2N4119.
A bit more investigation this morning.
I have on error 10 ?A10U6 and A10U5 Pin 13 the correct 10 Volts, the drivers U16... are ok.
The inputs are correct as listed in the manual.?
On A10U5 PIN14 I see 8 Volts, should be -24 Volts,?
May be its an error in the manual?
If I open Q21, which is connected to PIN 14, then error 8 and 5 comes up, as expected.
Connecting shortly PIn 14 of A10U5 to -24V clears ?the error 10.?
Hmm very strange.?
I tested Q4 and Q19, they are ok with multimeter, as JFets can be tested with a simple multimeter.
However, I am waiting now for the 2N4119 and will replace them. This are the only involved cal switches mentioned in the flowchart.
Ralf
Ralf Rosche