Picked this up today. Wood looks pretty good, needs a good cleaning on the metal parts. 6JE6 had a short on pin 8, CRT is weak but at least all three guns are about the same weak and it does come up so I should be able to test it out. Looks unmolested (all the screws were in the back, and the chassis topside looks good). I will do the soft startup in a bit and see how it goes. Worst case is I have a CTC16 in a termite destroyed cabinet with a good CRT that woull make an easy swap. Tube tuner with a SS power amp.

Great score Dave,congratulations. I have that exact same one i picked up last year, as well as a similiar one that my parents bought when i was a kid that i fixed up. Ive got a soft spot for these things, if you need any extra parts or any questions i can help you with, feel free to get in touch.BTW, the model is called The Stockholm and its SAMS folder 818. take care Bruce

roger that. I its on the variac so far so good. The chassis is super clean.

1st try, got audio so at least tuner is working, HV would not come up, I stopped it when the HOT current went up to 300ma. Will be checking for drive next. a quick check of the HOT grid with a standard DMM gave -35v. Should have been more neg, but that may have been the loading of the meter. I will put a scope on it and see hot it looks. I pulled the shunt off just to make sure the HV was not getting shorted to ground.

wow that is a nice set dave mine has been in storage I dont know when it will ever come back out

well, I checked the drive wave form good PP correct shape, then checked the voltage again, this time with my vtvm, hmmm does not go neg, double check with a VOM same thing, I think I was using the DMM and was seeing a +v grid not a -grid, damn digital displays. Well I smoke the DMM when I had it in resistance mode and connected to B+ argh so not sure what it is, but forsure the HOT grid has a positive bias. I let the tube cool off and, pulled the HOT and hooked up to the grid, the instant I plug in I get a surge of +vdc on that grid. It drops as the horz osc warms up. I figure the .01 coupling cap from the horz osc to the HOT is leaking. Will check that next. I just hope I can do it with out too much in the way of pulling the chassis out. Thats one thing about combo that can be a bear, all the extra wiring.

What's pin 8 shorted to? -35 volts grid is too high, and would no doubt cause the tube to overload. My RCA manual shows -56, so something's amiss. First suspect would be a drifted 10 meg resistor (R169), which would put a more positive voltage on the grid.

I think it maybe ok, I replaced the coupling cap, will reinstall in the set and try again. Prelim check on the bench looks good (cat current around 200ma). I am having some arcing from the HV rectifier filament leads to the cage, insulation breakdown, I will see if I can just dress them away for now and give it another try.

this thing must have been some tv shop's tube dumping ground, 12 hard shorted tubes, evey pcb effected (even the tuner had a shorted tube) mostly off brand tubes (not orig rca's).

I am pretty sure I have all of them. there are one or two questionable looking caps some dipped caps that look like they have gotten very hot at some point, one sits right next to a power restor. The resistors look different from what I have seen on a lot of sets, they seem like they have a courser appearence, some of them are very hard to read, the color bands have degraded, not sure if its from heat or just age (I think when new they prob did not look all that great), but they all test very well.

I have seen several shorted tubes in sets that sat unused for years. I wonder if its whiskers? Can whiskers form in a vacuum?
I have had good luck banging the tubes on the table or blowing the shorts open with B+ voltage. They never seem to reshort.

I remembered you exp with fixing the shorts, was trying that as well, no luck.

Aw man, we sold a number of that exact model combo 'back in the day'. Seeing the pics makes it seem just like yesterday.
Trusting y'all already know about reflowing the two ground stakes on the far right end of the chroma board. They go open and kill the heaters on the 6GU7's.
Bill(oc)

thanks for the heads up old coot, I will def do it.

Dave.... Dave.... Dave....

If you keep finding all the good stuff, there will be nothing left for the rest of us... Just kidding...

One of my neighbors has this same set in the basement. I've been trying to get it for years. Her dead husband bought it, so it's not going anywhere. I've gently reminded her kids that I would restore the TV if they ever decide to let go of it.

When i picked this up last year and removed the CRT for cataract repair, it was without a doubt the easiest removal i ever thought possible, the safety glass literally stayed on the floor when i lifted the tube. I hope you have fun with this Dave...

I like how the bezel on that one is green, just like the CRT.

oh yes much fun, I have to say this hobby keeps me sane this time of year.

I did manage to check that one CRT grid coupling cap (it was very dark in color unlike the other two) sure enough it was weak on the cap tester. Prob would not have made a diff but what the heck. when I get some time I am going to go thru my pulls and see if I can find some tube for the shorted ones.

The HV has a leak from one of the HV tube filament leads to the HV case. I am going to just get some plastic and dress it away for a temp trial.

cleand up some gunk off the front bezel, looks better already, looked like years of smokers tar accumlation. Got most of the tubes from my stash still need a few more, I am sure I have them, just have to dig. I am trying to use up my stash of pulls, saving the NOS since they are boxed and neatly stored.

I am tempted to get some silicone caulk and carefully coat the filament leads around where it was arcing. It would be easy to get at since it was in the middle of the lead coming down from the HV cup (mounted on top RCA style).

THats what I did on a heathkit GR-295. Silicone works like magic!

I will stop by the store and pick some up. I always end up with a tube in a gun thats solid, maybe I can find a small squeeze size. I really dig the way this thing looks, for a combo its quite pleasing.

Ill pick you up a few feet of that wire next time Im at the electronics store.

You could pull those two wires out of the socket and put several layers of heat shrink over the bad spot but even that is tacky.

got the last of the tubes, just have to find a few minutes to put it all back in and see how it goes....

I did not even check the 3A3, swapped in one from a working set, and I got a full raster :D 25kv at about 185ma

going to check the one just to see how it checks out.

Almost time for the rockford files will be hanging it up for a while

checked it the 3A3 had zero emissions, did not see the filament light up.

1st screen shot. The tint is off but the control works I just did not bother to set it correctly. this pic was taken in a VERY well lit garage, so that old CRT still has some life in it.

Congrats, looks like it will end up being a decent performer!

185ma.@ 25KV. That is a healthy sign indeed. Back in the day, if we could get it down to 200ma. with good width and regulation, it was considered a good portent of longevity.
Bill(oc)

wow and the color works without having to change the crystal, go through 5 different 6gh8s or tweak on the coils.

what odd is I dont really know why I had the orig high current, the only thing I did was to replace the HOT coupling cap (the .01 tested a bit weak on my cap tester but not much just a little, certainly not enough to resolve this)

I think what was going on was the HV filament lead was shorting to the chassis, when I pulled it out an bench tested iit I could see/hear the arc.

after dressing it away from the chassis (short term fix) the arc resolved and the HOT current came down. I assume this was the base problem with the cathode current.

focus on that 1st pic was not very good. I plan to check the focus tube (1v2) and will check the focus voltage at the CRT.
and need to check the contrast control to see if its effective, maybe a weak Y signal (has all the orig eletrolytics, so I was thinking maybe the 12BY7 cathode bypass cap). I have seen low Y result in loss of detail.

finally I have to figure as bad as the cateract is, that has got to be hurting the pic some.

well now that it has base line working status, I will pull the chassis and check all the can caps. I am pretty sure the main filter caps on the B+ are ok as the ripple was normal, but I know some of the other sections are ofter used for bypassing or decoupling and can cause odd problems. Considering its age I think its prudent to at least test them while I have it all apart. That will also allow me to do a through cleaing of all the dust and crude inside the cabinet. I will also clean and lube the tuner while its out.

Dave that set is sweet.I can't understand how you find all these,as I am in Florida too,and have never found a roundie in the wild .Great find!

tested 1 can all sections test fine, second can 1 of 4 tested tested fine, did not get to the others, but I suspect they will be fine as well, 3rd can tested 1 of 4 tested fine. will check the others later but I suspect they will be fine as well.

checked the .001 2kv plate to ground cap on the Vert out tube. its one of those hard white shelled caps. It tested correct for value, but the eye would only null to about 3/4 fully open. On leakage again it would not fully open, and that was at 450v. All I have is some 1.6kv dipped caps. My guess is they are prob better than the 2kv that were in there when they were new, but I will prob go ahead and order some anyway if I can find them.

There is a .001 plate cap on the 6aq5 that is also a 2kv, argh...

I have some 2kv .001 disc caps but the one in there are 10%. I dont think it would matter on the audio, but not sure about the plate to ground on the vert out.

I added a micro sized fuse holder right by the horz out tube socket for the cathode of the HOT. I have a 300ma fuse in there. I also bypassed the fuse with a .1uf cap. With the cap in place it should be very easy to check the HOT current, just pop the fuse out and hook up the milliamp meter. I dont know if the cap will have any effect on the fuse, I know there is some voltage drop across it in operation, not enough to effect the HOT bias, but maybe the pulse could cause a false blowing of the fuse? fuse fatigue?

anyway I think I will now check to see where the takeoff for the B+ is on the pcb (its on the audio board) and see about putting in a line fuse there as well.

I went ahead and replaced that 2kv 001 with a disc cap, and pluged it all back in, still get a good raster, did not have time to hook up the tuner, so at least I did no harm to the HV with my HOT cathode fuse mod.

let me make that sound nicer, you need to invest in some of those square chemical fuses if you want to protect the set and dont want the fuse to open from general use :D

I wish I had my camera (AWOL) I cleaned up the knobs, reinstalled the chassis, hooked up the audio, did a brief center converge (OTA pics), set the gray scale up, after a few minutes it makes a very nice color pic, excellant flesh tones, deep colors, etc...

Sound is good as well (I had not tested that since I had to disconnect the speakers to get the tuner into the service position.

the CRT is weak but does come up after a few. I am looking forward to pulling the cataract out to see how much nicer it will look.

I am going to give it a rest and tackle the SS power amp, I only had one channel, not sure if it was the amp or the tuner. Have not tried the TT to see if it spins.

I did a real quick rub down with some restrofinish, looks a lot better, not sure if its worth the effort to restore the wood work. I have not done much of that, I may choose a set that is not as cool looking to start off with my wood refinshing skills.

I hope the phono cart is not DOA, they are hard to come by and pretty expensive considering what they are.

I hope the phono cart is not DOA, they are hard to come by and pretty expensive considering what they are.

Tell me about it... I flew to a different continent to get a replacement ceramic for a crystal cartridge :D (well, I was there on vacation and took advantage of it... but that explanation doesn't sound anywhere near as impressive...)

Good luck with the resto- I love reading about other people's repair stories.

well the SS amp was in pretty good shape, used compressed air to blow off the 45 years of dust, yuck...

it had two .0027 paper caps on the input, both leaky, hope they did not fry the transistors. Two small 10uf coupling caps were leaky and had a high ESR, replaced those, there was one 40uf 250v cap that was a bit leaky as well, and a single 500uf 50v cap (think it was a bypass cap for the power transistorss) was leaky. the rest were ok (a couple 500uf 50v on the output and a triple section 250v filter cap for the tube stereo power supply).

anyway will try it out tomorrow, at least can test it by touching the tape input and see if both channels work.

the tube stereo will def need some work, there were paper caps in the MPX board, so at the very least those will have to go. The AM was working but the FM was dead. Did not check anything at all on that, so maybe just a dead osc tube in the FM tuner.

well of course there was no way I waiting until tomorrow. guess one of the leaking B+ caps may have been the prob with the FM, as it was working fine now and both channels sound nice and clean. the MPX light is working but I did not try to see if there was actual separation in the channels. I wil pull the radio chassis tomorrow and replace those caps and give it a general going over. The face plate is VERY dirty, so I will clean it up when I pull the stereo. I can see some of the silver paint is warn, not sure how to fix that, but maybe on of those paint marker pens may do the trick.

this thing really bumps....

well about out of gas, replaced the two papers (leaky of course, just checked for the heck of it) and 3 eletrolytics, all tested with high esr, could not check two of them for leakage, too low a voltage, like 5 and 15v my tester only goes as low as 25v, but they needed to go anyway.

Cleaned and oiled all the moving parts, scrapped of some mild rust spots that were on the metal face where the dial pointer slides, a little lithum there just to smooth it out, oiled all the pulleys etc... cleaned the pots and switches.

cleaned the white plastic back part of the dial face that obscures the chassis when reading the channels. the chassis was very clean. I just find it hard to understand the usage of those dumb paper caps, I figured they were stopped by the late 50's

more progress today, the stereo tuner faceplate cleaned up very nicely as did the knobs, hot soapy water and an old toothbrush did the trick.

on the plastic there is lettering that stands proud of the backing, RCA, new vista etc... was silver but much of it was worn off. I think If I can find or fabricate a small rubber J roller with the roller made from fairly hard rubber, I could just use it like inking lettering with some silver paint. I dont trust my hands to try and touch up with a brush, and since the lettering stands proud, I am pretty sure it would turn out nice.

Going to clean out the bottom of the cabinet under the tuner today and reinstall, hopefully the stereo will not need any more work as its a bit of a PITA to hook it up to the amp and speakers. Pretty sure it will be fine. I have worked on other RCA tube tuners, they work very well.

Cart is good will have to get a new needle. TT operates normally, just dirty as heck, but seems to be coming clean with no corrosion. removed platter bearing, will repack. normal stuff lube everything that moves. This one is going to be a record turnaround time from pickup to ready to use. Easy to become my favorite due to the ultra cool styling.

all back together, Its missing the blue lateral adj, I am going to look around and see if I have a spare, the bracket is there, but the screw adj is MIA.

The TT works smoothly but I will have to do a re-tread on the idler wheel, its not gripping well enough to cycle thru the tone arm sequence, I am pretty sure its just slipping, the rubber was not very pliable.

the free floatiing cart holder needs a new felt (it actually rides on the record).

the TV switch turns off the amp when the TV is one. I can defeat this by just pluging in the amp directly into the power line, bypassing the TV chassis socket. that way I can use the aux input (tape) for the DTV box, but I will still have to disable the speaker cut out that disconnects the speaker when the TV is on. I really prefer using the stereo to drive the TV audio, I dont know why zenith and RCA did it this way, magnavox was better in that they used the stereo amp for TV (mono of course but still...)

I will do it in such a way as to be easy to reverse.

The TT works smoothly but I will have to do a re-tread on the idler wheel, its not gripping well enough to cycle thru the tone arm sequence, I am pretty sure its just slipping, the rubber was not very pliable.



Depending on what shape it's in, if it's just dried out, soaking it in some glycerine for a day or two will do wonders to rejuvenate rubber. I've done it with a couple of direct-drive tape drives for some of my older PCs.

If that doesn't work, maybe you can flip it around? I used to charge $10 for that service back when I was still repairing VCR's on a daily basis, it was pure profit.

some photos, oh and where do I get glycerine?

more photos.

there is still a slight misconvergence, I just ran out fo time, did not hookup the cross hatch gen.

If that doesn't work, maybe you can flip it around? I used to charge $10 for that service back when I was still repairing VCR's on a daily basis, it was pure profit.


I dont follow the flip it around?

Oh and I forgot to mention, the stereo FM separation sounds like its working fine. I will normally would use my small stereo transmitter to test, but again ran out of time, the OTA stuff seemed to be working. I will have to go play the rock station and wait for some led zep, or maybe queen bohemian rhapsody to come on, those are good test for separaion.

You should be able to get glycerin at just about any drug store. It's often sold as a moisturizing agent for dry skin or numerous other skin conditions.

It's a fatty acid, and quite friendly to rubber since it is not highly polar like an alcohol. (also non toxic!). It soaks in quickly and basically restores the flexibility of the wheel.

I dont follow the flip it around?


I think he meant take it off and turn it upside down. In a lot of my tape drives, the top half of the rubber capstan/idler are pressed agressively against the plastic roller in the cartridge, while the other half is not... if you flip it upside down, you can use this "unworn" half without issue. It may not apply to turntables though, since the whole wheel is usually in contact.

If you do have to re-tire, sometimes a single layer of heat-shrink can work really well, if the rubber you're covering is still a smooth surface - it will provide a new gripping surface without costing too much.

I will check out the drug store.

I have some square oring material that I have used in the past. I freeze the idler, chuck in a small lathe, turn down about 1/8, but the square o ring on, hit the inside joint with some CA glue, freeze it again, back in the lathe, the final sand it with an emory board. works pretty well.

Looks beautiful Dave, that CRT looks pretty good, did you say it was weak? Looks like it has some life left in it. Let us know what youre going to do with the cataract problem, ive got an FJP sitting in a tub of water for over a month now and so far, nothing...

I will wait for a warm day, take it outside, see how things go, maybe try the hot wire trick. Not going to do the heat lamps thats forsure.

I am in the middle postion on the bias. it takes about 2 min to come up to full brightness from stone cold.

and yes it tested very weak, but comes up to just in the green if you leave it be for a couple minutes.


was just playing around with it some, I think the RCA roundies make some of the best yellows even by todays standards (forget you quattro).

UHF checks out, was alble to pick up the LP local station with just a small loop antenna.

One of these days I would like to try DXing for OTA broadcasting in Analog.

cool link
http://books.google.com/books?id=NVMEAAAAMBAJ&lpg=PA73&ots=nzlKZIQt8y&dq=rca%20the%20stockholm%20model%20color%20tv&pg=PA73#v=onepage&q&f=true

I had some tong oil that was in my resto box, decided to try some of that, wow what a nice way to make old wood cabinetry pop:yes:

I really like the tong oil, its very controlable (you pretty much cant go wrong). I never have had any luck with ureathanes, varnish or shellacs. I aways end up with some defect in the finsh, with the oil, you just wipe it off and let it dry.

going to put a few more coats on (have to wait at least a day or two between IIRC). I am hoping I can mask off and paint match the one area of the mask. Its an edge and should present no problems as far as matching (the hard edge should make that easy)

tung oil is great!i use it exclusively on my restorations.i dont care for poly at all.i use lacquer sometimes but tung oil is my favorite.if you cut it with some mineral spirits it make a spit coat and really shines.your crt looks decent enough to keep.the roundies produce some fine yellows as well as reds.nice piece and i am happy it was saved

yea this one turned out really nice. I just out sitting in the garage and I got some whole lotta love come on to test the stereo MPX, and Later Queen Bohe Rhapsody just like I wanted, very good separation, I dont even mind that the power amp is SS, I can at least say its Germanium vs Silicon :yes:

I tried the glceryin on a old idler I had lying around, the rubber was more like hard plasic, after letting is set in the lotion all day with no noticable effect I decided to try brake fluid, heard of that before but did not want to try it on a ilder I needed so this one is the test case.

I know I can do the lathe trick (heck I was even thinking of just turning one out of some alum and putting a V groove in it for an o-ring) add a ball bearing and it would be about as good as it gets, but that is a bit of over kill.

Not a big fan of these older TTs from zenith or RCA, I like the imperials MUCH better on my maggies.

THE HOT WIRE DOES NOT WORK ON THE RCA STYLE!!! only the green zenith soft rubbery type.
Let it bake in the hot sun face up for a few hours and then rock it while lifting. If it doesnt come off I would put it back in. You know how easily these old crts crack and go to air. They are very fragile.

Simpsons look real good. I dont see much color bleed or anything.

I tweeked the focus, looks even better now.

I have put about 4 coats of tung oil on it, 0000 steel wool between coats, looks great. I also used the 0000 on the metal pull knobs and tuner handles, cleand up the gunk that was left, very nice and shiney. The TT seems to be working better the more I use it, for a while there it was having a tough time on the cycling but lately it works fine. I stole a needle from another RCA that I had a new diamond needle. Sounds excellant. Every now and then there is a miss fire and the record drops the arm lifts and just settles down and then turns off. I can see the little sizing lever is not working right when that happens. My guess is it just needs more use to continue to loosen up.

I tried the brake fluid on the spare idler several days, no change. going to just retread it.

touched up the purity, had a tough spot to work out, did another degauss, think I got it. used a dot/bar/crosshatch gen to touch up the convergence, just a tiny bit on the dynamic was needed. Roundies seem so much easier to get it right for me anyway. The CRT seems to be getting better if that is possible, I reset the bias to the top spot on the switch, still have plenty of brightness, tracks well etc....

I will get some more pics in a bit. the only thing I have to becareful of is the purity rings are very loose. I may try some toothpics to hold them in position.

I just know its going to look great when I get the cat off.

here are some after convergence. there is still a slight purity issue along the top.

I am going to give it a rest and try again later. I could not get the red cloud very small in the center, maybe just could not move the yoke back far enough.

since it was so large it made it difficult to see how well I was centering it.

Nailed the purity, re did it, this time I was able to center the red cloud and get the normal sets of 3 around it. Slid forward, lookin good now. I will check it again when some B&W programing comes on, that seems to show it the best.

looks good!nice rca roundie color.another beautiful set saved!

looks good!nice rca roundie color.another beautiful set saved!

roger that, this one has certainly taken top billing in my inventory of sets. May motivate me to get off my tukas and make that cabinet up for my other CTC16.

They just dont make them like this anymore, its such a shame to hear about one that gets trashed. I see a lot of consoles where the TV has been ripped out, and a BPC put in or just turned into a liqure cabinet.

I dont get why people dont do the tinest bit of research to find out that the set is fixable.

I had a conversation the other day with a younger person, when I told her the CRT could make a very nice pic, she was skeptical, I explained that indeed some CRTs made late in the 90's may have been garbage (by design IMHO to help sell the upcoming flat screens) but these old sets make for a very nice picture when setup right. Plus I could care less about most current programming (except for sports) so I dont really need all the whiz bang aspect ratios etc...

anyway enough rambling got to go get ready for RTV tonight.

a few more. I have tried it at as low as 105vac, loses some vert height. 110-115 is fine and where I would like to operate it just to reduce heat.

these are after the purity setup

pictures are great.cataract is marginal and picture is outstanding.

Its a beautiful thing Dave. I cant tell you what a pleasure its been watching you do this, and the picture looks great.

I think we need a "the stockholm" fan club....:yes:

Good job there Dave. Great trip down memory lane.
:music:
Bill(oc)

make a nice large close up of the turn table idler whell...may have one

[QUOTE=DaveWM;2996819] They just dont make them like this anymore, its such a shame to hear about one that gets trashed. I see a lot of consoles where the TV has been ripped out, and a BPC put in or just turned into a liqure cabinet.

I dont get why people dont do the tinest bit of research to find out that the set is fixable. /QUOTE]


Back in the day when VCR's came out, the older sets were not compatible with VCR's because of the slow horizontal time constant. It was a tedious job to change that. People would not spend the funds on an old set.

...

you are right andy, I just like to make sure its working. I still has the orig diode pack, and I think there maybe one of those cap tube caps. I just cant remember now. If there is a white cap it will get replaced, but I will leave the Se diode pack in as long as its working.

It will prob be a while before I pull the CRT for cat removal. Waiting for warmer weather. Around here the summers get so Hot I am betting that a few hours in the sun will allow it to pop right off.

NOS 6C9 in the tuner seems to have resolved my FM distance issue. There is one station that I like that was just not quite making it (the MPX would drop out depending on where you stood). The new tube does not have that issue.

I did not bother to test just did a sub.

loving this set, but something I dont understand, If I watch it everyday, the CRT comes up to full brightness in what would be considered a normal time (about as long as it takes for the HV to come up), However, if I dont turn it on over a period of days there is a delay in full brighntess. The screen comes up but its quite dim, it takes a few minutes, but then back to normal.

Was wondering if anyone else has expereinced this? the CRT did test weak when I 1st got the set, I have not checked it since I got it up and running.

I am of course assuming its the CRT and not some other fault.

Probably cathode contamination. The contaminates settle on the cathodes after sitting a while, and take some time to burn off when you turn it back on.

The CRT might still be a bit de-activated from sitting. With use, they sometimes "wake up" a bit. Or, the CRT may be getting a little soft and needs time to warm up. I have one like that but the picture is great after about 5 minutes. The tube also tests good, but not as good as some of my other ones. Did you try the 8v heater method to wake it up?

Hey Nick, didn't mean to repeat what you said, we were posting at the same time:D

when I 1st tested it I did up the filament, not that much, just to see if I could get the emissions up, they did, but would not stay (left it there for maybe 1 hr) when returned. I would not even notice it if it was a daily driver, However I have not really spent any time to see how long it can sit idel before the problem popps up. I have a replacement CRT I plan to use that test very well, I just am on the fence with it since it produces a very nice pic other than this delay issue. I would not even replace it but for the bad cat that I want to get rid of. I may just do the cat and reuse it, I have a CTC 7 that could use the replacement CRT. Its not a dual anode but I figure it will work with maybe some tweeks.

Are you "on the fence" as to wondering if you should try to rejuvinate it or not? I agree that the CRT does seem to be on the "soft" side of things but if it's coming up on brightness and the tracking is good, nowadays that's acceptable.

Lately, I've noticed the hesitating of not rejuvinating tubes and sometimes even living with a brightner. Sure, we look at rejuvinating as the last resort but I believe rejuvination is better than the added stresses of using a brightner. And granted, if a brightner was there to begin with "depending" on how long that brightner was in use the tube may still be salvagable (or not).

Realizing that sometimes a tube can test poor and still produce a good picture, it is always better to see how it does after the set is up and running.

Things sure have changed with no Scotty around anymore!

I've taken various approaches to this. On my Zenith 5131/chassis 25LC30 the CRT will need cateract removal and I did check the tube and it's marginally ok. What I mean by "marginally" ok is that the guns all showed some emission but not all the same, weak with poor tracking. It's got life in it so I know that it will be a good canadate to leave until the set is operational and evaluate then. It will work just fine for producing a picture, and it may "wake itself" up in the process.

Another set that I'm starting on (57' B&W Zenith) had a brightner on it but the tube came up in emission on the tester, indicating some life even before letting it test for a couple hours. I did take my Beltron to this one and now it checks as new. I may have shied away from doing that but this was done as a last rush effort before Scotty shut down so he was my backup.

We've heard that a rejuvinated tube won't last long, picture won't be as good etc. but a CRT won't last very long on a brightner either and then theres no chance of resurrection with a rejuvinator at that point!

The Predicta in my Avatar is the original tube that I rejuvinated with my Sencore (before I got my Beltron) and it's been doing good. Now that I have my Beltron I use it for rejuvinating/cleaning and I like my Sencore for testing.

Dave, I don't want to hijack your thread and I can understand any hesitations where the tube is concerned as to what to do. If your tube continues to maintain the characteristics that it's showing, I'd bet it would respond quite well to a minimum rejuv/clean as your last resort.

oh no, no rejuv for me, my fence decision is to remove the cat of the soft tube and reinstall or just switch over to the strong tube. I would not dare do a rejuv unless it was nearly a lost cause, this is far from that. I may just de cat and use and save the strong tube for the CTC-7. I would like to see the strong tube installed in this set just to see how much faster/brighter it maybe, but if I go that far I could not see going all the way and installing it and saving the soft tube for the 7.

...

I've found that the "auto restore" function of the Sencore CR-70 is really good at waking up and tracking them without harm (when the 8v heater method isn't enough). I tried to hurt a crappy tube with it once and couldn't, not saying it can't be done but you really have to try to make it happen. It says hold the button and let it go through three cycles but I've found that one cycle is often just what you need. I had to do it on my CTC-9's red gun and that was 2 years ago and the tube still holds after sitting for a year and then I subjected it to hundreds of hours of use as of now. It tests really strong but still needs a few minutes to warm up if it sits for more than a week, so I guess maybe it's starting to get soft but man, what a picture!!

I have the CR-70. but am inclinded not to use it, the tube makes a perfect pic, just needs a couple extra minutes if it sits for more than a day unused. I was just wondering if this was something that others have experienced. My plan now is to get motivated (ha) and pull the CRT out, remove the cat, and reinstall. I think I will just save my strong tube for that CTC-7. curiious is there a lot of difference in the circuitry of the CTC-7 vs a CTC-16? I am just wondering if the eariler sets may have been more complicated and costly than the later sets.

If she's making a perfect picture, than I guess waiting a few minutes don't hurt. That case I'd leave it alone but I figured I'd share my experience with my tester. I also think saving the strong one for the 7 is a great idea, it's the set that will always be worth more and be more desirable.

one of my problems with the 7 is I am missing the back. Its a metal cabinet, faux wood grain, with Lots of surface rust, so not so sure of its value. I was thinking of stripping it and painting it flat black. The safty glass and mask are in good shape, the chassis has some rust, but IIRC the fly looked ok.

I think those have a metal back, maybe I can fab up something for it. I would be VERY nervous to have an exposed neck...

oh and of course only after I get it up and going to make sure its not a lost cause.

So... thats also contributing to my fence sitting...

I was thinking of stripping it and painting it flat black.

Not black! Then people will think that it's BPC... :thumbsdn: :D

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I have a B/W Philco with a 21" CRT that's also very slow to wake up. It tests low on emission, but with a brightener it's watchable (not perfect, but watchable) after a few minutes.

I have been debating whether to try the CR70's restore function on that one. I tried it one other time on a weak 17" tube, which helped somewhat but wasn't a miracle cure. Perhaps that would be wiser than running it on a brightener until it completely croaks . . . .

Re painting the cabinet black, I don't think that would be awful. I have a CTC-11 with enameled black cabinet and it looks fine (better than faux wood, which I don't like). When I started work on my CTC-7, I was surprised to see that RCA sold that chassis under 46 different model numbers. Who knows, maybe one of those cabinet options was black :)

Regards,

Phil Nelson

Just cover it with some wallpaper with flowers on it. That way it will be preserved until you get the fake wood vinyl stuff.

Dave, a very nice restoration. You have the vision of a museum curator! :thmbsp: To restore/not to restore, I like the high road you are taking. These old color TVs are a dwindling resource, and the careful consideration you give your CRT is a good thing - I'm gonna follow your example on my weak CTC-16 CRT - I'm gonna leave it alone. Crappy grayscale when cold, but warms up to a decent pix.

And I like your new addition to our lexicon - "De-cat" (post 78 in the thread) Simpler to type than Cataract Removal! :yes:

Congrats on this set, anxious to see your next project! (and I don't care what color you paint it either!):D

Cheers,

Im going to make a thread on this as so as I finish the video. Soaking in water is very effective at removing the safety glass. It just takes a few months.
At this point I would rather use room temp water rather than risk any kind of heat or force. The round crts are just to scarce.

Lol!! its prob been done :)
just cover it with some wallpaper with flowers on it. That way it will be preserved until you get the fake wood vinyl stuff.

prob be a while before I get to the 7, I have a few others that need some attention. Looking forward to the video of the H20 de cat.

maybe adding some yeast to the water would speed things up? I get what looks like mold or fungus in there, make some pva beer while you wait.

I have a 17 with a great testing CRT but a bad cat that I would like to try the water technique, not to mention the roundies I have that I would like to do.

listening to some LP's today I could not help but notice how much better the highs are reproduced. seems like I may have to dig into the tuner MPX output at some point and rework the de-emphasis networks. I did this to another RCA(had forgotten that until just now). The LP's sound great so I figure either something has drifted in the tuner OR maybe just todays programming has been over worked towards the bass side of things for better thumping. I used to have the local public radio station to test on since it seemed to have the least "bass" processing going on, but they dropped there music format a couple years ago. Maybe it was an attempt back in the day to have a Hi filter cut as well, to get rid of hiss. I have other vintage gear that does something like that, just not as crude as chopping it all off up high.

swapped out the CRT for the one I did the de-cat on. I used foam stick on weather strip all around the edge of the lens. Lined it up on the CRT and used some packing tape on the top and bottom to just hold it in place.

the actual replacement took about 45min start to finish, most of which was from note taking on measurements on the neck parts.

Powered it up and I got a nice bright pic, but it will of course need a purity and convergence setup. I decided had done enough, so will give to that later next week when I am in the mood for it.

the old CRT is now sitting in the nasty bong water in the kiddie pool starting the de-cat process on it.

did a 1st pass a the purity and convergence, I had to swap the blue and red static magnets around and did some minor work on the dynamic.

I am really impressed by the overall color and esp the brightness of the set.

I will button it up and snap some pics it a bit.

fighting with the purity, can't get the center red blob (yoke pulled back, blue and green screens turned all the way down). I wonder if I installed the purite magnet backwards...

checked my before photo's its on right. I can get it pretty much correct with the yoke back in place, just bugs me, this is the 1st time I could not get the blob centered with the green and blue triad blobs around it. I can get a red cloud but one side extends over pretty much to the edge. and I only get two clouds each of green and blue.around it on the the other side.

I have a couple of the dynamic pots maxed out, I wonder if the dynamic convergence is effecting the ability to set up the center red blob?

I center the dynamic pots when setting purity, then do the complete dynamic setup. It's always possible the dynamic setup is throwing off other things, just start over and follow the manual. That's what I do whenever I think I'm smarter than what's written. lol

yea I thought about doing that. Will mark the location of where they are, center them up and then start over. I guess there is not way to "center up" the right coils short of just detuning them by backing out the slugs.

I have spare convergence coil and was even thinking of just plugging in and unplugging the mounted assy. Not sure if it was a good idea to just leave the convergencs socket empty



I got bit by the yoke winding, while sliding back, I got a finger on thebell side, I guess the insulation on the windings is not quite enough to keep that from happening. ouch....

Pics with new tube

in the B&W you can see the slight purity prob in the upper right, looks a bit greenish

looks great!is that an rca crt?the ctc 15 and 16 produce the best picture in my opinion.purity shouldnt be an issue though.did you degauss it?deguass the rear of the set also.i had a similiar issue once.turned out to be something magnetic on the shield.dont know how it hapened but i degaussed the shield and all was well.again,the picture looks great and another roundie saved!

yes thats a RCA hi lite. I degaussed the Pi$$ out of it from the front but not the back.

No sheild around it, just the mount clamp. I am going to try anoher set of purity rings just to be sure. Also will try a different location, just in case I have some odd magnetic field near by.

Not even sure how I would get to the back to degausse, but I assume It would be a good idea to remove the purity rings before doing that?

Those are some great looking screen shots. Looks like you've got that gray scale spot on too....does it stay uniform throughout the brightness range?

Dave,
The purity setup procedure is as follows:
Get an all red screen (blue and green screens off), slide the yoke all the way back and center the red blob (using the purity rings). Slide the yoke forward gradually, looking for best red purity. The "sweet spot" will occur approximately 1/2 to 1/4 inch before the yoke fully seats against the CRT bell. Clamp the yoke at that position. No kidding. This is the RCA factory procedure and the way we always did it 'back in the day'. Same on the 19 and 25 inch rectangulars, but the 'sweet spot' is usually about 1/4 to 1/8 inch from the bell.
Bill(oc)

Bill try as I may I can't get the red blob in the middle (the procedure you described is what I did). Red screen up, yoke back, best I can do is get the red in the middle/and left side. I normally can get the red blob and have the blue and green sort of around it in 3 separate clouds. This one just does not want to behave. I try rotating the rings together as well as operating them separately, and a combo of both (rotate together and try apart).

I did not try the grey scale tracking with brightness will get back to you on that.

those rings usually dont go bad.try another yoke?had a 15 back 25-30 years ago that had the same issue.was a bad yoke.we played with it for a few days and changed it out.took care of the problem

roger that I have a NOS yoke just looking for a home.

I am sure there is something up, I have done roundies before that worked just fine on the purity setup.