Musical Fidelity B1

[dynoPort]

The transistors' cases give no ohmic reading exept the two nearest the R68 which are 60kohm to the others but those two are 0ohms to each other?

 

[jez]

Sorry but have given considerable amount of advise already and I'm guessing that you don't have much experience of this sort of work..... i can't talk you through every possible reading on every possible component.
Last bit of advise..... try lifting one end of R61 and R62 (both 4R7). If everything stays cold now then that proves that the output stage and psu are ok.

 

[dynoPort]

Thanks for all your help R58 went red hot when I did the above, I agree this is a bit beond my experience!

 

[mjf]

hello.
is it only one channel that burns the resistors?
can you measure the res around the drivers and predrivers,with a multimeter?
greets

 

[dynoPort]

hello.
is it only one channel that burns the resistors?
can you measure the res around the drivers and predrivers,with a multimeter?
greets

not sure what predrivers are? I'm going to order new BD140 BD139 x2 see if that works!

 

[mjf]

........i mean the small transistors (bc184/bc214) connected with the driver trans. bd137/138..........
yes,my guess is that one of these is bad.
greets

 

[studyaudio]

Hi all,
I am using the MF B1 but recently, I have found that the capacity C18(220uf ) was so hot even more than the 2N3055.I have replaced new Zener ZD3 but the problem is not solved.
I am appreciating anyone who help me solve the problem.
Regards,

 

[luciano63]

not sure what predrivers are? I'm going to order new BD140 BD139 x2 see if that works!

I know this thread is a bit old but I ask:
did you then solve the problem of r68 smoking?