Tacho

[sozfingers]

Ray doesn't include the diode board required to make the tacho work on a series two, easier to solder in when the loom is out?I noticed the connector block to the back of my tacho has two white wires, and one green, the green goes to the no 7 fuse, so is live, one white wire goes to the other spade, not sure yet whether it goes back to the neg side of the original coil, the other white seems to have no place there as there are only two spades?Speedy cables tell me to put a separate live to where the green one went, which I have done, and connect the yellow wire they have introduced with their upgrade to the edis coil pack which I have done ( although I cannot understand why I cannot use the original white wire from the original neg terminal to do this job). I haven't tried to start the engine yet as what puzzles me is that Speedy cables told me in their instructions to connect the TWO original wires together and forget about them. As there are three wires, and Speedy cables don't manage to get anyone to ring me back, wondering if there is any advice out there?as you may gather, electrics are not my strongpoint..

[christopher storey]

I think you will find that the connector block contains the inductive loop of white wire within it. Thus what looks like two white wires is in fact a continuous loop of a single white wire, one end going to the ignition switch, and the other to the switch terminal on the coil in the original setup

[chrisvine]

I contacted Ray about the compatibility of the EDIS kits with the S2 tachometers and he wasn't aware of a problem with the RVI type.

My understanding is that the RVI tachometers work by sensing the charging cycles of the coil via the induction loop Christopher has pointed out. I think the green supply powers circuitry detecting and amplifying the signal from the loop to drive the needle.

One side of the induction loop is connected to the supply (fuse 7) and the other side to power the coil. Ray's kit uses the white wire connected to the coil to power the coil pack, therefore the working of the tachometer should not be impacted.

Some additional info:

http://www.autosportlabs.net/MJLJ_V4_ve ... tion_guide

[sozfingers]

Autosports lab sold me their "amplifier" which I have soldered in to the coilpack feeds as Ray suggested,There is no supply now to the original white wire to the plus side of the old coil, so I need to link the green with one or both of the whites that go into the jackplug?I will see which white gives me a live at the coil end rather than connect all three together?might have been coincidence the tach failed after fitting the edis, but as it has been running fine for 46 years, I doubt it, it could be that S.Cables have built in an amplifier when doing the recon on my unit, I told them I was upgrading to electronic, but their instructions came back saying "fit yellow wire to neg terminal on the coil." As the coil has been replaced with a coil pack, this is where i have soldered the amp?but, it is just this note about connecting the wires together has thrown me, as they state "two wires" where they are three. I am going to connect the green to the white wire which goes to no 7 fuse, if I get ignition, I will use the white wire which connected to the neg, which has become redundant?? to carry signal back the the tach rather than feed a new wire through...

[christopher storey]

The green wire and the white wire have completely different, and totally separated, functions . The green wire provides the motive power for the moving coil apparatus which drives the needle and ( possibly - I cannot now remember the exact circuitry even though I have rebuilt mine twice ! ) the electrical power to amplify the signal from the sensor. The white wire has NO electrical connection as such with the tacho itself - it merely goes through - but is not connected to - the inductive sensor in 2 loops , pulsing with current ( on the original setup ) each time the points open and close. The sensor " counts" those fluctuations in the electrical supply to the coil in rather the same way that a current flows in the HT winding of the coil when the Low tension winding current is interrupted by the operation of the points. Thus the white wire and green wire cannot be connected together . Not having experience of EDIS, I'm sorry that i cannot make any positive suggestion as to how to overcome this problem

[sozfingers]

Thanks for that Christopher but my Haynes shows the white wire coming from the feed side of the no.7 fuse, then to the tacho, then on to the + side of the coil,I am going to assume this carries current to the coil, so will link it to the other white wire which should earth out and give me the warning light and power for the Edis?will report back if smoke occurs, my diagram shows an inline fuse between the no.7 feed and the "control switch" on this circuit, I have never spotted this before, any idea of its' location ??

[sozfingers]

All ok, can't believe that I am the only one to go down this route though.The two white wires get linked together, and the green which fed the tach originally, is used again on the single spade left there by Speedy cables. This gives the feed back to the coils via the feed from no. 7. Engine fired instantly and the tach is spot on stable, so, just got to put everything back together now, by the way, Uryks rear brake set up is so good, the handbrake resists the discs turning even on partial setting without being overcome by torquing the hub nut up to 140 foot pounds?pretty good..