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Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 18th Sep 2019, 9:04 pm   #1
Pamphonica
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Default Pamphonic Pam 600 17" 1959 TV - my first TV restoration

Being mainly a radio and audio restorer, this was my first full TV restoration. I am NOT familiar at all with TVs so it was an interesting voyage of discovery, and took me an elapsed year of odd hours here and there to fix. The set was requested by my close friend Nick, the son of Paul Taylor, co-founder of Pamphonic (in 1931), so I wanted it to end up just right, and reliable.

Ebay provided a donor, a bit dearer than I had hoped, but in lovely cosmetic condition, requiring only a thorough inside and out clean. The high-gloss case finish was incredibly good and virtually un-scarred, amazingly. The tube proved in excellent condition, only slightly marred by the discoloured "polaroid" front screen.

I splashed out on an Aurora, and quickly found that I had to reduce the output by 12dB as it was definitely overloading the TV (sound on picture). I also acquired a set of the excellent 4 volume Television Servicing by Patchett and started reading!

On cautious run-up on a variac, I got some sounds of life but nothing impressive. The HT was being dragged down. Finally, re-seating a valve in the tuner cured the HT fault (but see later!), and I got a raster, but incomplete frame scan. Voltages were about right (HT still low) , but no sync, and compressed field at bottom.

At this stage Chris Wood and Brian Summers kindly came up with quantities of spare valves which were very helpful. And I found a copy of the excellent original Pamphonic service manual (28 pages or so!) on Ebay - a real godsend compared to Trader sheets.

I methodically replaced all the waxy and hunts capacitors, especially the very oozy ones in the line ouput section, & changed a valve ( PCF80), and replaced the "piece of wire" fuse, checking after each couple of items. I also checked resistor values, changed over-value ones and re-checked specified voltages at valve pins (with an Avo 8). Now I had a picture for a while but it kept vanishing after a few minutes. Occasionally changing channels to and fro helped. I suspected a tuner fault as the tuner output signal was vanishing.

More capacitor replacing (mainly electrolytics) and the removal of an old bodge round the horizontal hold pot (R77 - replaced) resulted in a better picture but still this wretched intermittent fault! All voltages fine but sync still a bit iffy. (This version of the Pam 600 has no flywheel sync). I also cleaned all valve bases with DeOxit on a fine brush, and re-tightened the contacts which stopped all the odd crackles.

Breakthrough...! I removed the lid of the tuner and shone a bright light inside. There, lurking on top of the pcb was a loose solder splash, which had been moving in and out of various valve pins. Aaaargh! Anyway, splash extracted and intermittent fault solved. Just the weak sync to sort out.

The project had to be put aside for about 6 months at this point. Finally, with encouragement from Chris Wood and Len Smyth, I worked methodically through the sync chain and found an open-circuit cap I'd missed, in series with the sync signal (C20). I replaced that and the associated diode and voila - fabulous, locked picture. Len suggested I replace the PL84 to cure a slow picture growth on start-up, and that was it.

Back in its case for probably the 20th time in 9 months and off it went to Nick Taylor, who was over the moon. The picture is sharp and bright.

I know many here would have got it working in an afternoon, but for me it was a steep learning curve, and incredibly satisfying when I had finally restored it all myself.

Thanks to so many people here for their encouragement and help. I am no longer a TV virgin!

-Jeremy
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Last edited by Pamphonica; 18th Sep 2019 at 9:09 pm.
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Old 18th Sep 2019, 9:06 pm   #2
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

the re-worked boards and the final results....

With grateful thanks to Chris, Len and Jeffrey for their support and advice.

-Jeremy
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Old 18th Sep 2019, 11:15 pm   #3
Richard_FM
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

Well done for getting it sorted, especially as it needed a fair amount of work to get it back to working order.
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Old 19th Sep 2019, 12:15 am   #4
martin.m
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

Well done, nice to see a lovely old TV restored and working. Sadly many good 405 line sets were scrapped in the early 1970s.
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Old 20th Sep 2019, 8:44 pm   #5
akuram1
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

We rented out loads of these and they looked so much nicer than its Pye brother. The Polaroid screen gave a nice picture.
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Old 20th Sep 2019, 9:33 pm   #6
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

Hello Jeremy,
Nice job! These Pye chassis were very reliable but the Polaroid screen never caught on. I wonder if this was the reason it was launched under the PAM name like the 710 transistor radio and the first printed circuit TV the PAM 500. Pye had got their fingers burned with the V14 and didn't want another upset with a new product release but that is another story.
Has your screen been removed or possibly faded? I seem to remember it was difficult to see the CRT when switched off. These were true Polaroid screens and you had to check the colour difference with a 'shilling' if you removed it for cleaning and didn't make a note of which way round it was fitted. Very few of these survived. Regards, John.
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Old 21st Sep 2019, 9:29 am   #7
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

The Polaroid screen is definitely still there. I removed it to see if it was just dirt, when I was doing the clean-up. It looks dirty but is just faded and there is no way to remove the taint. I think it looks fine as it is and it’s a bit of an interesting oddity. And yes, I did the trick with the silver coin to make sure it was the right way round when put back in place.
-Jeremy
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Old 21st Sep 2019, 7:12 pm   #8
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

We have a PAM Polaroid 800 series at the museum. It also appears to have faded over the years. That also gives a cracking picture.
To get the linearity spot on, almost every resistor in the odd frame timebase required changing due to rises in value and of course all the wax caps. Well worth the effort.

For guys not familiar with the PAM Polaroid screen, these receivers must not be confused with the dual standard ITT 'Deep Scene' that just has an almost black sheet of what ITT described as Oraglas over the face of the tube. The PAM is a true Polaroid filter screen. John.
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Old 22nd Sep 2019, 4:58 pm   #9
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

that's a cracking picture Jeremy and I don't suppose the chassis is the most accessible in the world, my only bent-ply tv, a murphy, is awaiting my restoration when I'm feeling brave. I'm sure we all remember our 'first time'.
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Old 22nd Sep 2019, 7:25 pm   #10
Pamphonica
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

Actually the chassis was quite nice to work on. Vertical pcbs, set at 45 degrees. Once the chassis comes out (remove knobs etc and 3 screws), you can work on the pcbs quite easily even though they are vertical, as you have access to both sides.
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Old 23rd Sep 2019, 10:28 am   #11
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Default Re: Pamphonic Pam 600 17" 1959 TV - my first TV restoration

Great interesting and worthwhile restoration. Never seen that Polaroid front screen before.
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