Sound Skulptor forums

Build help and troubleshooting => 501 Single Host => Topic started by: Ralph on August 28, 2022, 07:41:56 PM

Title: Switcher is not working as expected
Post by: Ralph on August 28, 2022, 07:41:56 PM

Hi
I have just soldered the Switcher and tested it and made a little error shorcircuiting +19v to ground very briefly with my DVM probe and was afraid that i have ruined the circuit.
I have made following tests with a ordinary laboratory linear PSU and a Electronic load to test the performance

Input voltage 12V
Current
10mA    +19,1V   -19,01V
50mA    +18,9V   -18,5V
100mA  +18,8V   -16,6V

I wonder why the negative voltage is not able to deliver more than a few mA.
Normally a SMPSU is much more robust, so maybe I have burned a component even though I just think I emptied the capacitors, but everything looks good.

Any suggestions would be appreciated

Title: Re: Switcher is not working as expected
Post by: JPK on August 29, 2022, 08:07:06 AM

I would try to replace D3 (SB160).

Title: Re: Switcher is not working as expected
Post by: Ralph on August 30, 2022, 10:16:09 AM

It seems that i was making a measuring mistake, because i just measured each rail separately and the switcher is only using feedback from the positive rail. When I take both rails and put some load on it just works fine. I have not worked with switch mode power supplies before and was a little puzzled about what to expect.
Thanks for help.