Plate Voltage

[shortyK]

Anybody venture an accurate guess to what the voltages might be on the early Mark I's. I understand you can measure the voltage at pin 8 of the tube while fired up. But, not that brave yet.....



sK

 

[Boogiebabies]

It's pin 3 to ground and probabaly 460 or less with a load.

 

[shortyK]

Thanks for the correction. See why I asked


sK

 

[Boogiebabies]

Now, asssiming I take no liability for your further electrical exploration, I use an alligator clip to the negative post of my multi meter and clip it to the chassis or the best available ground. I then use the red to probe, very carefully with no coffee or red bull in my system. One slip on a phenolic socket and " SMACK" you have carbon all over pin three and down the side of the socket. I also use only one hand and keep the other in my pocket. I am not going to be the circuit to ground. I learned this the hard way with 490 plate volts going through my arm to my head and then to my balls.
It was a quick and load blue zap, all from mywrist touching the chassis with my left hand. Luckily the blast had moved me two feet in a nano second and
left me with only glowing and painful dental fillings for a few hours.

 

[Boogiebabies]

Read this, it is great. Mesa was teaching us amp diagnostics in their owners manuals eons ago.


http://mesaboogie.com/manuals/Mark%20I%20Maint-Repair.pdf

 

[Boogiebabies]

Dont get confused by the preamp plates at pin 1 and 6. Read further. It spooked me for a second.

 

[shortyK]

490 plate volts going through my arm to my head and then to my balls.

Trying to make a point here :shock:

Thanks, valuable information.


sK

 

[Boogiebabies]

No, it is exactly how it happened.