Hi all. Can anyone help me.
I am after a Thorn 3500 chassis TV.
These came out in Australia in the mid 70s as AWA, Thorn or Baird ( Radio Rentals sets ).
Good money paid working or not.
Any help steering me in the right direction would also be appreciated.
Cheers.

Remember them well, but I doubt you'll find one. They were hated by most techs, were hopelessly unreliable and so were practically being given away where I worked in 1975. For most family members one of these was their first colour TV.

A couple of years later when its original Mazda CRT had faded away I grafted a 22" 90 degree self-converging CRT into one of these for my sister-in-law. It ran quite cool with the rail turned down by about 20% due to the easier-to-drive CRT and the absence of the convergence board. Kept going without any problems for as long as they had it.

Good luck!

I think they were the only CTV we saw in Australia that did not contain a single IC....

Is this the one?

https://vintage-radio.com.au/default.asp?f=3&th=975

If so I have some spare PCB's and other bits you can have.

Jeff

No, that one is newer, it's a Mitsubishi G chassis (or possibly a K chassis).

The Thorn 3500 was 90 degree delta gun - old school. Basically it was the BRC 3500 series with a mains transformer and VHF turret tuner added. Imported from the UK in the days when no-one could get enough colour TVs to meet the demand.

The co. I worked for at the time had some in their rental fleet. Didn't last long.

They all looked the same - 22" or 26" CRT, push-through presentation, woodgrain vinyl covered plywood cabinet.

They did have an excellent plastic-wallet service manual. Needed it!

Here is a link to a British HMV that used pretty much exactly the same chassis, sans mains TX:

https://www.radiomuseum.org/r/hismasters_2711_brc_3500.html

It's strange how distance,(time), makes the heart grow fonder.

I quite liked the 3504 chassis. Probably because I worked on so many.
I won't say that they were unreliable, but I'm glad that the company were not making parachutes.
They were one of the sets used in the Colour TV course at R.M.I.T. There were no ic's in them and were therefore excellent for training purposes. An oscilloscope could be applied to any point.

I have a feeling that near the end of the run, I did see one that had a production change to the I.F. Board, which had an I.C. Fitted . The set had two horizontal output transformers wired in parallel.
The one that drove the tripper failed frequently, the other, I never had fail.

I agree with Ian Robertson about the Mazda tubes. Not the best example of a tube.

Realy, there wasn't much that went wrong with them. Just tripplers, G2 switches, Horizontal transformers,
the edge connector on the Beam Limiter board, the overload cut-out switch, Spark gaps, The power supply, the vertical stage, The RGB thick film, and the convergence adjustment pots.
That is some of the more common faults that kept us fed.


Wayne.

Yes Wayne, add to your list most of the many trimpots (especially on the beam limiter board which always looked like an afterthought) and that 2μF cap in the line output.

Considering that there really weren't that many brought into the country we certainly used to see a lot of them!! I had a bit of a soft spot for them, they used to work OK once you fixed all the faults and set them up properly, i.e. setting all the trimpots and voltages in the correct order. If you had one with a non-Mazda CRT in it you had a reasonable TV. For my in-law's set I transplanted a Philips CRT from an otherwise dead Decca (weren't THEY are piece of s**t?) and it was quite reasonable. Lasted until they bought a 63cm NEC in the 90s.

Yes the 3504's were a dog of a set but the 4KA's were at least as bad if not worse.

Those hideously unreliable thick film modules.

They were not good for customer relations as their constant failures made the tech look bad.

I knew all the main faults for both sets as I saw so many.

They were a very good training ground for a young Tech, as I was back in the seventies.

When aligned properly both sets performed well. Just not for very long.

"When aligned properly both sets performed well. Just not for very long."

That's for sure....!