Electronics > Repair
Fluke 289 not quite sorted.
ElecSeb:
This means the green light from the power button is "ON"?
And concerning SCOPE -> I will measure, but I do not have a working unit.
Samogon:
OL on open corcuit is ok.
nixxon:
--- Quote from: Samogon on October 22, 2018, 07:57:40 am ---OL on open corcuit is ok.
--- End quote ---
The meter never displays "OL" in resistance measuring mode. After selecting resistance mode on the rotary switch the DMM displays 25 Mohms initially wile open circuit. If I measure anything with a resistance lower than 3.7 Mohm, the open circuit resistance is displayed as ~3.7 Mohm.
The DMM is latched to ~3.7 Mohm max. (while open circuit) until the rotary switch is rotated to some other mode and then back to resistance mode. Then the DMM indicates 25 Mohm again open circuit.
ElecSeb: Yes, the power button shows a green light for a few seconds while the DMM is booting. Just like a fully functional 287/289.
nixxon:
Today I was troubleshooting the Y1 crystal with the low amplitude signal, still 200mVpp. The input position sensors were however acting up again, beeping all the time. I managed to silence the beeps if I put a piece of paper or a piece of tape along the optical path. It is almost like the transmitter in the middle was transmitting at a wrong angle and that the piece of paper reflected the IR light back onto the receivers.
[EDIT: This makes sense because when the top cover is separated fromt the PCB, the optical path from DS2 to both Q24 (A jack sensor) and Q27 (mA/uA sensor) is removed]
The Y1 frequency was all over the place, varying between 32.667 and 32.720 kHz (using short gate time on the frequency counter due to significant frequency variations)
The Y2 crystal was pretty steady and varied only between 32.7660 and 32.7661 kHz (longer gate time possible with the stable frequency).
The green light is not lighting up any more during booting, and there is no relay clicking during the boot. (Normally there is a relay click as the green light turns on, and another click as the green light turns off)
[EDIT: It seems that the green diode has failed as it measures 1.9 ohms both ways.]
In other words, there were quite a few setbacks today. :(
ElecSeb:
Well, start with "off-state" and measure all V on the defined testpoint +-33 TP.
My fluke 289 is turning the greenled on for a short moment, then turns-off, but no screen.
Also no power from the torex PWM IC.
But unfortunately I do not have a lot of time during the day to test mine. I will try this afternoon.
I have created a XLS with all TP and reference values found in this thread (ON & OFF).
Furthermore I have created a second tab with all components I have identified so far. On mine I have tested all SOT32 elements (which are all OK).
I need to add this test data to this XLS before upload.
And last I have added a link to the specific component (I do not guarantee it is 100% correct, but I think it will come close, but any addition later on will be great!).
Only thing I am missing at the moment is a comprehensive TP layout. IN earlier posts some mention TP which are unknown to me (cannot find them visueally and in Calibration manual they are also not mentioned).
Hope to add this info to this topic soon.
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