Tektronix 2247A no trace question

[rdl]

I have a Tektronix 2247A that I got over 10 years ago. Though I don't use it that much since getting a DS1052E, and when I do it's usually just one channel, but yesterday I actually tried to use channel 2 and found that there's no trace. I'm sure it worked at one time. What I'd like to know is whether this might be an easy fix or not. So if anybody wants to take a guess, I'd appreciate it. Even with just one channel it's still very useful and I'm not sure it's even a good idea to go poking around inside and risk making things worse.

edit: channel 2 not channel B

[David Hess]

Channel B?  What channel B?

Channels are designated with the numbers from 1 to 4 and sweeps and triggers are designated with the letters A, B, and C.

[rdl]

Sorry, I meant 2. All channels have a trace except channel 2.

[David Hess]

There are some non-intrusive measurements that you could make which would determine the failure or at least narrow down the possibilities.  Many of them are repairable but will require unsoldering parts and replacing them.  You will need the service manual which has schematics.

The oscilloscope also has some self diagnostic routines which might point to the problem.

Likely failures which could cause what you describe are:

1. Failure of the input amplifier.  This would be difficult to fix and require a custom Tektronix hybrid.
2. Failure of the JFET or CMOS analog circuits which control the trace position.  This would be easy to fix.
3. Failure of the digital I/O circuits which control trace 2.  This would be easy to fix.

[rdl]

I was able to track down a copy of the service manual. I couldn't find an operation manual, but I found one for the 2246 which seems close enough and will be a big help. When I first got the 2247A, I just followed general scope usage guides to figure out the basic usage and never bothered with the more advanced features (though I did figure out some parts).

For now, I don't think I'll take any chances. I finally have all my electronic stuff in one area instead of two different rooms, so If I need more than one channel I can turn on the Rigol. The rest of the time I'll be able to use the 2247A.