Yves,?
?
Thanks, I wanted to do the measurements, took the coverplate off because I figured that was needed to reach the testpoints.
While removing the coverplate I figured I might aswell have a look at the board. Doing that didn't make me very happy.
?
In at least 3 spots somebody has been tinkering with this board, can't imagine HP shipping it with these resistor "fixes"
?
Close ups (right lower corner)
Looks like someone tried to replace R25 and R26 with one resistor
?
That would connect 2 gain control lines together:? (This is from the 8590A clip but the PCB layouts look equivalent)
?
middle two:
R101 and R93, both 5.62k¦¸are replaced with a a 4.7k¦¸. The 5.62k is different from the CLIP value anyway, might be the A vs E version.
?
Those are in the Vlin voltage line to the 6th and 7th gain stage.
?
It looks like all original resistors are still present. I'll check the original resistors, if they measure according to the colorcodes I'll restore the board back to original.?
Afterwards i'll do the measurements.?
?
Marco
