Hi all.
I know I have asked before but I am putting it out there again.
I am still searching Thorn 3500 chassis set.
Either Thorn, AWA or Baird. Condition unimportant.
Any help in even steering me in the right direction would be a fantastic help.
Cheers.

I have very bad memories of the Thorn 3504 Chassis.
Quite unreliable and not a very good performer.
As I recall they were dumped on the Australian market cause no one else wanted them.
Then came the 4000 Chassis (AKA 4KA) which was even worse.
They were rebadged as AWA here.
The poor public who had a good run from their AWA B&W sets unsuspectedly bought these lemons.
They did the TV service industry no favours as we were always blamed for their unreliability. ("It's the same fault you fixed last time!")
No it isn't.

Anyhow good luck with your search but I think pretty much all of them went to land fill.

For a short time the co I worked for had lots of these in their rental fleet. Basically because it was all they could buy at the time.

Capable of acceptable performance when set up properly, they didn't stay that way for long. A bit like a British car....

All in landfill a long time back and good riddance!!

They did have an EXCELLENT service manual though! If you find one of those (A3 size yellow vinyl wallet with clear plastic pockets) it will be well used!

British cars hmmm yes it was mainly Lucas wiring issues in many cases.
They were not water tight.
The Austin 1800 was called the car of the century and we all wondered which century they were referring too.
Other things that use to amaze people was that BMC was so slow to change to a full synchro box ......when other manufacturers had all ready made the jump.
Crappy heaters compared to a early jap car which was surprising as English weather is often dull wet cold .
But they did have forsigh and build cars with east west engine in a era when no one did and today the front wheel drive east west engine is in everything.
Ohhhh I guess I should mention the old SU carbie..... simple reliable and you could balance them using a piece of garden hose stuck in one ear.
Yep I'm glad I gave up working on cars after my time.
Pete

Ah memories of the 3504! A couple of firsts and onlys come to mind:

Only all solid state colour TV with NO ICs. Not one.
Only hor frequency buck regulator that took rectified mains of 300v down to 60 volts. Sounds dangerous and it was. Needed a crowbar overvoltage protection circuit and a thermal circuit breaker to avoid disaster.

Then there was that strange beam current limiter PCB, clipped onto the top of the power supply module like the afterthought it certainly was.

And the generally poor component quality, particularly the many trimpots. The hor yoke coupler cap that used to spill its guts. The many PCB mounting hex nuts that would rattle loose. The feeble Mazda CRTs with doubtful colourimetry and shadowmasks that would dome and upset the purity with the slightest provocation.

And those were its good points.

What about that large wire wound resistor (10 OHM I think) in the vert deflection coupling which would go open and divert all the deflection current through the vertical convergence circuit.
Fried pots, burnt up resistors, cooked pcb, etc, etc.
Every time I saw one in a customers house the purity was woah full and needed a complete setup.
What a pig of a set.

Are you sure you want one Shane??

Thanks everyone for your comments. I too know what a disaster they could be but purely want one to add to my collection and don't care if it is not working. I have 3 of the 4KA sets 2 thorn and 1 AWA that are all working with one being unused for most of its life and was still wrapped in it's plastic cover but the box had gone to God. All part of a collection along with many others.
If anyone has any other early first release set that they want to sell, please let me know.

Don't give up ShaneH.

If you enjoy fixing TV's as well as collecting them, then a 3504 is just like having a car.
Service it regularly, keep it tuned up, and fix the faults as they occur.

You are not far away from TV Collector. He might be able to assist you with parts for this model.

Do you repair TV's yourself ?

Probably not relevant anymore, increase R441 to 4k7 to get rid of teletext lines.
Of the two horizontal output transformers, only the one with the E.H.T. overwind ever fails.

Three working 4KA's ? Another set that I did not mind. Brilliant picture tube. Pity that tube died quickly, the yolks got shorted turns, and so on.

Please post pictures of your collection.

I have a Rank Arena C1451 Delta tube set that you might be interested in.

Wayne.

Thanks Wayne.
Most sets are currently in storage due to lake of space and I would have approx 60 sets. Some are duplicates that I strip for spares.
Have you got an image of the Rank set.
I might be interested.
Yes I do my own repairs.

Shane.

The 4KA would be a difficult one to restore as the Thick Film modules ,which were a constant source of trouble, would be impossible to find now I think.
Used to have boxes of them in the 70's.
The 4KA was a good performer when all of it's many faults were rectified.

I always thought the colour was terrible on those sets compared to others of that period and they tried to solve that by bringing out a different chroma decoder module which didn't solve the poor colour issues those sets had.

We had a small shop in Malvern, Vic, imported 2x 3504 sets from Thorn UK for an early adopter for big bucks.
Needed an ext chroma-lock as Au Broadcasters were not officially sending colour programs, but actually were, without burst.
I remember them as new and beautiful.

Also imported a test used ex-rental BRC2000-prior model, which was switchable 405/625, bigger cabinet, clunkier.
I believe this was the worlds first all-transistorised colour TV.
Prior models were hybrid.

Yes you are right about the BRC2000. Incredibly complex TV, I studied its design back in the late 1960s. I would not call it a clever design, but it was the first.

The 3500 was a cost reduction of the 2000.

"..The feeble Mazda CRTs with doubtful colourimetry.."

A bad TV starts with a bad CRT. I'm sure I know this set as where I worked in '76 they had one for a loaner (think it was badged AWA) and a few times was drawn into the delusion that I could tweak it good, but no, it wouldn't work. As I recall the picture was grainy with garish oversaturated red/yellow character, not to mention the funky convergence!