Tom M'Guinn

Does anyone know the pin-outs for the DME FQS? The **** has always been loose on my spare DME (who knew it was even separate from the switch?), and I'm not 100% certain it is oriented on the post the correctly. When the **** comes off, the post it sits on will keep rotating through the positions without stopping at 0 or 7. The **** is keyed to the plastic post it sits on, but the plastic is old and in bad shape. For those old enough to remember TV *****, I'm trying to make sure the **** isn't pushed on such that it shows channel 7 even though the TV is really set to channel 5. The FQS appears to have 4 leads soldered to the DME board, and I'm hoping I can confirm which position the FQS is in by the continuity of the pins.

I realize it's a needle in a haystack, but it wouldn't be the most esoteric thing known to the assembled masses here...

mikeyoman

At first I assumed it was a binary switch with one pin common and the other 3 for 0-7.
However the circuit shows it to be 6 pins, 2 & 5 connected together and 3 & 4 connected together. May be why only 4 pins soldered to the pcb.
It's not going to be easy figuring out the correct position as it connects various resistors together to feed a total resistance (voltage) value to the multiplexer on the board.
I thnk the full circuit is available on the frwilk.com website

Sorry not much help really

Tom M'Guinn

It's some help. It confirms what I saw on frwilk's website. I would have assumed it acted like a dip switch, but apparently not if frwilk's schematic is accurate. I may just unplug the O2 sensor and see if I can figure it out based on how the AFR responds.

mikeyoman

given the circuit you could trace which resistor goes to what pin - how you would know which pin is which on the pcb not sure.
Believe the circuit diagram is an accurate bosch one ?
Good luck

blown 944

If you get ahold of Josh. His serial data logger will tell you right on screen what position it's in. Along with quite a few other sensors etc. I think ge's findlizibg knock and another input. But as of right now it logs many things.

It's a nice tool to have IMO.

Tom M'Guinn

Thanks for that suggestion -- sounds like a great tool. After careful study in the daylight, I was able to find the two flat sides of the post to get the **** keyed correctly. The end of the **** was mushrooming a tad making it difficult to confirm last night, but it was pretty clear in the bright light... Am still curious how it works though.

White_951

When's that thing gonna be available....

blown 944

You'd have to ask him. AFAIK it is sellable now without knock sensing. I think he wants to get the few extra options done so he doesn't have to do another release. I have used it for some time now and have found it to be valuable in many ways.

White_951

I saw your readouts last month...can't wait to try it out.....