I picked up a fully loaded Zenith Chancellor roundy combo
 

So I've had a goal of getting a Zenith space command 600 roundy, and getting a loaded roundy combo with tube stereo and remote preferably in a Danish modern cabinet.

Several months ago I found one with everything except the Danish modern cabinet for a crazy price(1500), which I negotiated down to a dumb high price (500), set up a time to see the set and see if the CRT was good, the amp was tube and the condition good enough to merit top dollar, and the seller went MIA on the scheduled day... Only to inform me a few days later they were in the hospital with 'pneumonia'...given no covid vaccines were out yet back then. We assumed covid and let the whole thing fade into memory.

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Back on Wednesday a friend found it relisted for $300 in a way that I thought it was a different set/seller. It was 30 minutes away so I went to see it. The new listing also showed the original manuals. If the CRT was good $300 wouldn't have been bad. When I got there its finish was shabbier than the pictures would suggest and I found the neck cover knocked loose from the back. Removing the back cover revealed it had been necked so hard the glass from the base to behind the convergence coils had disintegrated leaving the all neck hardware behind the yoke wrapped around the naked gun...
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After seeing that I almost walked out in disgust, but curiousity demanded I have a look at the amp to see if it was tube or Solid State. I was impressed to find a 7 tube 7K31 amp chassis with push-pull 6BQ5s... Probably Zenith's best console amp of that year. And a 12 tube tuner. Still half way wanting to walk away I negotiated down to $150 if he could find the remote and manual he had elsewhere in the house.
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The TV chassis is a 25MC43 with UHF and space command 600. The only option this thing didn't get ordered with is the reverb chassis for the stereo (part of me wants to find one). Whats interesting is the TV is a 65 model but the Sam's for the stereo indicates 1963...the cabinet, it's badging and the tuner definitely look 1963. It's interesting Zenith would mix parts from different model years like this.
This set is monsterously heavy to the point I pulled the chassis and yoke before moving it and it still was like carrying a heavy intact TV only console up the stairs of the basement it lurked in. I learned remote Zenith's have a lot more complicated tethering between chassis and cabinet than non-remote sets.

While I was there I picked up a Philco 84 cathedral, a Delco console chassis, knobs, dial bezel/glass and speaker (bottom of the cabinet was gone so I saved what could be saved), and a Kraco cassette to 8-track adapter.

When he pulled out the manual there were other manuals in the folder and I got a free manual for my portacolor out of the deal.
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The set had one last surprise...when I pulled the necked CRT (to facilitate unloading the cabinet from my truck) I discovered that the CRT in it was a Setchel Carlson branded CRT!...Now I wish even more that they hadn't necked it. That's the closest to a Setchel Carlson roundy I have gotten.
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I plan to salvage the safety glass and stickers and chuck the rest of the ruined CRT.
I have a CRT that was earmarked for a set that's almost used up it's current CRT that I'll probably use...I need to find another good 21FJ/FBP22.

I've got other stuff on my plate at the moment but I look forward to fixing this elephant in the coming month.

Nice deal even if it needs a universally-available CRT. A 7K31 amp is truly hard to find in anything, much less a combo! I have that TOTL record changer and same tuner in a 1963 MK-2635, a very common console HiFi.

Are you sure that chassis is 25MC43? If so this is a rare bird indeed. K-models were '63s so maybe the best SS amp for '65 was no match for that 7K31.
I have a 65 Zenith 25MC36 combo with a 25ABP22 and 140 "watt" stereo receiver that is all SS. No separate amp chassis either. If that SS receiver were in your combo instead, value would be half or even less with a busted CRT - LOL

Every Zenith with that earlier (TOTL for 1963) 12- tube tuner chassis I have found was paired with 3K31 amp, like one I have and others I did not buy for that reason. All seemed to have those better speakers though.

Zenith SE6BQ5 amps are not very powerful, yet do sound very sweet when all restored especially if you replace often cracked-looking ceramic disc caps with mylar film-dips. I bet that preamp and 7K31 amp chassis would rival a similar Fisher amp.

That’s a pretty awesome set! Too bad about that jug/yoke but that shouldn’t be too hard to find. And with the PP stereo amp that thing could probably really rock. Is the stereo reverb option just a reverb tank like you would find in a guitar amp?

Just curious as to the EIA code on the crt label.

So I put the stereo on the variac today and it came to life... Because Zenith! Right channel is a bit weak and MPX isn't working but with all the bumble bees and ceramic body tubular papers in it I'm impressed it works this well. I posted a video of it up on Facebook. https://m.facebook.com/groups/233107...9611167070738/

I need to look into it. There's about 6 different Sam's for the tuner and amp and the only one I could pull without moving a TV away from my filing cabinets didn't show the reverb...Just it's socket and reverb delete jumper plug. Based on what goes to the plug there should be tubes on the reverb chassis...The delete plug connects a 20W resistor to ground to load the B+ to compensate for the reduced load with the delete. It would be cool to find and add the reverb to it... gotta find the reverb chassis number first.

If you click the pic you can zoom in and read EIA 274....RCA. Which jibes with the legend that RCA sent engineers to SC to find out how the made a better picture than RCA TVs despite using an RCA made CRT. Looking closer at the safety glass there are a couple deep 2" scratches in the center of the viewing area so I can't even save the safety glass.:thumbsdn:

Yes the TV chassis has its ID sticker clearly legible.
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It's facinating that they put chassis 2 model years apart into the same cabinet, but not totally shocking to me either I have a Y line rectangular console (20Ysomething) and a 20CC50 table top that both use the same face and single knob VHF/UHF tuner.

Thanks for confirming my gut feeling about that amp. I had a hunch it was rare/special but I haven't owned or opened many Zenith stereo consoles so I have a limited frame of reference.

It's already pretty darn good so I'd imagine with a full service it will be one of my best tube stereos. Once I get time to look at the TV chassis I kinda want to variac it and see if it would have worked if the CRT hadn't gotten crunched.

Tom, the FB link doesn't work here.

.

I replaced the link with something more likely to work... Not sure how to directly link the video so click on the "+3" picture and scroll down to the video.

Zenith service manual HF-9 confirms your HiFi equipment matches a model 7500 and undoubtedly a top of the line model, using a color chassis 27KC20QS and that's space command of course! Just add the KV-24 reverb tank
Attachment 203051
Attachment 203052
I will see if a 1965 HF-13 has any info on a later combo.

I DID find the reverb in HF-9, so PM me your email so I can attach a pdf.

EDIT: Here is CM-106 for the TV
https://www.ebay.com/itm/33391339164...YAAOSwUylgRVJk

PM sent.

It's cool to see the listing in the HF9 manual. That 40W (20W per channel I assume) audio rating is nice to see. I was stealing time from other stuff when I read the Sam's and forgot to check audio power. That honest 20WPC was probably better than the SS amp in any console that year.

Have you verified that the H efficiency coil is intact? That's the very first thing I'd check on any Zenith of that vintage. Even before the CRT.

If my experience with early 60s Zenith HiFi tells me the ratings given in these manuals is honest, the later solid state ratings give much pause!

If this console was a special item in the 1965 line-up, maybe if you already could get 25" rectangular why settle for a 21" round:scratch2: I bet this amp sealed the deal when someone heard the stereo part, TV being a 25MCXX was the last wider-chassis 21" set, which this cabinet could certainly accommodate.

New for 65 (?) was the solid state TOTL Zenith chassis 8MT25 where two (121-270) in push-pull and a 55 volt single-ended power supply = 120 watts ??? I have restored damn near the same chassis in an RCA and Maggie TOTL model already:boring:

Trying to figure out how to use this site yet
But are you sure about the power Ratings of a P-P 6BQ5 of this set ?
I think more like 12-13 Watts per channel would be correct I would think
nice set BTW

I have a parts chassis and a couple spare forms (one of which is spoken for for a convergence coil in another set) so I should be able to deal with it if bad... I'll check on it eventually.




The spec I quoted was from a Zenith service manual image Davgoodlin posted. Its not impossible Zenith overstated it, but it's also not impossible to achieve it in class AB. The max plate dissapation power in the 6BQ5 datasheet is 12W. Theoretically if you ran the tubes at the max plate dissapation and class AB biased to the ragged edge of going into class B you could get almost 24W out of a Push Pull 6BQ5 amp. At an amplifier calibration presentation at one of the last ARCI radiofest meets at the old Holliday Inn venue the presenter stated 20WPC as being about the max a HiFi PP 6BQ5 amp could do.

That amp is so cool. How many console amps let you null the DC imbalance in the output transformer for lower distortion? Looks like you need to have it plugged into the preamp for the negative feedback to work, I bet there is a tone control of some sort in the loop. And an actual split load phase inverter - how deluxe! This thing might actuslly not embarrass itself with better speakers and stuff.

That said, the speakers have big magnets too, and does it have the 2 gram phono cartridge? Condition is kind of nasty but this console is really really cool, what a nice find. Look forward to seeing it make a picture! Can't comment on the tv, don't know the first thing about non RCA color TVs of that era. I wonder if the zenith roundie has the buzzing discriminator and the slightly weird greens like the later zenith tube sets can.

The output balance is a cool circuit. I was nerding out over it in the sams last week.
The feedback goes to the presence control, which according to the audio section instructions effects the mid-range of the audio making it possible to have the soloist stand out from the band.

Zenith used the 6BN6 in every TV from the mid 50s till they replaced it with SS audio....in some sets they hid it in a multi-section compaction, but it was there if the detector was tube.

Some of the SS chroma detector sets had somewhat odd green/color in general. The gated beam color detector tube color demodulators this has tend to produce beautiful color. My 29JC20 gated beam looked better than my RCAs before the lousy Sylvania CRT started dying. Same with my old gated beam 25MC33 that I regret selling to a flake that used to visit this site.

Zenith's gated beam tubes and IC color demods were both ultralinear compared to the pentodes or other tubes used by other makers. Differences in greens and other colors between gated-beam and IC Zeniths was likely due to differences in phosphors over the years combined with changes to the demod gains and angles to compensate. The all-sulfide CRTs in particular used a zinc sulfide green with cadmium added to make it yellower and brighter, resulting in visibly desaturated true greens and cyans. Also, because the white point was already moved towards cyan to take some load off the red gun, cyans looked grayish by comparison. This was reduced to a degree when rare earth red was introduced and cadmium was removed from all formulations for environmental reasons. This gave pretty much a standard phosphor set for years to come, but manufacturers differed in the white point they set and the compensating adjustments in the color demods.

In the end, basically the same phosphor set was selected as the standard for PAL, HDTV and still photos (sRGB), but the compensation was moved to the camera or computer instead of the receiver/monitor.

So I've had some time to pick at this. I bought this set 2 days before I was supposed to leave on a 2 week vacation so the variac job was stolen time.

Since getting back I confirmed that the H Lin coil is intact and the slug moves freely.
http://videokarma.org/attachment.php...7&d=1626829509

Also looking closer at the chassis I've found some interesting things. Someone wired the outlet half of an extension cord into the chassis (I presume to make the remote control something else).
http://videokarma.org/attachment.php...8&d=1626829509

The convergence yoke has one of the bridges between the clover petals cracked and a metal band wrapped around the whole clover. I've never seen one of these clovers intact and installed so I don't know if this is factory or an aftermarket repair.
http://videokarma.org/attachment.php...9&d=1626829509

Some of the work on the TV was done by the type of neanderthals who remove half the screws on a cover then bend it open like a can of sardines. :yikes:
http://videokarma.org/attachment.php...0&d=1626829509
http://videokarma.org/attachment.php...1&d=1626829509

The good part is it appears the stereo hasn't been worked on. Every unshielded tube is original Zenith with 48-51 week of 1962 date codes. All the audio tubes worth anything are good. The 6FQ7s aren't super strong but the rest are including the made in Holland 6BQ5s (which I believe are rebadged Philips).

Thanks to Dave I have the info on the KV-24 reverb I now know what reverb it should have had. While on vacation I was excited because I remembered I had a chassis that I got years ago with some FM MPX decoders that wasn't one, and a spring unit. I couldn't find the spring unit and the reverb driver chassis I have is I believe for an older Zenith...the circuit looks the same but it has its own power supply (which the one for the Chancellor lacks) and different plugs.
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Also I found a CTC16 with a bad flyback that's generously donated it's CRT to the Zenith. I fixed the cataract yesterday.
http://videokarma.org/attachment.php...4&d=1626830570

I love that you have so many cool sets that you can just "find" a 16 chassis laying around to take parts out of! That set is quite a looker too.

Thanks, though I wish I kept enough mediocre sets to just scrounge parts for ones I like. I picked up the CTC16 on what was a whole day drive to south of Minneapolis and back to pick up my Capeheart early color.

There's actually someone interested in the CTC16 who may end up putting a CRT and flyback into it. If I had a flyback and more room (or I didn't already have another 16 I like better) I'd try to fix it and keep it.

I think that RCA 16 is a real peach, never seen that control layout before. I have no flyback for it, so good its found a home.

The CRT is going to make that Zenith really a looker, like any decent 21". Is the CRT a Colorama rebuild or Hi-Lite (OEM-new)?

As far as your reverb spring, you're getting close. Those seem universal and ones in my Motorola's were made by Gibbs manufacturing in Janesville, Wisconsin. Cannot comment who made the reverb tanks RCA or Zenith used because I've never seen one.

developments and realizations
 

So I hauled the whole thing into the basement over the last 2 days. I pulled everything but the speakers, TV face bezels and wiring harness to make it lighter.

I learned the reason why the audio is K line (1962) and the TV is M line (1964)...It's a frankenset! Inside the changer side speaker box I found a K line tube chart with a piece of wood sitting loose on it...That wood had an M line TV tube chart on one side and blond photofinish on the other. Also the power switch wiring off the remote (and presumably to the chassis) is someone's back job. So someone killed a 25MC43 to make this set have a newer chassis.

Most of the rest of the installation is fairly tidy. I should try and figure out if the remote chassis and bezels are original or from the M line donor. I suspect it is a mishmash.

Over the next few days I want to get the TV good enough to do a shadow mask check on the CRT I gathered for it and start on a proper restoration of the electronics.

Last night I got the TV to live. Changed all the bumblebee caps, the focus rect, variaced, wiggled tubes and adjusted user controls and got this... Surprisingly the color is good despite the center coax lead to the tint control being snapped off the pot.

http://videokarma.org/attachment.php...1&d=1634694029

The speaker leads to the horn tweeter were loose and touching the changer before I brought it down which could explain the weak channel. So the audio might be good as is (still going to recap it).

I think the CRT bezel is the original K line, the control panel from the M line, ,and the remote chassis from the K line. The chassis supports degauss, but there's no coil. The power button looks like it's wiring goes with the chassis but had a molex for the remote hacked in.

Anybody got a picture of the M line Zenith degaussing coils?
I'd like to add degaussing but I'm not sure what route to take.

calamity
 

So the CTC16 CRT only lasted about an hour in opperation (split between 2 days ago and today) before it got so gassy that HV dropped off and the neck lit up like a neon tube.:thumbsdn:
Story of my life.

This is the 4th gassy picture tube I've had and all 4 of them have the copper evacuation nipple...I think those copper evacuation nipples have a higher failure rate (failing leaky) than glass ones.
http://videokarma.org/attachment.php...1&d=1634793423

Bummer.

Impressive progress, for sure.

A broken cloverleaf was so common in the 60's that every time I worked on a Zenith I replaced it, need it or not. The shop always had a stack of them readily available.

Two failure components are K1 (vertical integrator) pin 11 circuit and K2 (vertical feedback) pin 9 in the 6BA11 circuit. They look like a 3 legged disc cap. Each has a different color code, but I forget the colors and which is which. One of them was a sure bet to fail (I’ve forgotten which one). When it does the vertical pulls up from the bottom and acts real goofy. Like the cloverleaf, replacement of these two items was automatic, need it or not.

You should replace these if at all possible and save some grief down the line. I’m sure you can get some advice here on fabricating replacements, if necessary.

The main thing is to enjoy your project.

Thanks for the advice.

The clover is broken on one of the joints between leafs. Someone decades ago fixed it by wrapping an aluminum band and with a spring joining the ends around the clover. Not sure how I feel about it yet or if anyone has a replacement.

I'm busy making a good CRT for it presently. I took a gamble on a $10 badly cataracted 21FJP with a badly damaged/badly repaired bakelite base that tested NOS on the 2 guns that had connection.
Someone whacked the base pretty hard and busted most of it's bakelite skirt....then pressed it down crooked and HOT GLUED it such that the remaining part of the skirt stuck out enough to block removing or installing the neck deflection hardware. At least the glue was easy to clean just power up the heater and let it melt the hot glue. :rolleyes:
I got the safety glass off first (never done an RCA cataract removal indoors with heat lamp and gun before today) successfully, then removed the old base in a way that saved the leads by strategically destroying what was left of the broken base. I harvested a new base, and am dissolving the old factory base glue on the tube with ammonia cleaner (it's really effective on that stuff).
Once enough of the the old glue is gone I'm going to install the new base with high temp sensor safe silicone and reattach the safety glass.

If I can get good purity and static convergence (which is what I resurrected the chassis to check on the last CRT) then I'll start seriously fixing the TV.

Good luck on the base replacement. Selective demolition of the old base allows pins to be heated and removed one by one. Moving those leads is to be avoided, once carefully straightened.

I have done one by soldering extensions onto all 12 leads, that allows them to be guided into the CRT base's pins a whole lot easier. Again with less moving of leads, better visibility to guide them in.

Bob Anderson is an expert on such materials and recommended the silicone windshield repair goo. It is not hard when it sets, but allows very little movement.

Yup. I did it that way earlier today. I used high temp sensor safe silicone because I have used it before and it's held in opperation.
I siliconed the safety glass back on after confirming the base was on and soldered right.
The neck shot is the previous one I did since I can't photo the neck while it's in a bucket to allow the safety glass caulk to dry.

As far as the clover leaf assembly; has anyone had luck reproducing them on a 3d printer?

There has been chatter about that, but no one seems to have taken the challenge. I would certainly pay for one if they became available.

I have been told by some younger techs that an .stl file coulc be developed on that assembly, literally a 3D CADD file the printer needs to reproduce it.

Well the new better replacement picture tube is in and I've got good purity and static convergence.
Now I can start trying to restore the chassis in earnest.
I was able to get audio for the first time by wiggling tubes, but it's weak so I have more to do there.
I'm happy with where I'm re-starting from.
http://videokarma.org/attachment.php...1&d=1635302936

I love these big old roundies, especially Zeniths, especially especially with their TOTL hifi thrown in. I would wager I'm nearly as excited about this one as you are. Lots of pics as you go through the process please!

Anyone happen to have a picture of the power switch and remote chassis power harness plugged into a 25MC chassis the switch and remote harness are hacked up enough that they don't make anymore... I'd like to fix it such that it looks atleast somewhat like factory work.

This is a 25MC46. The plastic Molex housing has a tab that snaps into a rectangular hole in the chassis.

chassis

Thanks! This helps me greatly. :thmbsp:

I was able to dig up some pictures of the connector on chassis on older L line sets but none as clear as yours. Seeing that 2 of the wires from the molex have connectors that plug onto the chassis terminals and the third (looks like the black) wire runs under chassis gives me a good idea of how I should rebuild mine.

So here's how it turned out.
Before and after.
http://videokarma.org/attachment.php...8&d=1626829509
http://videokarma.org/attachment.php...1&d=1635620612
The red wire is a stand in for the front panel power switch.

I also cleaned up the audio output transformer replacement someone made. The transformer is a Zenith part but not the right part number so I have to look into that....My best guess is the pirated the one from the old K line chassis when they Frankensteined the M line in.
http://videokarma.org/attachment.php...1&d=1635620612
http://videokarma.org/attachment.php...1&d=1635620612
There's something frustrating about seeing a transformer where they bothered to solder the speaker leads but only mounted one of the 2 mounting tabs of the transformer (in the wrong place) because they didn't cut the primary leads long enough to reach and wanted to use wire nuts on the primary..... It's like whoever did the work was saying "I CAN do this right, but I'm too lazy to bother following through".

Last night before I built up the power switch I got the remote chassis working. Which consisted of oiling moving parts, making one good remote out of 2 damaged ones, and running everything through it's paces.

Since this console was a frankenset before I got it I seriously considering making the remote opperate the stereo when the TV is off... It's going to take some engineering, but I think the remote chassis design lends it's self to doing this. This idea is going to be down the road a ways. I need to verify the TV works correctly and get the stereo working perfect first. Once I have the kinks out then I'll be comfortable upgrading it from a stable base.

Well my franken-chancellor is alive for Halloween.
http://videokarma.org/attachment.php...1&d=1635725663http://videokarma.org/attachment.php...1&d=1635725663

So I changed all the ceramic Elmenco caps in the vertical and the weird non-linearity persists. I'm going to check vertical tubes and look at the couplates and lytics in the vertical next.

Anyone else have an issue where the yoke centering rings move but don't seem to have any effect?

I also cleaned up the HV cage too. I decided to silicone the mouse chew on 2 of the wires. And I installed a solid state focus rectifier (the original Zenith focus tube was dead) leaving the original tube to act as a decoration.
http://videokarma.org/attachment.php...1&d=1635725663