Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jonas on February 02, 2023, 12:30:39 pm

Title: MANLEY dual mono block microphone preamp won't power up
Post by: Jonas on February 02, 2023, 12:30:39 pm

Hi, I'm not sure I posted this to the correct place but I hope so!!

I have a MANLEY dual mono block preamp on the bench that will not power up.  I have no schematic (more than likely will not be able to get one). I have not tried to power it up yet. I plan to do a thorough inspection to look for the obvious; burnt components, leaky caps, broken wires, bad solder joints, etc.  I can get high res pics as well....

Below is intel from the owner

1) installed in a rack with other equipment but not frequently used, but power is typically left on.
2) tubes checked out OK (qty 2 - 12AX7 and qty 2 - 12BH7A / one per channel)
3) 1 AMP slow blow instantly blows when turned on


Any suggestions on how to proceed?

Title: Re: MANLEY dual mono block microphone preamp won't power up
Post by: sluckey on February 02, 2023, 01:04:36 pm

Build and use a current limiter light bulb.