View Single Post
Old Jun 2nd, 2009, 09:58   #9
asneddon
Master Member
 

Last Online: Nov 30th, 2021 00:46
Join Date: Jan 2009
Location: Dunedin
Default

I've been hacking away on the rev counter every now and again for the last couple of weeks. I ended up getting a later model (3rd Gen) rev counter (Wooden dash type) and the innards are all mounted on the same casting as the gen 1 and gen 2 rev counters.

I tried to get the face off the gen 3 and I was going to stick the face from the gen 1 I have, but I couldnt get it off without breaking it. So next I pulled the electronics out of the gen3, de-soldereing the two leads to the needle movement.

First idea was to run two cables from the gen3 guts to the two spade connectors on the gen1. This didnt work. I then dissconnected the coil thats inside the gen1 in series with the spade connectors and tried again (See last photo on post #6) . No luck. I'm not sure why this didnt work. It would have been nice as then you could use gen3 guts as a replacement for early Jensen sender units.

Next I stuck the Gen3 guts into the Gen1 I have. and soldered the gen1 needle movement onto the output of the Gen3 electronics.

I then ran a new (white) cable from the coil into the cockpit via the hole where the temperature guage senders go, into the 'frankenstein' rev counter, and then back out via the main wiring loom by the battery. I can get movement from the guage, but it jumps around like a mad thing and doesnt seem very accurate at all!

At this stage I realised I probably should have checked the Gen3 rev counter first before buggering about like this! I have no idea if the guage worked before I pulled it apart! Damn.

Also, the Gen3 guage seemed to have the electronics insulated from earth. The whole inner casting was protected via a rubber gasket against the guage outer body, and was joined via rubber insulated bolts. I couldn't get any movement without supplying an earth though. I'm not sure how this would have worked in the car. The casing needs an earth for the dash lights to work. There is a +12V to the guage, and the two connectors for the coil-distributor cable. These will switch to earth via the points, but they never connect to the electronics in the guage. They are just wrapped around an inductive pickup. If the electronics never have a path to earth then I dont see how anything works.

So, anyone have a working rev counter, preferably a Gen2?
asneddon is offline   Reply With Quote