UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Reply
 
Thread Tools
Old 13th Oct 2021, 9:07 am   #1
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 8,241
Default Philips 20" G8 colour receiver 1977.

PHILIPS 20" G8 COLOUR G20C560/05 1977

A good while back this rather rare Philips 20" G8 was presented to me by another Forum member. The G8 had been with it's original owner from new and had obviously been cared for. It has been stored fully wrapped in a very dry garage. It was time to see if it was possible to get it working and after it's first test I must admit once again I felt I had been handed a very easy repair if you could call it that! All the panels are original dated the last week in 1976 and the first week of 1977 and I can't see anything that has been replaced. The sign off date code is January 1977. [703] It is fitted with the combined tuner/I.F./decoder board.

The 20" version of the G8 is often confused with the 20" 570 fitted with the PYE CT200 chassis is quite rare and was produced late in the G8 production run. The appearance is quite similar but the 570 compared with the G8 is a Wolf in sheep's clothing.
Upon unwrapping the cabinet appeared to be in very good condition with all the knobs and bits and bobs present. Removing the back and examining the panels date codes appears to show that that they are all original the earliest being Christmas week 1976.

A quick check for shorts on the HT line [memories of 800m/a fuse blown and a faulty lopt/tripler] all proved groundless. The only suspect area are the four green plastic cased 2700pf 3rd harmonic tuning caps that after a long period of use went O/C creating havoc in the line output stage. A long search through my pulse capacitors turned up nothing and a search on the Internet proved fruitless other than a supplier from a country I cannot pronounce with at least a 52 week delivery date. If anyone has any suggestions I will be most grateful!

I thought it wise to bring the variac into use. With it set to 120V I hit the mains switch and to my surprise the rustle of EHT was heard. I left it connected for a few minutes then advanced it to 175v. No fireworks and a loud hiss from the speaker. It looked good so far.

After a few moments a raster appeared, a bit small due to the low mains input. I fed a signal into the aerial socket via a modulator and DVD player and to my surprise test card F appeared with full sound. I was still nervous about those green caps but gave it full mains for a minute and after advancing the colour control was rewarded by a good quality colour picture that required a small amount of setting up. The 20" Mullard badged A51-220X is marked 'Made in Japan' I believe manufactured by TOSHIBA appeared to be bright and crisp.

The chassis was covered in dry dust and with the confirmation that it was in fact working, considered that now was the time to remove each panel and give them a very careful clean with a small artists brush and the vacuum cleaner. They all cleaned up well allowing component identification to be easily seen.

It was noticed that the small blue Posistor that forms part of the automatic degauss circuit was missing or at least the blue bit was! All that was left were the two connecting leads with their Porcelain insulating tubes. A hunt through the Philips bits produced a NOS one in it's original Philips packet. Philips Service, 604 Purley Way, Croydon Surrey. Happy Days! With the new posistor fitted you now had the familiar buzz when switching on from cold.

It was now time to set up the purity grey scale and basic convergence. This was soon carried out to produce a very acceptable colour picture. HT was set at 190V, 5V less than stated. It does not sound a lot but it's surprising how this reduction reduces the stress in the line output stage.

The nasty channel selector unit was sprung apart and the Y shaped contact forks were cleaned together with the printed contact surfaces. The earlier arrangement used in the original version of the G8 the 1971 520 series was very satisfactory and once set did not require further attention. Just why Philips produced this later contraption we will never know!

The setting of the presets controlling the 12V supply and frame output mid point voltages were checked and found to be correct and thought it wise not to poke about further unnecessarily and upset the old girl.

At the present time I am only operating it for a limited period just in case those green time bombs decide to awaken..

The cabinet is very good with only a few small chips missing at the bottom corners. It had originally been fitted with a stand. To allow ventilation and protect the base of the cabinet I fitted a set of plastic feet with the appropriate screws, not east to locate!

The front was cleaned with a solution of 'FLASH' crystals, hot water and cloths. A rather spooky thing happened. I have several packets of the old style FLASH, the green crystal type. As I reached down to get a packet from the cupboard under the sink a Flash advert appeared on the TV that was on the counter top just to my left. It was tuned to Sky News or Yesterday at the time. It was the exact moment I picked the packet up!

I am very happy with the results obtained from this late model G8. The picture is exactly as I remembered them back in the 70s. They were very much a landmark model at the time.

The use of the TOSHIBA tube is very noticeable in the red parts of the picture giving a much more vivid brightness than the conventional Mullard Delta gun of the period.

The pictures show the results after basically setting up the convergence and the panels before and after cleaning.

Pictures: Chassis before start. Signals board half cleaned. Signals board fully cleaned. Timebase panel Test card F.
Regards, John.
Attached Thumbnails
Click image for larger version

Name:	G8 (5).jpg
Views:	240
Size:	129.3 KB
ID:	243298   Click image for larger version

Name:	G8 (2).jpg
Views:	221
Size:	47.1 KB
ID:	243299   Click image for larger version

Name:	G8 (6).jpg
Views:	211
Size:	46.1 KB
ID:	243300   Click image for larger version

Name:	G8 (3).jpg
Views:	207
Size:	30.5 KB
ID:	243301   Click image for larger version

Name:	G8 (7).jpg
Views:	284
Size:	87.8 KB
ID:	243302  

Heatercathodeshort is offline   Reply With Quote
Old 13th Oct 2021, 10:00 am   #2
FERNSEH
Dekatron
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 6,811
Default Re: Philips 20" G8 colour receiver 1977.

Hi John,
excellent results. Can't remember the exact year the 20" G8 was introduced, was it 1975 or '76?
Philips made a good job making this compact receiver taking advantage of the combined signals and decoder board which was introduced 1974? designed to replace the separate P C boards employed in the earlier G8 models.
Despite the set's compactness reliability was better than the large screen version.
Along with the 20" Pye 725, the 20" G8 continued to be available from wholesalers in 1978.

DFWB.
FERNSEH is offline   Reply With Quote
Old 13th Oct 2021, 12:09 pm   #3
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 15,763
Default Re: Philips 20" G8 colour receiver 1977.

John,

That's really lovely! I've never yearned for a G8 before, but that set looks very appealing.

Presumably ousted by the indestructible KT3 chassis later in '78?

Nick.
Nickthedentist is offline   Reply With Quote
Old 13th Oct 2021, 12:35 pm   #4
mcousins
Triode
 
Join Date: Oct 2009
Location: Perth, Australia
Posts: 24
Default Re: Philips 20" G8 colour receiver 1977.

What a nice story, if only all old finds went that smoothly!
Didn't the G11 supersede the G8 prior to the KT3? I only remember due to the countless TDA1170 frame output faults I dealt with!

Regards - Mark
mcousins is offline   Reply With Quote
Old 13th Oct 2021, 1:05 pm   #5
dazzlevision
Nonode
 
Join Date: Sep 2003
Location: Near Swindon, North Wiltshire, UK.
Posts: 2,912
Default Re: Philips 20" G8 colour receiver 1977.

Yes, there was a 20” CRT G11 set made. I think there were EHT flashover problems, as the cavity connector was located near one corner, rather than top centre…?
dazzlevision is offline   Reply With Quote
Old 13th Oct 2021, 1:59 pm   #6
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 8,241
Default Re: Philips 20" G8 colour receiver 1977.

The KT3 was one of the best colour television receivers ever made. I repaired countless numbers and the only faults I ever encountered were an O/C 4.7 ohm surge limiter and the odd tripler that used to trip the power supply at a very fast but quiet rate. The 14" versions had a very good long life tube but the 16" and 20" ones suffered a very short life.

The TDA2600 frame chip in the G11 was destroyed by a useless holder. It was not possible to solder the chip directly onto the board due to the retaining spring and holder. Urgg!

I think the 20" tube may have been employed in a B&O but it was a long time ago! John.
Heatercathodeshort is offline   Reply With Quote
Old 13th Oct 2021, 1:59 pm   #7
gallowfields
Pentode
 
Join Date: Feb 2018
Location: Durham, County Durham, UK.
Posts: 138
Default Re: Philips 20" G8 colour receiver 1977.

looks like a mullard 20inch crt from the pictures john, brian
gallowfields is offline   Reply With Quote
Old 13th Oct 2021, 2:17 pm   #8
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 8,241
Default Re: Philips 20" G8 colour receiver 1977.

Yes it is Brian but on the blue label it says 'Made in Japan' I don't think it was financially viable to produce a 20" tube in the UK.

Mullard also imported the 22" A56-120X from Canada during the mad rush for colour in the early 70s. It had a yellow label and may have been manufactured by RCA. It could be recognised by it's slightly blue tinted glass. Unfortunately it had a very short life.

As far as I know it was not fitted in the 22" G8. I only came across it in the PYE 697 series. It was usually the red gun that collapsed. John.
Attached Thumbnails
Click image for larger version

Name:	A51-220X.jpg
Views:	88
Size:	76.9 KB
ID:	243328  
Heatercathodeshort is offline   Reply With Quote
Old 13th Oct 2021, 2:25 pm   #9
agardiner
Hexode
 
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 493
Default Re: Philips 20" G8 colour receiver 1977.

What a fantastic result. Lovely picture. Amazing to think this set is now around 45 years old!
agardiner is offline   Reply With Quote
Old 13th Oct 2021, 2:48 pm   #10
Welsh Anorak
Dekatron
 
Welsh Anorak's Avatar
 
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 5,599
Default Re: Philips 20" G8 colour receiver 1977.

Looks great!
I have one of these 20" sets in quite a sorry state, cabinet wise. Must get round to it. As far as I remember it was retired due to a short-circuit mains (yes, mains!) transformer. I was given another one by a kind forum member which I must fit...
It wasn't possible space-wise to fit the twin-panel IF and decoder boards to this particular version - the manual told you so.

PS. The blue-label A51-220 tube was also used in the Pye 20" 725 series. The G11 did have a 20" tube, the 20AX A51-500X with the odd side mounting EHT connector which was in just the wrong place when you closed the right-side door. B&O also used this CRT. Don't think the Rank T20 used it, though as ironically there wasn't a 20" version.
__________________
Glyn
www.gdelectronics.wales
Welsh Anorak is offline   Reply With Quote
Old 13th Oct 2021, 3:17 pm   #11
McMurdo
Dekatron
 
McMurdo's Avatar
 
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 4,457
Default Re: Philips 20" G8 colour receiver 1977.

hi john, RS do a 700VAC / 2kVDC rated metallised polypropylene capacitor, brand KEMET (aerovox) with a value of 2.7nF, I guess the G8 needs two parallel pairs ?

Back in the 70's our TV repair man appeared from behind our G8 (and a cloud of panatella smoke) and with a grunt, threw one of the big dirty green cylindrical ones into the lounge bin from some distance. I retrieved it after he'd gone, but I couldn't think of a use for it.
__________________
Kevin
McMurdo is offline   Reply With Quote
Old 13th Oct 2021, 4:58 pm   #12
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 8,241
Default Re: Philips 20" G8 colour receiver 1977.

Thanks for that info Kevin. It took me a while to find it in the RS lists [stock number 882-9149] but unfortunately they are in packs of 25 and I will never use the remaining 21. I will have to investigate. Thanks again, John.
Heatercathodeshort is offline   Reply With Quote
Old 13th Oct 2021, 7:09 pm   #13
Philips210
Octode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 1,860
Default Re: Philips 20" G8 colour receiver 1977.

Hi.

Great set John!

I had exactly the same model back in 1983 and found it very reliable once the usual dry solder joints were dealt with. The picture quality was very good, nice sharp well defined colours and the convergence was very good too. That later convergence board was not their best effort though. The aluminium framed front mounted convergence assembly in the 520 series was more reliable.
When I first opened my set I remember being surprised in not seeing the usual magnetic shield around the tube and realised the A51 220X tube had an internal magnetic shield unlike the 22" and 26" versions.

There can't be many of these 20" G8s around now.

Re Glyn's post #10. There was a 20" version of the RRI T20. I used to look after one for a friend. It used the A51 500X 20AX tube that did indeed have a side mounted final anode cavity connector on the tube.

Regards,
Symon

Last edited by Philips210; 13th Oct 2021 at 7:36 pm. Reason: typo
Philips210 is offline   Reply With Quote
Old 13th Oct 2021, 7:18 pm   #14
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 8,241
Default Re: Philips 20" G8 colour receiver 1977.

Hello Symon,
Now you mention the Bush 20" version of the T20 I do remember having one in for repair. They were very rare and were probably only a few pounds cheaper than the 22". John.
Heatercathodeshort is offline   Reply With Quote
Old 13th Oct 2021, 7:22 pm   #15
bobhowe
Heptode
 
Join Date: Jun 2005
Location: Sunderland, Tyne and Wear, UK.
Posts: 529
Default Re: Philips 20" G8 colour receiver 1977.

Hi John nice set brings back memories watching great TV programs in the 70s liked the remote control version you could change channels by jingling keys or the Budgie squawking happy times kind regards Bob
__________________
Kind regards, Bob.
bobhowe is offline   Reply With Quote
Old 14th Oct 2021, 8:01 am   #16
alanmoore
Tetrode
 
alanmoore's Avatar
 
Join Date: Mar 2009
Location: London, UK.
Posts: 64
Default Re: Philips 20" G8 colour receiver 1977.

Hello John , another great write up , amazed this set needed so little work.
Very hard to believe this set is now 45 years old .
All in all a fantastic result.
Had a scary thought ,I was just 17 years old when this set was made ,how time flies
Regards
Alan
alanmoore is offline   Reply With Quote
Old 14th Oct 2021, 9:12 am   #17
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 8,241
Default Re: Philips 20" G8 colour receiver 1977.

Hello Alan,
Yes it is amazing how time passes. When you are 20, older guys tell you how it seemed only yesterday when certain things happened and you tended to dismiss or ignore their comments. We never thought we would get old!
Yes the G8 is 45 years old and I have attached a picture of the front of the 560 so that younger guys know what I am talking about. I was 28 years old when this G8 rolled off the production line at Philips factory, Commerce Way Croydon. John.
Attached Thumbnails
Click image for larger version

Name:	G8 Front.jpg
Views:	117
Size:	130.1 KB
ID:	243380  
Heatercathodeshort is offline   Reply With Quote
Old 15th Oct 2021, 12:32 am   #18
Hybrid tellies
Nonode
 
Hybrid tellies's Avatar
 
Join Date: Jan 2004
Location: Bristol, UK
Posts: 2,593
Default Re: Philips 20" G8 colour receiver 1977.

I don’t think I ever came across the 20” version of the G8 but can imagine that like yours they produced great pictures. I would have been 16 when this set was born.
__________________
Simon
BVWS member
Hybrid tellies is offline   Reply With Quote
Old 15th Oct 2021, 1:26 am   #19
Maarten
Dekatron
 
Join Date: Dec 2007
Location: Haarlem, Netherlands
Posts: 3,308
Default Re: Philips 20" G8 colour receiver 1977.

Quote:
Originally Posted by Heatercathodeshort View Post
Yes it is Brian but on the blue label it says 'Made in Japan' I don't think it was financially viable to produce a 20" tube in the UK.
The white stamped code on the bell (or absence thereof) can give a hint as to where it was made. Philips had relations with Matsushita for valves, not sure about picture tubes.

A few years later, the UK CRT factory became an important production location for 20-21" tubes (smaller tubes being made in Taiwan, Spain and Austria, larger ones in The Netherlands, Germany, France and also the UK).
Maarten is offline   Reply With Quote
Old 15th Oct 2021, 11:25 pm   #20
The teleman
Pentode
 
The teleman's Avatar
 
Join Date: Dec 2007
Location: County Durham, UK.
Posts: 225
Default Re: Philips 20" G8 colour receiver 1977.

I can honestly say I never came across a 20” G8 for repair , I have seen them in homes many times ,
David ( Fernseh ) remarked about a 20” PYE 725 now this I have never seen I didn’t know they produced a 20” set, in fact I don’t ever recall a 20” pye set until the G11
Please correct me if I’m wrong , better still , has anyone got a picture of one ?
Chris
The teleman is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 7:35 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.