On Sat, 29 Jul 2017 16:02:34 -0400, "tom"
wrote:

Dave,

The "large transistors" are TOP223Y off line switching regulator ICs. Google
the part number for the datasheet and reference design.


Would you think one of those component testers would be able to
identify the PWM reg, at least with a go/no-go result?

From testing around there were no shorts around the devices but that
doesn't stop them being OC or just non-functional?

Cheers, T i m