Notices
928 Forum 1978-1995
Sponsored by:
Sponsored by: 928 Specialists

Odometer problem - burned resistor on circuit board

Thread Tools
 
Search this Thread
 
Old Jul 9, 2019 | 05:46 PM
  #1  
jas79's Avatar
jas79
Thread Starter
Intermediate
 
Joined: Jan 2016
Posts: 38
Likes: 0
From: Ronneby, Sweden
Default Odometer problem - burned resistor on circuit board

I've got a broken odometer on my 1986 Euro S. I replaced the odometer gear some years ago, and after that the odo worked fine. Now it died again. I guessed that iy was a gear issue again, and took it apart. No broken gear, and it counts fine when rotating the mecanism. There must be a electrical issue in the odometer. The speedometer works, so the impulse sender on the differential, the flexible circuit board, wireing etc must be OK. The problem must be in the odometer instrument. I found this excelent thread about problems i the instrument. It´s only one problem with it. The pictures are missing.

https://rennlist.com/forums/928-foru...rs-intact.html

I soldered the step motor out of the board, and checked it according to the instructions. It works perfectly. I found one burned resistor on the circuit board. In #17-18 in the thread they talk about checking a resistor, that should be 22 ohms. Which one on the board is that? Anyone got the pics from that thread?

Anyone know the value on my burned resistor? I soldered it out of the board, and it is about 48 ohms now. I don´t know if it is the correct value, but it neeeds to be replaced. Maybe some other components too? It is the UAF2115 chip.

Any inputs and ideas are welcome!

/Mattias

Reply
Old Jul 9, 2019 | 06:26 PM
  #2  
Majestic Moose's Avatar
Majestic Moose
Burning Brakes
5 Year Member
 
Joined: May 2016
Posts: 840
Likes: 56
From: Nazareth, PA
Default

According to this thread it should be 33 ohm and it may have burned out due to a shorted capacitor.
https://rennlist.com/forums/928-foru...r-failure.html
Reply
Old Jul 10, 2019 | 04:48 AM
  #3  
jas79's Avatar
jas79
Thread Starter
Intermediate
 
Joined: Jan 2016
Posts: 38
Likes: 0
From: Ronneby, Sweden
Default

Thanks for that link, very useful!

I will report back after replacing the resistor and capacitors.

/Mattias
Reply
Old Jul 12, 2019 | 02:15 AM
  #4  
Douglas Stout's Avatar
Douglas Stout
2nd Gear
 
Joined: Jun 2019
Posts: 2
Likes: 0
Default

I have the same burned resistor on my 85. I have no speedometer or odometer at the moment. It would be nice if someone sold just this circuit board, vs having to buy a complete speedometer assembly
Reply
Old Jul 12, 2019 | 06:11 AM
  #5  
Majestic Moose's Avatar
Majestic Moose
Burning Brakes
5 Year Member
 
Joined: May 2016
Posts: 840
Likes: 56
From: Nazareth, PA
Default

I sent in my speedometer to Specialty Gauge and he replaced the board.

Cory Shepherd
Specialty Gauge
8110 Weatherwood Ct
Unit 202
Manassas, Va 20109
703 402 4008
Reply
Old Jul 12, 2019 | 12:30 PM
  #6  
Landseer's Avatar
Landseer
Race Director
15 Year Member
 
Joined: Sep 2007
Posts: 12,162
Likes: 383
From: Johnson City, TN
Default

Maybe they will rework amp gauge too. Mine pegs out. Stan and I measured 12 volts. Must be something similar.
Reply
Old Jul 12, 2019 | 06:59 PM
  #7  
jas79's Avatar
jas79
Thread Starter
Intermediate
 
Joined: Jan 2016
Posts: 38
Likes: 0
From: Ronneby, Sweden
Default

Report after repair:

I replaced the 33 ohm resistor, the 47 and 100uF capacitors, and now the instrument works perfectly!

I checked the removed components, the 47uF capacitor was broken but the 100uF was OK.

THANKS TO ALL HELPFUL RENNLISTERS - this forum is fantastic!!!

/Mattias
Reply




All times are GMT -3. The time now is 04:29 PM.

story-0
10 Best Non-Flat Six Porsches You Can Buy For Under $100K

Slideshow: If you have $100K to spend on a Porsche but want something a little different, these are the 10 best non-flat six Porsches you can buy.

By Joe Kucinski | 2026-05-28 15:36:11


VIEW MORE
story-1
Porsche's Top 5 Most Questionable Naming Decisions

Slideshow: For a company obsessed with engineering precision, Porsche has occasionally named its cars in ways that left even loyal enthusiasts scratching their heads.

By Verdad Gallardo | 2026-05-27 18:43:48


VIEW MORE
story-2
Pogea Racing's 964 Porsche 911 Reimagination Stands Out in a Crowded Field

Slideshow: Pogea Racing's latest Porsche 964 project blends carbon-fiber construction, modern chassis upgrades, and up to 500 horsepower while keeping the air-cooled 911 experience firmly analog.

By Verdad Gallardo | 2026-05-23 10:34:27


VIEW MORE
story-3
6 Convertible Top MYTHS Most People Don't Understand!

Slideshow: dispelling common convertible top myths

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-4
2026 Porsche 911 Club Coupe is Spectacular, And Everything Wrong with the Porsche Market

Slideshow: The 2026 Porsche 911 Club Coupe is being resold $150K above sticker and that is a real problem.

By Joe Kucinski | 2026-05-21 11:52:54


VIEW MORE
story-5
Talos Takes Your 991 Porsche 911 GT3 to the Next Level for a Cool $1.13 Million

Slideshow: Talos Vehicles has transformed the Porsche 911 GT3 RS into a carbon-bodied, race-inspired machine that costs well over $1 million before the donor car is even included.

By Verdad Gallardo | 2026-05-19 13:39:04


VIEW MORE
story-6
9 Vehicles Porsche Helped Engineer that Aren't Porsches

Slideshow: Long before engineering consulting became trendy, Porsche was quietly helping other automakers build everything from supercars to economy hatchbacks.

By Verdad Gallardo | 2026-05-15 12:44:44


VIEW MORE
story-7
9 Features and Characteristics That Only Porsche People Understand

Slideshow: Some brands build cars. Porsche builds traditions, obsessions, and a few habits that stopped making sense decades ago but somehow became part of the charm.

By Verdad Gallardo | 2026-05-13 18:46:13


VIEW MORE
story-8
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way

Slideshow: Six years and 500 Rennlist articles later, these are the biggest changes at Porsche.

By Joe Kucinski | 2026-05-11 09:52:55


VIEW MORE
story-9
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)

Slideshow: Some Porsches exist for very specific reasons-others feel like they were built just to see if anyone would notice.

By Verdad Gallardo | 2026-05-06 18:00:32


VIEW MORE