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Old 3rd Dec 2018, 11:33 pm   #1
Mikey405
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Default An early Philips colour set - A long and boring history.

Hi everyone.

I’ve really been meaning to post something up about this set for a while but for one reason or another I’ve never really had a chance. Well, now I’m down in Devon for a week with not too much to do, I thought I probably didn’t have an excuse for putting it off any longer.

The set in question is a 1963 / 1964 Philips 21KX102A – The British version of the original Philips 21KX100A set made, as I understand, for the Canadian market in 1963. The set itself uses a modified version of the K4 chassis; the modifications largely being concerned with the different frame rate (50Hz vs 60Hz / 59.94Hz), the different line rate (15,625Hz vs 15,750Hz / 15,734Hz) and the fact that PAL was the colour encoding method employed as opposed to NTSC. The line and frame rate modifications are fairly trivial compared with the change in colour standard: This latter modification involved adding a fully-transistorised decoder panel which contained a lot of the extra bits-and-pieces required for PAL decoding – as well as a fair number of mods to the main chassis to disable some of the un-needed NTSC stuff.

I got the set some 25-ish years ago from a good pal of mine called Tony (who many of the TV-types on the forum already know, but whom I didn’t know before Tone’s kind offer of the set). The way the set came my direction was after Tone responded to a "wanted" advert I’d put in "Television" magazine for a line output transformer for a Philips G6. "I don’t have one of those", Tone said on the phone, "but I do have a Philips K4 if you’d like to have it – but you’ll need a van to collect it." I’d never heard of a Philips K4 at the time and I thought Tone meant a K70 or something similar – but I had no idea why it would be so huge that it wouldn’t fit into the back of my Allegro estate. There wasn’t really any "Internet" as such back then to look the set up – or at least none that I had any access to, so I was none the wiser. Anyway, a van was duly hired and I drove up from my parents’ house in Exmouth where I was living to a pub somewhere just outside Dudley, all the time wondering what this monster set was going to turn out to be and why I needed a van to collect it.

I duly turned up and was met by Tone and one of his pals who’d lumbered the set over in a BT van to the pub where we’d agreed to meet. When I saw the set I was absolutely amazed and delighted. I’d never seen one of these brutes and had not the slightest idea that they even existed. Tone explained the history of the set, that it came from a pal of his called Malcolm who go it from the BATC many years previously but that the line output transformer had died and that is why the set was now out of use.

I was so delighted with the set that the journey home was a bit of a daze, but eventually I got the set to my parents house and stuck it in the corner of my room. And there it stayed for a good few years. I loved the set so much that I didn’t care that it didn’t work – I just loved looking at it. Eventually I moved into my own house and the set moved with me. Eventually I decided I was going to move to Solihull with my job so the set was wrapped up with lashings of industrial cling-film to protect it and was moved into the garage whilst I sold my house. One night though, disaster struck. A Philips N1700 video that I’d decided to stack on its side on a high shelf decided that it didn’t like the idea of staying on the high shelf any more – and came crashing down on the back of the poor old K4, smashing the back cover and destroying the Philips AX53/14 tube in the process. I was absolutely mortified. Luckily however, the K4 came with a spare CRT which, after I’d confessed my mortal sin to Tone, I was informed was actually better than the tube that was in it. I moved the set back to my parents’ house so that I wouldn’t have to leave it in the garage in its sorry state.

A few months went by and I decided to try and get the set sorted out. First the tube had to be replaced. I put the set on its front, removed the old tube, cleaned the inside of the glass implosion screen with Windolene and newspaper, and fitted the new tube. The whole job took about 2 hours give-or-take and I was feeling very pleased with myself – Until I lifted the set up and saw a big lump of newspaper that I’d managed to leave in the corner and had to carry out the whole job again. I subsequently found out that I could have just removed the glass screen without removing the tube, but it never occurred to me at that moment...

The next thing was to replace the dead line output transformer. I managed to get a brand-new one from Holland (which was a modified-type to overcome reliability problems with the original sort) and that was duly soldered in. Not a particularly easy transformer to change because of all the delicate connections to the focus and EHT rectifier valves etc.

Next came the moment of truth. The set was plugged in, an aerial lead connected, and the old monster was turned on. After 30 seconds there was sound, even some EHT was heard – but alas no picture. In fact the tube heaters were not alight. Hmmm. I put my trusty Fluke on the heater pins and there was suitable voltage there but still no heaters. On taking off the tube base and measuring the pins for continuity, there was none. It was completely open circuit. “Damn” I thought. An open circuit heater connection in the tube, after all that trouble.

Laying the set on its front again however, revealed that the tube pins were a bit grotty and green, and the subsequent poking of a wire down the hollow ends of the heater connections showed that the heater was actually intact, it was just that the connections to the pins were open circuit. Heating up the pins and feeding some fresh solder down the holes brought continuity back to the connections. Feeling very pleased with myself, I put the set back on its feet again ready for another go.

The set was plugged in again, the switch was pressed and after 30 seconds – "Hey Presto!" – a picture and sound! The convergence was all over the place but it was a colour picture and I was absolutely delighted. There was a terrible line jitter with a slightly concerning "clicking" noise from the lopty every time the picture wobbled about and the line-lock kept changing, flicking the picture to one side but that could all be fixed. I was absolutely over the moon that the set was working.

And then it wasn’t.

After about 10 minutes of fiddling around with the convergence etc. With a huge smile on my face, the EHT suddenly went off and with it the picture. Another few seconds and the PL504s started looking a bit upset so the set was turned off. Despair! After checking the voltages and waveforms on the line output valves it was quite clear that the new lopty had also failed. From my huge elation at getting the set working, a sudden gloom came over me and the set was put back together and pushed into the corner. And there it stayed. For years.

Eventually after many years I brought the set up to Solihull and decided to have another stab at it. I’d managed to acquire another original-type K4 lopty from somewhere in what looked like very nice condition. It didn’t look burnt or got-at and all the connections to the EHT rectifier and focus valves looked sound. On performing a ring-test however, it was clear that it wasn’t very well and that there was likely a shorted turn somewhere. So the transformer was duly sent to our own Mike Barker for servicing. The transformer was stripped down (no mean feat I am told), the faulty primary expertly rewound and the transformer put back together again. Apparently the overwind was intact – which was a surprise to me – but unfortunately it couldn’t easily be rewound without a vacuum-oven so it may still be a little delicate. The new lopty was soldered in though and the set tried again.

30 seconds later and there was a picture and sound! Mike’s rewind was absolutely spot-on and I was delighted. The nasty line jitter was still there and this was rather concerning because every time the picture wobbled there was a nasty "clicking" sound from the lopty and I’d occasionally see an arc in one of the PL504s. Replacing both the valves and their holders didn’t provide a cure and the clicking / jittering continued. A lot of to-ing and fro-ing commenced whilst I tried to work out what was causing the jitter. The set has a very complicated direct sync AND flywheel sync line oscillator stage (direct sync for quick locking which then switches to flywheel sync once the picture is synchronised – all controlled by feedback from the line output transformer and the sync separator). It also has an EHT stabilisation triode on the primary side of the line output transformer which is fed with pulses directly from the lopty to control DC feedback to the PL504 grids. So due to all this feedback going on, the nasty jitter seemed to appear anywhere I put my scope and it wasn’t at all certain where I should start to look for the fault. An hour later it was all academic anyway as the overwind suddenly gave out and the set died again.

Another couple of years went by and another lopty was tried without success (another faulty overwind) before I mentioned the whole sorry tale to another very clever pal of mine called Keith (of this forum). I mentioned that I’d thought about putting a Pye 691 overwind on the transformer and using a tripler but that I was a bit clumsy and didn’t really think I’d be able to do it without damaging the transformer. Keith then extremely kindly offered to make the modification for me – he took Mike’s rewound lopty away, split it in two, and expertly fitted a Pye 691 overwind to the bottom of the transformer before bringing it back soon afterwards. Keith had even supplied a suitable tripler and focus unit. Some short time later and the whole lot was fitted in and all the connections were soldered, insulated and ready to go.

The boost-voltage trimmer was first turned to its minimum-voltage setting before the set was plugged in and turned on. After 30 seconds or so a picture appeared – hooray. It was black and white this time though, lacked width and the nasty jitter with false line-lock were still there – but it was a picture and I was over the moon again. Using my trusty Fluke high-voltage probe, I measured the EHT and set the boost voltage trimmer so that I had roughly 24KV at zero beam current. There was still a bit of a lack of width though (which Keith had mentioned there might be) so some suitable high-voltage pulse caps were dug out and soldered in to try and get the correct width. Every cap I tried though ended up heating up and eventually going short circuit so the correct value cap was made up using a string of high voltage caps in series, and this seemed to cure the width problem entirely.

Next my attention turned to the line-jitter and the very worrying clicking noises it caused to come from the lopty. Various caps, valves, resistors etc. were tried but nothing seemed to cure the fault. Until I spotted the two components that I should have changed immediately. These were the two small low-value ceramic hollow dog-bone caps that, with the PCF80, made up the line oscillator itself. I forget the values as I don’t have the circuit to hand but I think they were in the region of 100pF and 150pF. Replacing these put a complete stop to all the jittering and false-line-lock shenanigans.

Next up was the lack of colour. This was a bit of a swine due to the PAL modifications and the difficulty in working out what connected to where without any real modified circuit diagram to look at. The only clues were the translated Dutch instructions on how to convert the NTSC decoder to PAL with the new printed circuit board. Anyway, the problem turned out to be a combination of three things. The first problem was simply that of a wire coming adrift from the PAL decoder. The next problem was that the VDR, which supplied a constant voltage to the screen grid of the colour killer valve, had fallen in half. Keith again came to the rescue here and suggested using a Zener diode to drop the HT voltage down to something suitable. I ended up using two fairly hefty Zener diodes in series and it worked a treat! The last problem with the colour was simply that the motorised colour saturation control, which had become as stiff and grungy as the other three controls (Volume, Contrast and Brightness), just would not turn. The colour control was stuck in the "minimum" setting and refused to budge an inch when the button was pressed to increase the saturation. Taking out all the controls and cleaning / lubricating them provided a complete cure.

So, I now had a stable colour picture. The last thing to do was to fix a slight problem with frame foldover at the bottom of the picture. The answer to this one was provided by Tone – There is a lamp in the cathode circuit of the frame output which helps to regulate the height as the set warms up. The lamp as fitted was a 6.3v 300mA variety but it was not lit and Tone said that he remembered that it was quite bright when he had the set. Tone managed to find the correct value from the Interweb somewhere and it turned out that somebody (probably me) had replaced the bulb sometime in the last 25 years with the wrong value. On replacing the bulb with a 24V (can’t remember wattage or current off hand) version, the bulb was nicely lit up and the frame foldover was gone.

The last thing to do was set all the preset controls as per a translated German service-article. This included things like the beam-limiter, the zero-point for the line oscillator discriminator, the frame hold control (the frame circuit is quite amazing) and various other odds and ends. Finally the grey-scale was set up, the picture geometry and shift controls were adjusted and the purity and convergence tweaked (not too bad for one of my efforts but Tas would be able to do it better I’m quite sure).

And that was that. Thanks to my amazing pals Tone, Keith and Mike and all their expert help, the K4 is now working reliably in my lounge. The set’s longest continuous outing was about 16 hours in one go several weeks ago and it didn’t bat an eyelid. I really cannot thank my clever pals enough for all their amazing assistance – I’m absolutely delighted with the set now. And even if it did take 25 years to get the set working, it was well worth the wait.

And thanks everyone who made it through this long write-up. I hope it hasn’t been too boring.

Thanks everyone.

Kind regards.

From Mike.
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Last edited by Mikey405; 3rd Dec 2018 at 11:51 pm.
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Old 3rd Dec 2018, 11:38 pm   #2
Mikey405
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Default Re: An early Philips colour set - A long and boring history.

A few more piccies.
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Old 4th Dec 2018, 12:31 am   #3
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Default Re: An early Philips colour set - A long and boring history.

Hi Mike,

What a wonderful TV, I could stand admiring it all day when I've been at your place for the Solihull bash. I'm glad to see you have it up and running reliably now. I hope it gives you many years good service.

Great write up!

John Joe.
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Old 4th Dec 2018, 12:41 am   #4
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Default Re: An early Philips colour set - A long and boring history.

Hats off to the dedication and determination in getting this beast of a set working! A genuine piece of history of the development of colour television in the UK. I've always fancied the idea of importing a US 'color' roundie and somehow run it from an rectifier/inverter at 120v 60c/s and NTSC from a standards converter. Unfortunately my pockets are not very deep and my house too small.
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Old 4th Dec 2018, 12:52 am   #5
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Default Re: An early Philips colour set - A long and boring history.

I've seen the set with my own eyes and indeed was present when it came back to life with Keith's modded LOPT. The sound quality has to be heard to be be believed.
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Old 4th Dec 2018, 1:35 am   #6
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Default Re: An early Philips colour set - A long and boring history.

Wow. Its the sort of thing you expect shango066 to be looking at, out in his back yard.

I can't imagine how much it would have cost new.
Is there a UHF tuner in there?

It occurs to me, with those motorised controls, it would have been trivial to add a cable connected remote control, like the Pye I once had, that masqueraded as a Dynatron.

Was that an option?
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Old 4th Dec 2018, 2:49 am   #7
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Default Re: An early Philips colour set - A long and boring history.

I can't claim to know that much about about TV restoration Mike but I know your fascinating account was anything but boring. If I ever get involved in TV's I will have you on my Guru list with Steve P/Fernesh/HCS/Studio 235/Mike Barker et al. Apologies for any omissions!

Dave W
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Old 4th Dec 2018, 8:14 am   #8
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Default Re: An early Philips colour set - A long and boring history.

What an amazing story and what valuable piece of TV history that set is.

Thanks to your hard work and enthusiasmit it has survived. WELL DONE.

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Old 4th Dec 2018, 9:27 am   #9
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Default Re: An early Philips colour set - A long and boring history.

Great write up on a very rare and interesting set, there is something very appealing about round tube colour sets.

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Old 4th Dec 2018, 9:55 am   #10
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Default Re: An early Philips colour set - A long and boring history.

Well done after all those soul-destroying obstacles. It's a beauty of a set and the picture looks like a Philips should. It has a very american look to it from behind! I assume there's no need for one of those troublesome bonded implosion guards if it has a front glass panel.
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Old 4th Dec 2018, 10:17 am   #11
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Default Re: An early Philips colour set - A long and boring history.

Wow, what a magnificent beast, and what a cliff-hanger of a write-up! Well done to all concerned.
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Old 4th Dec 2018, 10:32 am   #12
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Default Re: An early Philips colour set - A long and boring history.

Mike.
Thank you for sharing that incredible story with us!
Ive just been sat here reading it with a coffee and I was totally engrossed, almost like a will it? wont it work ending.
Congratulations on the final result and to all your friends on helping you bring it back to life.
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Old 4th Dec 2018, 11:09 am   #13
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Default Re: An early Philips colour set - A long and boring history.

Quote:
Originally Posted by McMurdo View Post
It has a very American look to it from behind!

Do you mean the fat

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Old 4th Dec 2018, 12:04 pm   #14
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Default Re: An early Philips colour set - A long and boring history.

Beautifully over-engineered masterpiece of a colour television receiver.
I remember at Mikey's last bash the set was switched on for more than twelve hours and constantly displayed perfect colour pictures and sound. No variation of picture height or width, Philips got away with a PCL85 for the frame output valve, in fact there are no special colour TV valves employed in this set. Two parallel PL504s for the line output stage. The sound output stage is clever too, if my memory serves me well PCL85 and PCL86 triode-pentodes are employed in a tranformerless circuit.
Not forgetting the motorised sound volume, brightness and colour controls.

Imagine if all colour TV sets were made like this one.

DFWB.
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Old 4th Dec 2018, 12:18 pm   #15
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Default Re: An early Philips colour set - A long and boring history.

Brilliant write up, anything but boring!! And what a fantastic TV set, I wonder how many actually still exist? Shame about the original CRT, but good that you had a spare, and it looks to be a very good one too, I can imagine the feeling of absolute horror when you found it after the VCR dropped on it! It’ll go nicely alongside that monster of an Ekco colour set you have!

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Old 4th Dec 2018, 12:53 pm   #16
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Default Re: An early Philips colour set - A long and boring history.

What a fantastic looking set. A great well told storey Mike with so many twists and turns in the 25 year plot.
It sounds a very interesting set with some unusual features, two parallel PL504's for the line output, a tranformerless sound output stage using a PCL85 and PCL86 plus that lightbulb in the cathode section of the frame output valve. I would love to see the circuit diagram as much as I would like to see the set working.
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Old 4th Dec 2018, 1:11 pm   #17
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Default Re: An early Philips colour set - A long and boring history.

Similar sound and frame output stages were employed in B/W receivers. They got away with a relatively small frame output stage because of the 70 degrees deflection angle.

That said, good story and nice set!
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Old 4th Dec 2018, 2:07 pm   #18
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Default Re: An early Philips colour set - A long and boring history.

What a lovely looking set. Well done on the restoration.
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Old 4th Dec 2018, 2:29 pm   #19
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Forgot to ask, I'm curious about the full model number and serial number. Is the full model number 21KX102A/00 or 21KX102A/15 or something else? The serial number could be used to estimate the number of sets produced. If you don't want to post the serial number in public, I won't disclose it either if you pm it.
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Old 4th Dec 2018, 2:30 pm   #20
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Default Re: An early Philips colour set - A long and boring history.

What a stunning set and a superb restoration and write up Mike.
Very well done Sir.

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