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My high voltage wire came in so I finished the Flyback wiring. I decided to use some new 20Kv 22awg wire. I've used this stuff before and it has worked well for me. The working H.V. is about 12 to 14Kv.
I used some heat shrink to increase the diameter of the wire and to provide some extra abrasion resistance as it passes through the then guides. I then soldered it to the 1B3GT tube socket and used several layers of heat shrink tubing to provide some extra strain relief on the wires as they go into the tube socket. I then used some lacing cord to tie the wires together before they go into the tube socket shell. I also used some of this wire for the plate cap wire for both 6BQ6GT and the 1B3GT tubes. I'll terminate the CRT HV lead during the dry fit phase. https://tvrestorerguy.com/wp-content.../100_8165a.jpg https://tvrestorerguy.com/wp-content.../100_8168a.jpg https://tvrestorerguy.com/wp-content.../100_8169a.jpg https://tvrestorerguy.com/wp-content.../100_8172a.jpg https://tvrestorerguy.com/wp-content.../100_8174a.jpg |
OK guys, I have some questions for the disc capacitors in this TV. I know they should be good, but I tested one and it was 50% high. So I'm thinking that maybe I'll replace them. There are only 10 of them.
My question is what do I use to replace them? I know I need ceramic disc and I'm thinking of getting 1KV type. I know there are by-pass and coupling caps. Do I get COG, NPO, Z5U, Y5P, etc? Below is a simple chart I made up that shows the SAMS parts list and the cross for each size cap. Also the Item Number of each cap. I checked the old Allied Catalog archive but they don't really list the specs for those caps. Any help would be appreciated. https://tvrestorerguy.com/wp-content.../100_8184a.jpg |
I have finished the main chassis except for the IF Strip.
We, the VRPS of Dallas, has our annual convention this weekend so there will be very little work and posting on my progress. https://tvrestorerguy.com/wp-content.../100_8188a.jpg |
I looked up your disc cap numbers in a 1953 jobbers catalog. Z5U and 5YP type caps will work fine. The originals were rated for 500 working volts DC or better. The tolerances were 20%. The .01 cap should be 600vdc or better according to one brand.
Ed |
Great information. Thanks Ed.
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On the electrolytic's heating concern: I tend to believe ambient heating from transformer and tubes is the dominant factor, but I suppose there could be a small accumulative effect. Many manufactures mounted cans under chassis with little concern for airflow. At any rate it would be interesting to check their temperatures relative to surrounding surfaces of the chassis.
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During this weekend swap meet at our annual convention, I managed to get a few "donor" E-Caps for C4. This E-Cap is the smaller diameter kind.
I restuffed it basically the same way as the others. I use some R/C wing tube that I had after building a model. This stuff works great. I kept the caps out of the sleeve because they put a slight pressure on the sleeve and I thought it would deform the round sleeve. I haven't cleaned out the cans yet. https://tvrestorerguy.com/wp-content.../100_8232a.jpg https://tvrestorerguy.com/wp-content.../100_8231a.jpg https://tvrestorerguy.com/wp-content.../100_8230a.jpg https://tvrestorerguy.com/wp-content.../100_8235a.jpg https://tvrestorerguy.com/wp-content.../100_8236a.jpg |
The bottom side of the chassis is done. Every resistor, film cap, electrolytic, disc, and mica cap was replaced. Now on to the topside. The HV cage, tuner, yoke, etc.
https://tvrestorerguy.com/wp-content.../100_8249a.jpg |
I replaced all of the resistors in the tuner today. 3 of them were a bit tough. I relied on the coil method for those 3 and a few other places. I cleaned the tuner assembly and then replaced the resistors. I then used De-Oxit and a business card to clean the fingers where the tuning strips slide through.
As a side note the average the resistors were 23% from their nominal resistance. The lowest was 3% and the highest was 62%. Of the 9 resistors replaced, 5 were way out of tolerance, 2 were 12% (just out of tolerance), and 2 were 3% (well within tolerance). Pretty close to what I've seen through the 6 chassis I've restored. Where at least 50% were out of tolerance. 25% were just out of tolerance, and 25% were with in tolerance. https://tvrestorerguy.com/wp-content.../100_7984a.jpg https://tvrestorerguy.com/wp-content.../100_7983a.jpg https://tvrestorerguy.com/wp-content.../100_8284a.jpg https://tvrestorerguy.com/wp-content.../100_8291a.jpg https://tvrestorerguy.com/wp-content.../100_8002a.jpg |
As a still-improving restorer, I love reading these thorough restoration discussions and picking up new techniques and correcting my improper methods. I learn so so much from these detailed walk-through restorations!
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Glad to hear that. All the best with your restorations.
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On to the turret. This turret is massive and very well built. First a photo 'walk around".
Here it is just removed from the chassis with the outboard cover removed. https://tvrestorerguy.com/wp-content.../100_8294a.jpg The aft (motor driven end), if so equipped. https://tvrestorerguy.com/wp-content.../100_8295a.jpg Looking at the side that faces to picture tube. https://tvrestorerguy.com/wp-content.../100_8296a.jpg This is the side that faces forward. It also has the oscillator adjustment tool and drive gear. https://tvrestorerguy.com/wp-content.../100_8297a.jpg Close up of the front end. https://tvrestorerguy.com/wp-content.../100_8298a.jpg A close up of the detent mechanism. Another indication of the quality of this TV. https://tvrestorerguy.com/wp-content.../100_8302a.jpg The aft end ball race adjuster. The turret is suspended by 2 ball bearings. The front end uses a race and 9 "free range" ball bearings, while the aft end uses a thrust bearing. The aft end race can be adjusted in or out to get all the "play" out yet still spin freely. https://tvrestorerguy.com/wp-content.../100_8304a.jpg The front end race. https://tvrestorerguy.com/wp-content.../100_8303a.jpg The aft thrust bearing and the 9 balls for the front race. https://tvrestorerguy.com/wp-content.../100_8305a.jpg A close up of the front shaft where the balls ride. https://tvrestorerguy.com/wp-content.../100_8306a.jpg A close up of the aft section where the thrust bearing rides. https://tvrestorerguy.com/wp-content.../100_8307a.jpg I took this picture to "locate" the actual strip according to the number stamped into the turret. https://tvrestorerguy.com/wp-content.../100_8311a.jpg |
I removed each strip and then I cleaned all the parts and removed some light rust from the inside of the cage. The strips will be dealt with later.
The turret is copper plated steel and while cleaning and polishing it, I rubbed through the plating. My idea was to clear coat the polished copper plated turret to prevent it from tarnishing. Then I remembered that I had some Rust-Oleum Metalic Copper spray paint. A couple of quick coats and we are in business. Here is a picture of the aft end where I masked off the thrust bearing race and the new paint. Not much difference. The turret looks very good painted. https://tvrestorerguy.com/wp-content.../100_8317a.jpg Here is a picture of the turret installed into the cage and the free end play adjusted along with the drive gear installed. The turret spins very nicely with no end play. https://tvrestorerguy.com/wp-content.../100_8347a.jpg The end play is taken up by screwing in on the aft ball race. When adjusted just right, the large nut is then tightened to "lock" the assembly. While this might lock the assembly, there was some greenish looking liquid applied to the lock nut and race to prevent it from coming loose. I used some Super Corona Dope that I had to lock the assembly down. https://tvrestorerguy.com/wp-content.../100_8352a.jpg A close up of the front end after assembly. https://tvrestorerguy.com/wp-content.../100_8353a.jpg |
Next up, the tuning strips. There are 12 strips in all. Channels 2 thru 13. On the turret there are 13 spots for strips. One of them is left blank. Perhaps the blank position was forward looking for a UHF converter.
Each strip has some coils and capacitors. No resistors. https://tvrestorerguy.com/wp-content.../100_8355a.jpg https://tvrestorerguy.com/wp-content.../100_8356a.jpg I cleaned the fingers using contact cleaner and an acid brush cut down to about 3/8 inch. https://tvrestorerguy.com/wp-content.../100_8359a.jpg https://tvrestorerguy.com/wp-content.../100_8361a.jpg https://tvrestorerguy.com/wp-content.../100_8362a.jpg After they were cleaned, I used some De-Oxit and a Q-Tip and swabbed each side of each finger. I also marked on the bottom side the channel number. |
UHF channel strips were available for these tuners and IIRC were more common than UHF converters/outboard tuners with these sets. Watch a youtube video of an old Zenith film 'Fog Over Portland' for an interesting look at Zenith's UHF preparations.
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Let's get those strips mounted and the assembly installed.
I mounted the cage to the main chassis and installed the "idler" gear. The idler gear was lubricated and bolted to the bracket, which was then screwed to the cage. https://tvrestorerguy.com/wp-content.../100_8366a.jpg I then soldered on the wires removed when taking off the tuner assembly. Then the tuner was installed on top of the cage using the witness marks left when originally installed. I then screwed the first strip in place using the 2 4-40 screws and lock washers. I then carefully lined up the strip to the tuner and tightened the strip screws. This was repeated for all the rest of the strips. https://tvrestorerguy.com/wp-content.../100_8370a.jpg https://tvrestorerguy.com/wp-content.../100_8371a.jpg I then carefully rotated the turret and could hear some fingers clicking rather than a nice wiping sound. There were 3 strips that made this noise. After careful examination I could see that these 3 strips were bowed up in the middle. I then bent the mounting ears on the turret down just a little bit using an adjustable wrench. https://tvrestorerguy.com/wp-content.../100_8375a.jpg Remounted the strips and the problem was solved. I had a nice wiping sound on all the strips. I then applied some DE-Oxit to each side of each finger on each strip, then ran it through the tuner contacts. I did this twice to be sure I had clean contacts. I then installed the cover to protect those strips. |
The tuning shaft was the next item to be installed. I lubed the end that was nearest to the gear, and the channel selector knob shaft as it passed through the front of the chassis.
https://tvrestorerguy.com/wp-content.../100_8376a.jpg https://tvrestorerguy.com/wp-content.../100_8377a.jpg I then aligned the turret with the channel selector by rotating the gear that attaches to the turret. I then tightened all the set screws and very lightly lubed the gears. |
I installed the fly back and HV cage. No issues.
https://tvrestorerguy.com/wp-content.../100_8380a.jpg https://tvrestorerguy.com/wp-content.../100_8383a.jpg |
I replaced the 2 560 ohm yoke resistors and the 56pf 1Kv cap. I used a 56pf 3Kv COG disc cap. None of these 3 components were listed in the Sams parts lists but were listed in Riders.
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Tomorrow I should be able to attach the yoke and focus coil wires. Then do my resistance check. Then if all is good, then the first power up.
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Looking great! I wish I had your patience!
Just curious... what is the ch number sequence of the strip placement and the ch number sequence of the indicator dial. From what I can see in the pix, it looks like the indicator dial is in numerical order but the strips are placed in a "most likely sequence for a given area" order. Scratching my head over how that works.:scratch2: jr |
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The resistance check so no errors.
I then powered it up with the rectifier tubes out. The filaments all glowed nicely. Then rectifier tubes in and I got B+ voltages. The high B+ reads 328V vs 360V and the lower B+ reads 186V vs 130v. https://tvrestorerguy.com/wp-content.../100_8393a.jpg I have 11.5Kv and the picture looks washed out. All I've done so far is adjust the front controls. V Lin, V Size, Bright, Contrast, H Hold, V Hold, and the Buzz control on the back. https://tvrestorerguy.com/wp-content.../100_8395a.jpg https://youtu.be/1U6SL5BV6-Y Any idea as to where to start? BTW, the test CRT is an 8YP4 with the adapter harness. |
Possibly an open peaking coil in the video chain, somewhere 'upstream' of the sync take off point.
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I just checked L15, L16, and L17 again. They all ohmed out good. See post #43 for the schematics.
Are there any more coils that I need to recheck? |
How about L12, L13, L14 and diode M4 ?
jr |
It was the video detector diode. I replaced it with a 1N34A that I had.
https://tvrestorerguy.com/wp-content.../100_8400a.jpg |
Here is where I am using the original CRT that tested on the low side of good. All I've done is twiddle the front and back controls.
https://tvrestorerguy.com/wp-content.../100_8401a.jpg https://tvrestorerguy.com/wp-content.../100_8402a.jpg I have another CRT that tests on the high side of good. I'll use this one for awhile during set up etc. I'm a happy camper. |
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I have had a bit of a set back. I was just starting to display a test pattern to adjust the picture when I heard a HV squeal coming from the HV cage. After some trouble shooting, it looks like the FB is the source. I'm going to have to replace the FB. I'm checking on the availability of one locally. ETF lists 2, 1 from 2 different manufacturers. The FB part numbers are:
Zenith = S17233 Thoradson = FLY-52 Merit = HVO-53 Stancor = A-8267 Triad = D-45 Ram = X070 ???? = HO-217 |
Before condemning the flyback verify the drive voltage at The output tube is good, AND that the oscillator frequency is correct. I've seen plenty of good flybacks make death squeals from the frequency being off...they also stop making HV when the frequency is off.
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The freq. 15, 850. so that looks good.
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The squeal seems to have diminished some. Barely audible now. I'll check it in the morning and see what happens. |
Some sets like to make more horizontal stage noise than others. Some of my tube sets I can't hear the whine, others when audio is muted I can tell they are on from the next room. I had a ~2007 Sharp that was the worst I've ever heard....I could hear the high pitched whine from that clear across the house I lived in back then (distances you'd have to shout at your loudest to be heard across)....That set ran for at least 5 years like that before being donated or sold in working condition.
I'd keep an eye on Horizontal cathode current and grid drive as well as boost voltage. As long as those are within tolerance may as well run it as is...It may get better. If something genuinely is wrong with the fly worst case scenario it will let go eventually. If it stays as is it is long term then it is probably just fine (perhaps a bit annoying, but fine). |
If there were any issues with FBT there would be obvious symptoms on screen. I would have a poke around while the set is running with an insulated prod (plastic pen perhaps) to see what is making the noise. It might not be the FBT at all. Gentle pressure on each component should reveal the culprit. In Aus our line frequency is 15.625 Khz and I find I now have a notch in my hearing at that frequency.
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The last few days have been spent on some details.
I polished up the E-Cap cans and installed them. https://tvrestorerguy.com/wp-content.../100_8498a.jpg https://tvrestorerguy.com/wp-content.../100_8497a.jpg I then repaired the broken shaft on the fine tuning mechanism. I found some 1/4 inch phenolic rod on eBay and bought several 6 inch pieces. The guy was from Fort Worth and they arrived the next day. After I traced out the positions of everything I tapered the one end using my disc sander at first then my drill press to true it up. I then cut it to length and cut the groove for the keeper. To do this I used my battery drill clamped to the bench. Then turned it on and cut the groove with a hacksaw blade. Took all of 3 minutes. After cleaning up the pieces I pressed them into position. I installed the shaft and the keeper. Then restrung the dial cord. https://tvrestorerguy.com/wp-content.../100_8486a.jpg https://tvrestorerguy.com/wp-content.../100_8488a.jpg https://tvrestorerguy.com/wp-content.../100_8490a.jpg https://tvrestorerguy.com/wp-content.../100_8491a.jpg |
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