linux-dude
Member level 1
Hi,
I'm restoring an old CRO, Hung Chang 5604, that i had for about 30 years. It's been in storage for many years, but did start up, and after general cleaning and fixing switches/potentiometers that had corrosion, it appeared to be working properly for a few hours. Today when i switched it on, a new issue showed up as shown in this video: [video]https://www.dropbox.com/s/hnyvgkb0t2w2tf1/cro-failing.m4v?dl=0[/video]
I noticed that apart from the "zooming" issue, the blanking circuit goes haywire as well. The problem is not heat related and shows up instantly after power up from cold state.
My guess is aged/bad electrolytic capacitors and possibly dried out/broken insulators on power transistors (they looked suspect). I have little experience with HV/CRT repairs and hope someone here could suggest possible causes.
I hesitate to spend a lot of time with the CRO powered on, as i fear that something burns out. Is my fear rational?
The schematic: https://www.dropbox.com/s/wi4egee2y...0mhz_readout_oscillosc ope_1988_sch.pdf?dl=0
Thanks in advance,
Mike
I'm restoring an old CRO, Hung Chang 5604, that i had for about 30 years. It's been in storage for many years, but did start up, and after general cleaning and fixing switches/potentiometers that had corrosion, it appeared to be working properly for a few hours. Today when i switched it on, a new issue showed up as shown in this video: [video]https://www.dropbox.com/s/hnyvgkb0t2w2tf1/cro-failing.m4v?dl=0[/video]
I noticed that apart from the "zooming" issue, the blanking circuit goes haywire as well. The problem is not heat related and shows up instantly after power up from cold state.
My guess is aged/bad electrolytic capacitors and possibly dried out/broken insulators on power transistors (they looked suspect). I have little experience with HV/CRT repairs and hope someone here could suggest possible causes.
I hesitate to spend a lot of time with the CRO powered on, as i fear that something burns out. Is my fear rational?
The schematic: https://www.dropbox.com/s/wi4egee2y...0mhz_readout_oscillosc ope_1988_sch.pdf?dl=0
Thanks in advance,
Mike