Rev counter and mpg gauge not working

[Andyrb]

Noticed yesterday that my rev and mpg gauge stopped working, fuses seem ok, what else could cause this?
I have recently fitted a transponder to the coil, but removing this makes no difference.

Thanks in advance

[Brianmoooore]

Are the SI lights behaving as they should?
What's a transponder?

[Andyrb]

SI indicator is showing 1 green light so assume it's working ok. It's a race car so has a transponder fitted for timing reasons

[Brianmoooore]

The tacho. plugs into the main cluster circuit board. It's a fairly common fault for the equivalent pins on the speedo. to suffer from cracked joints where they are soldered to the speedo. circuit board, so I suppose it's conceivable that the same could happen to the pins on the tacho. board.
It's a good idea to swap fuses over with ones of a similar rating when you check them. A 'soft' blown fuse is not always obvious.
I suppose the transponder is "fitted to the coil" simply top pick up switched ignition live power? In no way connected to your problem, but that's not an ideal connection point - the supply here will be very 'dirty', with all sorts of noise and spikes on it. A far better place to connect would be to the purple wire from the ignition switch.

[Andyrb]

Thanks for the response, will double check the fuses. Point taken on the coil connection. An auto electrician i am not