Hill Audio Multimix 16

[Jopair]

recently became the owner of a Hill Audio 16 channel mixer. Reviews of it are interesting and I want to start testing it out, using it as mic preamps pre converter.

The power supply to this unit has something wrong:

I tested 3 of the 4 fuses. 3 were bad, so I replace them. If I connect my multimeter in resistance mode connected to the fuses, 2 of them will individually light up either the psu power LED or the phantom power LED. When testing the other two fuses, no visual indication of yes or no. I re soldered a joint that looked obviously bad and now I'm stuck as what to test next. I've gone through most of the components and they all seem functional. There is however a orangeish tint over 1/4 of the back of the PCB. A few other forums indicate this could be solder residue but should wipe right off and not be the cause of this issue.

Any insight would be greatly appreciated

 

[Walrus]

Here are the schematics....
www.hill-audio.com/?dl_id=23

You can measure the supply rails with the PSU disconnected from the mixer.

 

[Jopair]

What would you test? I'm a tinkering electronics person at best. I have a multimeter but am needing a bit of helping know where to start and what to look for.

 

[Jopair]

Hmm okay... Thanks anyway guys

 

[Walrus]

The manual tells you what voltages to expect on the fuses in the supply, and they should be within a volt or two with the mixer disconnected.
If a voltage is much too high, then the supply is faulty and needs repair.
If they are correct but a fuse blows when the mixer is connected, then there is a short in the mixer.
If the channels are easily removeable, put your meter, on Ohms, on the output side of the blown fuse (with the power off!) and  take them out one at a time until the short circuit disappears.
That will hopefully give you a partially working mixer.