Im trying to fix my sons MXR Dyna Comp. It has a green PCB but I'm not sure about the year. 05-16-01 printed on PCB, so maybe 2001??
I found a schematic on electrosmash.com but Im not sure its the correct one for my pcb (see below )
I only have a bodgers knowledge of electronics, just enough to be dangerous to myself
The (470k) sensitivity pot was dodgy so i removed it, took it apart, cleaned the wipers, tested resistance and put it back together.
I've re-soldered the pot but the box doesnt work at all any more. Bypass works fine, guitar feeds into amp, but when I push the button the LED on but no sound output. The problem occurrs with battery and transformer (seperately).
Cables to amp and guiar are correct input/outputlights.
I unsoldered the pot again to check the board, when I put an ohmmeter on the top pin where the pot should be (it is marked tp1) I cannot get continuity anywhere else on the board.
The scheamtic shows the pot connecting to R17 and Q5.
R17 = continuity good to the middle and lower pin of the pot (which are bridged on the PCB).
Q5 = open circuit on all legs to the upper pin of the pot (tp1) -but I dont see a broken trace.
Is Q5 the correct transistor for the other side of the pot for all schematic versions of the mxr dyna comp? (or mine?)
If it is, then I can just run a jumper wire. I recon I might have messed up a trace when I de-soldered the pot originally. If not, if someone can tell me where the pot trace leads to it would be much appreciated.
any help appreciated:
many thanks
I found a schematic on electrosmash.com but Im not sure its the correct one for my pcb (see below )
I only have a bodgers knowledge of electronics, just enough to be dangerous to myself
The (470k) sensitivity pot was dodgy so i removed it, took it apart, cleaned the wipers, tested resistance and put it back together.
I've re-soldered the pot but the box doesnt work at all any more. Bypass works fine, guitar feeds into amp, but when I push the button the LED on but no sound output. The problem occurrs with battery and transformer (seperately).
Cables to amp and guiar are correct input/outputlights.
I unsoldered the pot again to check the board, when I put an ohmmeter on the top pin where the pot should be (it is marked tp1) I cannot get continuity anywhere else on the board.
The scheamtic shows the pot connecting to R17 and Q5.
R17 = continuity good to the middle and lower pin of the pot (which are bridged on the PCB).
Q5 = open circuit on all legs to the upper pin of the pot (tp1) -but I dont see a broken trace.
Is Q5 the correct transistor for the other side of the pot for all schematic versions of the mxr dyna comp? (or mine?)
If it is, then I can just run a jumper wire. I recon I might have messed up a trace when I de-soldered the pot originally. If not, if someone can tell me where the pot trace leads to it would be much appreciated.
any help appreciated:
many thanks
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