Hello,

I was testing my brand new, homebuilt power supply yestreday. A combination of stupidity and bad luck led to the following. The box of the power supply touched the open 220v fuse holder. I had failed to realise that the jacks i had bought were not isolated. That meant that for a brief millisecond, before the fuse blew, 220v were running straight through my beloved mn3205 equipped AD3208. The effect is obviously dead now. My question to you is what components are fried for certain and which ones might have made it.

Its hard to tell exactly what happened from your brief description, but its possible that the delay is OK.

It sounds like the power supply box was the conductive path for the 10 or 20 amps that it took to blow the fuse. The current will take the path of least resistance, and its possible that the resistance of the box is so much lower than the path through the PS and to the delay that the PCB itself did not see the 220.

I would fix the wiring issue, remove all the chips, then power up the delay and see if the 9 volt regulator still works.  Use a 1K resistor from the 9VDC to ground and verify that it regulates under a load, and also check the 4.5 VDC node.

If the regulator still works, put the chips in and check the delay.  If the reg checks out, you can't do any further damage by just sticking in the chips and trying it.

Thank you for the response. The 6 output power supply is working alright. The delay however is not. I replaced the opamp. There is at least sound going through now, but no delay whatsoever.  The problem is that the chips used are only available through Small Bear.  I live in Norway so the easiest/most expensive thing would be to order and replace every chip. Would you reccomend doing that?

Get an order from Small Bear! If Steve sells the parts and all you're ordering is some ICs then you won't be set back too much by the shipping costs Give it a go