Euphonix AM713 psu repair

[ferrochrome]

One more measurement. I disconnected AD board for input 1-8 and powered it back up. Here's the measurements at Q4:
1: -25,3
2: -20,5
3: -25,2

-18v is a bit high compared to the still approx 18v + rail. I'm not sure if this is way out of spec or if I can conclude that the only fault lies in the AD board

 

[ferrochrome]

Well I replaced that 100nF cap and it's running fine at -19,2V / +18,2V. The cap sat between the + and - rails before the opamp nearby, I'd guess to remove any noise on the supply. No wonder it burst into flames when it shorted. Herregud, this old beast does it's job well converting capi pre's on drums. Sounds great!

 

[GitouMan]

I have the schematics of the Euphonix converter control board connectors and PSU. I think this will help you. Vert Fonce studio.View attachment 97901

Any chance there is more schematic information from where this is coming. I would like to do a full refurbishment of my decade old converter line up.

 

[vert_fonce]

Unfortunately I don't have any other Euphonix schematics. Perhaps you could contact Berkeley Audio, knowing that the designers of these converters are also those who created the Pacific Microsonics converters, which inspired the Euphonix converters. J-Philippe

 

[RoadrunnerOZ]

So, I replaced the melted mje182 and checked voltages before plugging in the connectors for the other boards. Measurments:
1 (emitter) : -27,5
2 (collector): -18,21
3 (base): -27,0

+18v rail measures 18,17v

I’m a bit suspicious that these results above have changed after the cap blew - the voltage you are now reading being higher - there mast be some other component in the regulator stage not functioning properly. You should have -18.2V.