Looking great! The loop is showing up looping capacitance in the switch contacts. I would clean All the switch contacts in the Vertical, display offset, and horizontal control. The noise in the trace is possible that it might be bad silicon but more likely switch contacts. I had a 577 that did that with some cranky opamps in the amplification chain. The DC collector supply sweeping is generated by the mains line frequency. There is + polarity which is the sweeping curves then there is + DC. The main difference between the 2 setting is there is a small filter capacitor switched in to the collector supply. The + setting is no capacitor just the rectified voltage from the transformer. The DC setting switches in the capacitor. These capacitors are hiding in the collector supply and are part of that cage. Also when doing the switch cleaning pay special attention to the Invert/zero/cal switch. The tube drive signals go directly though that switch pack. Any contact issues in that switch specifically will cause the display to do very strange things. One other safety note on this unit. The intensity and focus pots use insulating shrouds as well as some long plastic standoffs as well as insulating shaft couplers. They did this because these two controls are floating on the -4KV drive voltage for the CRT. If I remember the calibration document the measurement point for the -4KV is one of the intensity pot legs.
Looks like you rebuild lots of Tek stuff. I have a bunch of TM500 plugins and they all have sticky/stuck push buttons, ganged usually. I would like advice on cleaning them. I've seen pulling the retaining clip on the front spring and pushing the insides out the back. what about the gang mechanism? how to get that working well without breaking it.
Those style gang switches are the worst! They always cause the worst kinds of faults in my repairs. And its because they get dirty so easily. I have a pretty good succss rate with refurbishing them just with Deoxit sprayed anywhere I can get to penetrate the internals of the switch. On a lot of Tek stuff I've seen, these style snap action gang switches are very easy to penetrate because usually the backs are open and/or the pins on the top have spaces just big enough to get the cleaner into (the downside to this is that is probably how they get so dirty in the first place 😂). Once I've applied the cleaner, I just exercise them over and over (push in and out). If the switch is completely sealed, sometimes it is worth it to drill a tiny hole into the top of switch with a dremel tool to get the cleaner in! @@IMSAIGuy
It's already drawing great, the diodes are tested with AC voltage, my 210 is tested primarily with alternating current mapping, only for the three-wire ("sense" unfortunately 210 does not have) connection of the tested component, the DC component is used. I don't have much experience with what you have, I've met him twice in my life. EDIT: If you look at the test sockets, the three in a row above each other are measuring and the two next to them are Sense inputs for four-wire measurement. Nice day 🙂 Tom
My bet? Clean the pot and then you will be able to find the bad cap that is causing the loop in the drawing. On a functioning CT, caps produce circle/loop images.
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Voice is gone from screaming at you to clean that obviously flaky pot.
contacts, contacts and contacts.. thank you for showing us!
Looking great! The loop is showing up looping capacitance in the switch contacts. I would clean All the switch contacts in the Vertical, display offset, and horizontal control. The noise in the trace is possible that it might be bad silicon but more likely switch contacts. I had a 577 that did that with some cranky opamps in the amplification chain. The DC collector supply sweeping is generated by the mains line frequency. There is + polarity which is the sweeping curves then there is + DC. The main difference between the 2 setting is there is a small filter capacitor switched in to the collector supply. The + setting is no capacitor just the rectified voltage from the transformer. The DC setting switches in the capacitor. These capacitors are hiding in the collector supply and are part of that cage.
Also when doing the switch cleaning pay special attention to the Invert/zero/cal switch. The tube drive signals go directly though that switch pack. Any contact issues in that switch specifically will cause the display to do very strange things.
One other safety note on this unit. The intensity and focus pots use insulating shrouds as well as some long plastic standoffs as well as insulating shaft couplers. They did this because these two controls are floating on the -4KV drive voltage for the CRT. If I remember the calibration document the measurement point for the -4KV is one of the intensity pot legs.
Looks like you rebuild lots of Tek stuff. I have a bunch of TM500 plugins and they all have sticky/stuck push buttons, ganged usually. I would like advice on cleaning them. I've seen pulling the retaining clip on the front spring and pushing the insides out the back. what about the gang mechanism? how to get that working well without breaking it.
Those style gang switches are the worst! They always cause the worst kinds of faults in my repairs. And its because they get dirty so easily. I have a pretty good succss rate with refurbishing them just with Deoxit sprayed anywhere I can get to penetrate the internals of the switch. On a lot of Tek stuff I've seen, these style snap action gang switches are very easy to penetrate because usually the backs are open and/or the pins on the top have spaces just big enough to get the cleaner into (the downside to this is that is probably how they get so dirty in the first place 😂). Once I've applied the cleaner, I just exercise them over and over (push in and out). If the switch is completely sealed, sometimes it is worth it to drill a tiny hole into the top of switch with a dremel tool to get the cleaner in! @@IMSAIGuy
Awwwahhh It's a BOY !!! cheers.
LOL.
Looks like classic symptoms of poor switch contacts/dirty potentiometer.
Nice progress! Switch contacts might want a good cleaning?
Achievement unlocked :) Woo hoo!
Great progress! 👍
Only, don't sneeze, when it's working... 🤧😂
Looks like lots of bad connections in switches and potentiometers from weather abuse..
maybe tapping on those pots when they go loopy? or freeze spray to isolate wonky components
It's already drawing great, the diodes are tested with AC voltage, my 210 is tested primarily with alternating current mapping, only for the three-wire ("sense" unfortunately 210 does not have) connection of the tested component, the DC component is used. I don't have much experience with what you have, I've met him twice in my life.
EDIT: If you look at the test sockets, the three in a row above each other are measuring and the two next to them are Sense inputs for four-wire measurement.
Nice day 🙂 Tom
Question which of the Tektronix Curve Tracers can you enter change the CRT’s on?
My bet? Clean the pot and then you will be able to find the bad cap that is causing the loop in the drawing. On a functioning CT, caps produce circle/loop images.
Mine has same exact problem, becomes unstable at random and trace wanders off screen. Pretty sure it's dirty switch contacts
Sweet
Showing that the CRT and flyback are good you’ve tripled your money already. Check out TekWiki.
oh, I'm well aware
first!