Has anyone seen this before?

[Crazylogix]

Bill, In post #17 you say you received the whole power supply driver card. Where did you order the complete card from, If you don't mind me asking. Thanks!

 

[Bills amps]

I ordered it from Crossfire. I can usually get both sister boards if I need them. I rebuild them most of the time but in this case i wasnt sure what mods had been done and wasnt taking any chances.

 

[Bills amps]

Well i dont have any drive wave on the outputs so it popped most of them on start up. Im guessing that is why it died in the first place. I did replace the 21844's before i did anything. trying to weed out all the mismatched parts. i guess i over looked something. So now i have pulled off all the output fets and no output drive on either high side or low side.
So i guess i get to start over on the card and find whats is a muk.
Note it blew the same 4 fets that the previous tech had replaced. The amp has 4 banks of 4. but no drive on any gate pads

 

[Perry Babin]

I'd suggest going to a low-voltage rail setup. The outputs have a much better chance of surviving. You can also use higher current rated, lower voltage outputs to increase their chance of surviving.

 

[Bills amps]

Will there be drive without transistors on the board?

 

[Bills amps]

And i am not sure by what you mean "low voltage rail setup".

 

[Perry Babin]

Read through this thread starting at post #64.

4000.1

 

[Bills amps]

Perry didnt you share a build for a tordial power supply that was about 1000 watts that had the irf3205 driving it as a kit?

 

[Perry Babin]

Yes, but not a kit. Chapter 109 on the BCAE1 site. It would probably do about 1kw short term but 400w would be more of what you would expect if used for an amplifier and driven hard for long periods of time.

You don't need anything complex. All you need to do is to generate a low voltage rail so that there isn't as much stored energy in the rail caps so the outputs have a better chance to survive. The link from post 27 does that.

 

[Bills amps]

i see. but these transformers are well siliconed to the board with no room to get underneath. that was the only reason i asked. And i dont have a dual output power supply for +/- .

 

[Perry Babin]

From the photos, it looks like there is plenty clearance. A small plastic rod, a spudger or a bamboo skewer can be used where there are only large windings to make a slot. You only need 5-6 turns of small wire.

If you have a junk amp that the power supply could be repaired, you could use it to make the 5-6 turns but having a second switching supply could cause confusion.