Thorn 9000 Series (9200) The NZ Version....

The rest of the photos!

Hi Glen,

What a fantastic save from the recyclers, wish ours were as accommodating over here instead of the jobsworth brigade.

I've never seen a 9000, come to that I've not seen an 8000 series either, I've read about Cyclops though. Look forwards to your findings once you get it in the workshop. I was going to say get it on the bench but like you, most of the TV's I'm getting these days won't go on the bench

Chris

Hi Chris - Yes it was a good save indeed. I was pretty chuffed myself when I picked it up.
My problem with getting it on the bench is that since I now run my Audio & HiFi servicing business from home the benches have always got a customers repair on them so I have to find a time when at least one bench is clear and I'm not tired and are in the 'mood' for some TV Tinkering!
Cheers G.

Fantastic find. I had many 9600 series sets out on rental. The 9200/9600 series was a magnificently over engineered chassis. Surprisingly reliable for such a complex design.
UK versions used the RCA S4 CRT. The UHF only versions employed the Thorn made SC4 tuner which was a replacement for the obsolete Mullard ELC1043 vari-cap tuner. I might still have some service info for these sets.

Till Eulenspiegel.

Vivid memories of tripler replacement on these sets. If you left that bit of pipe lagging off, the thing hissed like a snake. Most were on their last legs by the time I saw them.

What a great find, My favourite Thorn chassis and it looks great.
Still got a couple of NOS triplers stashed away.
I still live in hope of finding one of them.

I can remember the 9XXX sets. I did not see more than one or two.
The SYCLOPS was used to hide the SMPSU switching noise in the blanking period.
What I do remember was going into industrial CCTV where they had a design that was causing problems.
There was a switching noise line on the screen.
I "pinched" the idea and had a fiddle and got it spot on and the production department adopted the modification.

I also think its 9K8 the 9000 looked far less crowded
we quite liked them once we got are head round the psu (which turned out to be quite reliable)
nearly all the large screen (9k6/9k8) needed new tubes one thing to watch was to make sure the heater series resistor had not been shorted out or your recon tube would not last very long.
I was also surprised to get a shock from the ultrasonic hand set !
Rob T

Rediffusion had loads of these out on service (RT539/20). Most fault were s/c R2540/3.3 ohm w/w surge resistor and thick film unit. The triplers failed on a regular basis. After 3 years the crt,s were well past their best. The picture quality was brilliant, no convergence to set up compared with other sets in 1975.

The 9800 series was a disgrace. I generally like lash up things but this chassis went too far. Essentially a development of the 8800 which was just a cheap and cheerful version of the 8500 series which was in turn was a beefed up 8000. 25KV for the 19 and 22" CRTs. The 17" 8000 series was a 20KV chassis.
So the development was: 8000 17" CRT, 8500 19", 8800 22" and finally the 9800 22 and 26" CRTs.
Instead of the 25KV jellypot used in the 8500 and 8800 the Thorn designers of the 9800 opted for a Mullard split-diode line output transformer and added an over volts protection to the horrible thyristor power supply. We all know that this kind of power supply is not nice. A similar thyristor arrangement was used in the G8 and A823 chassis.
I liked the 8000 and 8500 series CTVs. Tolerated the 8800, but as for the 9800 I couldn't get rid of them fast enough after the costs had been amortised.
The 9600 was something much better, a really clever design just like the original 9000 series.

Till Eulenspiegel.

What a fantastic save from the recyclers, wish ours were as accommodating over here instead of the jobsworth brigade.

Oh, not all of them - I picked up a nice Grundig cassette recorder (C410) in its optional leather case out of the skip a couple of weeks ago and they were okay with that - if somewhat bemused!

Hi Glen
Your pictures brought back memories for me. The 9200 looks very similar to the 9500 which was one of the first sets that I ever worked on, that was in the late 80's they were out on rental and getting old, allot of the tubes were getting tired but otherwise were still preforming well. I haven't seen one in years.
I don't remember having to change many triplers on them, The same cant be said for the 9300 where it seamed like every second one that came in need a tripler.

I have always liked the Thorn models. A great find

Frank

Can anyone refresh my memory, but SYCLOPS... That stood for SYnchronous Conversion Line Output Stage, didn't it?

I remember a TV engineer from York (Ralph), who I knew quite well, absolutely hated them for one reason or another.. It seemed to me though, that this had to be a pointer to the future because this system gave a more energy efficient power supply, just more complicated to fix then transformers or a bunch of wirewwound droppers.

Would I be right in thinking that line oscilator had to fire up in an instant, to start the SYCLOPS operation? I think that's where Ralph used to get in a tangle, looking for PSU faults, when it was the line oscilator at fault (or was it the other way round?).

Marion

Upon reading the post responses am I correct in assuming that the 9000 series are rare in the UK now?

I'm not sure how you gauge rare as there could be many sitting in peoples collections.

However if you take e-bay as an example I see no end of 50's 405 sets of all shapes sizes and manufacturers coming up in the UK week after week. How often have I seen on e-bay the 2000, 3000, 3500, 8000, 9000, 9600, let alone all the other manufacturers? Hardly ever if at all.

The consensus seems to be that the smaller 405's got put away in lofts as they were easy to do so. They also represented a significant investment to the generation that did not waste and throw away. Conversely by the time CTV's were long in the tooth, they were too large to stuff away and we as a society had started to embrace with vigour the throw away mentality. The 80's CTV's may even be fewer, as for the 90's CTV's, they will probably end up being the rarest of all, as they offer little interest to any of us now but may to future collectors.

...and don't forget that in the seventies the majority of colour TVs were rented, so when they came off service the they were broken up. In the late eighties many ex-rental TVs finished in those large warehouses where the sets were flogged off to the trade or the public. Many will remember those ex-Thorn rental TVs with the black Fablon covered cabinets. Most were just clapped out junk and finished up at the local dump.

Till Eulenspiegel.

The 80's CTV's may even be fewer, as for the 90's CTV's, they will probably end up being the rarest of all, as they offer little interest to any of us now but may to future collectors.

The hideous black plastic cabinets did them no favours. On the other hand they are great for watching 4:3 programmes in RGB mode.

I'm not sure how you gauge rare as there could be many sitting in peoples collections.

as for the 90's CTV's, they will probably end up being the rarest of all, as they offer little interest to any of us now but may to future collectors.

I still have about a dozen such sets..

Marion

Can anyone refresh my memory, but SYCLOPS... That stood for SYnchronous Conversion Line Output Stage, didn't it?

SYnChronous Line Output and Power Supply, BICBW.... you'd hope the oscillator circuit would free-run when started until locked by a signal.

Bit like Salora's 'IPSALO' circuit; Integrated Power Supply And Line Output. However 'evil' they may be, they do make sense although line-locked power supplies can bring their own problems with them. (For the record, 'line-locked' here means 'locked to horizontal scan frequency' and not to 'AC mains frequency', which I always thought a bit American.)

I've found a reference to the latter on Finnish Wikipedia, but I don't speak a word of Suomi!