No rpm with 7pin hei board mods?

Vili · Post by **Vili** » Wed Aug 16, 2006 11:03 pm

Hi
I have vr sensor and 2 triggers on crankshaft damper. Rpm is displayed on megatune if I remove these mods (but MS spark control doesn't work) :

.Remove D5,D8,R10
.Remove jumper between XG1-XG2
.Fit wire between XG1 and right of D5 (non band)
.Fit wire between bottom of R10 and small hole above D9 (this is a +5v source - you could also use the hole to the left of D4)
.Fit 1.3k resistor in place of D8 (1k-2k ok)

When I reinstall mods, rpm is 0 all the time. I troubleshooted yesterday and outcome of that was MS doesn't work at all anymore. Possibly a short circuit occurred. New processor etc should help...
But can anyone help me what to do with the HEI-install after the board is working again?

Post by **jsmcortina** » Thu Aug 17, 2006 2:18 am

Did you remove the original jumpers first? The HEI7 mods are known to work so there must be a wiring error somewhere.

James

Vili · Post by **Vili** » Thu Aug 17, 2006 2:57 am

I've got a V2.2 board. XG1 and XG2 aren't connected. What jumpers do you mean?
Thanks for helping.

Vili · Post by **Vili** » Wed Aug 23, 2006 5:30 am

Now I did the following wiring, and I've got RPM displayed again. I didn't find out what is wrong on my board after scoping the circuit for 2 evenings. But could this solution work also for ignition triggering?

Post by **jsmcortina** » Wed Aug 23, 2006 5:43 am

That will give an inverted input. I'd have thought if you figured that out then you'd be able to debug the original board?
What we are trying to achieve with the "HEI7" mod is same/similar as "alternative to schematic 2" over half way down:

http://megasquirt.sourceforge.net/extra/setup-msns.html

James

Vili · Post by **Vili** » Wed Aug 23, 2006 10:58 pm

Will this give a non-inverted input / does MSnS work only if input is not inverted?

Post by **jsmcortina** » Thu Aug 24, 2006 4:23 am

Just use the standard circuit.

James