| Products > Test Equipment |
| FLUKE 189 DC reading problem [with video] |
| << < (8/9) > >> |
| windsmurf:
It really doesn't look like its anything in the digital electronics. I still suspect something around the dial, as Joe mentioned, and possibly something in the input. You might try swapping out the PTC to make sure it isn't having strange intermittent issues.... swap out with resistor temporarily if you don't have a spare. |
| CDaniel:
Current input should be completely independent from V/ohm/cap and has no protection ... so it's not the input PTC , MOV and so on , as I thougth myself initially I asked before if the analog voltages are ok , besides the precision reference that ASIC should have dual power supply for the analog internal Op Amps . Inside is the ADC and the True rms converter . Other Fluke multimeters have those as external IC's , much easier to troubleshoot even without the schematic. |
| IconicPCB:
In post number nine on the first page of this topic a photo shows some MOVs. I need to identify and source a MOV from the manufacturer of the RED MOV. Please advise the name of the manufacturer if known. |
| BigB_52:
Hi, I have a Fluke 189 which was in storage for a long time with batteries in, when I took it out the battery was corroded, I cleaned the battery cartridge, placed new batteries and turned it on the meter was running for itself without measuring anything, probs were in the air and no matter where the selector switch was. I opened the meter to inspect inside found nothing wrong, no battery liquid leaked and it was supper clean, I changed the supper cap, nothing changed in the result, I sent it for calibration they reported “the meter can not register calibration constants. I tested the eprom 93c56 that holds the calibration constants, it is fine,I can read from and write to it with no problem with an external eprom programmer. Since it came back from calibration facility, the UNCAL mark is on the screen All the time, and the mere shows 0000 in all conditions, even when I activate calibration mode the measurement is zero, the measurement does not follow the input to match the required voltage calibration menu, Any one has any thought in that? Thanks BM |
| EyeDontKnow:
What was the final diagnosis or fix ? I have the same symptoms on my 189......nearly exact readings as the OP. Problem may have started when I "zapped" the leads when measuring +18vdc. But maybe not. *The REF43 test as working. *Pulled MOVs, they tested fine. Without the MOVs (empty) the meter has the same problem as before, no change. *PTC thermistor tested good as well (1k). *PTC and blue MOVs replaced with new, because I had already ordered them. *Red MOV tested fine but not replaced because I have yet to find a replacement part #. (??) *Two resistors adjacent to MOVs test good, in circuit. *String of input resistors (1.5 Meg (x6)) test ok. *Large power resistors near MOVs test good, in circuit. What to do ? I rely on this meter !! |
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