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#46
12-09-2024, 12:35 PM
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Quote:
I ended up dividing the resistance: I replaced the burnt terminal strip and the 10k with an 820 ohm 10 watt in the same position to duplicate the original wiring and to minimize wiring capacitance changes. I wired in series with it an outboard 9.1K 20 Watt resistor well away from other components. In addition I had to replace the wires which were burnt and insulation crisp. Last edited by Penthode; 12-09-2024 at 12:38 PM. 
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#47
12-22-2024, 01:58 PM
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From Mike today.
Update, December 22, 2024 Greetings Marshall. More progress here. I finished the rebuild of the vertical/sync board. I ended up replacing every component on the board, including the 7 pin socket for the Vert. Output tube 6AQ5. The socket pins were badly corroded. I will report now, that on every board, there has been some kind of crusty film that needed to be removed. I am not sure what it was but I did a lot of scraping with a small razor tool that I made on the end of a stick to aid the process. Perhaps some kind of chemical that was used by a previous tech, just not sure. I have never seen this before but it is on every board. Again, too there were a number of out of spec resistors on the vertical/sync board. I have started on the video board this evening but no pictures on that one yet. But I can tell you that both of those tube sockets will need to be replaced as well. I get the feeling that this set spent a lot of time in a warm room and was left on for many hours at a time since the tube sockets are cracking from the many years of heat from the tubes. Maybe in a Hotel lobby environment, or something like that, to make an educated guess? Long story short, this set has had a lot of use. Many components out of spec, and many repairs, some of which were not professionally done. You can see a bit of this mess on the picture of the Vert/sync board where components were tacked on top of the board and not installed directly to the holes in the board. Not good practice. OK, here we go with the new pictures. Pix 1 Vertical/sync board before rebuild Pix 2 Vertical/sync board after rebuild Pix 3 Parts replaced on the board Happy and safe Holidays and a good New Year! Mike https://visions4netjournal.com/wp-co....b4-Recap.jpeg https://visions4netjournal.com/wp-co...r-rebuild.jpeg https://visions4netjournal.com/wp-co...-replaced.jpeg Good day Mike, That first pic, what a mess! Beautiful, close to pristine wood cabinet, but a horror show chassis. We have a good 21AXP22, that says something. Best holiday wishes to you and yours, Marshall Visions4 Magazine https://visions4netjournal.com/
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#48
01-21-2025, 12:16 AM
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Update, January 20, 2025
From Mike, I have done a complete rebuild of the Video Board. All components were replaced since I had to do a full scrape of the top of the board to remove some kind of residue from previous repairs. Not sure what this stuff is, but it is not rosin from a solder bath treatment. I have found it on all of the P.C. boards of this chassis. I made a special tool from a small razor blade to help in the process. Also, both tube sockets needed to be replaced. They were both crystalized from heat and the socket pins were exposed from the top of the board. I removed the top cover of the I.F. board and it appears to be clear of this strange residue. I notice a small crack on the I.F. board where one of the mounting screws secures it to the chassis. Fortunately it is not in a critical place of the electronics. It is only a ground, and the ground is good. It bothers me a bit though, that this made it through the assembly line without being caught. However, before this chassis is finished, I will be beefing up all of the grounds on the P.C. boards with wire soldered to the chassis from ground points on the boards. This insures a good ground from P.C. board to chassis. From the looks of the I.F. board, there will not be too much to do in the way of component replacement. I may replace both the Audio and Video detector diodes due to their age but that will probably be all unless I run in to some surprises during R.F.I.F. allingnment. The picures are as follows: Pix 1 Video Board before rebuild Pix 2 Scraping with tool. Pix 3 Sockets removed and board 1/2 scraped of residue. Pix 4 Parts replced on Video Board Pix 5 Video Board after rebuild Pix 6 Video Board after rebuild with tubes installed. Pix 7 I.F. top of board with cover removed Pix 8 I.F. board with crack at mounting bolt. Yet to do: Add grounds to P.C. boards. Replace several more caps in main chassis Make screws for Yoke Clamp. "special" Make up a back cover. Add H.V. cover that is missing. Do AFPC alignment of Chroma Circuits Do R.F. I.F. alingment check and adjust as needed. Cheers, Mike https://visions4netjournal.com/wp-co...4-rebuild.jpeg https://visions4netjournal.com/wp-co.../Scraping.jpeg https://visions4netjournal.com/wp-co...-scraping.jpeg https://visions4netjournal.com/wp-co...-Replaced.jpeg https://visions4netjournal.com/wp-co...r-rebuild.jpeg https://visions4netjournal.com/wp-co...ith-tubes.jpeg https://visions4netjournal.com/wp-co...-Top-view.jpeg https://visions4netjournal.com/wp-co....F.-Crack.jpeg
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Last edited by etype2; 01-21-2025 at 01:48 AM.
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#49
01-30-2025, 03:37 AM
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Update, January 29, 2025
(Full restoration from start to date or scroll to Update, January 29, 2025: https://visions4netjournal.com/vinta...-tv-page-twoa/ ) From Mike, Greetiings once again. I have added ground wires to the necessary boards but no pictures on that. Not much to it really. I have moved to the high voltage cage to change several caps in the horizontal centering circuits. In the process, I found a number of issues that needed to be addressed in the focus circuit. There was an extra resistor installed that really should not be there. It wasn’t hurting the operation but it was poorly installed and had no purpose so I removed it. Also, there was a resistor missing in the voltage divider for the focus voltage. Seemingly, there was also an extra resistor going to nothing as well. I also removed that one. I used the terminals that were freed from that removal to install the missing 2 meg 2 watt resistor that should be there for the voltage divider. Not sure what all of that was about. ?????? I also discovered some poor wiring on the focus control. A “cold” solder joint that was obviously intermittent mechanically. I replaced all of the wiring on the focus control to original specs. I observed some wax leakage from the flyback and removed what was easy to remove. The pictures are as follows. Pix 1 Top of chassis with all boards rebuilt Pix 2 Chassis bottom without the covers installed yet. (Later) Pix 3 Focus control circuit with extra 56 K ohm resistor Pix 4 H.V. Section before repairs Pix 5 Wax from flyback transformer Pix 6 Cold/poor solder joint on focus control Pix 7 330 K ohm resistor not connected to anything with black focus crt wire mis-wired. Pix 8 Chassis shot of flyback Pix 9 Caps replaced, wiring corrected. Notice 1 Meg 2 W resistor added and black focus wire in defferent place Pix 10 Focus control wiring repaired Yet to do: The tuner needs attention and I have already started on that. R.F. I.F. alignment. AFPC alignment in chroma circuits Chroma Bandpass alignment Make extention for back cover Make new wing bolts for yoke clamp Whatever else I can think of. There must be more. https://visions4netjournal.com/wp-co...s-rebuilt.jpeg https://visions4netjournal.com/wp-co...ut-covers.jpeg https://visions4netjournal.com/wp-co...-resistor.jpeg https://visions4netjournal.com/wp-co...e-repairs.jpeg https://visions4netjournal.com/wp-co...m-flyback.jpeg https://visions4netjournal.com/wp-co...s-control.jpeg https://visions4netjournal.com/wp-co...ted-to-it.jpeg https://visions4netjournal.com/wp-co...t-flyback.jpeg https://visions4netjournal.com/wp-co...lack-wire.jpeg https://visions4netjournal.com/wp-co...-repaired.jpeg
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Last edited by etype2; 01-30-2025 at 03:49 AM.
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#51
01-30-2025, 11:33 AM
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Fantastic job. I'll be referring to this thread as I start work on mine.
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#53
01-30-2025, 02:17 PM
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Quote:
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Last edited by etype2; 01-30-2025 at 02:20 PM.
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#54
02-14-2025, 11:41 AM
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From Mike today,
Update, February 14, 2025 Good Morning. I had to do some work inside the tuner. Two of the B+ power resistors were out of tolerance. The main tuner cover was not installed properly by a past tech so I had to remove the tuner from its mounting assembly and straighten the cover so it fits properly. Also, the cover for the antenna input balun unit was missing.. I had a spare! Here goes with the list of pictures. These will be sent over 3 emails. Pix 1 Parts replaced in H.V. cage. Pix 2 Cover missing on Antenna balun unit. Pix 3 Cover replaced from my spare parts. Pix 4 Tuner 10 K ohm resistor down in value to 7 K ohm. Pix 5 Tuner side view with 10K resistor replaced. Pix 6 Tuner 12 K ohm resistor up to 17 K ohm. Pix 7 Tuner 12 K ohm resistor wide view. Pix 8 Parts replaced in tuner. More to come soon. Mike. https://visions4netjournal.com/wp-co...H.V.-cage.jpeg https://visions4netjournal.com/wp-co...r-missing.jpeg https://visions4netjournal.com/wp-co...are-parts.jpeg https://visions4netjournal.com/wp-co...wn-to-7-K.jpeg https://visions4netjournal.com/wp-co...10-k.res_.jpeg https://visions4netjournal.com/wp-co...up-to-17K.jpeg https://visions4netjournal.com/wp-co...wide-view.jpeg https://visions4netjournal.com/wp-co...-in-tuner.jpeg
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#55
02-22-2025, 12:30 PM
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Update, February 22, 2025
From Mike, I have changed the video detector diode which improved the contrast by a fair amount. I also changed a similar diode in the color killer section only due to its age. It was the same part number as the video detector, general purpose signal diodes, 1N64. There appears to be a small problem in the chroma phase circuitry where the hue changes by a fair amount as the set warms up. Not sure what that problem is just yet. When I was doing the AFPC alignment (Automatic Frequency and Phase Control) of the chroma circuits, the hue never came out right which indicated a phase problem. This turned out to be the 3.579545 MHZ crystal was slightly off frequency. After replacing the crystal, the AFPC adjustments came out right, but I am still left with the hue change after warmup. More on that later. Another thing that I am not happy with is the resistor in the power supply that I chose to reduce the B+ voltages due to the solid state rectifiers I installed to replace the 5U4 tubes. I have ordered a better replacement for that resistor. I have done a full alignment of the Chroma Bandpass amplifiers and the RFIF strip. Improvements came from both. I will be working on the new special screws for the yoke clamp and the modification of the new back cover which needs to be made wider for the cabinet. Pictures will be sent over 2 emails. Pix 1 Chroma Bandpass Curve after alignment Pix 2 R.F. I.F. curve after alignment. Pix 3 A good Jetsons cartoon shot to show good color. Pix 4 A shot of a girl from Hawaii 5-“O” w. good yellow! Pix 5 A shot of a flying helicopter on Hawaii 5-“O” EDIT: I changed the Burst Amp transformer and that seems to have fixed the drift. If there is any drift now, it is very minimal. The drift was dramatic b4 the transformer swap. Cheers. Mike. https://visions4netjournal.com/wp-co.../DSC03281.jpeg https://visions4netjournal.com/wp-co.../DSC03289.jpeg https://visions4netjournal.com/wp-co.../DSC03296.jpeg https://visions4netjournal.com/wp-co...4-rotated.jpeg https://visions4netjournal.com/wp-co...3-rotated.jpeg
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Last edited by etype2; 02-22-2025 at 06:40 PM.
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#56
03-12-2025, 05:14 PM
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Update, March 12, 2025
CTC-5 Update From Mike, Greetings Marshall. We are in the homestretch with this one. Still some HUE shift but that might be my JIG CRT. Replacing the Burst Transformer helped a lot but still some shift of about a 5 to 10 minute warmup. I will be connecting this chassis to my set 21AXP22 crt within the next 2 days. I hope to get a better idea of its performance from that. I hope the Hue shift goes away with that test. I have installed 2 brand new tubes in the sweep circuit even though the ones in the chassis seemed to be working OK. Those tubes are the Horizontal output and damper tubes. 6CB5 and 6AU4. I did this due to their age. I will keep the old ones for test purposes since they still work properly. I feel better knowing that those tubes in the set are new. The yoke clamping bolts were missing so I had to make new ones. They are unobtainable. I was able to contstruct them from some 10-32 threaded rod, some small nuts and wing nuts. J-B Weld epoxy played a big role in the process. If all goes well I plan on delivery of this by the end of this month. I will figure out timing and let you know soon. I stll have to find or make a new cover for the deflection yoke since it has deteriorated over the years. I have a plan in place for that. As for the back cover, I will be finishing that at your house and I will bring all of the materials and tooling to do so. The measurements are still a bit unclear so I think that doing it there is best. I have found the proper chassis bolts so that is no longer an issue. I think the “pencil box” screws are missing also so I will be bringing those too. Pix 1 is what the original yoke clamp bolts look like. I took this one from my set for the photo Pix 2 is the 2 that I have fabricated for your set. See you soon. Cheers, Mike. https://visions4netjournal.com/wp-co...lamp-Bolt.jpeg https://visions4netjournal.com/wp-co...amp-Bolts.jpeg
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#57
03-22-2025, 01:29 PM
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The Plan
March 22, 2025 Hello again. Well, things have slipped a bit with the delivery timing. I have been pulled a lot of different directions this month. It is looking more like the first week in April. I have not had time to bring the chassis into the house and connect it to my tube for final evaluation and that really needs to be done. I keep running the chassis on the bench when I am in the shop and it is still rock solid. I may go through the AFPC alignment one more time on the chroma circuits to see if the slight drift in HUE tightens up. Again, I will know a lot more about that when I hook it up in the house. It all may be my jig CRT drifting. Either way, see you soon. Mike
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#58
06-27-2025, 02:46 PM
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We are back after a long hiatus and a persistent problem with a hue shift.
Update, June 27, 2025 Greetings. After taking about 6 weeks off, it is time to re-visit this project. There appears to still be a shift in the hue. Cold spray has shown no sensitive components. However, there are 2 capacitors located inside the CW Driver Transformer can. They cannot be accessed with the cold spray so I have elected to change them. I had to order these since they are 5% tolerance and the best I could do is 10% in my stock. There are 2 capacitors in the can, a 680 pf and a 1000 pf both of the silver mica type. The wires on this transformer are very small and delicate so there are no second chances if something should go wrong when changing the capacitors. I also plan on changing the socket on the 6CB6 CW oscillator tube. It is very dark in color and probably should just be replaced whether it is problematic nor not. The pictures will be sent over several emails. Onward! Pix 1 Schematic showing the caps inside the can Pix 2 Bottom view of XFMR Pix 3 Moved several coils out of the way so I can get to the XFMR wiring. This unveiled a very suspicious looking ground connection. Pix 4 6CB6 Osc. socket discoloration. Pix 5 XFMR wires disconnected Pix 6 and 7 XFMR removed and ready for dissassembly Pix 8 External components removed. These will all get replaced with new. Pix 9 XFMR dissassembled Pix 10 The 680 pf cap shown with the 1000 pf behind the coil. https://visions4netjournal.com/wp-co...WXFMRcaps.jpeg https://visions4netjournal.com/wp-co...CWXFMRBot.jpeg https://visions4netjournal.com/wp-co...round-con.jpeg https://visions4netjournal.com/wp-co...B6-socket.jpeg https://visions4netjournal.com/wp-co...ires-disc.jpeg https://visions4netjournal.com/wp-co...removed-1.jpeg https://visions4netjournal.com/wp-co...removed-2.jpeg https://visions4netjournal.com/wp-co...comp-rmvd.jpeg https://visions4netjournal.com/wp-co...FMR-disas.jpeg https://visions4netjournal.com/wp-co...f-showing.jpeg
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#59
07-03-2025, 02:22 PM
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Bandpass Cap Replacement
Update July 3, 2024 Greetings. I have acquired the 2 new silver mica capacitors. The following pictures explain. Pix 1 The new 5 % tolerance 680 pf cap. Pix 2 The new cap installed Pix 3 The other cap on the other side, a 1000 pf old cap. Pix 4 New 5% 1000 pf cap installed Pix 5 Bandpass XFMR re-assembled Pix 6 The repaired ground with busswire attached. Next, we install the XFMR and replace the 6CB6 3.58 MHZ local oscillator socket. https://i0.wp.com/visions4netjournal...337.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...338.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...341.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...342.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...343.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...344.jpeg?ssl=1
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#60
07-13-2025, 04:22 PM
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Update July 13, 2024
From Mike, Good morning. The work on the CW Driver transformer is complete. The 6CB6 3.5 mhz local oscillator tube socket has also been replaced. The AFPC (hopefully final) alignment went as expected. 6 photos follow over 2 emails. Pix 1 The CW Driver transformer with the external componects replaced. The old one had to be removed and discarded in order to disassemble the unit for the internal capacitors replaced which was previously described. Pix 2 The badly overheated tube soket for the 6CB6 local oscillator. Pix 3 The socket removed. Pix 4 New socket installed. Pix 5 Chroma pattern after AFPC alignment. Pix 6 Real time image over the air. Best I could do. Onward to cooking it on the bench for a few days. Stay Tuned!! https://i0.wp.com/visions4netjournal...345.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...346.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...347.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...348.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...ted.jpeg?ssl=1 https://i0.wp.com/visions4netjournal...364.jpeg?ssl=1
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