Regulated Split Rail Supply Sagging

Puffin

Member
2006-02-19 8:15 am
U.K
I have built a regulated split rail supply 24+ Ov 24- to power an old Exposure Pre Amp. This is dual mono with a board for both channels. The boards are marked DC input 24vdc for a split rail supply. The boards also have an LM317 and 337 after the DC input.

The pos rail of the PS is drooping to around 10v and the negative rail to around 2 volts. I did make a supply for this years ago and from memory it was an unregulated supply and it worked fine. Any ideas anyone?
 
I have built a regulated split rail supply 24+ Ov 24- to power an old Exposure Pre Amp. This is dual mono with a board for both channels. The boards are marked DC input 24vdc for a split rail supply. The boards also have an LM317 and 337 after the DC input.

The pos rail of the PS is drooping to around 10v and the negative rail to around 2 volts. I did make a supply for this years ago and from memory it was an unregulated supply and it worked fine. Any ideas anyone?

One immediate thing you can check is whether the input to those regulators also sag. Diagnose.

Jan
 

Puffin

Member
2006-02-19 8:15 am
U.K
Ok, some pics and a part schematic. This is all there is on the sellers page. This was an ebay buy at not much money. I tested everything after I had built it with a DBTester and it was good. When I put the full fat mains through it it blew one of the rectification IN4007 diodes. I replaced the diode, but it didn't want to work, so I bypassed the on-board regulation with a bridge rectifier (seen in the pic) it tested all ok at +/- 24v.

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This is a pic of one of the pre-amp boards.

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