Tube red plated.

moltenmetalburn

moltenmetalburn

Active member
Red plated on me last night after making a bunch of weird noise at startup.

Amp went silent and I looked and saw the redplating.

Is amp potentially damaged or just need tubes?

What should I check? Are fried resistors easy to locate? Burnt?

No bad smell at all.

Ordered a quad of output tubes and now just waiting nervously.
 
Probably just need to replace. I've had PTs red plate in numerous amps...just replace them all and go from there.
 
You will need to pull the mains and HT fuses to check them for open. Use a meter on the diode test setting and listen for an audible beep if they’re good.

Pop the new tubes in and bias then up. Screen grid resistors dont go every time a tube redplates and you’re likely fine.
 
Awesome thanks gents! The timing is crazy, I literally decided to sell the day before to cover my dream amp lmao. Was stressed as I need the cash to make it happen.
 
moltenmetalburn":84ic4bfy said:
Awesome thanks gents! The timing is crazy, I literally decided to sell the day before to cover my dream amp lmao. Was stressed as I need the cash to make it happen.
Click to expand...

Use your Meter to measure the screen grid resistors to make sure they are all good. I never have an issue reading them across the power tube pins. Replace fuses. New tubes, rebias.
 
Good idea to test the resistors with tubes pulled - couldn’t hurt. The screen grid resistors are tied to B+ so it goes without saying unplug the amplifier and verify no voltage exists in the caps first.
 
You must log in or register to reply here.
Back
Top