I have an Arcam Alpha mk1 with seemingly a faulty transformer. Two of the rectifier diodes D203 & D204 are shorting either way, if the transformer secondary wires are a removed from the pcb then they are as a diode should be. D203 & D204 are ok with the transformer connected. I have a new replacement transformer but I get the same shorts with that as well! Am I wiring it incorrectly? The original arcam one has orange blue orange but I'm not sure how the new Noratel one would match this?
chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://www.farnell.com/datasheets/90564.pdf
chrome-extension://oemmndcbldboiebfnladdacbdfmadadm/http://www.farnell.com/datasheets/90564.pdf
I doubt the transformer(s) are faulty.
Just measure the secondary volts with them isolated. DVM's can give incorrect readings where large values of C and or L are present.
If the voltage is OK then you have some shorts on the board somewhere.
Just measure the secondary volts with them isolated. DVM's can give incorrect readings where large values of C and or L are present.
If the voltage is OK then you have some shorts on the board somewhere.
Yes the voltages are ok. The main outputs on the left channel had gone and been replaced Tested all the other transistors.
Try using a bulb tester and power the amp up. You should get some clues from measured voltages as to where the problem lies and even whether there is a real issue or not.
Thee is also a short across C209.
If the screw connecting the heat-sink to the PCB is removed then the problem goes away. I just can't find the source of the fault!
If the screw connecting the heat-sink to the PCB is removed then the problem goes away. I just can't find the source of the fault!
C209 is across a rail. It is one of those things you need in front of you if the problem is physical and only occurs when its all screwed together.
Just make 100% certain you are not missing something more obvious like two or more diodes in the bridge being faulty. I can't really visualise it without seeing one tbh 🙂
Just make 100% certain you are not missing something more obvious like two or more diodes in the bridge being faulty. I can't really visualise it without seeing one tbh 🙂