Hello all,
I recently picked up a non-working Mark Levinson ML-II amplifier that I am working to bring back to life. I started it up on the dim bulb tester and unfortunately there seems to be a short. Bright bulb.
I tested DC at the speakers and there was none. I tested power to the amplifier boards and there was very little, in the millivolts.
I then turned to the power supply and there seems to be my issue. Below is a screenshot of the power supply primary side circuit. I am getting full voltage from my AC mains but not at my primary connections. It seems there is a 4.7nf capacitor in that circuit that has gone bad, tests high ESR (Photo Below).
I'm wondering if this could cause my short... I'd like to replace this capacitor but I am wondering since it is on the mains side if I need a special capacitor... safety rated. I found the one below, would this work?
https://www.mouser.com/ProductDetail/KEMET/PHE450HA4470JR05?qs=PoZJcSwa6DyYJ6rxNB8hEQ==
Any help greatly appreciated, I want to be extra careful from a safety perspective on the mains side.
I recently picked up a non-working Mark Levinson ML-II amplifier that I am working to bring back to life. I started it up on the dim bulb tester and unfortunately there seems to be a short. Bright bulb.
I tested DC at the speakers and there was none. I tested power to the amplifier boards and there was very little, in the millivolts.
I then turned to the power supply and there seems to be my issue. Below is a screenshot of the power supply primary side circuit. I am getting full voltage from my AC mains but not at my primary connections. It seems there is a 4.7nf capacitor in that circuit that has gone bad, tests high ESR (Photo Below).
I'm wondering if this could cause my short... I'd like to replace this capacitor but I am wondering since it is on the mains side if I need a special capacitor... safety rated. I found the one below, would this work?
https://www.mouser.com/ProductDetail/KEMET/PHE450HA4470JR05?qs=PoZJcSwa6DyYJ6rxNB8hEQ==
Any help greatly appreciated, I want to be extra careful from a safety perspective on the mains side.
The cap link is ok.
Test cap with a multimeter for a short.
If cap is short then I would expect fuse to blow too.
Test cap with a multimeter for a short.
If cap is short then I would expect fuse to blow too.
Just checked, no short on the cap. There were no fuses when I opened it up... I've only had it on the dim bulb since then... Maybe two problems, power supply and something else. Hope it's not the transformer...
