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  #31  
Old 08-15-2018, 10:30 AM
Espo Espo is offline
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You're right, old_tv_nut, I did do that, didn't I. I guess I'm looking for a quick solution to a problem that requires deliberate troubleshooting. Sorry about that. It's not easy trying to help someone from a distance, and I appreciate the effort. Now to answer your question. The picture control does seem to work correctly. It's the brightness that had been working, but stopped. The syncing problems have been consistently present.
Also, I did replace and wiggle the tubes, Kramden66. That doesn't have any effect.
Thanks for the troubleshooting advice, Electronic M. The controls do affect the direction of the vertical and horizontal lines. Can you tell me if I would need an oscilloscope to check the video levels, or can it be done using a multimeter? I've got one, but it's been a while since I've used it.
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  #32  
Old 08-15-2018, 11:41 AM
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OK now - if the picture control goes through a range of weak picture to too strong, and there is no change to the sync, then it is likely the sync separator circuit that is the problem.

An oscilloscope would be helpful if you have a reference telling you what amplitude the waveforms should be. If not, you would just be guessing. I can only make this general statement, but maybe someone else here can give you a reference.

It sounds like you need to know the normal signals at the input to the sync separator and in various parts of the sync separator. Before you do that, though, a check of DC voltages in the sync separator circuit may point to something.

Edit: I see Riders has waveforms, so there you go.
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Last edited by old_tv_nut; 08-15-2018 at 11:46 AM.
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  #33  
Old 08-15-2018, 01:04 PM
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Here are the latest developments. It turns out that I already had replaced those mica caps, so that rules that out. I had the brightness control working correctly for about five minutes after turning the set on while on its side this morning. Then I lost it. I thought I'd let everything cool down, and try it again but no luck. Regarding voltage readings on the sync separator tube there are differing results expected on the Sam's Photofact and the Rider's voltage charts. On the Sam's chart pin 4 should read -2.6 vdc. On the Rider's chart pin 4 should read -5.2 with the picture control set to minimum, and -9 volts with it set to maximum and depending on the noise level. I'm reading -4.6 volts and the picture control is not changing it. I'll continue trying to find a mistake I may have made along the way. Thanks for the help.
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  #34  
Old 08-17-2018, 12:13 PM
kramden66 kramden66 is offline
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Sometimes if one of the pins on the CRT is not making proper contact you won't be able to control brightness , that would explain the sync but maybe you have two issues not related , you could wiggle the the CRT connector to see if that's the brightness issue
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  #35  
Old 09-03-2018, 05:31 PM
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Hello all,
Sorry for the delay in responding, but I grew very frustrated at my inability to solve the problems with this set, and had to walk away for a while. I wish I had half the ability of many on this site. Well anyway, I'm back at it. I've taken pictures of signals at various points, and need your help in determining where to go from here. You'll find pictures of the signals I'm referring to in the link that follows. The brightness and contrast are working, but most of the time I don't have horizontal or vertical lock. I hope you're able to help me out of this rut.

Photo #1: Video signal to first video amp. Scope is on the 2 volt scale.
Photo #2: Output of first video amp. Scope is on 2 volt scale, probe at X10.
Photo #3: Input to kinescope. Junction of C141, R148, and green lead to kinescope. Scope is on 5 volt scale.
Photo #4: Cathode of D-C Restorer. Scope is on 5 volt scale.
Photo #5: Plate of D-C Restorer. Pin 2 of V114-B. Scope on 5 volt scale.

fine.http://www.earlytelevision.org/pdf/r..._rider_tv2.pdf
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  #36  
Old 09-03-2018, 08:34 PM
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It looks like the video amplitude at the kinescope is about right (schematic says 38 v p-p, If I'm reading the scope scale right you have about 25 v, but that should vary with contrast setting). I think you should measure the signals in the sync separator. Schematic says input to sync sep, pin 4 of V119 6SH7 should be 35 v pp, output (Pin 8) should be 75 v p-p. Check the output first, if it's not good, check the input. If it's not good, check the signals around the 1st sync amplifier.
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  #37  
Old 09-04-2018, 06:56 AM
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I'll check those signals soon. I chose to focus on the areas before the synch circuitry, because the signal does not consistently look like it does in the pictures. The signals vary in voltage and noise levels quite a bit.
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  #38  
Old 09-04-2018, 10:53 AM
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Quote:
Originally Posted by Espo View Post
I'll check those signals soon. I chose to focus on the areas before the synch circuitry, because the signal does not consistently look like it does in the pictures. The signals vary in voltage and noise levels quite a bit.
If you are feeding it a live TV signal and not a test pattern the signal will vary.
The Synch pulses should have a constant tallness and never be swamped by noise...Changes in areas of the signal other than the synch pulse typically are not noise (unless your screen gets snowy with signal sometimes) but rather changes in video content. If you want to make sure the signal and the circuits amplifying it are stable feed the set a test pattern from a test pattern generator or feed it signal from a DVD player that is paused on a frame that gives a nice waveform.
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  #39  
Old 09-04-2018, 12:42 PM
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Interesting. I don't have a test pattern generator. Can I continue using the VCR hooked up now, or do I have to use a DVD player?
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  #40  
Old 09-04-2018, 12:45 PM
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Yes, if you can pause a DVD on a frame with a blank grey screen that would result in the least confusing scope trace because the picture signal is constant. That may cover up a problem however if the picture information is effecting the sync, but it is a good start. Next best would be a scene with just two levels of grey, maybe the credits on a movie.
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  #41  
Old 09-04-2018, 03:15 PM
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VCRs (if playing tape) would be the least recommended signal source for troubleshooting...Especially sync troubleshooting.

VCRs record the complete signal on tape and play it back...As such the most minute lack of precision in the mechanical systems results in sync errors in the VCRs output. Sets made before 1970 were not made with VCRs in mind and will have a harder time correctly syncing to tape than say an 80's TV set, but even the newer sets will show some errors if the signal is bad enough.

Use a DVD player, OTA DTV/cable/sat converter or test pattern generator for troubleshooting.

If your DVD player lacks RF output then you can plug it's A/V output into the VCRs A/V input, tune the VCR to it's A/V input and use the VCR to RF modulate the DVD signal. The VCR should not cause sync issues as long as you do not use it to play videotape.
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  #42  
Old 09-05-2018, 07:23 PM
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Hello again. I used a DVD player, and ran it through my VCR to get these signals. Sorry about the extra trace in the pictures. I couldn't figure out how to make it disappear. I appreciate all the help so far, and could use some feedback as to where to go from here.

Photos #1 and 2: Output of first sync amplifier. About 60 volts. Probe X10, Scope X2 scale.

Photo #3: Input to sync separator. About 25 volts, which would be low. Should be 35 volts. Probe X1, Scope X5 scale.

Photo #4: Output of sync separator. About 80 volts. Probe X10, Scope X5.
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  #43  
Old 09-05-2018, 09:15 PM
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Can you explain why you have two waveforms for the output of the first sync amplifier? H and V rate? Neither one looks very much like the waveforms on the schematic. The first one, that appears to be H rate, appears to be inverted compared to the schematic.

Picture 3, input to sync separator, seems to have a lot of video. (On the schematic, it shows mostly sync pulses with a little video leaking through.) As a result of the excess video, the output of the sync separator has a lot of video also - it should be purely sync pulses.

I would start by checking the first sync amplifier. Check DC voltages. Check component values. Do you have a known good tube to substitute?
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  #44  
Old 09-06-2018, 02:08 PM
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I must have been rushing. I hope these pictures are more helpful. I'll follow your advice and look for the problem in the sync amplifier section. I'll look for another tube. I bought a replacement for that already, but didn't check it on my tube tester. I'll do that today. Here are new pictures taken today.

Photo #1: Plate of D-C Restorer. It's 15 volts, and should be 9 volts.

Photo #2: Output of first sync. amp. It's 75 volts, and should be 35 volts.

Photo #3: Input to sync separator. It's 32 volts, and should be 35 volts.

Photo #4: Output of sync separator. It's 90 volts, and should be 75 volts.

By the way, I enjoyed looking at your webpage, especially the World's Fair section.
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  #45  
Old 09-06-2018, 05:11 PM
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Did you download the Rider manual? In case I wasn't clear, that's the one with the waveforms I have been referring to.
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