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Anyone got a schematic for a Teleton 12" VX1110?  

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Alastair
(@alastair)
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I'm having a little play around with the Teleton CTV that Mike kindly sent down with John, (Jayceebee)...

--Cheers again Mike--Love it!

A great little set, brings back memories does this! This particular set has a dark picture for some odd reason. I thought maybe the CRT was tired but actually its pretty good. Tested with a Muter, it reads G = 1.2mA,  B = 1.1mA, and R = 0.4mA

I ran the heaters only for a few hours but R only came up slightly. A Soft and careful tickle with the Muter restored the R to 1.05mA. I didnt do anything else at all to the tube--only the low R cathode was cleaned.

- Anything over 0.7mA tests as good with the Muter. So--Tube is good, but we have a dark picture. Very sharp and contrasty image, just dark. Quickly advancing the brightness cont gives a bright image--for half a second, that then reduces down--Like the ABL is over-active.. Picture doesn't expand by much, so doubt its EHT issue.

Bright bits of overcontrasted image are pretty bright...

Not having much luck in finding any info or schematics Ive checked various voltages such as A1's which are around 400V--but without knowing exactly what they are supposed to be, I'm a bit in the dark--along with the set! Its not possible to achieve frame-collapse grey-scale setting--there's nowt on the screen with the A1's fully up as well as user-controls fully up.

I have no idea whether RGB or CDA type drive is used on this set--but suspect CDA...

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Topic starter Posted : 29/10/2016 10:48 pm
PYE625
(@pye625)
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Hi Alistair, that has whetted my appetite for some pictures wink

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 29/10/2016 11:00 pm
crustytv
(@crustytv)
Vrat Founder Admin

I have the service data for this which includes schematics, waveforms and set-up data. Yes you're correct its CDA. I will get the data scanned and uploaded to the library up top.

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Posted : 29/10/2016 11:14 pm
crustytv
(@crustytv)
Vrat Founder Admin

For now to get you up and started, here's the section you're interested in with voltages and waveforms.

vx1110cda.jpg

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Posted : 29/10/2016 11:25 pm
crustytv
(@crustytv)
Vrat Founder Admin

Alastair,

The service data manual for the Teleton VX1110 now resides in the service data library, this is accessed up top via the 'service' menu tab.

A member has to attain a forum rank 3 ( 1000 points) to gain access to service data, as laid out here. This is achieved via posts and activity. However the Mods and I have at our discretion the ability to raise a users level. You were level 1 with 70 points, in recognition of the community spirit you displayed by offering all those TV's to various members, I have fast tracked you to level 3. What all that waffle means is you now have access to the data library.

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Posted : 30/10/2016 11:37 am
Nuvistor
(@nuvistor)
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A few interesting points in this circuit, it is obviously an early set with using so many valves.

First thing I noticed was the decoder uses a circuit that does not require a delay line nor is it simple PAL, this must have been to get around the PAL patent. I am not sure if the circuit will cancel phase errors or if they rely on the tint control, where phase errors are small it would not matter.

Second thing I noticed was the use of a "UIF", which got be wondering with this being an early design if the UHF tuner was typical USA type with a diode mixer in the tuner, i.e., a conversion loss and the gain is  made up by extra IF amplification. The USA VHF tuners circuits I have seen use a mixer with conversion gain so perhaps would not require the extra UIF.

It will keep me occupied for a while trying to understand the circuit, still there's only the dusting and hoovering and that can waitthumb_gif.

Frank

edit. Just noticed it is live chassis although it as a mains transformer and excluding the CRT, the heater chain adds up to an interesting 117volts.

Frank

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Posted : 30/10/2016 12:26 pm
crustytv
(@crustytv)
Vrat Founder Admin

The set is from 1973/4. Here are some photos of the VX-1110 from 2014 for those wondering what it looks like.

Teleton1.jpg

Teleton4.jpg

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Posted : 30/10/2016 12:59 pm
Nuvistor
(@nuvistor)
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Something we don't see very often, the boost diode with all connections on its base, I  thought the top cap was missing until I checked the circuit.

Frank

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Posted : 30/10/2016 1:18 pm
Alastair
(@alastair)
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Ah--Wow, Cheers Chris, the scheme you posted was most helpful. It indicates I should have A1 voltages in the range of 570-600 odd volts. Ive got barely 400, so there's an issue with the supply to the hot end of A1 pots, probably over in the timebase area....

The Teleton is by UK standards an oddball. Seems its a bit of an oddball by USA standards as well, I don't think many/any were sold there.

The 12" CRT is (Possibly) the smallest Delta-Gun type CRT made in any quantity. Interesting--The above diagram from Chris of this set lists a 510ALB22 as the set's CRT--Which is a 19" CRT!

It uses valves that are of American type/format, some being Compactron Duodecar 12-pin type, such as the 17JZ8 field Osc/O-P and the 31JS6A/C line-out and that have 450mA heaters, but the set is Japanese, made by the General Corp of Japan, later to become Fujitsu General. Looks as though premium American built sets of the 60-70's used 6.3V Parallel heater-chains and a big mains-transformer, series chains were less popular from what I can see...

The boost-diode/damper valve, 17DW4A has no top-cap. An American? innovation as far as I know, only in 12-pin Compactron design--there were a number of Sweep-Tubes (Line-Output Valves) that also had no top-cap as well, the 24W 6HJ5 was one of these, The anode being connected to a pin that had unused pins either side for isolation...

Replacement valves are easy to get--But From The States, however they are cheap, as they are 450mA heaters and of little interest to the audiophools which is nice...

The set is in my W/S at work, so if I get a minute tomorrow I'll have a poke around. Tuesday--I'll be losing my W/S for a few weeks (its based in shipping-container) as the yard where it is, is being re-purposed, and not sure where I'll end up!

Thanks also for the upgrade and the service-info, and if I find any more nice old sets, I'll grab 'em and I'll post them here for whoever wants them,--but if I should ever find a G6--Its Mine, haha!.

--You never know whats going to come in to what is in fact the main recycling plant of Swansea,  where I'm based...

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Topic starter Posted : 30/10/2016 2:22 pm
ntscuser
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nuvistor said
Just noticed it is live chassis

Metal cabinet too I believe and no earth connection? electro_gif

Classic TV Theme Tunes

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Posted : 30/10/2016 6:10 pm
Alastair
(@alastair)
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Cabinet is steel, earthed too according to scheme--Will check its earth bonding for a larf...

Its defo got a three conductor mains-lead....

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Topic starter Posted : 30/10/2016 6:57 pm
Mikey66
(@mikey66)
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I recognize the set in post 7 laugh

It is now yours Alastair, BTW there should have been a small box with some of the oddball Japanese valves with the set

Here's the thread on UKVRR  http://www.vintage-radio.net/forum/showthread.php?t=111542

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Posted : 31/10/2016 1:23 pm
Alastair
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Ah--Yes Mike, There was certainly a box with the set with some oddball Teleton valves in, I had forgottren to mention  it earlier.

I checked the earth bonding--There Wasnt Any! The Metal Cabinet is electrically Isolated from the Chassis by elaborate plastic mounts holding the studs for the chassis screws. The electronic chassis is connected to the Neutral side of mains, as is usual in most all UK Valve b/w and early colour types.

The Three conductor mains-lead, the earth wire is connected to a tag-strip, that has what appears to be an arrangement/spade connector--Thats not used, doesn't look as though its ever had anything fitted to that tag, no markings in the solder coating, so I'm thinking its a fair idea to attach this tag to the outer steel cabinet for safety-earth...

I made a bit of a presumptive boob--As I often do! I had thought I had low A1 supply, whereas its OK. I have approx 700V to the focus taps from where 600V is applied to the high-end of the A1 pots.

Checking the 10GK6 luminance output pentode cathode, the voltage should read 6.5V in fact its only 4.8V the Anode is supposed to be 210 and is 230 odd, not wildly out but could be contributing to lack of brightness, I suspect it could be a little low in emission/transconductance...

Odd choice of valve that--Its very like an EL84 in its ways--except the 450mA heater. Set up like it is, in the set its dissipating only 1.3W on its 14W anode--A much smaller valve could have been used--The wonderful weirdness of Teleton, Brilliant!....

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Topic starter Posted : 31/10/2016 7:18 pm
Alastair
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Ah--There's interesting....

I just looked at the thread on the other site about this set. The pic of the 17JZ8 down to air, also shows that tag-strip with the earth wire on. It also has a lead attached!

Going to have to find that and reattach...

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Topic starter Posted : 31/10/2016 8:47 pm
PYE625
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Alastair said 

--You never know whats going to come in to what is in fact the main recycling plant of Swansea,  where I'm based...

Sounds like a great place to be..... I would be bringing tonnes of stuff home.

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 31/10/2016 9:00 pm
Alastair
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Andrew--That is actually a bit of a problem--for me anyway! I dont have a lot of spare room! Probably just as well, I would end up like one of those hoarders you see on the telly!

Sometimes things come along that I cant see junked so if they are of interest I pass them on usually.

Thinking of this low brightness issue. Ive been looking at CRT data-sheets to determine the voltages etc. I cant find any data-sheets for the CRT fitted but looking at the likes of A56-120X, a Minus 100V on G1/Cathode gives a just extinguished raster.

The Teleton 12VARP22 Cathodes are at 200-210V and the G1 100-110V.... the difference being--100V. I also remember my previous Teleton many years ago had a dark picture, that I always put down to a poor tube--Maybe it wasn't after all, but the set Made sorta on the low brightness side--Or maybe the CRT is quite different to a similar aged and format British 22" CRT, which is more likely!....

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Topic starter Posted : 01/11/2016 10:05 pm
ntscuser
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I remember a report in Practical Television claiming that the picture from small Japanese colour sets was generally much brighter and sharper than contemporary British sets and there weren't that many Japanese brands available at the time so it sounds as if the Teleton has lost much of its original brightness.

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Posted : 01/11/2016 11:48 pm
Alastair
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Kine Bias, a three-position tag setting, relating to picture brightness....

Hmm--I searched that on Google. 'KINE' appears to be an oldy worldy English language reference to Cows, Plural--the Moo-Moo sort that eat grass and give milk! The only other time the word appears refers to some very vague reference relating to American TV sets CRT voltages.

In the Teleton, its a potential-divider chain setting the G1's voltage via  three-position tags and pluggable flylead, near the bottom of the CDA board. The highest (brightest, but still too dark) setting giving a 50% division of voltage between the CDA anodes output and the CRT G1's The CDA Anodes are at 150-180V, the G1 at 100V-ish

--Quite how Cows relate to CRT's completely escapes me, apart from both being big and rounded!

When I get access to the set again, (As its in my W/S, now the other side of the plant, prob be a couple of weeks) I'll have a check of the bottom end of this pot-divider arrangement, maybe alter the resistor chain there to give a little more--seeing all the tube-base voltages are reasonable to the schematics.

Ive also got a new 10GK6 Luminance O/P valve on its way, so that'll go in first....

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Topic starter Posted : 02/11/2016 7:11 pm
Cathovisor
(@cathovisor)
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The Colonials do have some odd names for CRT electrodes - 'ultor' being one of them - but I'd wager "kine" as having a Latin or Greek root, as in kinema.

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Posted : 02/11/2016 7:35 pm
Nuvistor
(@nuvistor)
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Seems to be a standard term in many USA mags of the 50's and 60's.

http://www.thefreedictionary.com/kinescope

There was also a kinescope used to record to film from a CRT screen.

http://www.earlytelevision.org/gpl_pa-303.html

I did spot the adjustment in the circuit but thought the term was more well known this side of the pond.

Frank

Frank

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Posted : 02/11/2016 7:57 pm
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