I bought two Tektronix oscilloscopes at a estate sale. I am starting to get into electronics and wanted to get an oscilloscope to learn with. Since they were selling two for a decent price I decided to buy both. I am lucky to have a very Patient wife.
So on to the sick puppies.
I looked them over quickly for anything that looked burnt/particularly bad and did not find anything. I proceeded to turn them on one at a time.
561b:
I started with the smaller 561b and fiddled with the knobs and got a trace but after a while the trace went away. I did not notice any pops, bangs or magic smoke. There is no evidence of a trace even when turning up the intensity.
I checked the low voltages and -100 was -104, I adjusted that down and the other low voltages seemed to come into spec.
I do not know where to go from here as the troubleshooting is not as clear as in the manual for the 535a.
535a:
Took a look at this guy second. Started out with no trace. After a quick google search I read this article:
http://www.lydecker.org/Tektronix_535A.htm he mentioned in the article that the contacts on the tubes may be at fault. I wiggled the tubes a little and I got a trace. YAY!
Then I turned it off and started cleaning the contacts for the tubes with contact cleaner. I got part of the way through - I have cleaned all the contacts in the plugin, the left side of the scope, the door on the right side of the scope and the bottom of the inside of the door on the right side of the scope. Now there is no trace
I am hoping I did not fubar something. I did notice that the trace seems to be above the screen as the up arrow light lights up and i can see a faint, fat vertical line about when I turn up the intensity. The vertical position knob did not affect the position of the line. I do have a second plug-in and it seems to give the same issue.
I followed the troubleshooting steps outlined under 'Troubleshooting the vertical amplifier', 'No Spot or Trace on CRT'. When shorting things as instructed it showed the trace near the center as specified. The manual has this to say about my perdicament:
'If tube replacement does not correct the trouble, then look for open peaking coils, defective resistors and shorted or leaky capacitors.'
I cannot exactly go to my local Walmart and pick up different tubes for it (even if I could I don't think I would buy them there). Is there a good way to test tubes without a tube tester, I do not exactly have one at my disposal.
I am going to bring the manual to work and scan in the Schematics on our big scanner. The manual can be found here: INSERT URL but the schematics are separate making it hard to read.
Some background on me:
I am a computer person by trade, my speciality is Cisco networking. I have not done much in the way of electronics repair except a laptop jack replacement and other small repairs of the like that are obvious. This is not obvious to me. I work on my car when it breaks, I dabble in woodworking, I go to school, I work full time, I have 3 kids and a wife. I must have too much time on my hands
. I was put down this whole path in part because of the videos on youtube from EEVBlog, it seems like a great community.
Please be patient with my post as I have less than no idea what I am doing. I will try to improve the post and add more information as I troubleshoot more. Let me know if any more information is needed.
TLDR: I have no idea what I am doing and I could use some help repairing two old Tek scopes.
Edit: Images broke.