unseen
Newbie level 5
Hello.
I have a GOS 602 scope, (same as the Tenma 72-6800 which already has a thread here on forum) which works fine. I only got it a few days ago.
My concern is, that the -8V regulator (U601) and the 4 vertical power transistors (Q313, Q314, Q315, Q316) get extremely hot. 80+ deg C, or maybe more. Measured with a simple K-type probe. The Q313, Q315 slightly hotter. I noticed, that the ADD BAL pot is a bit off center.
A couple of times when after pushing the power switch, a loud buzzing noise came from inside. (the green LED was on)
After turning off and back on again, it worked ok.
So rare, that I could not track down the source.
Inside looks very clean, no burning marks.
Any thoughts?
Thank you.
I have a GOS 602 scope, (same as the Tenma 72-6800 which already has a thread here on forum) which works fine. I only got it a few days ago.
My concern is, that the -8V regulator (U601) and the 4 vertical power transistors (Q313, Q314, Q315, Q316) get extremely hot. 80+ deg C, or maybe more. Measured with a simple K-type probe. The Q313, Q315 slightly hotter. I noticed, that the ADD BAL pot is a bit off center.
A couple of times when after pushing the power switch, a loud buzzing noise came from inside. (the green LED was on)
After turning off and back on again, it worked ok.
So rare, that I could not track down the source.
Inside looks very clean, no burning marks.
Any thoughts?
Thank you.