NZ made Colour TV - Pye CT104

[GLENZ32]

Hi guys its been a while since I've posted anything of interest up on here and this recent acquisition I thought was worthy of posting for something a little different.

What you are looking is a New Zealand made Pye. Its chassis is denoted as the 'CT104' and this set was made towards the end of Pye TV manufacturing in NZ.

There were predecessors to this which go back to the 1970's - Pye colour sets started out with the CT101 (Now very rare) CT102 (I have one), CT103 and 104. All these sets were designed and manufactured in New Zealand.

The CT104 was a fairly modern design for the early 1980's using IC's in various stages and a diode split line output transformer, but in some areas they still used conventional circuitry.

One of the reasons I went out of my way to save this one as it is the 'exact' TV that I grew up watching as kid in the 80's at my grandmothers as I used to stay there most weekends and some weeknights as the local school was closer to her place.

I remember the set never giving any trouble and when she died in 1987 it ended up with my Uncle who used it until the picture tube went flat in the mid 1990's.

In my TV servicing days I used to repair these and most of the ones I saw seemed to have weak CRT's, failed LOPT's and other irritating faults. I seem to recall there were two versions of the LOPTs and one was more reliable than the other, luckily this version has better version.

I actually found this outside a major chain store advertising the "TV Take Back" recycling scheme that they had running around the time of the analogue switch off here in Wellington. I went into the store and expressed my interest in the TV and they said they'd call me when they were done with it..and I was fully expecting not to hear back from them...but they did and I went and picked it up.

Prior to getting the Pye, I had not seen of these in years and was quite pleased to have it my possession.

Upon getting it home I plugged it straight in pushed the power button expecting it not to work, but when it came on and clear bright snow appeared I was a bit shocked, so connected the pattern generator and was rewarded with spot on colour bars!
Removing the back revealed a re-gunned picture tube back in 1988. I think the tube types were Toshiba's in this model and they didn't seem to last.

So I guess I got lucky with the Pye and have been watching the thing and really impressed with how well it goes. The vertical needs a tweak but apart from that it seems to be fine.

Overall a nice design and the chassis and access is easy and its good to work on.

BillyT may have some more input or comments on this model but I think I've covered the basis of it. Have attached some images. Enjoy.

[arjoll]

I remember seeing those around the place when I was younger! At first glance the styling isn't a million miles away from the Thorn Precision 20 my parents had from about '77 until '83 when it was replaced with an NEC. Vertical slide controls and all that

[Welsh Anorak]

Hi
Looks nothing like any Pye we're used to - seems to have something of a Japanese look about it which your mention of the Toshiba tube would bear out. The LOPT is an unfamiliar design. Unusual - and welcome - to see socketed ICs.
Looks a nice set.
Glyn

[paulsherwin]

Agreed, it looks very Japanese or American, like early 80s Sony Trinitrons. UK TVs had much more rounded cabinets, including Japanese ones made specifically for the British market.

[Nicklyons2]

Indeed I echo the above, it has the look of the Japanese sets made with the USA in mind. I used to look after a couple of Teletons which looked, externally, very similar except for a rotary tuner. Nice set though -a good survivor and well done to the shop for bothering to let you know.

[Focus Diode]

Nice looking set, rather like a cross between a UK Thorn 9000 and Philips KT3 to these eyes. Many thanks for uploading the pics for us to enjoy.

Cheers,
Brian

[Maarten]

The back has a distinct Philips K9/K11 look to it, the circuit board itself also looks very Philipslike but it differs in every possible detail from the sets I know.

[GLENZ32]

Thanks guys for all the nice comments. I have to agree with the styling it has got a Japanese/USA look to it - We would have copied something that was similar looking more than likely. And the board layout is very much like the Philips KT3. I'm glad that I saved this one Cheers

[Billy T]

As far as I am aware, the CT104 was a 100% Pye Waihi design, though like most sets, naturally it owes more than a little to the application data provided by the manufacturers of items like the Lopt & ICs etc, a possible reason for similarities that some readers have observed.

Pye used Japanese CRTs for all sets after their version of the Philips K9, and I think that their first small screen set (CT101) used a Japanese delta gun CRT as well. Philips thought well enough of them to share their 18" and 20" models and brand them Philips. In turn, PYE took the 22 and 26" Philips K9 and with some cosmetic changes, branded them PYE.

That's good news on the acquisition of your CT104 Glen, they were a good set in their day.

Cheers

Billy

[Hybrid tellies]

What an excellent find, that tube looks good. To our eyes the chassis looks similar to a KT3 but even better. Well done to you and the store for saving this beauty.

[Billy T]

Originally Posted by arjoll

I remember seeing those around the place when I was younger! At first glance the styling isn't a million miles away from the Thorn Precision 20 my parents had from about '77 until '83 when it was replaced with an NEC. Vertical slide controls and all that

There may be a similarity in the controls but if so, that is the only likeness! The Precison 20 was streets behind the CT104 in performance, reliability and serviceability. The CT104 design was elegant and simple to service, while the Thorn was a generation or more behind it in both design and serviceability.

PYE NZ consistently turned out straightforward chassis that were reliable and easy to service. I wouldn't lay the blame on Thorn UK though, I'd blame their NZ outpost, who thought the TX574 was a winner, while Philips was out there promoting the K9. Other manufacturers combined to build variants on another modern chassis based on Philips technology and moved forwards from there. The TX9 was several years too late in arriving!

That said, Sanyo wiped the floor with the lot of them, locally assembling sets that were rarely seen for service and with CRTs that never died. Copying Sanyo, I cut down our CRT changes on Philips service contract sets by installing filament transformers and an 'always on' half-power filament supply. Like the Sanyo, it used half the mains switch to short out the standby resistor.

Them's was the days........

Cheers

Billy

[arjoll]

Originally Posted by Billy T

That said, Sanyo wiped the floor with the lot of them, locally assembling sets that were rarely seen for service and with CRTs that never died.

When dad was advised to get rid of his Precision 20 "while he could" he got a Sanyo on an in-home trial - and hated it. He settled on the NEC, preferred the colour, and that same set is still running 31 years later having never been serviced - my brother has it with a Freeview satellite box feeding a Mitsubishi E30 VCR, output on channel 2 to the NEC.

[Okto1984]

It's always nice to find something that has taken a while to locate. Better still when it works well

[GLENZ32]

Those old Sanyos were a good set..the later versions weren't that great - the CRT's always went flat and the electrolytic caps all dried up. The earlier chassis were far better. I never liked the TX9's - pig of a thing. I'm not surprised the NEC is still going!
Cheers

[Billy T]

Originally Posted by GLENZ32

Those old Sanyos were a good set..the later versions weren't that great - the CRT's always went flat

Refresh my memory please Glen, (my Sanyo manuals are not to hand) - did the later Sanyo designs use an HF filament supply off the loptx, or a 50 Hz filament transformer like the original 510VRA?

Expanding on my previous post, during my time as a service manager, statistically I observed that there was a significant difference in usable CRT working life between those with LF (50Hz sinewave) and those with HF (line derived) CRT filament supplies, and the virtually instant application of EHT with 100% solid state CTVs appeared to rip the cathodes with every power-on.

We used a darkened hood enclosure in our stores area for final set-up and despite the CRT cathodes being stone cold, at switch on there would be an instant flash of blurred colours at the center of the screen, which would not be seen under normal lighting conditions.

Since the filaments were not yet heated at that stage, it seems possible that the virtually instantaneous application of EHT was adversely affecting the unheated cathodes. I do not profess to know what the precise mechanism might have been, but the CRTs of sets that displayed this effect invariably had a much shorter working life. I did wonder whether HF harmonics were causing localised overheating via capacitive or inductive effects between the filament and the cathode(s).

For sets under service contract, to counter this rather expensive problem we installed 'always on' tapped filament transformers (6.3/7.5 vac) with a series resistor to reduce the output to 3.5-4.5 volts, and commandeered the neutral half of the mains switch to short out, in part or wholly, that series resistance at switch on (entirely legal in NZ, only phase needed to be switched). We found that 6.3 volts was usually sufficient, but if the CRT was particularly tired we could use the full 7.5 volts.

Permanent preheating minimised the rate of further deterioration and as a bonus, the CRT could be restored to normal performance, while at the same time taking the CRT filament load off the line output stage transistor and transformer.

I followed this policy for several years and during that period we enjoyed a significant reduction in our CRT usage, all for a minor cost in filament transformers and a few components. Modifications took a fraction of the time needed for a CRT change and full set up, so it was a win/win situation.

We did not use CRT rejuvenators either, we just did the modifications, heated the filaments with 9-10 volts 50Hz AC for up to an hour then hooked it back up, did a greyscale setup, soak tested it for a few days then sent it out the door.

What I do know for certain, based on several years experience and commendations for our much reduced CRT usage, is that these measures had a very positive effect on tired CRTs and also extended CRT life even further if carried out before any significant loss of emission was detected. Similar benefits were obtained with 'quick heat' CRTs, but needed to be applied before any significant deterioration had occurred in order to reap the full benefits.

I had one such 'restored' 26" Philips K9 set, purchased as "poor picture, needs new CRT" and following modifications I used as my personal TV for several years, and when I finally sold it, the CRT was still in good order.

Cheers

Billy

(I suspect that a similar effect might have been responsible for the poor CRT life expectancy of later Sanyo TVs, and also the last of the Philips mono sets (E1 chassis?) which went through CRTs at a startling rate.)

[GLENZ32]

Hi Billy - The later Sanyo sets used the line derived filament supply where as the older 510VRA series used the 50Hz supply - hence why those CRT's stayed in good health.
I reckon this CT104 and my mint low mileage CT102 (which has a 'fantastic' picture - The best I've ever seen on a 102) will have to be treated to the filament supply mod to save their CRT's.