Holy crap, this video couldn’t have been timed any better. Just this morning I received new tubes in the mail for my 1967 Bassman 50, and after installing them I noticed that even though it started working again, the output is low and distorted.

Fred will become the next "Mr. Jingles" (the mouse from the movie "The Green Mile").

The more you explain the scope readings the more I’m learning , Thankyou terry more examples please

I've been repairing amps for some years, but I'm always watching basic traing and other of Your repairing vids. Thanks for Your job! Much regards from polish tube guitar amps freaks!

Fantastic that you have an AMPLITREX! They provide a much more accurate depiction of the tube under test when used in computer mode rather than as a stand alone.

Thanks again and best wishes from Columbus Ohio USA

I KNOW THE COMMENT HAS BEEN MADE BEFORE BUT D LAB SHIRTS WOULD BE GREAT YOU MIGHT BE SURPRISED BY DEMAND 63 K SUBS JUST A THOUGHT

Nice one Terry..Great to see the signal and the explanation.. Great vid..Thanks again for sharing...Ed .UK..😀

Yay, Fred's back!!!

Thanks, Terry Disappointed at no Emmy. 🙃

Thanks for the tuition. 👍🏻👏🏻

Loving this Fred series, Thanks D-lab! Any chance on doing some Phase inverter scenarios? Explain the difference between using a 12AX7 compared to a a 12AT7 for Phase inverter and the reason for and against etc. Thanks cheers

Cool amp. Great condition. Thanks D Lab!

You are wonderful sir. Wonderful.

Your training is great! Thanks appreciate it

That's an abundant mouse. I was sure it could pass for a Rat King.

Thanks. Nice lesson.

Great topic and excellent video. Thanks & Cheers!

Thank you

Get Ol' FRED to da rescue!!

I have a 5e3 clone that the power tubes are barely warm I can hold onto them what could it be ? I’m thinking maybe a bad solder joint like you should us in a previous Fred video I’m re watching the basic training series I love it keep up the good work thanks again Terry

and thank you

Thanks for another interesting video. What is the voltage Vpp of the signal coming from your audio generator unit when you perform the initial testing?

Must be a Norwegian Wharf Mouse

The bad screen resistor went up to 20K homes when a good screen resistor should have been at 470 homes so the bad screen resistor that is at 20K is restricting and giving less current to the power tube and that is causing what type of distortion it look like a symmetry distortion how it would adjust the the width of the positive and negative push and pull maybe you can explain in the comments and get back to me that would help me out a lot but it has something to do with the restriction of current that would that is doing something to the tube to cause it distortion it might be a transconductance thing because transconductance is based on the current verse the voltage of the input and the output of the tube

Sensible steps to assist novices in diagnostics.

With the screen resistor being bad would that also make that tube be cooler in temperature ? How would I find this with out a oscilloscope

Hello D-lab, what are your thoughts on using higher screen values (~1k) to protect modern production tubes from overcurrent faults?

Hi Terry, I am looking at obtaining a LAG55 like yours. What do you think a fair price is for a retired tech like myself at a swap meet or ebay?

mouseman mouse house repair

Could anyone here tell me what might be causing this issue? New 6L6s installed in a 67 Bassman 50, but only one of them is glowing. The amp still works, but the volume is noticeably lower and the tone breaks up much easier than it used to.