| Electronics > Repair |
| Please help, FLUKE 8920A Multimeter Repair |
| << < (17/45) > >> |
| daisizhou:
Normally, I turn on the 8920a power supply and observe the digital tube or pointer to see if there is a flashing fault,If it is normal, I will press the "LOW RANGE ENABLE" button and observe again whether there is flickering. Do you mean to let me directly open the upper shielding cover and directly use the oscilloscope to measure the TP1 test point?If this is the case, how can I tell if the 8920a is working properly or malfunctioning? Because sometimes when the upper shielding shell is opened, the flashing fault disappears immediately. |
| Harry_22:
Hi! Let you do two additional connections on the PCB. Please see the scheme. Thus we add divider by 10 to reduce the signal from first OPA. I expect that "Low Range" mode will more stable and you will see 2MHz LED now. After modification please press "Low Range Enable" and measure the signal on TP1 by oscilloscope. |
| daisizhou:
Hi. Let me tell you good news. I tested today and the fault lasted for a long time. The fault phenomenon is that "700" continues to flash.I tested the voltage at the test point you need. Your latest connection, I haven't connected yet, if you need I will connect to test later In order to prevent mistakes, I took a video. The video quality is not very good. I hope you can forgive me.Thanks |
| Harry_22:
HI! I need your help. Below is a diagram from Microcap. In the ovals there is the correct voltage in rectangles under the voltages measured by you. It is necessary to supplement missed ones and check those already measured. Pay attention to very different values like at R27 and C24. Also measure the voltage at In+ and In- inputs. Please use a multimeter with mandatory monitoring by an oscilloscope 8.61V at the Out. |
| daisizhou:
ok .give me some time i will measure them. Before the measurement, I compared the voltage error values of my commonly used fluke 27 and TEK TDS2012C oscilloscope. If you need to get high precision voltage value, I would use fluke 8060a or 179C for measurement |
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