Photos soon (got to find the camera).

the goood and the bad and the odd...

The good is the cabinet, very nice. Also the chassis, no rust or other damage, looks like the set was nver moved.

the bad

CRT is acting flakey, red gun pulses, socket glue is loose, Fly is toast (burned up), flame and smoke on the intial test run.

the odd

the CRT was unpluged, hmmm, most of the screws were missing from the back.

My guess is someone tried plugging it in, and after smoke came out it decided in typical DA logic that unpluging the CRT (and prob breaking the socket joint) would make it ok. Just a guess, OR at some time the CRT was tested, and at that time the fly was also bad so the owner just told the service guy to button it up and not fix.




I am searching my stash of flys and have put out some calls. it takes a fly 277. the sylvania PN is 50-16016-1. hopefully I can find one or cobble something togehter. I am not sure what to make of the CRT. Hope its not on its last legs.

Sounds like a nice score!

FWIW, there is a NOS Thordarson FLY-277 available for $1 here:

http://www.collectibles-articles.com/antique/THORDARSON-FLY-277_330541510134.html

fly and back

wow! you are so lucky that flyback didnt start that magnesium chassis on fire and burn your garage and all your other sets up. This what happens when the manufactures dont bother to put fuses and use highly flammable metal chassis.

Fly 277 has to be the most desirable of all the flys. Not much chance of getting one of those, I have seen them on ebay but they grab a hefty price. I love the sweet smell of burning flybacks, please send me the old one

Try re-flowing the solder on the CRT pins, also, add a little new solder and that intermittent may disappear. Two part epoxy is good for gluing the socket back to the glass. Looks like she'll be a nice one.....Sylvania made some nice stuff.

This appears to be an RCA CTC15 clone...

If it is, I have a few of those flybacks in the RCA brand, NOS. The RCA part number is 113382.

PM me if you want one.

This appears to be an RCA CTC15 clone...

If it is, I have a few of those flybacks in the RCA brand, NOS. The RCA part number is 113382.

PM me if you want one.

What are the main differences between the ctc15 and 16 other than the hv rectifiers connection to the flyback?

What are the main differences between the ctc15 and 16 other than the hv rectifiers connection to the flyback?


Almost nothing.

I figured. It looks like most of the parts are electrically identical between all the rca clone round tube sets and rectangular tube sets, but not between round and rectangular. Seems like 80% of the sets were basically RCA circuit designs.

This appears to be an RCA CTC15 clone...

If it is, I have a few of those flybacks in the RCA brand, NOS. The RCA part number is 113382.

PM me if you want one.


PM Sent

What are the main differences between the ctc15 and 16 other than the hv rectifiers connection to the flyback?
Besides a major physical reconfiguration of the HV cage and relocation of the 6BK4, The 16 was the first with auto-degauss.

And as a matter of course on both CTC-15 and 16, always reflow the two ground stakes on the far right end of the chroma board. These crack and cause the 6GU7 heaters to go out. This is also true of the CTC-17 and 25.
oc

Sounds like a nice score!

FWIW, there is a NOS Thordarson FLY-277 available for $1 here:

http://www.collectibles-xxx....html
Unfortunately, that site is one of those Ebay-reposting-conglomeration-with-their-own-ads pages. It showed the flyback as available, but the real Ebay auction ended in March...

start that magnesium chassis on fire
Is it really magnesium, or were you using poetic license?

Phil "just curious" Nelson

I hear it's up before the poetic license Review Board.

:twak:

update. I managed to find a fly in my stash that was close, so while waiting for the correct fly from another member I was able to get it up and running. the HV was a bit low, and width was low (cathode current was about 175ma, basicly I had NO head room for bright scenes). Everything was working as it should but for the lack of headroom (the shunt tube current would drop to 0 on max bright scenes, and the HV would sag to about 19kv.

I received another flyback (the correct one) from a VK member, and just finished installing all the parts to it, and reinstalling the assy. I left my test fly intact as I know it works "somewhat". The only think I did was to use a miller focus coil 6350 instead of the orig since the orig was on the subbed fly, and like I said I did not want to disturb that until I get a chance to at least try the correct fly.

the only other issues were a weak contrast cap, and the normal weak color amp grid caps (.01's the one on the middle of the board seems to always be weak.

the vert lin was a bit to close to the end of the range, the 2.2meg resistor had drifted up to over 2.4, not much but as long as I am in it I replace that.

the vert electro cap tested fine. the doublers test ok, but were a bit slow to fully open, for example a new cap of the same value would open in about 13 seconds, the old ones would take about 30. I have all the caps I need to completely rebuild all the cans and will prob do that later...

only thing left to do is replace the 2kv tube cap on the primary of the audio out, its one of those ceramic tube types.

once I do that I will do the whole HV setup again and hopefully will have the head room to keep the HV constant.

progress the focus is better than it looks, camera issues.

HV setup

1st pic is the HV prob, then the HOT current (used a socket adapter with the cathode break in it, bypassed with a .47uf cap, 500ma range on the simpson 260) and the shunt tube voltage drop across the 1k resistor in the cathode circuit (test point KK and a pin on the 6bk4 which is exposed on the back of the fly cage). lousy pic of the HV prob I know, I tried several times..

I used a new focus coil (long story) which worked well (focus range right in the center).

other issues were pretty normal minor stuff.

Broke the pull on push off switch removing the knob, was able to find a new switch on the back of another pot, which is good since the old one looked pretty well toasted.

contrast cap was weak, the chroma board had the normal weak coupling caps between the demodulators and the color amp tubes.

replaced the white tube 2kv caps just to be safe. the one on the Vert primary was leaking the one on the audio primary was not (at 450v anyway).

all the PS caps seem ok, they get a little warm but so far so good, I have the full compliment for replacement if need be. I can make up some replacements on scape twist lock mounts so it would be a quick replacement.

CRT test fine. socket is loose so will deal with that when I get to removing the lens.

dynamic convergence needs to be touched up, had yellow screen in the B&W reception, think the blue was just converging well. I have a NOS diode pack that I may try out if the old diode pack test bad. I did not check any of the converge parts, will if converging does not go well.

Most of the tubes were ok, some shorts IIRC. HOT was fine, as was the vert multivibrator. 6AQ5 was weak, replace all shorted and weak tubes with NOS.

replaced a few out of tolerance resistors, the 2.2meg that come of the boost to the vert, and the 1K in the shunt tube come to mind, there were a few others but no show stoppers.

oh there was an open power resistor in the peaking circuit, that was new to me.

Color would not sync, adj the color osc coil about 1/4 turn (after trying a few different 6GH8's)

Able to get all 3 colors in setup mode on the lowest bias setting.

it did not look like it had been serviced before beyond a couple tubes.

HV was set to 23kv current is about 170-180ma shunt is anywhere from 100mv to 1.5v depending on brighness setting and picture content. for normal view its tend to hover between .5 and 1.2, very stable HV.

Dave, lookin' good. How 'bout some vanity shots of the cabinet?

will do tomorrow John, just got it all buttoned up. It is indeed a very nice well cared for cabinet. there is the brown stain around the speakers, my guess is cig smoke, but not sure about that. Anyone have any exp removing this?

If I can remove it down to the grill cloth, I was thinking some oxy clean or something like that. will of course try on some old grill cloth 1st to make sure it does no harm. No hurry, its not that bad.

Awesome job on that set:thmbsp: I love the cabinet I hope one like that shows up around here someday.

"Glorious Lollipop Color".... I LOVE it !!

not many sylvania roundies out there.glad you got this one.pics are awesome!

any info on a REA21FKP22? is it just your garden variety roundie, thats a new number to me.

The 21FKP is electrically the same as all the others, data sheet says grey bonded faceplate just like 21FJP.

http://tubedata.tubes.se/sheets/168/2/21CYP22.pdf

Great progress on the set :) Looking good, always nice to sort out all those niggly things with these old Tv's gives a feeling of satisfaction :yes:

The convergence neck components look just like those used in Zenith sets. I expect the crt neck components are interchangeable between brands as long as the picture tube is the same. That is a great picture by the way.

thanks, its getting there. I need to fuss with the B&K 1076 and work on the vert and horz lineairity.

The lines seem to spread out a bit on the very top and the horz is not very good, does not show up with out the test pattern.

I will prob scope the grid of the 6GF7 (vert output) and take a look a the waveform, but its so subtle I dont think I will see anything there.

will try a few tube subs there and see if it clears up. I have checked most of the resistors and caps (not the 680pf in the feed back) Everything looks good, no jitters etc... replaced the only resistor in the vert cire that drifed more than 10% a precision 2.2 meg.

it does not have an auto degausser, I have a kit that I may try installing, every time I move it it needs to be degaussed.

still fighting that darn tendancy towards line pairing...

fooled with it some more, tried some new vert tubes (6GF7), no change. every now and then I can get it to not pair up, but most of the time it does (messing with the vert hold, but its not a very reliable way to get it).

I couple of things noticed. I need to very nearly max out the lin adj (on this set its the one that feeds the plate from the boost, I know on some sets its called the vert height, I dont know why they cant make up their minds on this) to get the linearity as good as I can get it. Also I noticed its a tad jumpy, you can really notice it when there is some text near the top of the screen. I dont know if this "jumpy" vert is tied into the "jumpy" line pairing but it seems like it could be.

While I did test the various caps in the circuit with my old school cap tester the 2kv .0086 cap from the plate of the output side of the multivibrator could not be tested at rated voltage (tester only goes to 450v). there is also some little 680pf disc caps that I am not sure of the function.

I never did scope the grid output from the integrater the way the sams said to (bright down, tube out) to look for excessive horz hash.

I think I mentioned before the last tough dog line pairing issue I had was on a B&W maggie, it was from the yoke, some how it was getting horz back thru vert out transformer and back into the vert osc. I only found it by comparing a working set to the bad set and seeing all the hash on the bad set secondary.

I have another CTC-16 (this is a clone) so I could do the same, or just try a different yoke (I have an NOS). Its really a pita as the rest of the pic looks fine.

I dont know if the boost voltage could be causing this (if it had hash on it from a bad cap). I think I checked it, but not sure. again I could prob scope the it and see, again not being experienced in this I would need to look at a working set to see what it should look like...

Replace that feedback cap in the back of the circuit that has caused us this problem before. I dont care if it tests good, replace it.
The cathode bypass caps on the output triode have the same effect.

I will replace all those tomorrow.

replaced a couple in the vert, no joy, need to get the right cap (.035) for the final one. I did replace the .0082 1kv and the .1 that is connected from the boost to the 390v b+. Nothing.

I scoped the PS B+ the ripple was right on the nose about 1v pp riding on the 400v. there is of course some horz but it was very small and the sams showed it (I assume since it was a fat line on the sams).

For fun I scoped the output from the sync sep. looked normal (no excessive horz noise) and also looked at the vert out grid, again nothing odd. the pairing is very subtle and comes and goes. it is not always adjustable out iwth the vert hold in fact I am not real sure the vert hold is really taking it out when it does work, but maybe its just resolving as I adjust.

I checked the yoke for leakage, even went so far as to sub the yoke, again nothing. I have the .035 cap but its an odd ball fit so I plan to just order the correct one. I also was stunned to find I did not have a 47uf axial lead cap (the cathod bypass cap).

went ahead an replaced the .035, and the remaining .1 in the grid of the output triode of the 6GF7. changed the lineairity (more range now) but still have the line pairing going on. only thing left is the 50uf cathode bypass.

I am going to reset up the lineairity, then do the purity and convergence.

Its close just not perfect, like my CTC-16 in the stockholm. I will try a few more 6GF7's including the one in the stockholm just to be sure its not a tube issue.

I would really like to get these two side by side and scope the vert circuits, esp for horz noise, but they are both quite large.

Did you replace the vertical center control? I have seen that control cause some weird problems. In one of my ctc16 set's it shorted out and did damage to the power supply. BTW,You have a cool set.

did not look there yet. did it test bad, or did you just change it out?

I know it works, as I used it in the setup to center the horz line doing the setup routine.

[QUOTE=DaveWM;3008703]did not look there yet. did it test bad, or did you just change it out?
It had a burning smell to it so I just changed it out. Now I check the vertical center control when I pick up a new set and make sure the picture does not jump around when adjusting the control.

its pretty smooth, but I will check it again. good tip.

well at least I can report that I have good control of height and linearity, but still fighting the pairing. I tried a diff video source, blonder toung modulator, still there. sometimes I can dial it out some times I can't. and even if i do (vert hold) its only temp, as it pairs up again. I am going to try one more
6GF7 tube, then I think I will try subbing the tubes from my stockholm to see if that makes any diff (the sync sep and the vert osc/out).

Other than that I would have to drag the two beast together and start scoping them together, but I reall just dont have the room for that.

Davewm. Try looking at the AGC and see if adjusting the AGC control calms down the pairing. Grasping at straws here but the agc can effect the sync pulse going the vertical and horizontal circuits. What does your set do when you have the color pattern generator used as a signal source?

I did fool with the AGC seems to be working (goes from washed out to over contrast, but never breaks sync, but then again the box may not be putting out a strong enough signal to make that happen).

Good new!! after yet another tube swap on the 6GF7, I get a good clean sweep. I can adj the vert hold for an easy to obtain non paired up screen.

It pays to have a LOT of NOS tubes. While I have a good Mu tube tester I dont know how sensitive the grid emisson test is (its a mercury 1000).

I am calling this one fixed, at least that part.

One last little issue, seems like I often have to change the channel back and forth when the set is 1st turned on or even if I just switch signal source.

The screen will black out, sound is still there a bit weaker but there. one flip back and forth and all is good.

Sounds like it is time to clean the contacts of your tuner.

Tom C.

looks like the blanked out picture had to do with the 3rd IF tube, subbed it out and all is well again. I will check it for gas or grid emissions.

I dont know why flipping the tuner would allow it to work with the old tube, but it was very consistant. I will have to cycle it a few more times before I am satisfied the problem is fixed.

I am still no completly satisfied with the line pairing, I thought the new vert tube fixed it, its better but still a bit shaky (have to diddle with the vert hold to work out the pairing).

Guess it would be a good idea to reflow the solder stakes.

I did try a convergence plug (takes the conv board out but keeps the vert working) no joy same pairing so that clears the conv board.

One last little issue, seems like I often have to change the channel back and forth when the set is 1st turned on or even if I just switch signal source.

The screen will black out, sound is still there a bit weaker but there. one flip back and forth and all is good.

Try this theory on for size:

Horiz drops sync and the keying pulse hits the signal in the wrong place and this confuses the AGC.

The noise from channel flip wakes up the AGC.

This could be and probably is related to the problem with line pairing and signal level shifts.

Recheck resistor values, especially the high value ones in the AGC and any caps for leakage, where a signal from a higher voltage source is fed into the AGC (or to sync circuits.)

(Warning: With that said, I am not familiar with this model set and have not seen a schematic.)

James

James,

for fun I am going to put a bias box on AGC, try clamping it and see if that does anything.

I will check the values as you described. I "think" the fix of the 3rd IF tube is working now, but I have to try it a few more times to be sure.

The agc was acting 'funny' as I was not able to distort the pic or break sync when set to max CW, the new 3rd IF seems to have fixed that.

Oh an I did not do one of the things I promised myself a while ago, always scope the AGC voltage. Look for horz hash or any thing other than a nice DC voltage.

Meters dont catch this so a scope is a must. So will be scoping the AGC voltage as well.

scoped the TP for agc, def some horz noise on it. there is a .1 cap from AGC to ground that I assume is there to filter it. Looks like I will end up pulling the chassis again, I dont recal checking that cap. Could be some stray horz getting into the wiring from the sweep board to the IF board. With out pulling a working set out I dont know how much is acceptable.

ok both the good set and the bad set have a horz pulse in the AGC BUT on the bad set there is a very strong vert pulse as well, I dont know why I did not pick up on this before.

I am going to check over the vert bypass cap again.

this this is really kicking my rear. The AGC just does not seem to work right, full CCW just dims the pic some and full CW just a bit more contrast. I am used to going from full snow to overloaded pic (dark screen loss of sync).

AND its back to its old tricks of having to turn the channel to get the pic to come in (the AGC voltage skyrockets, over 10v+ flipping the channel returns pic and drops down AGC to near zero.

Sounds like your Automatic gain isn't being very automatic.

well I did a few more tube swaps, figured it could not hurt (famous last words). this time IF tubes, I had some NOS the last one was brand new and shorted, oh well I got it out before it did any damage. At least the AGC issue seems working somewhat again (do not need to flip the channel selector).

I realize IF tube swaps "could" mess up the alignment due to gain differences but then again I figure if things got bad I would just put the old ones back in.

Also the line pairing seems less. hard to say as it largely depends on the screen content as to how well I can pick it up.

Anyway time for a break again, will let everything cool done and will check again.

Oh and checking the video feed to the AGC, it was much lower than what sams said, so more cheking and I find the outpuf from the video detector to be about 5v PP sams says it should be 15 (this is at the grid of the 1st video).

So before I go nutz I check it to my CTC-16 hmm say PP, so not sure if the IF tubes were all just weak (this was done before the swap) on both the sylvania and the RCA or if the Sams is just wrong, 15v seems like a lot at the video detector output.

Anyhow I am chipping away at it. I sure am glad I dont get paid to do this, considering how many hours I fiddle away, I would never have a customer willing to pay. I really just dont know how TV guys back in the day made money. Of course with time I guess I would get better at diagnostics and not spend so much time second guessing and wonder what looks 'right".

...Anyhow I am chipping away at it. I sure am glad I dont get paid to do this, considering how many hours I fiddle away, I would never have a customer willing to pay. I really just dont know how TV guys back in the day made money. Of course with time I guess I would get better at diagnostics and not spend so much time second guessing and wonder what looks 'right".
Heh.. back in the day, there seemed to be three fairly defined classes of TV guys. There were the tube jockeys who did the house calls and pulled the sets in when tubes or fuses wouldn't fix the problem. And there were the shop techies who dug in and did the actual troubleshooting and circuit diagnostics. Of course those two classes did tend to overlap somewhat. Then there were the 'dog shooters', the supergeeks who took on the real brain-buster repairs, who usually worked by piece work (as opposed to by the hour).
oc

while comtemplating my next move on this set, I will go ahead and replace a funky Left blue horz pot, its very touchy.

I am short on 6KT8's and 6AW8's (sync/AGC and 1st/2nd video driver, will pick up a handfull of those from my tube guy. Have some pulls but they all tested kinda weak. I am hoping those may shead some light on the odd AGC, esp the tendancy for it to overload when 1st turned on.

it was not a 6KT8 but a 6KA8, an replaced it with an older used one and it seems to work better. I have a thread on this over at ARF as well for those who dont frequent both sites. I think I am getting close.

Dave, If your remove the RF input to the set so and adjust the AGC so there is clean blank raster, does the set still line pair? If so, then the problem is likely in the vert. osc/output. If not, the problem is in the video/sync, or maybe even an IF issue. Something to consider.

I have a B&K 1076, I can try a few things with it. Its out in the garage, but will be coming in soon, should be easier to work on then. the plan will be to try injecting a composite signal and see if that works better. I also plan to scope the output from the detector diode and compare that to the composiit signal from the digital TV tuner. I have done that in the past just to see how well the RF/IF/detector are working (by comparing the dvd comp signal on one trace with the comp from the set on the other). that gives a real good indication of how well the tuner and IF alignment are working.

I have gone thru and replaced or checked just about eveything in the vert osc section, the only thing left I I have not checked (since I dont really know how) is the VDR, but I have one coming soon so I will just replace that. its the one right after the .0082 cap from the plate of the vert out.

finally got it in the house, vert pairing does not seem to be an issue anymore, but now the pic seems noisy, dont recall if that is a new problems, like a weak RF amp tube. could also be related to agc, so I will try a new RF amp tube AND a bias supply on the RF just to see.

There is a tuner subber locally for sale, I am thinking about getting that, seems like a fast way to clear a tuner.

I nver did get the scope out and go over the video signal again. too lazy I guess.

oh and even thru the noise I can see the same kind of ghost as the maggie has (both are CTC-15/16 clones). So either they both have a design flaw, or they both have the same problem, or my signal is bad. Not something I am overly worried about.

If you have another known good set with a transformer power supply (or a hot chassis set with an isolation transformer) this can work good as a tuner check out device. It doesn't matter if it's color or black and white. If you suspect tuner problems in the suspect set, sub in the test set's tuner using the 45 mhz IF output and if you suspect IF problems in the suspect set, hook its tuner IF output to the test set's IF input.

I used a Zenith B/W set with a solid state tuner this way to help find problems in an RCA CTC-28. The picture was very weak and snowy but the RCA set's tuner produced a good picture on the Zenith set. It turned out to have one bad IF tube and and bad 1st video tube.