| Electronics > Repair |
| Agilent 53132A Counter Repair (FIXED and Upgraded) |
| << < (4/29) > >> |
| HighVoltage:
OK, the PCB is cleaned with alcohol and stayed in an oven for 1 hour at 50°C to get the rest of the alcohol evaporated. |
| EPTech:
Really that corroded! Makes you wonder from what environment it came out of. :o I do not want to discourage you but there may be more going on than some bad caps. Be sure to post the pics after that clean-up. |
| HighVoltage:
Yes, it must have been awful in that environment for this unit. I am actually surprised how some people treat expensive test equipment badly. This was not the first instrument I bought used that was full of sticky and corrosive dirt. All the sticky stuff is removed from the PCB and it looks really good now. Here are some more PCB detail pictures. |
| HighVoltage:
PSU is cleaned up with alcohol and was also one hour in the oven at 50°C From the first look the caps seem alright (not domed out). Time to take some measurements. |
| HighVoltage:
Voltage output was all zero on all wires at the output connector. So, I started probing at the input of the PSU. The fix was so easy.... Probing the voltages right after the input rectifier revealed open R2. R2 is a 15K Ohm 5 Watt power resistor. Replacing it gave about 101V across the resistor. That is just 0.66 Watt power and far lower than the 5 Watt rated power of the resistor. It probably died from too much heat because of all the dirt in the PSU. I will check the caps anyways of ESR, but I don't think they are bad. They are all Nichicon 105 degree rated caps. Actually looking closer at the PSU, it seems to be good quality built. Now, without connecting the PSU to the Agilent PCB, I am getting these output voltages: + 5V = 5.19V + 12V = 12.08 V -12 V = -11.88 V - 9 V = -9.16 V (with separate 9V ground) Next: Install the PSU in to the 53132A without fan, since I don't have a fitting new one. |
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