Tachometer question

[txdmc]

So I'm in the process of doing some cleaning/updates to 10686. I removed the binnacle and replaced all the bulbs. I plugged my connectors back in just to test before I put it all back together. Everything works but my tach, all the grounds on the printed board are good, What am I missing? Just did a fuse/relay/breaker update.


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[Chris 16409]

I would recommend getting a new printed circuit board. It should eliminated the electrical gremlins. Ed Uding sells a great reproduction board. The originals boards are likely oxydized. Once you disturb the board, it can likely introduce gremlins. Happened to a friend.

[txdmc]

Thanks I will look into that. It's just frustrating that everything but the tach works. Also it seems to be stuck on 8000 rpm with no movement. I wouldn't need to move the needle back would I? I also have the entire center console out including radio and hvac controls. I did disconnect a ground point maybe that's it? Doubt it though.


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[sdg3205]

You can GENTLY clean the contact points and traces on your current board. I take it the tach worked before? Unless you see a tear in a trace, your old board is probably not a write off. Sand the pin connectors at the harness. Follow the traces for the tach and make sure they aren't broken (they can tear easily). Ensure the pin connector is making decent contact. You can coax out the relevant contacts on the connector if need be. Also, use a meter at the tach and see if it's actually getting signal. Not unheard of for the tach itself to die.

[Jonathan]

Thanks I will look into that. It's just frustrating that everything but the tach works. Also it seems to be stuck on 8000 rpm with no movement. I wouldn't need to move the needle back would I? I also have the entire center console out including radio and hvac controls. I did disconnect a ground point maybe that's it? Doubt it though.


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I would not underestimate the importance of the ground(s) you have disconnected at the moment with the centre console out. This may or may not have compromised the instrument cluster ground. I would get everything back together as designed and see if the tachometer is working or not before buying any replacement parts.

...have you started the engine by the way? I assume you have and it is running at some RPM that the gauge isn't showing and not just you hoping to see the gauge go to zero with the engine off and the electrical plugged back in. That gauge doesn't zero itself like some you think should.

[dn010]

I've always had the problem of the flat "pins" of the printed board connectors either bending off to the side or bending up and back away from the plastic when I'd disconnect the connector, so it wouldn't make a connection with the connector once reinstalled. Worth checking out before replacing.

[txdmc]

Well well mystery solved! When the tach was removed I didn't tighten one nut down tight and there was not a complete circuit. Everything is working as it should!

[dn010]

$0.00 is always great!


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