| Electronics > Repair |
| Fluke 8845A 6.5 digit Multimeter smoking transformer |
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| murta79:
Did some more measurements... Disconnected the 20V output from the transformer.. still goes above 95 degrees C after 5 minutes. Disconnected the VFD-display / external interface power supply connector.. still goes above 95 degrees C after 5 minutes. Disconnected the 12V output from the transformer.. still goes above 95 degrees C after 5 minutes. Disconnected all outputs from the transformer.. still goes above 95 degrees C after 5 minutes What could be causing this, short on the secondary side in the windings ? |
| factory:
Probably shorted turns on the winding that got overloaded by the shorted MLCC. I've got several vintage HP TE with transformers that have failed in similar ways, one had the primary winding burnt open (from a trapped wire). Some AC voltage measurements of the secondary windings might reveal if the output is lower than expected. No load voltages should be higher anyway, if another forum member with this DMM could help with normal reading that would be very helpful. ;) I'm assuming it's too new to have a detailed service manual? :-// Having said that, you definitely need a replacement transformer. David |
| Paceguy:
I would suggest that you change that bridge rectifier, and while it's out check the PCB area under it. |
| murta79:
@Paceguy I did de-solder the rectifier to get underneath and clean, at the same time I also checked that it was ok. Since the transformer gets to hot even though I have no load connected to it I fear that some windings have shorted and that I would need a new transformer to be able to use the instrument :( |
| murta79:
Begun the transformer "repair" has... |
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