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Speedometer circuit board [message #247467]

Tue, 15 April 2014 07:01

cbwoodsr

Messages: 1063
Registered: February 2004

Karma: 0

Senior Member

I need the circuit board on the back of the speedometer...

Thankx
CBW

CBWood
77 Kingslay
MWC OK
ONLINE PARTS PROGRAM
www.GMCMHParts.com

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Re: [GMCnet] Speedometer circuit board [message #247469 is a reply to message #247467]

Tue, 15 April 2014 07:46

powerjon

Messages: 2446
Registered: January 2004

Karma: 5

Senior Member

Charles,
As old as these speedometers are you better off getting a complete unit and then have the miles reset. The boards are very brittle and the copper traces are very difficult to desolder without the proper tools and most of the time the traces will lift from the board. You will need a solder sucker as I call it and a lot of skill and patients.
<http://www.radioshack.com/product/index.jsp?productId=2062745>
A 20 to 30 watt Pencil iron, anything bigger you can turn a board into junk very easily.
<http://www.radioshack.com/product/index.jsp?productId=2062758>
I did board level repair for a number of years and if you re a rookie first timer then I wish you luck, take your time and don�t overhead the desolder point.

JR Wright
78 Buskirk Stretch
75 Avion
Michigan

On Apr 15, 2014, at 8:01 AM, Charles Wood <cbwoodsr@swbell.net> wrote:

>
>
> I need the circuit board on the back of the speedometer...
>
> Thankx
> CBW
> --
> CBWood
> 77 Kingslay
> MWC OK
> ONLINE PARTS PROGRAM
> http://cbwoodsr.no-ip.org/GMCParts/index.asp
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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J.R. Wright
GMC GreatLaker
GMC Eastern States
GMCMI
78 30' Buskirk Stretch
75 Avion Under Reconstruction
Michigan

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Re: [GMCnet] Speedometer circuit board [message #247481 is a reply to message #247469]

Tue, 15 April 2014 10:02

Richard Andis

Messages: 261
Registered: January 2013
Location: HELL Paso, TX

Karma: 0

Senior Member

powerjon wrote on Tue, 15 April 2014 07:46

Charles,
As old as these speedometers are you better off getting a complete unit and then have the miles reset.

The boards themselves dismount from the mechanical part of the speedometer relatively easy. There is a pretty good connector pin repair procedure outlined on the GMC photo site.

http://www.gmcmhphotos.com/photos/g6461-speedometer.html

I elected not to do the pin repair but just swap out the board from a salvaged speedometer in order to keep my original miles.

Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)

[Updated on: Tue, 15 April 2014 10:04]

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Re: [GMCnet] Speedometer circuit board [message #247532 is a reply to message #247481]

Tue, 15 April 2014 20:23

Rowlie

Messages: 55
Registered: April 2012
Location: Indianapolis

Karma: 0

Member

How hard is the board swap? I just got a salvaged speedo which I was planning to swap with mine due to problems with a jumpy needle and lights not working. Maybe I'll swap the boards instead.

Eric Rowland '76 Palm Beach Indianapolis, Indiana

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Re: [GMCnet] Speedometer circuit board [message #247533 is a reply to message #247532]

Tue, 15 April 2014 20:27

Otterwan

Messages: 946
Registered: July 2013
Location: Lynnwood (north of Seattl...

Karma: 0

Senior Member

Jumpy needle might be your cable, not your speedometer.

1977 Birchaven, Lynnwood WA - "We may not be able to stop all evil in the world, but I know that how we treat one another is entirely up to us."

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Re: [GMCnet] Speedometer circuit board [message #247536 is a reply to message #247532]

Tue, 15 April 2014 20:56

Richard Andis

Messages: 261
Registered: January 2013
Location: HELL Paso, TX

Karma: 0

Senior Member

Rowlie wrote on Tue, 15 April 2014 20:23

How hard is the board swap? I just got a salvaged speedo which I was planning to swap with mine due to problems with a jumpy needle and lights not working. Maybe I'll swap the boards instead.

The board only supports the electrical portion of the speedometer: High Beam, R and L Turn, and illumination.

A spastic speed needle is more likely the head unit in the speedo or cable.

You can probably replace the board without removing the speedo. I went ahead and removed the speedo and replace the board on my workbench. Use the eraser of a pencil to clean up any electrical contacts.

Valhalla - 1978 GMC Royale rear twin [SOLD]
Walküre - 1974 VW Thing (Toad)

[Updated on: Tue, 15 April 2014 20:59]

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