IBM PS/2 Model 25 CRT - No High Voltage

[Electronic M]

Originally Posted by Jimmy422

Silly question - can I measure G2 with a standard multimeter? I’m seeing some stuff on google that says a traditional DMM can’t handle it.

I do have a scope on the way though - what would you recommend checking with it?

Depends on the DMM, the TV and how clever you are. Some DMMs are only good to 600V and some G2s can get close to 1000V...Which would exceed what a 600V meter can handle......
.....I encountered that issue once on a friend's TV with their DMM. I needed to measure the 900V boost and the meter on hand was only good to 600V. I had a high IQ moment and realized that if I measured the voltage between the STABLE 400V B+ rail and chassis, and then measured the voltage between the 900V boost and the 400V B+ (a 500V difference) then add the 2 measurements I would effectively get the value of the voltage between the 900V boost rail and chassis ground without exceeding the voltage range/rating of the DMM! It worked like a charm and happened to be a key measurement to the diagnosis and eventual repair of that set.

[Jimmy422]

Originally Posted by Electronic M

Depends on the DMM, the TV and how clever you are. Some DMMs are only good to 600V and some G2s can get close to 1000V...Which would exceed what a 600V meter can handle......
.....I encountered that issue once on a friend's TV with their DMM. I needed to measure the 900V boost and the meter on hand was only good to 600V. I had a high IQ moment and realized that if I measured the voltage between the STABLE 400V B+ rail and chassis, and then measured the voltage between the 900V boost and the 400V B+ (a 500V difference) then add the 2 measurements I would effectively get the value of the voltage between the 900V boost rail and chassis ground without exceeding the voltage range/rating of the DMM! It worked like a charm and happened to be a key measurement to the diagnosis and eventual repair of that set.

Good to know! I took my chances and it appears to be outputting a whopping 20v.