| Electronics > Repair |
| [SOLVED] HP 34401a - Error 612, 613, 615, 617, 618, 619, 621 |
| << < (16/22) > >> |
| ua4yhz:
The measurement of resistance and "cont)))" does not work. I checked your voltage map and all the voltages were approximately the same as yours. Those that are written in black squares. When the inputs are disabled, the readings slowly show increasing resistance. The reading stops at about 800 ohms over the entire range of the resistance measurement. |
| Dr. Frank:
--- Quote from: ua4yhz on August 15, 2020, 08:32:36 am ---The measurement of resistance and "cont)))" does not work. I checked your voltage map and all the voltages were approximately the same as yours. Those that are written in black squares. When the inputs are disabled, the readings slowly show increasing resistance. The reading stops at about 800 ohms over the entire range of the resistance measurement. --- End quote --- The faulty values are inside the black squares, my correct ones are the hand written values. That's a first indicator that this OpAmp U201 is defect, again. Maybe you can copy your own measurements inside this graph, also, but please apply a resistor and state, which measurement mode you're using. I do not understand what you mean with "inputs are disabled". Are you using 4W Ohm mode and simply leave the jacks open?? Please make measurements only in proper configuration. Uh yes, and of course all this has nothing to do with U101, up to now. Frank |
| ua4yhz:
I just leave the nests open. OK, thanks Frank. I will look for the u102 chip and change it. |
| Dr. Frank:
--- Quote from: ua4yhz on August 15, 2020, 09:37:42 am ---I just leave the nests open. OK, thanks Frank. I will look for the u102 chip and change it. --- End quote --- nests? If you use 4W Ohm and let the jacks open, then the sense lines will simply drift to a random bias voltage, so that's no correct modus operandi. Although U 201 (!) is a good guess,I would first make sure, that it really fails, by posting your voltages here. Frank |
| ua4yhz:
--- Quote from: Dr. Frank on August 15, 2020, 11:49:12 am --- --- Quote from: ua4yhz on August 15, 2020, 09:37:42 am ---I just leave the nests open. OK, thanks Frank. I will look for the u102 chip and change it. --- End quote --- nests? If you use 4W Ohm and let the jacks open, then the sense lines will simply drift to a random bias voltage, so that's no correct modus operandi. Although U 201 (!) is a good guess,I would first make sure, that it really fails, by posting your voltages here. Frank --- End quote --- I repaired the device today. Q201 and Q202 are broken. U201 does not seem to be working either. I will order these three items and then unsubscribe after replacing them. |
| Navigation |
| Message Index |
| Next page |
| Previous page |