Badcaps Forums - View Single Post - ESR 0.6Ω capacitance -15% absolute must change?

caprider · 05-04-2022, 01:37 PM

I have one (of 3) hot swap Supermicro/Ablecom PWS-0050 SP382-TS server PSU that is mal functioning. Supermicro IPMI reports it as bad and led is orange on.

I took it apart tested transistors, diodes, capacitor but haven't found the problem. I'm a beginner.

In standby I have 5VSB, but not 12VSB, nor 3.3VSB. Here is the PSU Pinot: https://www.rcgroups.com/forums/show...Supply-Convert

There are 3 x 400V, 100uF capacitors on the primary side.

They measure:

- capacitance 85-86 uF
- ESR around 0.55 - 0.65 Ω (I've subtracted 0.15Ω that I measure when I connect my leads together)

I know it's a good practice to change them. But could this explain the whole problem? Or these are workables ranges?

Based on the physical dimension, the 3 caps are a bit expensive if not ordered from China. That's why I'm avoiding to quickly change them.

What do you think?

05-04-2022, 01:37 PM	#1
caprider Member Join Date: Jan 2022 City & State: Cluj-Napoca My Country: Romania Line Voltage: 234.6V 50.0Hz right now I'm a: Knowledge Seeker Posts: 24	ESR 0.6Ω capacitance -15% absolute must change? I have one (of 3) hot swap Supermicro/Ablecom PWS-0050 SP382-TS server PSU that is mal functioning. Supermicro IPMI reports it as bad and led is orange on. I took it apart tested transistors, diodes, capacitor but haven't found the problem. I'm a beginner. In standby I have 5VSB, but not 12VSB, nor 3.3VSB. Here is the PSU Pinot: https://www.rcgroups.com/forums/show...Supply-Convert There are 3 x 400V, 100uF capacitors on the primary side. They measure: - capacitance 85-86 uF - ESR around 0.55 - 0.65 Ω (I've subtracted 0.15Ω that I measure when I connect my leads together) I know it's a good practice to change them. But could this explain the whole problem? Or these are workables ranges? Based on the physical dimension, the 3 caps are a bit expensive if not ordered from China. That's why I'm avoiding to quickly change them. What do you think?