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HI, if ever this can help I found the solution for the problem why I posted here. I finally took the time to check every way of this trouble and I got it.
Just to resume, the stock radio was working until the engine starts. When the motor runs the radio don't.
It was simple. The radio was the problem. When the engine does'nt run the dc voltage at it was around 12v. Then, when the engine runs, and it is normal, the dc go up to approximately 13.4 volts what the radio does'nt like and I don't know why.
I just cut the black with red stripe wire and I've put a diode 1N5408 that reduces the voltage of .6 volts. It solved the problem completely and the diode does'nt seem to heat much.
Hope this can help.
Cheers
HI, if ever this can help I found the solution for the problem why I posted here. I finally took the time to check every way of this trouble and I got it.
Just to resume, the stock radio was working until the engine starts. When the motor runs the radio don't.
It was simple. The radio was the problem. When the engine does'nt run the dc voltage at it was around 12v. Then, when the engine runs, and it is normal, the dc go up to approximately 13.4 volts what the radio does'nt like and I don't know why.
I just cut the black with red stripe wire and I've put a diode 1N5408 that reduces the voltage of .6 volts. It solved the problem completely and the diode does'nt seem to heat much.
Hope this can help.
Cheers
AM - THANK YOU FOR YOUR HELP ON THIS. I know this is an OLD thread but your solution worked for me. I purchased the 1N5408 diode you mentioned and soldered it into my power line (my power line is Red with a Black strip), used some heavy duty shrink wrap and put it back together again. Now the radio works perfectly so far, THANK YOU. You can purchase these diodes online for about 29 cents plus shipping, since I already had the soldering iron and everything else I needed it ended up costing me less then $5 :-)
I just purchased a 1999 Boxster last week, my first Porsche :-). It only has 77,000 miles on it and the body is in great shape and mechanically it runs great as well. There are a couple of things to fix on it (radio / airbag light (seatbelt harness re-wire) and then put a new top on it) and I am amazed at all the great information I have found on this website rennlist.com. Thank you to all who contribute.
I will try and give an updated on the stereo as life goes on and confirm if this indeed was a permanent fix.
Just to confirm that the diode workaround worked perfectly in my case.
Problem in '99 Boxster was a correctly working CR22 radio (with the additional amplifier option) without the engine running (about 12.5V). Once the engine was started, voltage would increase to about 14.4V (which is normal) and the radio would switch on/off repeatedly. Briefly showing 'Porsche' every time it would start again.
The picture shows a quick and "non-invasive" way to check if dropping the voltage would help in your case.
Fuse B2 (Boxster '99), 7.5A, in the footwell fusebox is only used for the radio. Just remove the current fuse and replace with this:
I have taken another 7.5A fuse (or any other value), blew it, and soldered a diode on top of it. I used a 1N5405 because I had one lying around, 1N5408 is a safer bet. If the radio does not work, turn the "fuse" 180 degrees.
This is a workaround because it is not OK to remove the actual fuse from the circuit, even though the diode would probably also fail if the current is too high.
So, if this solves the issue, follow the suggestion above, remove the radio and properly insert the diode in the correct direction in the +12V supply for the radio.
Even then it remains a workaround in a way as I do not know why this radio starts to act up if the supply voltage exceeds a certain level. After all, it has worked for many years without a diode. Anybody knows what actually goes bad in the head unit itself?
08-26-2014, 09:54 PM
