Re: 547 scope HV transformer problem. One practical solution.


Hi Morris,

Thank you for your informative message. I went to the "files" section and found the transformer specifications. This is a big plus!

Meanwhile I am exploring other options. I started experimenting with the adjustment of high voltage.
- Lowered the CRT HV all the way from 1850v to 1655v (a 10% reduction). As expected the gain increased also about 10%. But the time-to-failure increased from 15 min to 25 minutes.
- Lowered the CRT HV further to 1500v (adding a resistor in series with the pot.) Gain increased in proportion, and the time-to-failure increased to 47 minutes.

47 minutes!! This time is quite acceptable! I don't need to keep the scope always on, since it does not need to help me warm the house in Houston, haha.

I honestly didn't see a difference in the crisp brightness of the display when lowering the HV from 1850, to 1655, to 1500 volts. And everything seems to stay adjusted in proportion, I didn't have to readjust the focus nor astigmatism. I am truly surprised at how well behaved the CRT and its supply are!

I didn't explore further to see if with even lower HV the scope could attain INFINITE time-to-failure. I am quite satisfied with three-quarters of an hour. My behind likes to get a break after sitting that long anyway...

Join to automatically receive all group messages.