Search found 9 matches

by pwu
Fri Aug 17, 2018 5:15 pm
Forum: Foot Pedals & Misc Mesa Stuff
Topic: Question about studio preamp footswitch
Replies: 3
Views: 2799

Re: Question about studio preamp footswitch

He's in Israel. Maybe not an option.
by pwu
Sun Jul 29, 2018 7:36 pm
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Re: Studio Preamp issues (SOLVED)

I saw no change in LED brightness. Mine are kinda dim. I think they’ve always been that way for the 10 years I’ve owned it.
by pwu
Wed Jul 25, 2018 2:57 am
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Re: Studio Preamp issues (SOLVED)

https://s33.postimg.cc/huc5x0yb3/37_E4_F8_F0-_E4_AA-4099-9_D96-_F8_E523_A21_C69.jpg For those curious, here is how she turned out. I know, some of the 10w resistors are overkill and too big, but their leads are insulated where needed and they work great. Yes, I fit a full size reverb tank in there:...
by pwu
Fri Jul 06, 2018 12:49 am
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Re: Studio Preamp issues (SOLVED)

There was a trace that somehow got to ground from the EQ switch middle tab. I lifted the LDR lead from the board and wired the wire directly to it. Did the same to the EQ LED leg.
All is good now 8)
by pwu
Mon Jul 02, 2018 1:47 am
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Re: Studio Preamp troubleshooting. Help please!

Output A is fixed. It was a broken trace between .1 cap and the 10k resistor.
Still haven’t solved the EQ not disengaging. If anyone has info or knows a thread that could be helpful, please post. Thanks in advance!
by pwu
Sun Jul 01, 2018 1:40 am
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Re: Studio Preamp troubleshooting. Help please!

Success! The new .1 caps fixed the issue! I thinking many other older Mesa Boogies have this issue with bad Orange Drop caps. Now, I've got two new issues: Output A isn't working. I'm guessing another cap crapped out, or a connection is broken/bridged. EQ isn't turning off. I replaced the EQ LDR, bu...
by pwu
Mon Jun 25, 2018 3:50 am
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Re: Studio Preamp troubleshooting. Help please!

I just pulled and tested all of the Sprague Orange Drop .1μF caps, and they are ALL bad! The other values I’ve tested are ok. Just placed an order for new parts, and I’ll report back once I get everything installed.
by pwu
Fri Jun 22, 2018 2:41 am
Forum: Vintage Amps (Before 1991)
Topic: SQL Errors
Replies: 21
Views: 772381

Re: SQL Errors

Can this thread be removed now?
by pwu
Fri Jun 22, 2018 2:24 am
Forum: Rack Pieces
Topic: Studio Preamp issues (SOLVED)
Replies: 7
Views: 2497

Studio Preamp issues (SOLVED)

I’ve got a Mesa Boogie Studio Preamp that is acting up. It’s worked perfectly fine in the past, but has been in storage for a few years and through a few relocations. The function of the Bass , Mid , and both Output Level potentiometers are not working properly. Cleaning them didn’t help. They are w...