Hardware Insights Forum

Hi,
I need a Leadman (POWMAX) LP6100 Schematic diagram . This PSU has the problem in primary section of both MJE13007 . After repairing the Primary section this PSU is running automatically when I attach power cord with it !!! It doesn't need to be switch !! I have checked the controller section - every diodes, transistors and PF's are OK , even I have changed the IC TL494 also but it is same result . When I was checking the controller section - I found that it is such kind of design that it doesn't need switching to power on !! Have you worked with Leadman (POWMAX) PSU guys ?? Are they run automatically without switching ??

Galib

Leadman/Powmax power supplies go straight in the garbage here, even if they are working, because they are motherboard killers at best, and fire hazardas at worst, so no one really has much experience working on them. Powmax means maximum POW!. In fact, many of their cheaper units are illegal here.

I can tell you, though, that it probably shouldn't run without being switched on. I'd check the resistance between the green PS-ON wire on the ATX connector and one of the black Ground wires. You can check out this as well (download/file.php?mode=view&id=119). It doesn't cover this specific PSU, but it does cover a typical TL494 design. I will stress again, though, that this PSU shouldn't be repaired, because it is VERY low quality.