LEDS pulse

[Nu-tra]

Before I plug in the power molex to my A12 all the power supply LEDS work... When I pug in the power to my A12 my power supply LEDS turn off then flash occasionally... The power LED on my A12 also Flash but way brighter.. I have doubl;e checked everything

[tpryan]

It sounds like the supply is going into thermal shutdown, though it has to get tremendously hot for that to happen. Does the blinking start immediately? Do you have the op-amp plugged into the A12? Are you sure you have the voltage regulators installed correctly? They are not interchangeable. Are all the protection diodes and electrolytic capacitors installed the right way round? Do you have a reliable DMM with which to make voltage measurements?

[Nu-tra]

The led on the preamp flashes fast

the center led on the power supply takes about 5 seconds to flash... The op amp is not in.. I was getting ready to set the voltage before i popped it on... I have a decent multi meter...

[Nu-tra]

found it! I forget what the yellow parts were called one was backwards.. I hope this solves it.. I'm ordering another A12 pre tomorrow.

V

[Nu-tra]

Still no dice damnit lol

V

[Nu-tra]

Got all the LEDS to light up!! set my DMM for DC voltage check and set negative to pin 4 in U1 and Pin 5... Adjusted to 16 I left the negative in pin 4 and pos in pin 3... nothing.. it just says 0 i treid adjusting the voltage... Checked all the stuff is says to check when voltage is way off...

Any suggestions? I'm almost there...

V

[tpryan]

I suspect C4 is shorted. Try lifting one of the leads and see if the voltage at U1, pin 3 looks better. If this is the yellow part that was in backwards, it's probably toast.

[Nu-tra]

The yellow part or the whole channel is toast? Can I get one from an electronic supply house? I was close Tim.. Sorry I let you down hehe

V

[Nu-tra]

It was C4 and U2 and U3 were swapped... All corrected... THose seem to get hot now so suppose they are ok.



V

[tpryan]

So did you replace C4, or just leave it out?