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-   -   FD Speedometer-Odometer Circuit Board - Components Only (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fd-speedometer-odometer-circuit-board-components-only-1112010/)

Xtuners 05-03-21 08:07 AM

On this mainboard ZD1 is missing, but it is the same as ZD2. I don’t see ZD6 here.

ZD7 is the one in the middle from the 3 yellow ones.

https://cimg3.ibsrv.net/gimg/www.rx7...13a139f7d.jpeg

Gen2n3 05-03-21 01:32 PM

Xtuners,

Thanks for posting your results on Zener diode testing for the Speedo board. How did you test them? It looks like you replaced ZD3, ZD5, and ZD7 with new components. What part numbers did you use for those diodes?

Nice work!

Xtuners 05-03-21 02:33 PM

Hi,

I used 32 Volt DC source, Multimeter and 1K resistor to test the zener diodes. The readings from the multimeter are accurate. The numbers on the diodes are also accurate and represent the breakdown voltage. They were not damaged. Replacing them did not solve my issue. What I want to do now is to place an order in some of the US online stores and get all the part numbers for you. I replaced all zener diodes, don’t mind the yellow color, normally they are all orange.

Angel Guard Racing Team 05-21-21 11:57 PM

Has anybody been able to find a replacement for the lcd???

Gen2n3 06-02-21 09:17 AM

@Xtuners,

What part numbers did you use for those replacement Zener diodes? That may help others who need to replace damaged ZD3, ZD5, and ZD7.

@Angel Guard Racing Team,

It is very unusual for the LCD to go bad. There are no known replacements. However one could cannibalize an LCD from another speedo.

Angel Guard Racing Team 06-02-21 12:03 PM

It was the polarizing film... I ordered a nintendo gameboy polarizing film to see if it works...

Angel Guard Racing Team 04-02-23 07:38 PM

I am helping a friend with his odometer, I replaced all caps but nothing. Then I noticed only 1v coming out of ic2 I replaced ic2 and it started working... After a few hours odometer went blank again... Any ideas or pointers?

Angel Guard Racing Team 04-07-23 05:50 AM

IC2 is still good but There is 0.15v getting to the odometer eeprom IC3 vcc (leg 8) those eeproms run between 3.3v and 5v.

C1, C4 abd C6 are getting 0.15v also.

TR5 looking at the flat side from left to right I get 0v, 0v, 0.15v.

That's all I have been able to test after odometer went out again because of lack of time.

I am testing on bench with power supply set to 12v, using D3 for 12v input, and PGND and ILL for gnd.


Angel Guard Racing Team 04-12-23 07:18 PM

Fixed it...

HomerandAbe69 08-31-23 02:29 AM


Originally Posted by Angel Guard Racing Team (Post 12556599)
Fixed it...

Can you update with how you fixed it?


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