And away we go..

Since the tach reader is cheap, that's probably not a bad plan.

If wiring to 7 pin all good.  Replace reader.

George, have you ever repaired the 5V board tach input?  Is it possible?

GGG posted:

If wiring to 7 pin all good.  Replace reader.

 

 Can you send me one with about 6"of wire leads? my soldering skills... well to put it bluntly "suck".

Still have my address.?

Send me an email, do need the spacer thickness if it has one .

John have not seen a 5v with speed issues not fixed by tach reader. G

I've never had a board failure in that area either, just figured you'd probably seen more of the boards and had a broader experience base.  It's interesting that the 3V boards do have a board failure that affects the speed control.

Different design.  Far more 5V failures un-repairable.  As far as Power Supply boards for 3V they are highly repairable.  Unless left powered on an torch the PCB.  Processor too, but it seems the traces and individual segments of the processor chip can be damaged.  What is interesting is I have never seen the 5V regulator damaged on a 3V board.  It seems to protect itself, only 2 3.3V power supplies that have been bad. So overall pretty robust and repairable.  G

Certainly the 3V boards are far more repairable than the 5V, no argument there.  It's a shame that several of the components are obsolete and you can't get them.