I recently gained another Scott 6T11 television. While one is enough for the average mortal, this one was a bit better than my other one, so you know how it goes....

My first set was serial number 1162 and marked "Model 6T11A". The new one is serial number 1889 and marked "6T11B".

Looking at both Sams and Riders TV, they mention production changes up through about serial number 500 (including two different tuners). They also mention the 6T11A, but no mention of the "B" suffix. Clearly, this is a later set...and there are a number of physical and electronic differences.

so..calling all forum members: if you have a Scott 6T11, can you post the serial number and the model number? I'd like to see if we can narrow down the changes. If you know a date for your set, please post that as well. Unfortunately, I do not have dates for either of my sets.

Thanks!

I will get the info from my Scott 6T11 and post it here tomorrow.

I believe its an "A" version.

My 6T11 has a small scan protection chassis that I don't see in the Sam's or Riders. As I recall it has a 6SN7 tube in it. This could be one of the changes.

My set has the General Radio tuner.

It's one of the sets I run fairly regularly.

Jim

Pay no attention to my previous post

Now that I look it is actually a 6T11B. This is what is stamped in the plate on the rear cover.

The serial number is 1622.

The tuner is actually made by General Instrument. It could be model TVA, TVB, or TVC. I found service info in Riders that matches what I have.

Channel 2 is at 7:00 position and the knob goes clockwise around with channel 13 at 5:00. I believe depending on the tuner the labeling can be different and backwards from this. No channel 1.

There is the scan protect chassis to which I find no reference to in either the Sam's or the Riders. This was original to this set not a mod. It has a plug to the rear of the main chassis. In the event of failure of either H or V scans the CRT is cut off, keeping in mind the high voltage is not part of the horizontal sweep circuit and the flyback doesn't have a HV winding at all.

Jim

Jim -

Thanks! That helps narrow down the switch between the "A" and "B" versions. Now here is the interesting wrinkle:

My "A" set (#1162) has the little outboard CRT protector using the 6SN7. My "B" set (#1889) does NOT have it. Since you set is a "B" version, do you have small tube covers over all/most of the tubes on the tuner chassis? My "A" set doesn't, but the "B" set does.

Both my sets have the GI tuner as well...but looking at my 1162 chassis, I think it may have been replaced at some point.

Thanks for the info...I hope we hear from other folks.

When I acquired my 6T11 back in the mid 1990’s it came all in pieces so I can’t verify the entire set or any of the what? Five chassis were all in the same TV set in the beginning.

Everything went right back inside the cabined just like it was supposed to.

My set has the little bayonet type tube shields on all of the miniature tubes, the chassis is polished aluminum as I recall.

There were markings in pencil on the main chassis that led me to believe my set may have served in some kind or rental or commercial use.

My main chassis has the bottom cover with the labeling for the controls you reach through the bottom. The chassis is easy to work on once you remove all the screws and the side plates and spread it out on the bench, as difficult as it looks from the bottom all put together.

Jim -

Thanks...perhaps the bayonet tube shields are an indicator of the "B" series sets. My earlier "A" chassis only has shields on a very few of the most critical tubes. Mine also has a good bottom plate...someone wrote "good" in pencil beside about half the tubes on the main chassis.

I having a hack of a time with the horizontal hold on this set....WAY too touchy. More troubleshooting this weekend. Thanks!

The Horizontal oscillator circuit is the RCA Reactance tube AFC circuit and it is usually so stable you don’t need a hold control at hand. Noting all the controls for the 6T11 are in that slot on the bottom.

I had to make the panel for the cabinet that covers the chassis and I decided it needed a tube layout on the under side so I scanned the one in Sam’s and photo shopped in the 6SN7 scan protect tube. I obtained a sketch of an original panel and made a duplicate and I took a picture of the high voltage warning label on the back and tuned it up in photo shop.

When I moved from Salt Lake City in 1998 to Phoenix and first turned the set on, the vertical size was short. I replaced some of the likely capacitors but finally stuck in a 6V6 in place of the 6K6 and it works fine. I suspect some thing in the V oscillator circuit relating to the boost voltage.

One morning I turned mine on and as I was about to walk out of the room I noticed the audio had stopped and I could hear a clinking noise like something getting hot. Looked in the top and the H-out and the 5U4 were glowing bright red. Hit the off switch quick.

A capacitor in the H-Out where the boost voltage takes off had shorted dead to ground. My set still works fine but in the path of destruction is the Power Transformer, H-Centering pot, the yoke, the Flyback, the H-Lin coil and a couple of tubes. Had to replace both tubes,

This is when I discovered it is not hard to open up the chassis and get to parts that are in tight corners. This set has an industrial feel to it.

I use my 6T11 regular, several times a week and I have never adjusted either the H or V hold controls. The focus drifts around a bit, the brightness and contrast are stable. I turn it on for morning news and by the time I have coffee in hand, the focus has drifted in.

The electrolytics are still original and most of the paper capacitors.

I found it easy to do optical alignment by removing the screen stop and sliding it forward while feeding a cross-hatch pattern form a B&K 1077 or what have you. You get a double image with the screen slightly forward and you adjust the space between the lines to be equal until you get the screen back in position. I can see the scan lines anywhere on the screen.

Jim

Thanks for the tips. Given the H-hold issues, I've still got a problem somewhere in the circuit. I had to replace a fair number of the paper caps in the chassis. I brought it up on a Variac (after the usual safety checks), and sound worked immediately. Several paper caps "sizzled" out, so I replaced most of the caps in the H/V circuits. I will make some time over the holiday to finish it up.

So...does anyone else have a 6T11 and can provide a serial number and description?

Mine is missing the back so, unfortunately, I cannot provide a serial #.

Evening all,
Have been coming up to speed on the 6T11 reading all the forum posts. I just acquired a 6T11 and awaiting its delivery. I was curious on the mention of an add-on beam protection circuit using a 6SN7.
Has anyone captured the circuit and adjustments. I would believe this addition is a vital upgrade to protect the 3NP4.
Thanks
Jack

Jack -

I have two of the 6T11 sets, one with the circuit and one without. I did sketch the circuit on paper awhile back, I'll have to see if I can find it and put it into a drawing program. I haven't found a period schematic showing this....

Gents:

I have a Scott 6T11 that I mostly fixed / restored a good dozen years ago and actually watch TV on quite often.

My set has the Scan Protect circuit which is the 6SN7 on a small chassis behind the main chassis.

I would like to see the schematic as well and I was too lazy to draw it out the last time I had the set apart. Neither the Sam’s or Rider show this circuit.

There are no adjustments I know of for this circuit. I don’t know when it was added to the design of the set but obviously a factory install when the set was manufactured.

If you loose either Vertical or Horizontal sweep you will burn a line in the 3NP4 CRT as the High Voltage has a standalone, regulated supply. I have a brand new, perfect 3NP4 with a burned line on the screen (spare parts) which is aluminized BTW.

Around 1998 my set suddenly developed a vertical linearity and height problem and the only way I could get it to sweep full screen was replace the 6K6 V output tube with a 6V6 which has worked unchanged for 10 plus years. This may be a problem in the scan protect module.

I had a failure of one of the two capacitors in the boost voltage circuit and it put a dead short across the B+ which included the Flyback, H-Lin coil, centering pot, yoke and power transformer. The set had been operating a few minutes and went silent / dark and I could hear the B+ rectifier getting bright red and crackling. I hit the switch on the plug strip and the Scott survived but had I been out getting more coffee it could have been fatal, didn’t blow the fuse.

The chassis is easy to work on. By removing some hardware you can take off the sides and easily get to all the parts without unlacing the harness that goes to the adjustment panel.

The main chassis on my 6T11 is polished aluminum and has a bottom panel with labeling for the various adjustments. You slide the set forward on the table it sits on and you can reach all the electronic adjustments like height, centering, holds and so fourth up through a slot in the bottom of the cabinet. I do the optical alignment by feeding a crosshatch from a B&K 1077 to the set and slide the screen forward past the stop and you get a double image slightly out of focus. You can match up the double lines with the optical adjustments and slide the screen back into position as you set the focus. I can see scan lines over the entire screen of my 6T11 indicating it is properly optically aligned and focused. The electrical focus drifts as the set warms up, I probably need to do a proper restoration some time. There were several versions of the aspherical correction lens and if you have the wrong one you won’t get even focus on the screen.

The mirror located under the lid is a front surface and easily scratched. Replacements are very expensive and any old mirror won’t work. The reflectivity is extremely high on the original mirror. The mirrors inside the optical box are also front surface.

The Scott is basically the RCA 630TS circuit with a simple B+ power supply. It has all of the design improvements used on the 630 which includes the Reactance control horizontal AFC. The set operates solidly and I run mine all the time.

Jim

Hi Kent,
If you find it just scan it in and I'd be happy to do the schematic in a design program.

On another note,
I've had a note on my desk to return some parts back to you for almost 2 years. I must admit after my cancer treatments the meds have deaden my brain in spots and have no idea what I need to return. So if you have memory please let me know.
Thanks

Jim, Kent
When this baby arrives is there a method to install a standard CRT for bench testing? It appears that the slightest oops and there's a burn and that another toasted crt. I believe the 3NP4 is a triode but another could be used with the addition of external support for the other grids in a 5FP4 like test tube.
If the neck is typical size I believe its possible.
Thanks
Jack

I don't think that it would be very easy to use another CRT to test with....when I worked on mine, I kept the brightness really low until I was sure the sweep circuits were ok. I have not seen another connector like that used on this tube, but I also don't work on many early TVs.

And on that other note Jack....I think I might have sent you some parts for a SW converter several years ago. However, I have little more recollection than that and I obviously haven't missed whatever it was....

No easy way to put in a conventional CRT in for testing.

The Protelgram yokes are similar to yokes of RCA 630 design of the era so one of those CRT’s in a box would probably hook up and work. You will need lower high voltage.

The Protelgram high voltage supply is a good 25,000 plus volts so X-Ray safety should be observed. The metal optical box does not fully shield X-Rays

Well since the HV is independant from the sweep a lower HV can be externally provided.
Kent might have an option with lower brightness. I'll have to start the bench work here possibly next week. I'd still like to try the crt i8n a box.

Did any of you have to refrost the front screen due to flaking?

Kent,
Thanks that sounds right. Let me look in my scott collection area.
THanks
Jack

My screen is good but the flaps on the sides have been taped where they fold. I need to try for new or find a way to replace the cloth folds.

Jim

I have one of these scott radio laboratories inc model 6t11b serial # 1873 projection tvs, along with the matching storage bottom. I would like to sell it, can you ggive me any idea what it is worth?

Where are you located?

Phil