Hello all,

1. This is my first post (I apologise in advance if I make any mistakes in this post..!)

Anyway.. this morning I picked up a Calstan* television, radio and record player three in one. From my relatively surface-level research (e.g trying to find a schematic on RadioMuseum), I couldn't find anything. I have a few questions:

2. It has a "Thomas" picture valve with a serial no. JR 46143 and underneath the serial number is printed "Type 23HP4". I also couldn't find anything online about it either.
3. On the chassis itself, embossed is "16Gtt0 Run 2" and under that is "B663t". Again, no search results for the chassis or the valve.
4. It is also missing five valves, with one I found just sitting freely inside with flyback transformer in its metal case. It's a Miniwatt 6HS8 6BU8 valve, from a quick Google search used for volume control. I'll try to attach some photographs of the chassis and picture valve. Any idea what the other valves would be?
5. One fuse is completely smashed, and I haven't had a close look at the other. What rating could it be?
6. Are all Aus televisions rated to the same wattage? Once I have gotten new valves and new fuses, I thought that I should plug it into my dim bulb tester and have a 100w bulb.

If anyone can direct me to finding a schematic or has one themselves, please let me know!

Also if you couldn't tell from my lack of vocabulary, I am new to the hobby
I think that is everything...!
Thanks,
Oli

*I think it is a Calstan, I mean thats what it says on the front, but as I said there is no info on a Calstan TV...

Calstan is a known maker of TVs and radiograms. Sadly I cannot identify the set for you, although others will know more.

A search for 23HP4 picture tube produced plenty of info, for example https://frank.pocnet.net/sheets/201/2/23HP4.pdf

6HS8/6BU8 is a typical valve used in B&W TV sets. Once you get some info on the TV, then you'll know where to plug the valve back into.

Once you get the missing valves and fuse, I'd suggest it would be a good idea to examine the components for burnt-out parts, and replace any wax capacitors you find, before you think of applying power.

As an aid to identification, you might be able to get a list of what other valves are there. Some sets have a sticker with the valve positions listed on a diagram. If you pull valves out, make sure you know which socket they came from.

I assume you can't reply directly to people..?

I did send Brad an email with photographs to place on my post, but maybe I did it wrong or (more likely) because it is the weekend he just hasn't gotten around to doing it, which is fair enough. (But thats common sense really). But I digress.

In regards to looking at valves for I.D, there are:

6HS8/6BU8
6CM5/EL36 (AWL)
6AU4 GTA (Miniwatt)
6EM5 (Miniwatt)
6C07 (AWA)
6CB6 (Radiotron)
6BZ6 (Toshiba)
6BZ6 (Radiotron)

In the flyback:

1B3GT (Mullard)

The rest are missing.

In hindsight it was probably a bit stupid for me to stick my hand in the flyback when I don't know how long ago it was powered on, but then again it is missing valves and has smashed fuses so maybe not ̄\_(ツ)_/ ̄

I assume you can't reply directly to people..?

There is no private messaging function on this website. You can email a member if they have made their address in their member profile public (addresses are hidden by default).

Oli, that valve lineup is nothing like any Calstan I have seen and I have all the schematics.

I think you might have a Frankenstein! The chassis sounds more like an AWA.

Email me some pics and I'll be able to tell you what it is and send you a schematic.

My email address is unhidden.

Possible candidates for 23” Calstan 3-in-1 TV’s:

C188TRG (1960) broadcast only (AM)
C180TRG (1961) broadcast / short wave
C183TRG (1961-1965) broadcast / short wave
C229 (1964) broadcast / short wave
C225 (1964) broadcast / short wave
C261 (1965) broadcast only (AM)

The schematics may be in the JR manuals under Zenith.

I’ll look later when I’m back home.

I checked Zenith as well as the KGH chassis. Nothing matches that lineup.

I suspect that 6CO7 is not a valid valve number. Please check it again.

I suspect that 6CO7 is not a valid valve number. Please check it again.

uhh, it says: 6CG7? or maybe 6CC7?

Email me some pics and I'll be able to tell you what it is and send you a schematic.

My email address is unhidden.

it sure seems that way! I have sent a few images through. Now that you point that out, I see that the chassis has been propped up bu a few pieces of wood, and it doesn't look factory.

Also there is a tacky substance covering the whole chassis and the radio, where could that be coming from, and how could I clean it off? Just with some disinfectant wipes?

6CG7 makes more sense (9-pin twin triode).

Tacky substance could be nicotine from smokers. That stuff gets everywhere and can do damage. Try to clean it all off if you can.

Morning Oli!

I have NEVER seen a Calstan / Zenith like that one! And I thought I'd seen everything!

The chassis shape is the same as what they used to use but all the ones I've seen used Philips valves and deflection components, and no PCBs, just point to point wiring.

Yours is AWA - MSP based.and it looks like it was a prototype.
The circuit could be based on the 1964 RTV&H magazine TV design. Same valve lineup but no PCBs.

Pity someone has painted it. Zenith used rubber stamps on the chassis for ID.

Probably be a good idea to test the CRT. You could make the tester I published a few posts back.or there is a simpler way..

Not sure what relevance the stamped numbers are. Maybe they were trying out a new machine!!

Calstan / Zenith were a very small and somewhat impoverished manufacturer. I doubt they ever made more than a couple of thousand TV chassis, ever, in the 10 or 12 years they were making TVs.

I will have another search though my JR circuits.

Wow... quite the find I guess!
I don't quite know what to say..
For the CRT Tester, is this the one you mean? https://vintage-radio.com.au/default.asp?f=12&th=147

Yours is AWA - MSP based.and it looks like it was a prototype.
MSP? Is that an acronym for something like Manufacturer's Standard Practice or something else? I apologise for my ignorance haha
Should I donate it to a museum or other? Or should I keep going and try to restore it myself?

Pity someone has painted it.
On the CRT..?

Also the bottom fuse is intact, written on it is : 3AG 3A.

It's a shame I don't have any other info on it, but as I was cleaning it up (wiping it down, etc, (Thanks Robbbert! )) I can see (and smell) that it was heavily smoked around.. but that's the era, I guess!

I'm emailing you a couple of schematics.

It's possible that the 6BU8 / 6HS8 you have may be a ring-in, or that Zenith substituted it for the 6BE6 and 6BL8 triode and made a model for which we have no surviving documentation. That would not be surprising.

MSP = Manufacturer's Special Products. The components division of AWA.

I was referring to the silver paint on the chassis - Zenith (Calstan) chassis are normally zinc passivate plated which is a gold colour.

You should not need to recap it at least (they are all polyester caps as far as I can see) and the resistors seem to be Philips carbon film. They rarely fail.

The 6EM5 and 6CZ5 are interchangeable, as are the 6DQ6 and 6CM5 for all intents and purposes.

Good luck trying to donate it to a museum! We can help you if you want to get it going, it's a pretty unique piece, TV chassis anyway.

I assume you know not to touch the coils in the IF stages.

was referring to the silver paint on the chassis
Ah I see.

I thought I'd ask ChatGPT for what its opinion is on what valves I need it said:

Let’s work backwards from what you have:
You told me:

Valve
6CM5 / EL36 ✅ Horizontal Output (like 6DQ6)
6AU4 GTA ✅ Damper
6EM5 ✅ Vertical Output
6CG7 ✅ Multivibrator / driver
6CB6 ✅ IF Amp (maybe 1st stage)
2× 6BZ6 ✅ IF Amps
6HS8 ✅ Not part of design — mystery guest
1B3GT ✅ EHT rectifier

You’ve got 8 functional/installed valves, but 6HS8 is likely a red herring, so we ignore it.

That gives you 7 correct valves installed.

✅ THE ACTUAL 4 VALVES YOU NEED
Let’s lock them in:

Valve Why it’s missing / needed
6AL8 Video detector / AGC amp — common missing part
2 × 6BL8 Sync separator and sync amp — essential
6BM8 or Audio Output Valve You have 6EM5 (vertical), but still need audio output — probably originally shared in a 6BM8

⚠️ Don't Order:
Another IF valve (e.g., 6BX6) — you already have 3: 6CB6 + 2× 6BZ6.


6BE6 / 6BQ7 — unless you confirm missing valve from the tuner section (which seems populated based on your numbers).

✅ So your shopping list is simply:
• 1 × 6AL8
• 2 × 6BL8
• 1 × 6BM8

What do you guys think?

I assume you know not to touch the coils in the IF stages.
I know now! xD

Mostly right but:

No such think as a 6AL8. More likely a 6DX8. Or perhaps a 6AW8. But I can't say for sure without tracing the board connections.

You can see how much difference there was between the 1502 and the 1504.

The audio out could be a 6BM8 or it could be another 6DX8. Not interchangeable!
I also can't see a 7 pin socket free so that rules out the 6BE6.

Let's see what I can glean from your pictures.