On Tuesday, 2 January 2018 02:18:06 UTC, Murray atuptown wrote:

Anyone know if there is a solution to low display brightness on a HP 54111D oscilloscope, like maybe power supply capacitor replacement?

The CRT power supply voltage described in the service manual is puzzlingly-low...only 120 VDC (?!?) The 300V switching supply is described as used for generating the 5V logic supply.

I haven't dug further, but wonder how a color CRT can get by with such a low voltage...or if the CRT module has an integral flyback supply for anode voltage, and repair being module-focused, isn't discussed.

The CRT thought led me to wondering if CRT rejuvenation was an option.

Thanks

Murray

Never do that. I've seen so many CRTs ruined by rejuving. Increasing heater voltage works better and stays good.

But if your PSU rail is way out of spec, surely it's obvious that CRT emission failure is not likely to be the cause of a dim screen.


NT