When you power on all faders default to 0.
But bank 1 ( 1-8) of faders are all stuck down to 0 when you try and push them up they just slam back down to 0,
i have tried swapping the two faders banks around from 1-8 to 9-16 and the same fader bank does the same thing, the other works fine on both ribbons, so it is the fader bank.
when on if you look at to photo's faders 5 6 7 the middle leg of the top NPN 2n6039 darlington pair ( the other bottom one being a 2n6036 pnp )is getting hot in about 10 seconds after turning on, they seem to get hotter from 1 being warm to 7 very hot, you can see the dark areas on the middle leg of the top one but only every other one,
I have done checks on them all against the good bank and all seem fine,
I have checked all the caps these seem fine and all the grounds seem ok,
All the fader motors are ok same ohms on the coils and the fader tracks are all ok,
The legs with the burning on faders 5,6,7 are all at transistors Q2 leg 2 at the 12v input ( nothing to do with the pen scribble and arrow on the paper ignor that )
At a guess i would think the pair of transistors are just leaking the 12v straight to ground through q3 2n6036, there is no shorts here to any of the other legs so maybe something holding open the gate when powered up ?
So,...any ideas please before i strip them down and take them out to check ? ?
- IMG_0182.JPG (Array KiB) Viewed 1971 times
- IMG_0181.JPG (Array KiB) Viewed 1971 times
- IMG_0184.JPG (Array KiB) Viewed 1966 times
....Dowww, thanks again.
