ok here is the deal, all tube zenith console. It had a brightener on it, I removed that, rejuv the picture tube and its playing now, decent pic, not the brightest but not bad, needs a mild convergence.

Question, do I start recapping or just leave it be. I has several of the plastic paper caps (the round brown ones) several white ceramic tube caps (1000v) and several electrolytics not counting the cans.

It's playing well but for how long....

it has the service save panel, so I was going to just lay it on its side, leave it all hooked up (no power of course) and start one cap at a time. I belive in do no harm but I also know that these caps are way past expected life.

Also it would be easy to just clip the old cap and pig tail on a new, I know not the prettiest but done neatly it would look fine. This minimizes the lead dress and stress on other parts that share the same mounting point.

Anyway just looking for some opinions, I rarely get a set that works this well to start with of this vintage.

oh and its a 20Y1C38 chassis

a couple screen shots, only thing done was to rejuv the pic (red gun only) and remove the brightener.

and I do have a replacement picture tube, I just have not replaced one before so am a little hesitant to jump on that.

crt looks presentable.save the other one just in case or something else might be in need down the line.as for recapping-my opinion is it couldnt hurt but if it is playing well?the installation is your discretion.i have done this either way and frankly it has worked out well.thats the beauty of this hobby,you can do as you please.i remember back in the experimental days,we would swap out crts just to get a certain look.so many tubes that were discarded because we didnt like the way something was.they were plentiful then.now-they are gold!that set looks good as is!

one thing that is nagging me is if there is a cap that if it fails will do damage to a part the is hard to find. I just check the vert out tube cathode, its not bypassed with a large cap (I was thinking if it started leaking or shorted it could foul up the tube bias and damage the vert out tranny). I am trying to find all those suspect caps to see what they do. Looks like a lot of screen decoupling which other than stressing the power supply does not seem too dangerous.

I dont change the caps on those zeniths until they fail. They are good quality caps. I have 3 sets with that chassis and cant say I have had a cap failure yet. You may have to tweak with the sound coils to get the buzz to a minimum.
Check the cathode current. Should be around 250 but always seems a tad higher like 275.
Check the HV, lowering the HV raises the cathode current and load on the flyback. HV regulation basically is achieved by loading down the 900 volt boost. I have been leaving my sets up around 26-27kv.

Thats good to know (that you have 3 sets with orig caps).

One thing I know it needs is a good tuner cleaning. I may get around to doing that. The UHF is jammed up jelly tight, the vhf needs to be jiggled to get good reception.

That is the same chassis I have on my big zenith console (the French provincal with the nice SS tuner with all the plug in transistors). I have not even tried that one out yet.

Thats good to know (that you have 3 sets with orig caps).

One thing I know it needs is a good tuner cleaning. I may get around to doing that. The UHF is jammed up jelly tight

Is this a set with the concentric tuning knob? If so, that inner wheel for the UHF swells around the shaft over time and seizes it. You will have to take it apart and carefully hone the hole with a drill bit slightly larger than the hole, or use emery cloth/light sandpaper in a non extreme case. Any forcing of it will strip the gears (if used un-repaired). Apply a light coating of silicone grease to the shaft when reassembling.

yep thats it. I will do as you say.

while futzing with the set I noticed a pretty extreme reverse pin cushion (guess that it the way to describe it, the horz bends up on top and down on the bottom). 1st I checked the tube, checked ok on tube tester, and its new. Next I check the tube pin resistance mearurements to the sams, ok. I tried the pin cushion adj slug and was able to get some of it out but still there.

Its like it just runs out of adjustment ranges. The circuit controlling this has a pretty low parts count. I was next going to try checking to see if it has any plastic/paper caps still in it (the pin cushion circuit). Should prob try a tube substiution just to be sure about that as well.

while fussing endlessly with the convergencem, I decided that something must be wrong. I makes almost no difference when plugged and unplugged (dynamic convergence).

So I decided to check the diode pack, hmm a long crack runs the length of it.

Tested 2 of the diodes, so far both are open. Squeezing the pack makes for momentary resistance readings. I checked the voltages on the conv board before pulling it, no DC reading where there should have been but AC reading instead (which is why I suspected the diode pack).

Anyhoo I have some 1n4005 diodes that I will use (the orig are 1n536).

I hope this does the trick...

That was painless, just snipped out the old diode pack (all were open) left the little bits in but for the ground which i heated up the little solder pot, and pulled out the remnants as I would be having 4 diode ends going in that common ground. I put spagatti on the diodes (color coded) and installed.

Whats nice is now that I have a good diode pack (well after I test it anyway) is I have a set of reading that I can use in circuit to compare other convergence boards with. It will not be fool proof, but hope it finds open or shorted diodes in circuit.

I am getting tired and its dark in the shop as my lighting is not the best so I think I will just bag it for now and reinstall tomorrow. I hope my convergence woes are over.

With out having a lot of experience the problem is knowing when a convergence board is working right, marginal, very weakly.

I have a new in box 17crp4 zenith crt in zenith box if someone needs it.

well it still did not work right, I found the convergence board was missing a jumper, I added that and it worked great, convergence went by the numbers.

after having it on for a while I noticed the vert was a bit jumpy, not rolling but rapid change in size. I cycled the serv-norm switch several times, seems like that cleared it up. will keep an eye on it.

at some point I will have t pull the tuner for a cleaning as it gets snowy now and then. I will try just working the tuner to see if it will self clean, but I am pretty sure its dirty as all get out (based on the dust and general filth of the rest of the set).

Im working on a 20xy1c38 right now and it has almost all the same issues. The most annoying is it acts like the hv regulation is slow. Between different brightness scenes the screen 'bounces'.
It has the pincushion issue and a vert linearity issue about 2 inches down from the top.

Otherwise good picture

yea the pin cushion was the worst it just seems to run out of adj before it gets all of it adj out. there is a RC in the grid circuit of that, not much else that can go wrong. is the pin cushion ok on the bottom? Mine looked ok on the bottom. the Linearity is just a touch off now, only see it in the last 1/2 from the top. I need to touch that up again.

vert is still jumping around, I cycled the norm/serv switch some more, but its still and issue.

there are quite a few coupling caps, a thermistor and various carbon comp resistors in the circuitl. I think I will let in run somemore just to see if use will help it settle down.

Have not tried tapping any tubes yet..

---

buzzing, a lot of it that needed constant fiddlling with the buzz pot. it would need to be adj after warming up and even then it was not all that good.

now for some reason after watching it for a few days an hour or two a day the buzz is gone and no longer needs to be touched up.

Geez I wish other stuff would just "get better" like my car....

the volume on this set is still somewhat weak, I am thinking if it has a cathode bypass cap, maybe that is open and its getting too much neg feedback. I have not checked the tubes in the audio so I guess I should start there.

They do get better by running them dont they>?? I still cant figure that one out. The volume is weak on mine too. The buzzing has also got a bit better on mine.
Did you measure you cathode current yet? Mine was 190ma
Post a picture for us?

Great info Andy, thanks! I have run accross those with open resistors.
http://boxcarcabin.com/zenith-Y4520-4.jpg

That is a very fine television apparatus you have there!! I would love to shrink myself small and live in the list!
(At least small enough to disable my wife's soap opera addiction) :)

Thanks! the louvers and off centered crappy channel master crt really bring it all together. The cabinets walls are Masonite, that think dark very hard particle board stuff. Its a bit unique

Ahh, yes, but I too have a Zenith, with a Channel Master CRT. Very off kilter as well. Maybe it's your sets long lost brother? Got it from JPDylon in San Diego a few years back.

thats my set but for a french provincal cabinet. did you see how the convergence board is accessable from the front, under the speaker cover, clever guys those zenith engineers.

pics...

So who's the gal riding with Jim?

Lindey Wagner, think it was the pilot RTV just started over again, the early ones are the best. The pilot had a different Rocky, Noah Berry was much better than the pilot episode rocky.

I like your cabinet better. The extra decorative bulk doesnt do much for me. Most of the later tube zeniths I have seen have the convergence there. I wish they could put the focus in front on these consoles.

yes its a very nice cabinet, very clean, understated and solid wood.

Agree the focus should be upfront. That cab style is prob my favorite, it matches that zenith combo I have. I hope to get on that one next.

I think I will need to clean this tuner it keeps requiring jiggling.

great,great sets!we sold a lot of those back in the mid to late 70s at the shop.always the best picture and the chassis s were bulletproof!love to have one for myself!

the screen brightness flickes somewhat. comes and goes (periods of no flicker the flicer). I assume this could be the HV regulation? or I suppose a dirty pot noisey resistor in the brightness control circuit.

I have tried cycling the brightness control. and the brightness range.

Mine does the same thing. Mostly one scenes with lots of brightness changes and motion.

funny how our two are so much a like. I wonder if a recap would make any changes, I don't really want to since its cool that it has all orig parts and still works so well. I almost think that a recap would simply be putting in cheaply made parts that will not last as long as the remaing life of these old parts.

Not actually knowing what contributes to high voltage instability, my order of attack might be 1) caps in the regulator circuit; 2) high-value resistors in the regulator circuit.

Anybody with experience of what typically causes such flickering, please chime in.

I would like to monitor the HV but think I would need a scope to see if it is the cause. My guess is my analog meter HV prob would be to slow and damped to see it.

I am going to try a few other things, for starters I plan to pull the IF lead form the tuner to get a blank raster. if it still flickers I will put the scope on the crt and check the bias to see if any thing there is going on.

maybe I could use the HV prob in current read mode and use it in series with the scope?

Iv had my fill of this thing. The vertical jitter is the most annoying then there is there is the brightness flicker. Besides those annoyances its got a good picture.
To look at the hv on my scoped, i would put about a 27k resistor in parallel with the scope, connect the ground lead from the probe to the scope then the scope to ground so you are measuring the drop across the 27k resistor using the probe as your high meg series resistance.

Its going back in the barn and then next one is coming in. Maybe the ctc68 or another zenith multi state. I also got that philco roundie i need to get going.

I will keep futzing around with it, if I find out anything I will post.

the vert shakes and the flicker seems to come and go.

I am going to try some tube tapping, and then look into parts around the regulator circuit and the vert. Will also check the pincushion cap on the grid of the pin cushion tube.

on the x1c38 you can pull the regulator tube and it will just go to max, i dont know on the y1c. It typically only floats up a few k so long as the brightness is up.

The regulator works by loading down the 900volt boost, loading down a low voltage winding on the flyback.

Ill pull mine when i get home and see what it does.

just read in the service manual from zenith that jittering vert could be due to a faulty service switch (the one I tried cycling several times) said something about making an "air connections" I assume they mean to just jumper it, also said meter may not see the resistance, therefore the recommedation to "air connect".

there was also talk about a diode/resistor combo to increase convergence range that I may look into (the right side is still just a bit out).

Lastly I think I will check on the cap that is connected to the pincussion coil. No mention of a problem but since its a tuned circuit I was thinking that maybe a out of spec cap may account for the lack of adjustment range, although its more like a lack of amplitude than freq since I can see the center widen to a point but then it starts to shrink back before its completly flat.

I am going to study that pin cushion circuit a few more times to see if I can get my head wrapped around it.

My tint control is maxed out counterclockwise, where is yours? I pulled the hv regulator tube and it did nothing for the brightness flashing. Pulling the tube out the hv goes form 25 to 27kv at normal brightness and up to 30kv with the brightness at minimum.

almost fully counter clock I would say about 10 degrees away.

I wonder if C129 the .01 cap that couple the hue pot to the L26 off the burst amp could be an issue?

ok finally got around to replacing the pin cushion tube. I tried a couple 6KT8's

one was an Elmento brand and very tall, it had a perfect pincushion correction but then I got some retrace lines when dark screen was present. I tried a shorty 6KT8 and the retrace was gone but the pin cushion was still slightly there. Guess I am going ot have to try a few more.

For you guys that used to service tv back in the day, was it common to have to try a few different tubes to get one to work? both of the tubes I tried were NOS.

oh and the vertical and flicker seems to have resolved, I guess just running if for a while may have driven out moisture or pehaps reformed a cap somewhere.

There was a slight ringing in the pix (right side brightish outline) that I got rid of by going thru the IF tubes. I was checking and subbing until I got to the 3rd IF which tested with shorts. I confirmed that the new tube did not have shorts and I tested the bad on two different testers (hickok 533 and a dyna quick). Replacing that tube did the trick no more ringing.

The other tubes tested just in the ok range, but a sub did not seem to improved the pic so I put the orig back in.


I assume the short was causing some oscillations in the IF circuit.

I should have check the signal with my scope, I would have liked to have seen what a ringing signal looked like. I would have put on a test pattern and then started at the grid of the 1st IF tube. I already chucked out that tube so too late to try it now.

I did notice the Horz out tube getter was getting brown around the edges. Is there a way to check to see how it is doing in circuit? I dont have a tube tester that can test it.

I suppose the only thing I could check is the HV but that could be effected by the HV rectifier, and or the regulator tube correct?

oh and the tube that is in there is not an orig its a Lindal brand and not the specified tube number.

I still need to pull the tuner/control panel, the tuner is just too flaky and I would hope that a cleaning will get me a more consistant pic. Also the VC is very noisey. I did replace the 6Z10 (audio detector/amp compactron) which did help the volume which was a bit low.

The AFC switch seems to have no effect what so ever, I assume it works like any other AFC to lock on to a signal.

The fine tuning control seems to have stopped working as well (afc off) it does not have any effect when pushed in and turned. I hope I did not strip anything with the frequent adjustments I was making, but at least it seems to have stopped on a good pic.

OR maybe the switch on the AFC is simply broken and its stuck in the AFC on. It was very balky. Anyway I will check into that when I get the tuner out for cleaning. That will also be the time I attempt to unstick the concentric UHF tuner.

oh and the tube that is in there is not an orig its a Lindal brand and not the specified tube number.

Finding the correct number and a better brand of tube might help. Some say a tube is a tube but that is not so, I've had bad luck with the few Lindal brand tubes I've encountered. They seem cheap, might not be regulating very well. Also, some of those tube numbers that are supposed to cross don't always act right in the circuit. That's why I like to put in exactly what is on the schematic or tube diagram.

I tried a new way to set the grey scale since I was not having any luck with the setup switch method. I use the DTV converter box and disconnect the antennal, this gives me blank dark screen with a "no signal' sign.

I use the screen drives to set the background to a neutral none color background, adj the focus.

put the antenna back on and adj the CRT drives (blue and green) so that adj the color level gives a decent color tracking as I turn up and down the color control.

pulled the tuner, it did not seem too dirty, but I did some brown off the fingers and the tuner strip buttons.

Next up was to free up the UHF. 1st I separated the tuner from the picture and volume control panel. Next up I removed the outer plate that allowed access to the stuck main UHF gear that drives the channel indicator. Removed the large circlip, worked off the stuck gear, sanded the inside with a socket wrench and sand paper to make a drum sander that would fit. worked it by hand, testing the fit as I went. when is seems free enough (turns easy but no slop) I put a bit of tuner lube on it ( I guess its safe on plastic and will not gum up) put it all back and reset the UHF indicator. replaced all the circlips, buttoned it all back up. Cleaned the tuner tube pins while it was out. The only casualty was the color knob, it cracked coming off. Some super glue and strong sewing thread wrapped around it and glued pulled the crack up tight.

used some pot cleaner lube on the VC and the pesky afc switch while it was out. Popped out a few strips on the tuner get get access to the fingers, channels 6-10, I never remove 3 or 4 just in case I were to break one.

the result, perfect tuning, not more snow etc.. no more critical setting. The UHF still seems a bit tight, but its not the gear. I did lube the UHF tuner shaft, maybe it will loosen up with use. It works fine just seems a bit tight. The fine tune on the UHF work as it should. I was able to get some OTA analog using it.

The UHF fine tuning is working again as is the AFC switch, and best of all the audio is perfect now, no more jiggling and fiddling to get it right, and volume is up across the board.

I will button it up later and get some screen shots. Over all the tuner was not a big deal at all.

well I have been watching it some more and still not satisfied with the pincushion correction. I put a scope on it and examined the output of the waveform from the plate of the pincushion tube, I noticed a a lack of a waist in the form. It had some just not what is showed on the sams. The P-P value was was off also, not sure what that is all about.

there is a resistor/cap network in the grid of the pincushion tube. I tried increasing the cap value, and the waist got wider not smaller. So my next check will be to take the cap out of circuit and check it.

There is also a 100mfd electro that comes of the cathode of the vertical output tube, it looks like that is the source of the vertical componet of the wave since it looks to bias the tube at the cathode. Its a little over my head what it is doing but I will start there.

I think I get the pincushion circuit.

looks like a horz pulse it applied to both the grid and the plate of the tube, the tube bias is controled by cathode bias which comes off the vert out transoformer.

So since pincushion correction along the top needs to have the vert deflection oppisite directions when on top and on bottom, the correction is derived by having the tube cut off (due to bias) and only the plate input of the horz being the driving force of the vertical adj (a cap smooths the horz pulses and applies to the vert yoke thru the pincussion adjustable transformer which is tunable I presume to the hors freq.

when the tube is NOT cut off by the cathode pulse then in conducts from the grid input of the horz freq, this gets inverted in the tube and nulls out the pulse at the plate, this is the waist I see on the scope.

Since the waist is not thin enough (i think) I have to presume either too much plate pulse is coming thru the cap that goes to the boost, or the tube is not conducting enough to null it out.

The grid of the tube is fed by a 220pf cap that goes to the same boost souce so it could be that it has developed some kind of interanl resistance (I doubt this since its a disk, OR the plate feed cap from the boost is perhaps leaking or drifted up in value (not sure about all this). Its a white ceramic tube .0012 1kv cap, so its prob a paper inside.

I recall my pulse at the plate was much larger than it should have been (which would explain the inablility of the tubes inverted pulse being able to null it out.

I am kind of suprized that zentih to not provide for an amplitude adjustment to the pincushion adj. the adjustable transformer just seem to tilt the correction more that increase/decrease the amplitude of the correction to the yoke.

well turns out the cap in queston was a disk cap .0012 1kv.

I really doubt it is the problem, and there is not much else to this pin cushion circuit. I did replace on of the Ecaps, a 100uf, no change, did replace a resistor in the grid circuilt of the pincushion tube it was a 15k that read 20k (10% banded), no change.

anybody else with this chassis have pincushion (top mostly) issues?

Dave, how many Zenith sets do you have of this vintage? I have a 67 and a 66. Both have pincushion issues on the top. The bottom is pretty good. I have two RCA CTC-17's that have not perfect pincushion too. I have never figured out if it's a problem with the set or if it's just the way it is. Pincushion on older sets always seemed to be a little bowed on the top. If anyone else thinks this too or if I am wrong, please chime in.

Take a pic of the raster with some vertical lines or something we can see the pincushion.

I've noticed top pincushion issues on early RCA's and clone chassis' too. Pretty common. Been awhile since I've seen an early Zenith..can't recall on that.

I will get some pics tomorrow

Another note, I have had three roundies, An RCA CTC-16, an RCA CTC-12 and an Airline (Magnavox), none of these sets excerpted pincushion issues that could not be adjusted out. All these sets after a proper alignment had great pincushion. Something happened with the introduction to the 90 deg rectangular CRT. I just fired up a 66 Magnavox with a 25GP22. Yup, bad top pincushion. Either it's as good as it's goona get or it deflects in the center the other direction with the areas on the sides of the CRT about 2" still bowed up so the effect would be a wavy line if you will. The round CRT did not have this problem because there are no edges you can see. The CRT is perfectly round.

I have a '69 Sony KV-1220U. Believe it or not it has a slightly distorted upper pincushion as well with no way to adjust it out. I have seen this with the early Sony's. The KV-7010UA (the very first Trinitron) has a distorted upper and lower pincushion.
also a late 60's Hitachi CFA-450 13" has horrible upper pincushion, bottom not bad. Not adjustable.

I noticed that around the 1975 model year sets (foreign and american) seemd to get the pincushion spot on.

I will get some pics tomorrow

Actually, looked back at the pics you posted in page 1. That pic of the test screen, looks pretty much like my Zenith and RCA pincushion. Now there are two things that come to mind. Does your pincushion pot hit the extreme end before the pincushion is out or does it distort the top center the other way but leave the edges of the raster still bowed upwards? Cause it should honestly have an adjustment variation to at least go both ways I believe. At least the Zenith I just messed with to check this out will.

on mine its a coil, as you adjust it, the pincussion compensation is like a small wave that you can move along the top, trying to center the wave seems to be the idea, but the wave is just not wide enough so be best i can do is to pullup the center. My guess is that this is just the limit of the adjustment, and before letter box for other narrow view formats it was not an issue as the only time I see it is when graphics or narrow formats are displayed.

That sounds about right the way you described it.
I guess you could try the alignment of the yoke. See if it shifts up and down vertically like a pivot. If it sinks down in the rear that can cause poor upper pincushion.

on mine its a coil, as you adjust it, the pincussion compensation is like a small wave that you can move along the top, trying to center the wave seems to be the idea, but the wave is just not wide enough so be best i can do is to pullup the center. My guess is that this is just the limit of the adjustment, and before letter box for other narrow view formats it was not an issue as the only time I see it is when graphics or narrow formats are displayed.

good point. I seem to recall that there is an adj that is an add'l blue adj for convergence tied into that adj. I recall cause I was reading a service manual and it called out a final step for which I could not see the adj (was not on the dynamic board and I was only thinking of the reg 4 adj for manual (reg 3 and blue lateral). then they mentioned on some note the final blue adj that was a nut you loosed on the bottom of the yoke to tilt it some more, I guess to be done after purity.

When I get brave I may mess with that :)

All wrapped up around the axles on my philco roundie the the moment.

side note on the zenith, the vert out tube seems to be either just a loose socket mount or a soft mount socket with rubber that has deteriorated some. check you vert out tube and see if the socket does not rock around somewhat next time you are into it. I can see what looks like loose fitting rivuts on the socket flange.

Yeah, my socket is weak. I need a new one soon, my set flatlines sometimes and I have to "bend the pins". Lol

ok here are a couple, in "the office" the format is reduced all around, on the commercial its the long format 16:9 i think its called.

in the zoom format where the whole pic is shown there is no noticable pincusion unless you happen to have some text (like the on screen display of the channel.

I am going to try to see how it looks with some OTA UHF analog later if I can get a better antenna.

It does not look to bad on the pics, I think the camera is not getting a good shot of it, seems worse in person.

update on the vert jitters, replaced C168 (.1 1kv) off the plate of the vert mult (6BA11). It tested fine for value but leaked badly at 450v (as high as my cap tester would go). I did not have a 1kv handy so I put two .22 630v in series. I will order up some .1 1kv next time I order from mouser. There was another .1 1Kv that is part of the horz eff coil circuit. it tested fine at 450v no leakage at all, but it will get replaced when I get those new ones. Not sure if its ok at the higher voltage.

I took the chassis out after struggling with one of the plastic connectors (what a pita). Anyway it was major league dirty, I mean disgusting, so I used the makeup brush (ask a girl), some compressed air in a can, and cleaned the underside. the top side got the same treatment and some slick stuff cleaner to get the goo off the chassis. Cleaned up the fly cage and anode lead, and the crt around the anode.

while I had the chassis out I checked some resistors, replaced one a emitter bias resistor that was a 10% that had drifted to about 30%. its on the only transistor in the set a video amp. I dont get why the bother to get a single transistor in the whole set.

I checked a couple of the screen bypass electro caps, all tested fine, good as new. amazing. I figured better to leave them in as I wonder if the new caps will last as long.

there was a .1 in the video path that couples the transistor video amp the video out tube. the audiophoole in me makes me want to go a change that out for a designer cap :yes:

while I had it out I check the crt, I had rejuved it on the red gun back when I got it, but I checked it again and it was a bit into the weak on my CR 70.

the tracking on the blue and green were very good the red dropped way down.

its gonna need a new 23v (I have one) but I just did not feel like taking the old until I put the chassis back in and made sure I did not goof anything.

I need to do a horz eff setting check. I never did that with this one, as the coil is in a place that is very hard to get out, but I just realized i can get at it from the bottom thru the service saver cover, duh...

oh there was one other out of spec resistor the cathode resistor on the vert multi. R115 should be 3300 was 4400.

I could not make out the tolerance it "may" have been a gold banded, but its hard to tell, the schematic does not say so I figured it was prob a 20% so it was not that far out. The vert circuit is working fine now so I decided to leave it alone.

the picture is really not that bad so I may just leave it for a while. it has a

25GP22A tube in it.

well the sams say 160ma on the hot, best I can do is 220ma.

gonna fool with it some more tomorrow. I swapped out the HOT, Regulator and damper tubes. No change.

the horz eff coil works but the changes are very very minor, maybe a 10ma swing max.

There is a 470 ohm resistor across the horz eff coil that the sams say to use only with a 6CJ3 damper.

My damper is marked as 6DW4/6CJ3

the eff coil current (jumper out) should be 180-220, I am right at 220.

Just for the heck of it I am going to check the bias voltage and waveforms of the HOT. Its only bias comes from the horz osc tube. should be -36v getting late so will check tomorrow, may just pop in a not horz osc just to see what happens.

swapped out the HOT with the alt 6LF6, changed the screen tap per the sams the the 230v, got the current down to 195ma (the other tap was a 375v).

I wonder if the 6HS6 (the sub for a 6LBL) on the lower screen tap would have still worked.

The 6LF6 was a pull but looked to be in very good shape. I will look into a NOS on later. the 6HS6 was a NOS (i tried a few, all the same 220ma).

gonna try another 6U10 before I start doing measurements and scope readings.

I forgot to check the line voltage, when I set it for 117vac I get 185ma.

clearly this set voltage regulation holds the HV very well. I am tempted to add some resistance to the screen to drop the HOT current since line voltage tends to be higher than that. Currently there is a 470 ohm resistor there.

there is also a confusing to me note on the sams. the is a 33k 2 watt resistor in the screen circuit (just before the above noted 470) R154, then in parens it shows 17k 5 watt. also not sure why a the lower resistor would have the higher wattage. thats odd, if anything I would have thought it to be the other way.

I also plan to add a B+ fuse like I did on the philco roundie and add a fuse to the HOT cathode circuit.

tried another 6U10 (triple triode, horz afc,osc,osc driver) just to see if it would have any effect, about the same, I am right at 185ma of the 180-220 scale when line voltage is set to about 117vac.

when switching out the 6u10 I did not get it seated very well, but was monitoring the current per the sams. I shot to over 400ma very quickly, so I unpluged and then reset the tube.

Seems like a design flaw, if that tube burns out you get NO bias on the HOT, which with out a fuse in the cathode circuit would do bad things fast.

I doubt the circuit breaker would save anything before a catostraphic failure.

Oh well just more of a reason to install that cathode fuse.

I guess back in the day a smoked HOT did not set you back 40-50$ just for the tube, not to mention getting a flyback.

Of course the real lesson is to know about how long you should wait for the raster to come up, and if it takes too long to turn off.

My notes on that chassis show I was at 190ma. I think your ok Dave http://boxcarcabin.com/vintagetvs2.htm

got a couple more with one of my fav movie stars

I have tweeked the pic, this is that old tube with a weak reg gun pretty darn nice even with that.

I am not touching it now

I went ahead and replaced the remaining 2 1kv tubular caps. it had 3 originally, one was leaking and since I cant test that high a voltage I decided to go ahead and replace the other two. One was a .047 and the others were
.1 all at 1kv. One of those was the one in the vert circuit that I replaced a few days ago with the rigged up .22 630v in series. I did not like the idea of that so now its all good.

I still need to add the B+ and cathode fuse, but will button it up and watch for a while.