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  #1  
Old 12-03-2017, 03:13 AM
kramden66 kramden66 is offline
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Motorola 19k3 chassis ts-101 help needed

I don't get any pic or sound , the mix Osc was not lighting , found a .2 ohm choke was open m jumped it with a wire , still nothing , tried sign generator , ripples / rf interference on screen on 6ah6 and 12au7 , 3rd if there is same but might not be as strong , 2nd if nothing , checked resistors , open coils etc , nothing found , here is a list



V7 video 6ah6 pin 1 is 18 volts , should be 1 volt
V5 third if 6cb6 pin 2 is .850 volts should be 1.4
V4 second if 6cb6 pin 1 is -227 should be -.5
V3 first if 6cb6 pin 1 is -.377 should be -1
V2 mix Osc 12at7 pin 2 is -1.5 should be -3.6
V1 rf 6cb6 pin one is -4.00 should be -3.2# pin 2 is 1 should be .5

SAMs online
http://www.earlytelevision.org/pdf/m...sams_122-5.pdf

Mike
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Old 12-03-2017, 12:49 PM
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Kevin Kuehn Kevin Kuehn is offline
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Mike, sorry I don't have an answer to your problem. But I couldn't help but notice something weird is happening to the clarity of these schematics during the process of Steve posting them on the ETF website. It appears as if they're getting thrown way out of focus. I've seen it happen in the past and I thought we had figured it out, but now here it is again with this Motorola schematic.
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Old 12-03-2017, 02:29 PM
kramden66 kramden66 is offline
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Kevin they printed out clear , only thing I can think of is they got compressed somewhere along the line , that would impact the clarity
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Old 12-04-2017, 12:16 AM
kramden66 kramden66 is offline
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If I knew how I'd bypass the tuner and if section and feed right into the video , audio I think you just feed into the volume taps, the outer ignoring the center if I'm not mistaken
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Old 12-04-2017, 01:21 AM
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Phil Nelson Phil Nelson is offline
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This article has some info about directly injecting video and audio in a vintage TV:

https://antiqueradio.org/A-V_AdapterForVintageTVs.htm

The TV used in that article was a different (Admiral) set, but you may be able to adapt the principles for your TV.

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html
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Old 12-04-2017, 04:43 PM
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Kevin Kuehn Kevin Kuehn is offline
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Mike,

If by chance you have a B&K analyst you can feed video direct into the video amp, you just need to get the polarity correct. Sometimes I've been able to directly inject component video into the video amp, too. Just depends on the TV circuit whether or not the signal needs inverting. Or maybe you want to permanently use component inputs? In that case Phil's article is of great help.

Last edited by Kevin Kuehn; 12-04-2017 at 04:48 PM.
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Old 12-04-2017, 05:21 PM
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Electronic M Electronic M is offline
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The B&K analyst can be a godsend in these situations. Not only can it inject video, but IF and several channels of RF too. Knowing if your If chain is good before going after the tuner is essential. You won't realize you fixed a bad stage if there is another bad one between it and your output unless you use signal injection.
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Old 12-05-2017, 12:40 AM
kramden66 kramden66 is offline
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In that article the schematic shows inject video to pin 4 , so the plus goes there and the ground to the chassis ground ?
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Old 12-05-2017, 02:45 AM
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Yes. But I'm not sure if your set uses the same tube type and pin out?

Last edited by Kevin Kuehn; 12-05-2017 at 02:53 AM.
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Old 12-05-2017, 01:06 PM
kramden66 kramden66 is offline
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The video circuit is similar , the brightness goes to a different pin ?
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Old 12-05-2017, 07:20 PM
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Not sure what you're asking. I was referring to the video amp circuit using a different tube type.
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Old 12-05-2017, 08:21 PM
kramden66 kramden66 is offline
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10lp4 in the admiral schematic , my Motorola uses 19ap4 .
If you look at the admiral video section and the Motorola looks similar.
I put up a link to the SAMs for the moto , that link to article shows a part of the admiral schematic .
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Old 12-06-2017, 04:52 PM
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The difference is the Admiral has a dc coupled video circuit, therefore they applied the brightness bias to the CRT grid. Notice the lack of coupling caps from the video amp plate to the CRT cathode. On your Moto you have a .1uf cap coupling the video to the CRT cathode, which allows the brightness bias to be applied to the same point.
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Old 12-06-2017, 07:33 PM
kramden66 kramden66 is offline
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So you don't think it will work injection the signal on the moto ?
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Old 12-06-2017, 08:45 PM
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I think it will work just fine. But you'll need to connect to pin 1 of your 6AH6(video amp), not pin 4 as in Phil's Admiral example.
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