Rangemaster debug,battery V on all 3 transistor leads!

Started by momo, April 12, 2008, 08:59:33 PM

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momo

Oh boy, im close to finishing my rangemaster....its on pcb and I checked for shorts and can't find any. I have to say, I like perf jobs more than pcb!...you would think that pcb would have more sucsess the first time but for me, all my perf boards work right away! :icon_rolleyes:

Anyways, im getting battery voltage on all 3 tranny leads, and I know the tranny is good as I tested on another identical pcb that works. Im sure its simple, but I triple checked the wiring, everything is where it should be. Its embarasing frankly, a Rangemaster is pretty simple to do, pretty simple to muck up I guess.
Here is a shot of how I installed the trimpot...which has no effect at all!



"Alas to those who die with their song still in them."

momo

OK, I just noticed something, now since the trimpot is used as a variable resistor, lug 2 is joined to lug 3, thats fine so far, but the leads going to the board are lugs 1 and 2 instead of 1 and 3.....but I don't get it, if 2 and 3 are joined together, it should make no difference if its 1 and 3 or 1 and 2?
Maybe thats it, I would like to know because changing it would be some major work with this tight setup.
thanks
"Alas to those who die with their song still in them."

zachomega

Have you installed the transistor yet?

The trimpot is used to replace which resistor? 

-Zach

momo

Its not in the pic but it was there, im using a 100kb pot to bias/replaces the 68k
"Alas to those who die with their song still in them."

zachomega

Make sure one end of that pot is grounded.  Also, make sure the emitter resistor is grounded correctly as well. 

-Zach