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None as far as I know. Same Sams covers both.
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How do I post some pictures? I haven’t seen any information on how to do this.
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Could perhaps that 56pf cap in the yoke on the horizontal core be a source of this problem?
If it were open/shorted, throwing the entire horizontal section out of tune, and thus, upsetting the balance of the power supply? |
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Sorry. That's why I rarely restuff cans anymore - can't see what's going on inside or make repairs.
Those brittle wires are a challenge and frustrating. Heating them gently with a heat gun on low or hair dryer usually makes them more flexible. At least until they cool down |
My preferred method is to cut the top of the can off and after restuff slip a cardboard can insulator sleeve (remove and reuse the original if there is one) over to hide the missing top. Much more serviceable and original looking than a straight rebuild or the adapt a cap.... I'm probably never going to use an adapt a cap in my work because for cheaper I can solder a period correct looking terminal strips underneath to hook the new caps to and then only have the underside of the chassis (which, let's face it, nobody sees) look unoriginal. The adapt a caps make the bottom AND TOP of the chassis look unoriginal and to me the top of the chassis is the most important part to keep looking original as it will be seen periodically.
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Hi- So I been trying to follow you guys on this one, I assume this tv is this schematic https://www.earlytelevision.org/pdf/...s30_manual.pdf I see you are not getting the -100V source... So my question is are you getting the 135V source, or is it high? If its high then R186C has to be open, or the ground lug is not making it to the chassis....? If the 135V is ok, then I guess you could possibly have an open R240?? anyway they deserve a sniff... What is the +275V source reading? If the 275V is missing, then you have to look at the path through R181, R211. But then you say the tv has stuff on the screen..... so 275V is there.... Or am I just off in left field here.... . |
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Ok, so I been thinking about this goofy power supply part of the day, and I think that if R186C was open, it would really mess up the chassis ground potential, and make readings off for each source. Or C224B Is Shorted (Unlikely). So I think the best way to figure out where the open resistor is, is to put the (-) volt meter probe on the green wire of the focus coil and move the (+) probe along each of the resistors towards the 275V source till you start reading high positive voltages, then you will find the open resistor when you hit a big positive jump..... So between R185A and R186A I think you should read about +82V if the set is working... Just re-adjust your brain to think of the -100V source as 0V with the (-) meter probe on it for reference. I have not worked on this model before, But my thinking is that with the point between R186C, & R240 making the ground point, or 0V potential, then using that point as a reference would make all readings off, if one of those resistors is open.... And with your (-) probe on the red-yellow wire (Center Tap) of the power transformer, know that your 275V Source will read closer to 375V and be OK. Just my thoughts on this one... . |
Picture problems in Crosley 9-408
Well it’s been quite a while since I last posted here!
I finally got around to having another look at this set. In the meantime I bought new leads for my multimeter as I was having difficulty getting readings with the old ones. I think this was causing problems with the automatic range function on the meter because now I have B+ of 282V and +128V. Pretty close to what is specified here (275V. and 135V.). My B- is much better at -20V. and -1V. Should be -18v and -2v. The green wire to the focus coil reads -108v. I also had a close look at the FP can capacitors and found nothing wrong here. I replaced four with the adapter-a-cap circuit boards and new components. The two twist locks soldered to the chassis seemed to be okay as well. C224 was re stuffed with new components even though the old ones looked good and measured with specs. C223 a three section can was left in place and not opened as I found nothing wrong with any of the other parts. I now am able to get a picture but problems remain. The contrast is poor and washed out with inadequate vertical height. I can get the vertical to lock but the horizontal will not, it will roll to the right if I turn the control to the right and left if I turn the control to the left. It is not stable and eventually drifts. Also there is a bright white band running horizontally across the picture at the very top where the blanking bar should be. I’ve replaced the mica capacitors and all out of spec resistors in the sync section. I don’t have an o-scope or any other test equipment. If anyone has any suggestions on how to proceed I would greatly appreciate it! Thanks in advance! |
"contrast is poor and washed out" "inadequate vertical height" "the vertical to lock but the horizontal will not"
These are all clues to something, but what exactly is the hard part. It still may be a power issue, who knows. This set pulls sync from the final video amp, at DC restoration, so if you have poor contrast (weak video), makes sense for there to be poor lock as well, but the lack of height is also a sign of a problem someplace. Still much to look into. :( |
It may be worth injecting composite video at various points between the detector and DC restoration diode (make sure to use a series cap around.1uF 600V to protect your video source). You may have to try s couple to get correct video polarity. If you get good sync injecting composite video of the correct polarity and better amplitude than the tuner/IF are making them the sync and osc system is fine and you need to trace the weak tuner/IF issue...if bad sync with good composite video then the sync separator or sweep osc is an issue.
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