petehall347
the brandy coffee man
check voltages at r765 .
i am suspecting you burned a trace on the board .
if its low there check j721 voltage
i am suspecting you burned a trace on the board .
if its low there check j721 voltage
Well shoot, I finally did it.
- Thread starter ringading
- Start date
ringading
Well-Known Member
Been awhile since I worked on this. I am checking the resistors. Came across an oddity. R743. SM calls for 820ohm but the resistor on the board is only 84ohm. Not sure how to proceed. I will probably replace it with another 84ohm resistor but is this common for the values to be so far off between the SM and the actual board?
petehall347
the brandy coffee man
yes the manuals are often different to the board .
ringading
Well-Known Member
Thanks petehall. Yeah, there seems to be quite a few mistakes once you start going through them.
I am slowly going through the board checking the resistors and no culprits found yet after going through the right channel side.
How would I check voltage at r765? Measure each side to ground separately?
Checked J721 to ground and I get -31V DC.
I wanted to check the relay as well to make sure it isn't fried - if it is then all of this other hunting is in vain huh? Trying to refresh my memory on how to do that - I believe I would measure resistance across the top somewhere? I will work on getting the cover off first. Not sure if there is a direct replacement for this one - Omron LC2-C-M, at least from what I can find in the forums like this.
I am slowly going through the board checking the resistors and no culprits found yet after going through the right channel side.
How would I check voltage at r765? Measure each side to ground separately?
Checked J721 to ground and I get -31V DC.
I wanted to check the relay as well to make sure it isn't fried - if it is then all of this other hunting is in vain huh? Trying to refresh my memory on how to do that - I believe I would measure resistance across the top somewhere? I will work on getting the cover off first. Not sure if there is a direct replacement for this one - Omron LC2-C-M, at least from what I can find in the forums like this.
petehall347
the brandy coffee man
yes measure each end . -30v one end .other end a volt or 2 less .
petehall347
the brandy coffee man
r765 is bad or something is drawing too much current through it .
will have a look at schematic later .
will have a look at schematic later .
petehall347
the brandy coffee man
something is overloading it ..think of r765 as a fuse .
test h707 first . and h708
test h707 first . and h708
