PCM1 issue

[HolmaN]

Greetings,
I'll try to describe my as good as I can. Note that english is not my native language tho, so feel free to ask what I mean if you don't understand.
Anyhow...

I've notice that my PCM1 in my 986 -98 "flicker" from time to time. (It's like the screen is blinking.)
It turns black for half a secod and get's back to normal. The audio is fluent meanwhile. I don't hear when it happens, the music goes on like normal.

Anyone who've had this problem?

• Problem with the powercable?
• Problem with the ground cable?

Edit: I've searched, but haven't found anything. Mostl likely because I don't know the proper word to use instead of "flicker".

With kind regards, HolmaN.

[Obertelli]

Your English is very good, HolmaN, as is your description.

The fact that your audio continues without interruption makes it clear that there is nothing wrong with the power supply and grounding. The fault is with the display alone, but without removing the unit and dismantling it further diagnosis is not really possible.

The unit is quite old now, so the most common faults would be a loose ribbon cable connector to the LCD display, a cracked ribbon cable (they get brittle with age), a "dry" solder joint somewhere which has gone to high resistance (modern lead-free solders are very prone to that and were especially bad until about ten years ago) or the LCD panel itself may be failing.

Even if you diagnose the fault, and intermittent faults are always very difficult to find and fix, the unit may be uneconomical to repair.

I'd suggest that you live with the fault and when it gets much worse it will be easier to diagnose and if you're lucky it may be an easy fix. Or you may decide to buy a replacement unit. This one is available from a trustworthy Porsche breaker in the UK but will need decoding. But they're all getting on now and can fail at any time, so you may instead decide that it makes more sense to upgrade to a modern alternative such as the Kenwood DNX4230BT and keep your current unit aside for refitting if you sell the car to someone who wishes to retain originality.

[HolmaN]

Originally Posted by Obertelli

Your English is very good, HolmaN, as is your description.

The fact that your audio continues without interruption makes it clear that there is nothing wrong with the power supply and grounding. The fault is with the display alone, but without removing the unit and dismantling it further diagnosis is not really possible.

The unit is quite old now, so the most common faults would be a loose ribbon cable connector to the LCD display, a cracked ribbon cable (they get brittle with age), a "dry" solder joint somewhere which has gone to high resistance (modern lead-free solders are very prone to that and were especially bad until about ten years ago) or the LCD panel itself may be failing.

Even if you diagnose the fault, and intermittent faults are always very difficult to find and fix, the unit may be uneconomical to repair.

I'd suggest that you live with the fault and when it gets much worse it will be easier to diagnose and if you're lucky it may be an easy fix. Or you may decide to buy a replacement unit. This one is available from a trustworthy Porsche breaker in the UK but will need decoding. But they're all getting on now and can fail at any time, so you may instead decide that it makes more sense to upgrade to a modern alternative such as the Kenwood DNX4230BT and keep your current unit aside for refitting if you sell the car to someone who wishes to retain originality.

Thanks for the reply mate.
All the speakers is replaced and so on, but that shouldn't mess with the screen.
I'll try to live with it for now, it's not that common. But when it happens, it happens a lot untill I "restart" the car.
Would it be possible to check the stereo without pulling it apart too much?

The system I use:
Amplifier: Ultimate A4 - 880 Watts 4-channel amplifier
Rear speekers: Ultimate Gothia 3 - 3 inch midrange speaker
+
Subwoofers in the door panels
2 speakers + dics in the front.
All from DLS as well.

[Obertelli]

Originally Posted by HolmaN

Would it be possible to check the stereo without pulling it apart too much?

Probably not. Checking for faulty LCD connectors and dry solder joints involves a fairly substantial disassembly of the unit.

The most you can hope for short of that is to remove the unit from the car, power it up, and then check the LCD performance when you vibrate or slap the unit. You might also find that the fault occurs more frequently when the unit is stone cold or when it's warmed up as thermal contraction and expansion can affect loose or faulty connections. But if that identifies the conditions which produce the fault symptoms then it will still need disassembly to try and locate the exact cause(s).

[Obertelli]

Update: it seems another common cause is a failed LCD backlight.

See here for a repair service.

[HolmaN]

Originally Posted by Obertelli

Update: it seems another common cause is a failed LCD backlight.

See here for a repair service.

My doesn't dim nor going totaly black tho
I'll have a look further on. It's not prio 1 I'm affraid.

[HolmaN]

Problem solved, it was when the navi was trying to load the disc. The disc was to damaged to be read, and that cuased this. Wasn't even a problem.