#226
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#227
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Executive summary: video injection requires adding a video preamp as described in the 1956 RCA Broadcast News article. I did breadboard such a preamp, but version 1.0 was disappointing and I set the project aside to work on other stuff for a while. On the positive side, those are pretty true-looking color bars. You are not far from having a very watchable CTC-4. The edge convergence might never be as good as the center convergence, but that's common in early color roundies. Whichever manual you follow, take Bill's advice -- go step by step in the order shown and do not skip steps. Phil Nelson Phil's Old Radios http://antiqueradio.org/index.html |
#228
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This is the best I can get on height and linearity. As you can see the height isnt quite high enough. I swapped vertical out tubes with a bit of improvement. Hmmm, usually insufficient vertical height would indicate bad filters maybe, but all have been replaced so it must be something else.
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#229
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#230
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I will be out of town for the 4th until next Wednesday. While I am gone, I will do some reading through the manuals and gather some extra info on the problem areas. Until then stay tuned! Everyone have a happy 4th of July and I'll be back on this set next week!
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
Audiokarma |
#231
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You likely have some bad capacitors in the vertical stage still. If you could put a circle pattern up from a generator or dvd, you can adjust for a perfect circle then you will see if the raster will fill the screen. Also check the circuit grounds in the vertical output stage. B+ could be a little low. If it is to low the picture will usually pull in horizontally some. Be sure and check the resistors as well. There may be some that have drifted high in value.
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#232
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After leaving no stone unturned in the vertical circuit (which isnt many). I found only one barely out of tolerance resistor a 2.2meg 1/2w coming off G1 of the 6AQ5 vertical amp then goes to ground. Not sure it is too critical and its just barely off spec I mean like less than 1% off spec so I might just leave it. All caps are fine except I did replace a .039 which comes off the plate of the vertical amp and goes to the red cathode of the CRT. The original the maroon drop cap tested OK but I had a cap on hand and replaced it. Dont think it will make the vertical any higher though..
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#233
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#234
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Lack of height is nearly always drifted dropping resistors coming from B+boost so look at R119, the height pot, R117 and R118. If they all spec out, lower the value of R119 till the picture fills the screen. If I had to guess our vertical output transformers are going soft slowly, only solution is to feed them more voltage. Those are Sams resistors BTW.
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Evolution... |
#235
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
Audiokarma |
#236
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Hmm... can you measure the high voltage? If it's high, it may reduce the scan size.
Also, if you have a variac, try adjusting the line voltage. |
#237
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Now that you mention it. I have been running the set off my PR57 and when the set is at full operation it does drag the line voltage down about maybe 5 volts. I never thought of adjusting the line voltage after the set has warmed up. This may be the source of my lack of height.
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#238
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Great, now I have even less height and now fold over! Looks like I need to retrace my steps here. All I did was replace a cap. I did clip the leg of a few resistors and soldered them back in. I will start by checking my connections on the resistors and cap.
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
#239
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I would run the vert. hold stop-to-stop before diving into it again. It may be locking at an odd sweep rate.
Also, on the line voltage issue, measure the heater voltage. If it's running signifigantly above or below the nominal 6.3 VAC, it'll tell you whether the line voltage is kosher or not. Last edited by old_coot88; 07-10-2017 at 08:13 PM. |
#240
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Good thing I traced my work back because I forgot to solder a cap back in circuit. All is fine now. Linearity isnt great but I got it as best as I can. I still think I might lower the value of r119.
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Admiral C322C2 Regent (Restoring) RCA CTC-7 Pensbury (Restored) RCA CTC-5 Westcott (Restored) CRA CTC--4 Director 21 (Restoring) |
Audiokarma |
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