hear, Dr. Bob. So based on my non-electrical mind and the connections, I only see four wires connected to the the unit in total:

1) Red into Reno connector - hot
2) brown into Reno connector - ground
(Both of these have direct connections from Reno connector to current radio connector)
3) red from somewhere in console directly into current radio connector - hot
4) black from somewhere in console directly into current radio connector - dead

If I understand you correctly, #1 should be the power to the unit, so throttle testing along that line should isolate the issue. Now do you happen to know what #3 & 4 are? You can see them in one of my pics and they are separate from the Reno connector. At any rate, testing throttle power impact on those should help me track the issue as well.

jwbeck17

Due to the warm spell today I was able to check the ground continuity, which reads fine, as well as the voltage on the two hot leads. At idle they are 14v but surge through acceleration to slightly over 15v. Not sure if that is normal. If normal, it's most likely the radio unit CDR-220. Just want to determine if in need to replace the radio or another part. Any thoughts?

WallyP

There are several "normal" (meaning that they are on some units) connections to a radio...

Constant power - may be red, often a thin wire (18 gage perhaps). This is always hot, keeps the memory for the settings and clock.
Operating power - may be red, usually a heavier wire (14 or 16 gage most of the time). This is switched (on with ignition switch ON or ACCESSORY) and supplies the operating power.
Ground - May be brown (DIN) or black (USA), constant ground/earth connection. On the '89, you might have an extra brown ground wire that connects to the DIN box and disconnects when the radio is removed, triggering the alarm.
Antenna/Amp trigger - May be blue from an aftermarket radio, any color on the car side, but on the '89 I think that it is gray or white on the car side, usually turns black before it gets to the required antenna amp on the '89. No power from car, but is powered when the unit is ON. This triggers the antenna to the up position, or the amp to ON. On the '89, I would expect it to power the antenna amp.

If you have the Factory Workshop Manuals, check the diagram on Page 97-325. On the upper left corner, there is a Throttle Switch for option M326, the Radio Berlin system. It appears that a wire runs from Fuse #22, which is the fuse for the stereo booster to the throttle switch, and from there to the booster. Interesting...

Pull the cover on the passenger door sill and find the power supply wire for the booster - a medium-sized red wire going to Terminal 2. Check for battery power on the wire - according to the diagram, it will be hot. Push the throttle pedal down and see if the power cuts off or varies. If so, it is a feature!

Another possibility is that you might be tripping an over-voltage circuit in the radio. Over 15 vdc seems to be too high - I would expect max system voltage to be 14.6 - 14.8, but I have been wrong before. I also see no way that the voltage would increase with acceleration - just with engine (alternator) RPM.

jwbeck17

Wally, thank you so much for the detailed post! And thank you for correcting my error, as I should have stated "increased rpm" instead of "acceleration". I can replicate the problem standing still but revving the engine.

What makes it a little tough to nail down is that instead of the original Blaupunkt unit there is an updated Becker unit with some additional wiring added, but the original wiring is there so that is what I tested.

As for the factory shop manual, I saw that throttle connection as well, but I wasn't electrically savvy enough to know which wire or fuse. With your details I can figure it out, as I found that interesting as well.

I'll test that booster wire in the passenger seat. In some of the earlier pics I was able to identify what was there, but not test the wiring.

However, I think the most likely culprit is that the increased RPMs are pushing too much voltage. I noticed the increase on the two hot wires when I hit the throttle. After doing some further research, it may be the voltage regulator is bad on the alternator. That could be the true issue, but I'll need to do some further testing to figure it out.

Thanks so much for the help and will post back with questions or answers.

the flyin' scotsman

Jason.....it would be an easy test to determine if the voltage regulator is not performing using a good Digital Volt Meter and measure the voltage at the battery or the jump post under the hood. there should be a couple of volts difference between engine off and running then an increase again once the engine is revved above idle......let us know

Avar928

She's just telling you to turn off the music and listen to her roar. The girl just wants to be the center of your attention always

jwbeck17

I have to admit, I think she likes me testing the rpm. Helga has a beautiful voice on her. When she goes to the track she loves to dance and sing.

upstate bob

Never listen to the radio. Two years after I had the windshield replaced in my daily driver I got stuck in traffic and turned the radio on. -didn't work. apparently the replacer didn't hook up the antenna. No problem. I don't care.

jwbeck17

Well today was nice enough to go out and test the voltage on the front battery post. The results were:

11.86v with engine off. Not run for 3 days and temps are cold
14.32v @ engine start and idle
15.4v @ 4000 RPM

Based off of that, I now think that the radio and the wiring are fine, but the voltage regulator is not functioning as well as it should. Do you agree? Could makes sense, as I had to get a new battery recently and at heavy rpm the interior and exterior lights tend to pulse.

Now I am debating if I should just change the voltage regulator or the whole alternator. I looked through the PO records and I believe it is original.

Thoughts in that?

Btw, I cannot thank you all enough for your help on this. I have learned so much from you, and this exploration has been fun thanks to your help!

jwbeck17

I'm bringing this one back to the chat. Had alternator checked and it's all fine, no issues. Not seeing anything abnormal in the connections either, but the issue still exists. I started to think more that maybe the issue is with the Porsche (Becker) CDR-220 radio unit. And when I looked that up, it sounds like I may not be alone...

Apparently power kicks on and off of these units and have several situations that cause it. 1) As the unit has a removable face, sometimes the connections get corroded, and so the unit loses power, and 2) the unit can't handle voltage spikes in the 14v+ range.

The first is an easy fix. a little corrosion spray, an eraser on the contacts, reconnect and done. Unfortunately that did not solve the issue.

The second situation sounds like my problem. Not sure if boxsters don't have the same voltage spikes as 928s, but that seems to be my challenge. I read one really odd post on how to resolve where a guy basically hooked up a halogen light dimmer to the radio fuse to limit the spikes and keep the radio voltage to 12V, and that got me to thinking maybe a voltage limiter specifically on the radio circuit is the right solution. However I am not well versed in electronics and wiring at all, so I probably don't know what the hell I'm talking about.

For those of you that are more electronically minded, do you get what I'm saying and can think of any solutions that a simpleton like me can do?

jwbeck17

Just closing this one out, as the problem was solved. The radio was fine after all. (I even had Stefan at SW Audio refresh the buttons on the unit to look like new!) as Capt. Earl suspected, the voltage regulator was the culprit. Here is what we found out.

The alternator had a KAE voltage regulator which was exhibiting the problem. I replaced it with another voltage regulator which was wlso KAE. Still had the same issue. Even swapped alternators, but the other one had a KAE voltage regulator as well.

Looking at both regulators, both seem to have that little nick in the end of one of the brushes after use. The rest of the nicked brush was unblemished and never touched the commutator.

Earl suspected that the KAE voltage regulator brushes were not seating correctly due to a possible defect.

I then ordered the internal voltage adjustible regulator from Dave Barton at Dave's Volvo Page. Earl and I then compared the brushes and noticed that the KAE did not line up with the Dave's adjustible one.

Once I installed Dave's unit, there were no spikes at all. Smooth voltage. All we did was adjust the voltage slightly to make sure that the current was a strong 13.9V at idle.

I tried the radio and it works fine. While I can't hear the radio at above 4,000 RPM, it's because the music is getting drowned out by the sonorous exhaust. And that is truly music to my ears.