Speedo started miss reading (Fixed now, faulty capacitor)

[mrfil13]

I have a rev2 turbo in MPH, the speedo was always pretty much accurate, recently noticed that its under reading massively now. The oedometer and tacho is correct so i presume the the speed sensor etc is ok?

Are there any electronics on the speed cluster that could need replacing? Or is it possible for the needle to recalibrating?

[platmatt8]

I would definatly check the gear box speed sender first.

[mrfil13]

Thats what i thought at first but the oedometer is spot on so the speedo cluster must be getting the correct signal.

Seems on the US forums they have found faulty capacitors on the back of the speedo to be causing low readings so i might take that out on the weekend and take a look.

[mrfil13]

Speedo working spot on now, there are 3 Capacitors on the speedo, all 25v, the big one at the front is 100 Microfarad, the one on the end was 6.8, the one at the back is 2.2.

I replaced the 100 and 6.8 Microfarad cap's but it was the 6.8 that was faulty, you could see rust/leak were the board meets the pins, when i removed it you could see the leak at the bottom.

All of these i got from Maplins, they were the low profile caps, i could not get 25v ones so got higher, below are the codes from Maplins just incase.

KQ63 - 6.8uF 50v
KQ70 - 100uF 25v
KQ65 - 2.2uF 35v

If i was going to do it again i would have gotten something to help remove the solder, other than that it was an easy job.

Here's the faulty cap.



And here's the actual leaking capacitor.