Michael Benno

Who is doing repair / refurbishment of these units? I seem to remember a few people doing this.


I discovered today I have a faulty final stage fan controller (92861842100) on my 92 GTS. The failure mode in my case is that only fan 2 is running and only at high speed. I ran through the test diagnosis in the WSM and it failed the final two tests which indicated the controller is faulty. I swapped the unit with a known good one (thanks @PorKen ) and both fans operate normally so this would tell me the final stage controller is faulty.

I found this service on the web https://www.fixyourboard.com/boards/92861842100.html, anyone use them?

Edit: please see post #10 for a list of current vendors:

Pagnobito

I can do them but I'm in the UK so may not be your first choice factoring in shipping.
Some can be rebuilt just by replacing the power transistors, some others have required a bit more like the comparitor ICs
jdsporsche

Michael Benno

thanks for the offer and insight on the inner workings.

I'll look for a domestic source since int'l shipping is gonna be crazy expensive.

Cheburator

the final stage doesn't weigh much and i get my rock auto parcels for next to nothing. it's actually worth checking the real rate for shipping

Eplebnista

I seem to recall Fraggle doing a tech session on rebuilding these at Frenzy 8 or 9 years ago. Maybe he did a writeup at some point.

fraggle

I'm hunting for my writeup. Maybe Greg Nichols has it somewhere?

Michael Benno

Crap.!

Now I am in the market to rebuild TWO controllers. My car killed the spare that @PorKen had lent me. Same failure mode, ride side fan stopped and the left side fan on high. I guess the fans are pulling too much amps and fried the internals.

I researched DYI but I think I will leave this job to someone that has experience in removing the back covers and replacing all the again components: MOSFET, Voltage Regulators, Capacitors, and various transistors.

Bertrand Daoust

I have a pic of Greg filming you when you were doing that tech session. That was in 2012. My first year at Frenzy.
Worth asking him maybe...

fraggle

Yikes. You may have a problem in the fans themselves that are trashing the units. You might consider wiring up each fan individually and getting a current vs RPM plot of some sort. One fan will have less RPM at 12V while pulling "x" current than the other. I have an optical harbor freight RPM gauge I'd use for that purpose.

Michael Benno

After much research I found three places to repair them, I figured I would post them here for anyone else in need. I spoke to each of these vendors and they all offered similar service, testing, component replacements.
1. https://www.jdsporsche.com/
2. https://electronikrepair.com/home-page
3. https://www.fixyourboard.com/boards/92861842100.html
4. 928srus stocks rebuilt units from JDS Porsche as well

There may be others as well.

Gary Knox

'www.electronikrepair.com' is owned and operated by a dedicated 928 owner in Mesa AZ. His name is Rich Andrade and he is also Membership Chair for the 928 Owners Club. I've known Rich for nearly 20 years, and he is dedicated to the 928 community. I suggest contacting him for your issue.

Gary Knox

khalloudy

I have used both JDS and Electronic Repair (Rich Andrade) and they are both super professional. Rich is stateside, so that might be more convenient...

Michael Benno

For those following along, I had two failed final stage units. The one from my 92 and a loaner from @PorKen 's 88. Ken lent me his but my car cooked it after a day or so of use (see thread). So I send both final stage units off for repair. Hence this thread to discover vendors that offer a repair service. In my research I personally discussed the repairs with the three vendors described above, they all seem to have extensive experience with this specific repair and were willing to take on the work. In the end, Ken and I decided to use FixYourBoard.com because they were also willing to test/repair the fan controller, which I was concerned may have been contributing to the cause of the final stage failure (since I had been through all other possible causes).

The repairs took about a week and the fee was $200 per component plus shipping. The vendor contacted me after their preliminary testing to confirm the units had failed their tests and were need of repair. The repaired units were sent beck with a summary of the replaced components (MOSFET, Capacitors, Voltage regulators, transistors, re-flowing the solders, and board flux cleaning), as well as, a successful component test, and 1-year warranty.

I haven't had a chance to test out the units in my car because I am still putting the timing belt back together (see thread). But last night, I was having a couple beers with Ken and I decided to install one of the repaired in is 89 supercharged monster. The repaired final stage seemed to function normally in the various test scenarios (low speed, medium speed, and high speed). Ken is running an aftermarket fan setup in support of his supercharger. He noted that his voltage gauge was reading higher with the fans on high speed and that the fans were running much quieter and stronger with the refreshed unit. Hopefully he will get some voltage readings to confirm some of his assumptions on why his fans seem to be operating better.

EDIT: I wrapped up the repairs to my GTS and was able to verify the build final stage amp, as well as, the rebuilt fan control module are both operating normally as verified by the WSM test procedures,

Anyway, I just wanted to share this as a resource for those of you out there wondering. This vendor seems to have a viable service. Three data points.

chart928s4

Sorry to be a little late to this thread, but I've had some experience that I hope is worth sharing. There are at least 4 928 devices that will at some point need reconstruction: Fan amp, LH, MAF, and climate head unit. (Others?)

Rich did my fan amp, and also my LH. I have used many other sources and they were mostly disappointing. In one case I actually got a unit back from rebuild DOA. Rich charged the same premium price generally as the other guys, but did both jobs correctly the first time with no drama and no slop or corner cutting.

I'm glad you seem to have had a good experience with the shop you chose - I have no experience with them and it's good to have alternatives.

I only have the two data points in favor and maybe 3-4 strikes against some other vendors, but that's enough for me. In the future I will not go anywhere else but Electronik Repair for 928 PC rebuilds.

GregBBRD

The biggest issue with rebuilding the fan amps is resealing them, so they are water tight.
Once that lower cover is pried off of the bottom, all of the little tiny aluminum "staked" raised posts have the staked part broken off and retaining the lower plate is....difficult, at best.
Additionally, the rubber seals are generally very crushed and require more force on them to seal.
Submerging it under water (with pressure applied to the breather port) is about the only way to make sure the fan amp functions for more than one season (especially in a wet environment.)

The electrical issues are generally very simple to repair.