CTC-5 Strathmore!

[Whirled One]

[I was going to post about this earlier this week, but I'm now finally getting around to it...]

This past Saturday, I was in Ohio to pick up the RCA CTC-5 "Strathmore" that Kinzbird was offering for sale here several weeks ago. I've got to say-- I'm just amazed at how beautiful this set really is! The cabinet is truly in superb condition, and is really just a darn nice looking console any way you look at it. Well, I think so, anyway. I've never seen a 50's color set in person outside of a museum, so what do I know...

These two pictures are ones I took right after a friend and I hauled it up to my apartment. [NOTES: In the "doors open" image, it looks like the volume/brightness knobs are missing, but that's because I had removed the chassis before transporting it, and the bracket holding those controls has to be removed in order to pull the chassis.]

I really like a lot of the little details on this cabinet, such as the round metal accents on the doors, the elaborate multi-layered mask and bezel around the picture tube, and the lettering ("C O L O R") painted in gold on the inside of the front glass.

Right now, I'm cleaning up the chassis a bit (it's pretty dusty!) and doing some preliminary tests, but hope to re-install the chassis in the cabinet this weekend and soft-start it to see where things really stand. The 6BK4 HV regulator has an open heater, though, so I'll have to dig another one up first.

Just as historical notes, here are some tidbits about this particular set provided by documentation and suggested by clues from inspection:

About half of the tubes are still original. Most of these have date codes of 56-48, but a few have 56-43 and one has a 56-39 code, thus suggesting this TV was built in December 1956 or early 1957.

The CRT is apparently also original, as it too has a 56-48 date code. Amazingly, it still tests good, with strong emission! [all three guns read in the low/mid 80's on the 0-100 scale on my B&K CRT tester.] Cool! That was a big relief.

All of the tubes, including replacements, are RCA brand. There is an old RCA service tag on the chassis dated 1972. Kinzbird's receipts suggest that it was indeed repaired exclusively by RCA service techs. I see a few "orange drops" in the vertical section, but the set otherwise appears to have seen rather few repairs in its day. Just when this set was taken out of everyday use is not known, but after the family bought a new TV, they simply unplugged this set and left it sitting in the corner of the living room-- where it remained until the day I picked it up..! It's certainly been cared for extremely well during its life.

After it was built, this TV must have sat in a warehouse or dealer showroom for quite some time before it was sold. The down-payment receipt is dated October 10, 1958, so it would have been one or two model years old at that point. This payment receipt suggests that the total price paid for the set was $574.32, which would certainly have represented a fair discount from its original list price in 1956. [I don't know what, if any, of that is sales tax or interest/carrying charges, or if there was a trade-in involved as well.] This follows reasonably from the information on Ed Reitan's web site that says that RCA did in fact continue to offer various "leftover" CTC-5 Deluxe consoles having full doors (like the Strathmore) well into the CTC-7 era. [I suppose sales of all CTC-5 sets were poorer than RCA expected, but I guess the top-of-the-line models were particularly sluggish sellers if RCA was still trying to sell off two-year-old inventory..!] Note: Does anyone here know what the original list price of a Strathmore was? In any case, it would appear that Kinzbird's Grandfather got a pretty nice deal in 1958..!

Anyway, I was just rather excited to get this set, and though I'd share some info and pics with the group. :-) Any further info (or corrections) about this particular model appreciated!

[Sandy G]

I got just 3 words to say to you: (1) You, (2) Lucky, (3) Dog !!! GORGEOUS set !! You ever get sick 'n' tired of it, I'd LOVE to take it off yr hands !!-Sandy G.

[bgadow]

I've got one of those "Radio & Television News" 1957 Color Television magazines & it lists the Strathmore at $795. So somebody got a good deal (and so did you!). Thats a handsome set, and with the doors closed its the kind you would walk past without guessing whats inside. From going through old Life magazines from that year, RCA was really pushing color tv hard. But I guess it was still a real hard sell. Anyway, welcome to the CTC-5 club-you are really going to enjoy it!

[John Folsom]

Congratulations on a great acquisition! The CTC-5 is a great set, and a lot of fun to work on. Keep us posted on your progress.

[Whirled One]

Originally Posted by bgadow

I've got one of those "Radio & Television News" 1957 Color Television magazines & it lists the Strathmore at $795. So somebody got a good deal (and so did you!). Thats a handsome set, and with the doors closed its the kind you would walk past without guessing whats inside. From going through old Life magazines from that year, RCA was really pushing color tv hard. But I guess it was still a real hard sell. Anyway, welcome to the CTC-5 club-you are really going to enjoy it!

Thanks bgadow! (and everyone else who has responed!) I've been wanting a 50's color set for a while, and it's pretty darn neat to finally have one, and such a nice example at that!

Anyway, I think your observation about the "mild-mannered" appearance of this set with the doors closed is actually rather important. I was thinking something very similar when I first saw it in its original location-- the wood used in this cabinet matched rather nicely with the wood paneling in the living room it was in, and (with the doors closed) probably made for a quite attractive table to hold a lamp and some framed photos in the corner of the room. If the set didn't match the other decor in the room or look so nice, it probably wouldn't have been kept around all this time. Sure, a Philco Predicta vertical "barber-pole" console looks pretty nifty today as a classic TV, but I wonder how many of those were tossed in the landfill because they started to look out of place against the new furniture that their original owners bought in the late 1960's and 70's..? Perhaps there's something to be said for "understated" cabinet styles after all.

[Steve D.]

Very nice Strathmore there. Forum member Steve K. has that same model in the Bleached Birch finish.
RCA was still trying to clear their CTC-5 stock well after the CTC-7 & 9's were in production. Some local store ads here in Los Angeles still offered new CTC-5's for sale in 1959. These sets were sold at discounted prices with generous trade-ins for your old set. I've owned and seen many CTC-5 models over the years and note that some have the word/decal "COLOR" on the inside of the safety glass and some don't. I'm not sure when RCA made this change. The CTC-5 "Lockhaven" model had the word COLOR on the mask itself as did all CTC-7 & 9 models.


-Steve D.

[Whirled One]

Update!

Well, I soft-started it yesterday afternoon, and when I ran it at normal voltage, and turned up the brightness far enough, I was greeted with a almost invisible and poorly focused raster with a brighter (but still dim) narrow shimmering vertical rainbow of color that appeared on the right-hand side of the CRT. The 'rainbow' only appeared when the brightness and contrast controls are advanced at least to their halfway points. The vertical and horizontal hold controls behave normally. The hue and color controls have no effect on the raster. There is no audio except for random static (which indicates at least the AF output stage is okay). Rotating the channel selector does produce some visual and audiable 'noise' as the switch contacts change, but that's it.

Well, at least it has a raster..! I let it run for a few minutes, and nothing seemed to get overly hot either, so that was a good sign. The flyback was still cool after I shut off the set. One thing that surprised me was how *quiet* the HV section was. Normally, I can hear the horizontal oscillator of TV sets (especially old ones) fairly well, but I didn't hear this one at all. Before I first swiched on the set, I set the brightness control almost all the way to its minimum, so I was really surprised to see anything on the screen when I turned up the brightness, since the lack of horiz oscillator whine made me figure the HV wasn't working.

One thing I quickly noticed was that the heater of the 1V2 focus rectifier wasn't lit. while the set was on, I pushed at it with a wooden stick just to see if it was a dirty connection, but that didn't do anything. The 1V2 gets its heater voltage from the flyback, but the 3A3 HV rect also does (though via a separate winding), and its heater was lit.

I saw only about 200V on the 300V B+ line (measuring it on the wiring harness that goes to the tuner), so I'm sure there's something fishy somewhere causing that. As I was still wondering about the dark 1V2, though, just for fun I replaced it with a new one (since I happened to have a few of those around) to make sure it wasn't something flaky in the old one (though it tested okay in a tube tester, and has a quite visible heater). The heater didn't light up with that one either, though the raster was now noticibly brighter for some reason, and now it produces a rather trippy pattern of colors whose colors change with the setting of the brightness and contrast controls. The focus is too poor to be able to dicern the individual scan lines, but if you turn the contrast control up enough, you can see what appear to be blurry retrace lines. The raster fills almost the entire screen even at low brightness, but blooms (and defocusses even further) if the brightness and contrast controls are advanced far enough. Note: I have not degaussed the tube or anything like that yet, so I'm sure the purity is going to be bad no matter what.

Questions: with B+ as low as it is, is it normal to even be able to get enough HV to see a visible raster on the screen, yet not have enough B+ for the IF stages to work? (I haven't measured the 380V B+ line yet, but I would suppose it is proportionately low) Of course, these could be two totally separate problems. Also, why would there be enough HV to get the HV rect tube to light up from its flyback winding, but not the focus rect? Hope it's not the flyback itself that's bad... One thing I noticed is that someone had jumpered a resistor connecting the focus rect to the CRT, so perhaps that's a clue about something. In any case, I would suppose my next step is to find out what the deal is that's causing the low B+.

[Steve K]

Hi Whirled:

I am the guy who has the blond version of your set. Yes, check low voltage supply first. I would replace the electrolytics first. I know some don't takethat approach but I feel safer with new capacitors in there. Then make sure that your 5U4s are good. They could be weak causing low B+. If that doesn't bring it back up then start disconnecting individual lines going to the different circuits to find out where you are losing the B+.

Steve

[Chad Hauris]

Are you sure the 1V2 might just appear too dim to see it...there isn't much filament power on such a low voltage filament type tube. Do you have another set using 1V2 that is a known good working set you can compare?

[Steve K]

Chad is correct, you will not be able to see a 1V2 filament lit.

[roundscreen]

Hi wirled one.
If your set had no focus voltage the crt would not light. There would be a blue glow in the neck. Like the other guys say, Go after all the caps. power supply first. Replace the 5u4s if u can. If focus problem is still there after u get b+ up and horz drive check ok then go after the focus control and that wire you were talking about.

[Whirled One]

Okay, it looks like the low B+ was mostly a "test equipment malfunction". (Sorry!) Y'see, I figured rather than use my usual DMM, it might make more sense to monitor B+ with my big old analog VOM, since it's easy to see the meter pointer from a distance and easier to spot up/down drifting than on my DMM, plus I could just leave it connected and not have to worry about the meter shutting itself off after a few minutes of inactivity like my DMM. Plus, it has a 1000VDC range, and it's 50K ohms/volt so there shouldn't be any significant loading going on. Well, after pulling the chassis, propping it up on a table (running it on a variac, with HV and vertical output tubes pulled, but a speaker connected) and tracing B+ voltages back towards the 5U4's, I increasingly began to think something funny was going on... Even after pulling the main B+ fuse (which comes just after the 5U4's and before any of the filter caps) I still wasn't able to get more than about 200V on the meter, and it was just as erratic as before. On a whim, I disconnected the power again, switched to the 250V scale, ramped the power back up, and watched the meter pointer rise up-- to about mid-scale, and erratically. At this time I started to hear a scratching/hissing sound from the speaker. Gee, that's odd, the B+ fuse is pulled, how could there be any audio? Then I smelled something burning. Wait! That's not the *speaker* making that sound-- that's the multimeter!! One fried VOM, coming right up. Measuring B+ with my "everyday" DMM, everything was hunky-dory and stable.

However, running the chassis by itself turned out to have a side benefit. Rather than remove the tuner from the cabinet, I decided I'd make use of the old "Tuner-Subber" I had found at a hamfest a while back. With the substitute tuner hooked up to the IF input cable from the chassis, I was surprised to find I was now receiving TV program audio at the speaker-- all
I had been able to get before (with the chassis hooked up in the cabinet) was a little random static. As it turns out, there is indeed a problem with the tuner. I put the chassis back in the cabinet, and with the set's own tuner, it's just as before with a dull blank raster. However, with the substitute tuner, I actually get something that looks like a picture! The horizontal frequency is way off, though, and the focus is still very poor, and there's no apparent chroma signal, but at least it's *something*! At least that means the IF, video amp, and audio sections are okay. Even with a working accurate meter, B+ is actually a tad low, but not bad (I see about 280-290V on the 300V bus), so I doubt that's the main culprit of the focus/brightness issues, but it's something to keep an eye on. The 1V2 is still dark (the heater is quite visible when running it in a tube tester; yes, I know, a lot of 1-volt miniature tubes, such as those used in old portable radios, have almost invisible filaments, but the 1V2 was quite easy to see on the tester, so I figure it should be visible here...), and I measure near-zero VAC across the heater pins (though it's also possible that my DMM can't measure AC accurately at such high frequencies). The flyback winding that powers the 1V2 heater has continuity, and it's really easy to spot on the flyback (it's just a single loop of wire) for that matter. Clipping that dodgy-looking jumper wire had no evident effect. Next I'm going to see if I can find an extra damper tube and horiz output tube just to see if replacing them affects anything (I did see some blue flickering in the HO tube, but not really bad), adjust the horiz osc coil, and check other components in the HV/horiz section...

Thanks for all the comments/advice so far! Sorry 'bout the B+ red herring, though...

[Steve K]

How far off is the horizontal frequency? If you have wide diagonal lines, set the horizontal control to mid range and adjust the horizontal frequency coil on the circuit board a bit to see if that will lock it in. If the frequency is far off then start by recapping the entire horizontal section. If it is not working correctly that can reduce all the high voltages. I assume that you tested/subbed all the tubes in those sections. There are several 10 meg or so resistors in the focus circuit that could increase in value so you will want to check those. Have you measured the high voltage and focus voltage? If you do not have a high voltage probe they are usually available on eBay,

Steve

[nasadowsk]

Hey!!! Where's the chassis pics???

Hmm, I owe you guys some pics too now that my CTC-7 is running...

[Whirled One]

'Nother update!

The tuner is working now. The original 6BQ7A RF amp tube had at some point been replaced with a 6BC8. The 6BC8 is listed as a substitute for the 6BQ7A in my old SAMS tube substitution guide, so that may have been OK. Replacing it with a new 6BQ7A brought the tuner back to life..! Reception is pretty weak, though. Just for good measure, I also replaced the 6X8 mixer/oscillator, but that didn't help much. Reception was also pretty weak with the "Tuner Subber" for that matter, so it's probably a so-so IF stage or something. Right now I'm just glad to see the tuner functioning!

I also saw another example of how outside factors can cause unexpected results. First, there was the bad VOM that made me persue what I thought were apparent B+ issues. Even afterwards, though, B+ seemed a bit low anyway. Well, now even *that* has been explained. Y'see, ever since the first time I started it up, I'd *always* been powering this chassis through a Variac, with the rationale being that I can reduce "inrush" current and avoid potential damage caused by switching it on/off while testing. [Plus, it was just convenient... ] Well-- one thing I hadn't considered was the fact that this is probably the highest-current-drawing device I've ever powered with this Variac-- this TV draws 380 Watts according to the statement on the back cover! So, I decided I'd measure the actual voltage output from the variac with my DMM. As it turns out, with that much load, the output from the Variac ran between 10% and 15% low. Turning up the variac until it matched "normal" AC line voltage here (~ 120 V) brought the B+ line right up to spec..!

Bringing up the AC input to its normal level also raised HV, but it's still very low. Steve asked if I had an HV meter probe. Actually, I do, but I kept forgetting to actually bring it out and measure the HV when the set was running... :-/ [Plus, I don't know about you all, but I get pretty skittish poking around a "live" HV section... at least the HV output on this set is readily accessible and easy to prod with an HV meter probe...] Anyway, so now I've measured HV. Before I realized how much voltage drop there was from the Variac, it ran at about 14 KV, but now it gets up to 15 or 16 KV (assuming this old HV meter is accurate, of course). It should be about 20 KV, so that's still quite low. Brightness and focus are still poor, although *way* better than it was at 14 KV. I've tried swaping all HV tubes except the horizontal output tube and the HV rectifier, but that's because I don't have any replacements for them. I'll be at a hamfest in a few weeks, though, so hopefully I can pick up at least a new HO tube. The 10 meg resistors in the focus circuit are okay. They read a bit high, but just within tolerance. The other focus resistors above the chassis seem okay too. When I pull the chassis again, I'll check the other components in the HV
section.

As it turns out, the horizontal frequency coil *is* the front panel horizontal hold control on this set. The "best" I can get is a picture with about 15-20 wrap-around "lines". There doesn't seem to be anything else to adjust that controls the oscillator frequency, so it looks like a little testing of the oscillator circuit (or just re-capping...) is in order. Swapping the oscillator tube had no discernable effect.

There's still apparently no chroma signal, and everything tends to be green, but I'm not worried about that just yet.

Thanks again to everyone for their help, and thanks for putting up with my long-winded posts..!