Powertech MP-3087 (Jaycar special) dual tracking repair

[w0lfie]

Hi all,

I bought a Powertech MP-3087 dual PSU from Jaycar many years ago (before I knew better) and it has been running largely well enough. One issue I've noticed is the voltage tracking in series mode is pretty bad. Sometimes it's pretty close (20-40mV) and sometimes the left PSU is 1-2+ volts off. I've confirmed with a meter that the outputs actually are wrong and not just being displayed as such.

I've searched around trying to find any schematics or a service manual but haven't found anything. Before I go down the rabbit hole of doing that myself, I wanted to check with the wider EEVBlog community whether anyone else has done this before me, even partially?

Does anyone have an inclination of what could cause the issue to happen or where it may reside? Any advice here would be really helpful

I'm happy to provide more information, just let me know what would be helpful.