BenQ GW2450HM - Panel is partially dimmed, works for 2 hours after replacing few caps
Issue: Panel is partially dark or dimmed, left side is okay (see photos attached).
Trial: Replaced three visibly bad capacitors on the power supply board (see photos).
First result: Monitor worked for two hours only. Two capacitors bulged again.
Diagnosis: After replacing those capacitors the monitor was connected via HDMI cable to a laptop. Laptop was connected to power supply and charging. Power cable was removed from the laptop end and put back. Maybe this was a coincidence but since unplugging the power cable it was noted that the panel had darkened again. Not sure if this happened at the exact same time or before disconnecting the power from the laptop.
The two replaced 680uF capacitors seem to be visibly bulged again when the replaced 470uF capacitor remains visibly ok. (Capacitor tester not available at the moment).
When powering up the monitor the panel will be "fully bright" for a fraction of a second (see photo).
On the logic board there are two 220uF 16V capacitors C605 and C606 which still could be replaced just in case (see photo).
Questions:
What are the possible reasons to cause the capacitor to bulge (generally and in this case)?
What could be measured in order to trace the failure?
Thanks in advance. I'm here to learn
Specifications:
Replacement capacitors from Hitano:
2 pieces: ELCO radial 680uF25V R.5mm 10x21mm, +105°C
Low ESR, RoHS
1 piece: ELCO radial 470uF25V R.5mm 10x16mm, +105°C
Low ESR, RoHS
Monitor:
Brand: BenQ
Model: GL2450-T
Type: GW2450HM
Manufacturing date: August 2012
Revision: 00-003-AA
Product number: 9H.L8RLA.TBE
Serial number: ET18C03468019
Trial: Replaced three visibly bad capacitors on the power supply board (see photos).
First result: Monitor worked for two hours only. Two capacitors bulged again.
Diagnosis: After replacing those capacitors the monitor was connected via HDMI cable to a laptop. Laptop was connected to power supply and charging. Power cable was removed from the laptop end and put back. Maybe this was a coincidence but since unplugging the power cable it was noted that the panel had darkened again. Not sure if this happened at the exact same time or before disconnecting the power from the laptop.
The two replaced 680uF capacitors seem to be visibly bulged again when the replaced 470uF capacitor remains visibly ok. (Capacitor tester not available at the moment).
When powering up the monitor the panel will be "fully bright" for a fraction of a second (see photo).
On the logic board there are two 220uF 16V capacitors C605 and C606 which still could be replaced just in case (see photo).
Questions:
What are the possible reasons to cause the capacitor to bulge (generally and in this case)?
What could be measured in order to trace the failure?
Thanks in advance. I'm here to learn
Specifications:
Replacement capacitors from Hitano:
2 pieces: ELCO radial 680uF25V R.5mm 10x21mm, +105°C
Low ESR, RoHS
1 piece: ELCO radial 470uF25V R.5mm 10x16mm, +105°C
Low ESR, RoHS
Monitor:
Brand: BenQ
Model: GL2450-T
Type: GW2450HM
Manufacturing date: August 2012
Revision: 00-003-AA
Product number: 9H.L8RLA.TBE
Serial number: ET18C03468019
Attached Files
O.k. then… unplug the power supply from the main board and put in a full size ATX PSU (yeeeesss! Exact that blown Powerman IP that I fixed a while back), plug it in and the old...
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