Kenwood CS-2150 oscilloscope repair

[eb5agv]

Hi all,

I am working on a Kenwood CS-2150 oscilloscope with a fault in the power supply (I hope it is NOT the flyback!). It generates a high frequency noise, coming from the flyback, but all voltages are low and, if I leave it connected for a while (just some seconds), something starts to get hot, as it smells a bit...

So far, I have found and replaced a couple bad transistors on the PS section.

Of course, I need to investigate further but have no schematics nor any other service info for the unit. I think the CS-2100 has a similar power supply. I wonder if someone could have the shematics and/or service manual for any of these units.

Thanks a lot!

JOSE
EB5AGV Vintage Amateur Radio and Test Equipment Site

 

[HiTech]

Have you tried to lift all the pwr. supply rails? Remove their loads and assure the supply itself is working properly and stable. Measure resistances of the various sections of the scope where those rails get connected to, looking for shorts or near shorts to ground. Further narrow things from there once you locate a problem area.

 

[eb5agv]

Hi HiTech,

Thanks for your message!

Yes, I know that is the way to go but this is a crowded instrument, packaging a lot of things inside and it is not easy to isolate sections (nor access them!), so an schematic would be very helpful.

Best regards,

JOSE
EB5AGV Vintage Amateur Radio and Test Equipment Site