Randall RH150 constant hum

[The Dude]

My best guess is that you are missing a ground somewhere. Since the amp was dropped, check the board(s) thoroughly for cracks. Particularly where there are mounting screws for the board or any other point that would be stressed in a drop. Check for broken pots and pot mounting, broken jacks and jack mounting, etc. It only takes one hairline crack to cause problems and they can be hard to see. Use a meter to check continuity on ground traces if necessary.

[Ceredox]

So, after looking for bad grounds a made a really stupid mistake. Long story short, I'll be replacing 2 transistors... But when I was checking the transistors, I noticed something on one of te traces on the board. It looks like someone scraped it with a screwdriver and severed the trace completely. I don't have a schematic so I'm not sure exactly what that circuit does but I can imagine it would cause a problem - hopefully my hum problem. It's between C21 and C15 on the output board.

[g1]

That looks like a deliberate cut to me. There may have been an error in the board layout that was corrected this way.
Be absolutely sure with the schematic before making any connection.

[Jazz P Bass]

That appears to be a factory cut in that copper trace. (because it is so nice?)
I would be real careful about reconnecting it without first figuring out why.

Have you attempted to contact Randall. (for a schematic & possibly an answer to the cut trace.)

[Ceredox]

Yeah, I suppose it's time I get a schematic from Randall. I'll contact them. On a side note, found this particularly interesting. It looks like Bruce Egnater had a hand on this board.

[Jazz P Bass]

It looks like Bruce Egnater had a hand on this board.

Oh sh#t.
Now the power transformer is going to fail.

[g1]

Good one .

[Ceredox]

Haha I use an Egnater Armageddon! Should I be worried for my power trabsformer?!

[The Dude]

https://www.google.com/?gws_rd=ssl#q...former+problem

[Ceredox]

OHHH. Very good to know. Maybe I'll be making a transformer upgrade soon.

[rene lbp]

Hi bros
i´m new in this forum
does anyone have the randall rh 150 schematic diagram
greeting

[Jazz P Bass]

Here is the RH200.

Maybe it is close enough.

RH200-.zip