Rectifier short - measure ohms from the bridge terminals to chassis floor. Hopefully there is no continuity.
And @ItsAllInMyHead is spot on.
Check fuses (both if your unit has 2 fuses)
Check PSU without an amp board
Check 1 channel, then disconnect
Check the other channel
Check both channels
And @ItsAllInMyHead is spot on.
Check fuses (both if your unit has 2 fuses)
Check PSU without an amp board
Check 1 channel, then disconnect
Check the other channel
Check both channels
You will need to get some 2.5 and 3.0A slow blow fuses.
If you're in the USA you can get a multipack slow blow fuse kit on Amazon that will serve your preamp, power amp, and other audio building needs for quite a while. And if one of the values runs low, top it up with your next Digikey/Mouser order.
I had a very similar experience with my build using the Thatcher PS. I used the Antek 3218 and with the variac I could get to full mains with a 2A fuse, but without the variac the immediate inrush would pop it. When I did the calc for the fuse, don’t have the formula off the top of my head, it wanted a 2A6 fuse. I popped in a 3A, been singing beautifully for months.
At the typical bias settings, each amp board is 1A4 Iq. 2A8 total current for a stereo pair.. 2A5 generally gets it done, but 3A has some margin.
Starting point for fuse size is based on a simple formula: Transformer VA / Mains Voltage. Examples:
300VA / 120V = 2.5A
400VA / 120V = 3.33A
300VA / 230V = 1.3A
400VA / 230V = 1.74A
Try the closest standard fuse value. If it blows, go up one size.
300VA / 120V = 2.5A
400VA / 120V = 3.33A
300VA / 230V = 1.3A
400VA / 230V = 1.74A
Try the closest standard fuse value. If it blows, go up one size.
Fuse A= Donut VA/ mains V
so, if 300VA/230V, it is 1A3
then choose first bigger standard value, so T1A6
T means Träge, Vaterland word for Slow Blow
depending of nature of soft start installed , if it blows often, go to first bigger value, so T2A
