Author Topic: Fluke 732A Power supply issue (Read 1161 times)

Louis_C · « **on:** February 07, 2023, 07:07:05 pm »

I have a Fluke 732A that I am repairing and I have a strange issue with the AC power supply. On the A4 board, test point 1 to test point 1 on the back plane board, I get 18.65v DC solid and steady (on battery, the batteries are new). When I switch to AC, I get 18.65v but, it will cycle down to 15.5v every 3 seconds. I can NOT get the cal light to come on, it just comes on for one second and goes out. I replaced ALL transistors on the A3 and A4 boards as well as the electrolytic caps and the rectifier. I still get the swinging voltage. Any ideas?

Simon · « **Reply #1 on:** February 07, 2023, 08:16:45 pm »

I have reduced your triple post down to this one. Please try to keep it this way, you will quikly discover that people don't like replying to the same thing twice.

Okertime · « **Reply #2 on:** February 07, 2023, 08:46:39 pm »

Does the position of the power-line switches S1 and S2 on the pre-regulator board A3 match your power-line voltage?

Louis_C · « **Reply #3 on:** February 07, 2023, 09:44:00 pm »

Sorry for the multiple posts. I'm still learning the webpage layout, I don't blog but, I need help. Anyway, yes I have the switched set to 120volt AC. I have the service manual and checked that first. It's a strange issue and I NEED this unit up so I can cal our 5700A that I repaired. It's one problem after another it seems.