Check all wiring one more time... it is easy to miss something. Look for shorts between FETs and heatsink, wires from pcb touching heatsink.
In my experience with amps, instant fuse blowing is likely a short in the AC power side; wiring, diodes, or a shorted transformer.
Any smoked components?
Try disconnecting all the boards from each other, and start adding them back in order, diode board, power supply board, then each channel. I would verify all components and wiring on each amp board before putting power back on them.
I had a couple of small problems when building my F5. All were carelessness on my part.
The Pass designs here are extremely well thought out, and my F5 is rock solid and stable now.
The dim bulb tester is no doubt a powerful tool. Can one operate F5 with an intervening variac at 1/3 or 1/2 the voltage value of its power rails so as to assist others to hunt for trouble and not overeat components by violating their SOAs? So,the generous DIYer starts with an F5 as designed, lowers the power rails, and tabulates/publishes key voltage data as a guide to augment the lightbulb test. A lifesaver.
Sorry, but you still didn't say if you have a light bulb tester on hand. They are easy to make and you probably have the parts you need around the house.
I was reading about it. I have to put a 40 w bulb or less in serie between trafo and power inlet right?
Assisting DIYers requires great peace of mind. If you can't treat it as a
meditation, then you will occasionally be frustrated.
I plug my light bulb tester into my variac so you can ease into it slowly...
Happy Hollydaze Y'all,
Elwood
Assisting DIYers requires great peace of mind. If you can't treat it as a
meditation, then you will occasionally be frustrated.
Q: Can I use a rubber bottle stopper as a gate stopper????
A: Oooohhhh--uummmm, oooohhh--uummmm, ooooohhh--uummmmm (repeated, with candles and incense burning in the background......)
Happiest of holidays, to all of you--and yours....... May we all build Class A in 2014.
40 and 60 watt lightbulbs in the U.S.
Heard on the news tonight, an item I had forgotten about....
The U.S. will cease production of incandescent 40w and 60w lightbulbs, at the end of this year (read, about 10 days to go). Stores will be permitted to sell out their remaining supplies until exhausted. (This ban was already in place on larger-wattage bulbs, if I recall correctly.)
If you are using such bulbs in your tester (or as constant current devices in your amp designs), now is the time to stock up.
(I can see the black-market now...... smuggling light bulbs in, via tunnels under the US-Mexican border....)
Heard on the news tonight, an item I had forgotten about....
The U.S. will cease production of incandescent 40w and 60w lightbulbs, at the end of this year (read, about 10 days to go). Stores will be permitted to sell out their remaining supplies until exhausted. (This ban was already in place on larger-wattage bulbs, if I recall correctly.)
If you are using such bulbs in your tester (or as constant current devices in your amp designs), now is the time to stock up.
(I can see the black-market now...... smuggling light bulbs in, via tunnels under the US-Mexican border....)
Rush mentioned it last week...
Not only do they work as wonderful non-linear sources, they also provide us with heat! Here I sat with a big honkin' 100 watter warming me and providing luminescence.
NP: I had enough patience to survive raising 3 sons...and then it wore out.