Instrument Printed Circuit Repair

[Fixer]

Yesterday i was talking to Mark at 928 International (thanking him for the seals and beautiful no-wing used hatch trim) and checking on remaining trim bits on back order.

I mentioned my printed circuit is definitely gone bad, been through it all and determined for sure by examining the circuit. He told me to send it to North Hollywood Speedometer and Clock. Heard of them but was very pleasantly surprised at their price.

They quoted me $120 to completely refurbish my printed circuit.
Expected the price to be 3 to 4x that..
They also quoted $140 to replace the speedo gear while at it, my speedometer is fine though think i will pass on that.

Went driving out in Chester County Pennsylvania yesterday with Astrid and kids, car runs like a champ, plenty powerful for me, love it. What 911?

[AirtekHVAC]

Niiiice

[MPDano]

Not to burst your bubble, but I bought a brand new PCB from 928 Intl a couple years back when they still had them for $101. Now that they are NLA, $120 to refurb is not sounding too bad.

[Danglerb]

I would want to know some detail about what "completely" refurbish means. Most have a few weak solder joints, but many have fingers on the connectors in bad shape, how can those be "refurbished"?

The metric I would measure them by is the replacement of the odo gear, which is kind of a known job and parts cost vs price and expected work on the board.

[Fixer]

Here is Hartmut's email to me, with a name like that he's got to be good..

Hello Matt,

The average repair of a Porsche 928S Mylar board runs app. $ 120.00 depending on it's condition. In addition you may want to consider having the odometer gearing of the speedometer replaced which frequently breaks down. The service of the gearing sells for $ 110.00. A firm estimate can be provided after we have checked out the instrument cluster. 1 year warranty. App. 1-2 weeks turnaround time. Shipping charges are additional.

We do accept Visa, M/C or Pay Pal. Our account is under info@nhspeedometer.com.
Upon shipping your instrument (instruments) please refer to our e-mail correspondence.

Our shipping address:

North Hollywood Speedometer
6111 Lankershim Blvd.
North Hollywood, CA 91606
Ph: 818-761-5136

We need to keep this guy in business, bubble not burst Dano..

[Fixer]

No burst bubble, happy for you. Just trying to prevent people from wasting their time completely re manufacturing their instrument cluster like many have. With a name like Hartmut you can't go wrong.

Here is Hartmut's email to me:

Hello Matt,

The average repair of a Porsche 928S Mylar board runs app. $ 120.00 depending on it's condition. In addition you may want to consider having the odometer gearing of the speedometer replaced which frequently breaks down. The service of the gearing sells for $ 110.00. A firm estimate can be provided after we have checked out the instrument cluster. 1 year warranty. App. 1-2 weeks turnaround time. Shipping charges are additional.

We do accept Visa, M/C or Pay Pal. Our account is under info@nhspeedometer.com.
Upon shipping your instrument (instruments) please refer to our e-mail correspondence.

Our shipping address:

North Hollywood Speedometer
6111 Lankershim Blvd.
North Hollywood, CA 91606
Ph: 818-761-5136

[MPDano]

I'm almost sure that was the name that was on the decal on my Cluster on my 81 Euro. I do remember is was a Hollywood address. He probably did a lot of Federalization of 928's back in the day.

[MPDano]

...and like Mike said, most issues are the fingers that attach at the connectors are pulled back. You can probably fix this yourself, but having a warranty can be a good thing.

[19psi]

Originally Posted by MPDano

...and like Mike said, most issues are the fingers that attach at the connectors are pulled back. You can probably fix this yourself, but having a warranty can be a good thing.

I've repaired flex circuits and fingers using the copper resin from rear window defogger repair kits.

[Fixer]

Originally Posted by 19psi

I've repaired flex circuits and fingers using the copper resin from rear window defogger repair kits.

Great idea.

[MPDano]

Originally Posted by 19psi

I've repaired flex circuits and fingers using the copper resin from rear window defogger repair kits.

I've tried some rear defogger repair kit and didn't have very good luck with it. Yours might have been a different kit.

[Fixer]

I went and bought Permatex Complete Rear Window Defogger Repair Kit. $12.99+tax

Read on the interweb it was developed jointly with GM.

I will give it a shot, if after the Quick Grid material is brushed over the corroded areas and my multimeter reads 0.00 ohms or no resistance then i will know without installing that it is repaired.

Will get on removing instruments tomorrow afternoon hopefully, piloting the Shark to Washington's Crossing (Lambertville, Pa) to check out the flea market with the family.

[19psi]

Don't recall what brand I used. Just what was available at places like Autozone.
Never used it on the 928 but I have used it to bridge flex traces in old computers and electronics.
I've also used it to coat the poorly made carbon discs on the bottom rubber button blocks of old video game controllers and TV remotes. Cleaning was always a temporary fix. First tried it about 15 years ago on some of my old Atari 5200 controllers and the buttons still work perfect today. Also used it to repair a few flex traces in the same controllers.

Let the stuff cure very well and don't bend things too much while putting it back in place (think of it as paint) and you'll probably be fine. For fingers that get inserted into a connector, I'd use a very thin coat.

[Fixer]

Thanks, will do. I will take photos
At the finger connection I should use scotch tape on the edge overlapping same as the clear film that has de-lammed..

[Danglerb]

No part of the 928 tempts me more to go non stock than the instrument cluster circuit board connectors.

OTOH sooner or later someone will put them back into production and we get another 20 years out of them.

[Kiln_Red]

Not sure what your symptoms are, but if the only issue with the PCB is that the speedo isn't working or working intermittently, you may consider doing the repairs yourself. Dwayne has an excellent writeup on the procedure and includes great suggestions for taking the opportunity to replace any burnt out bulbs in the cluster. Also, this gives you the freedom to look at the odometer gear yourself to determine whether you want to replace it or not. You can't go wrong at $120, either. So it's a win/win. Just thought it was worth sharing that there are alternatives to sending your cluster off.

[Fixer]

Here are the symptoms at idle this morning before i left nothing but speedo and tach but have warning lights (pic 1)

Family in Washington Crossing (pic 2, where Washinton crossed the Delaware during Revolutionary War, Christmas) went to a cool flea market and what a great drive.
I am really hooked on this car, it does everything so much better than the Carrera did, it's gone btw).
rest of pics:
The instrument connections were simply really cruddy, there is no need for the Permatex stuff, nothing wrong with the P.C. The pencil eraser didn't do the job, i had to use 1200 Gt 3M wet/dry sanding paper. The depressions left by the contacts were not getting clean using the eraser method. I plugged in the instrument cluster and all work fine now.
The printed circuit is made better than i imagined once out and not looking up under the dash
I will neatly put it all back together tomorrow after work.
Thinking i should coat the contacts but with what? Dielectric grease very carefully with a tiny brush not to make contact btwn one another or light oil??
Thanks for the help.

[MPDano]

Yup, pencil erasure never worked for me either, which is why I used a small exacto to lightly scrape mine and now it works perfectly. This is on my S btw, it's also documented in the "Common Issues" thread.

[AirtekHVAC]

There is also a "trace" pen available...I use it repairing PCs and game consoles....it's a little pricey, but works great. I think you can get it at radio shack.

[stepson]

[QUOTE=Danglerb;7152309]No part of the 928 tempts me more to go non stock than the instrument cluster circuit board connectors.
QUOTE]

Man, you got that right! If I had any gonads at all, I would hardwire the extra '84 cluster I have. But knowing my proficiency at this particular skill, I will wait until someone with a far better skill set elects to help me with that.