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Philips TVette (11TG190AT)

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sideband
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Finally!! Just bought one of these from eBay. It'll mean a drive over to Malmesbury to collect but rather that than risk the mail service.

I've been after one of these in good condition for a long time. Seller says the set switches on and shows a white screen which is promising. All I have to do now is arrange collection.

TVette.jpg

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Topic starter Posted : 02/07/2017 12:16 am
PYE625
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Good for you !  

Nice little sets they are too. thumb_gif

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Posted : 02/07/2017 12:21 am
Marc
 Marc
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Always thought the TVette was a nice neat looking set, maybe one day I might hunt one down

Good luck with it Rich, look forward to seeing more of it.

Marc.

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Posted : 02/07/2017 12:25 am
crustytv
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Hi Rich,

Glad you finally got one, I used to have one, other than some preliminary checks to ensure the regulator was OK and no danger of frying the tube, it was powered up and worked on both standards. I moved it on when I disposed of the B&W collection.

If you don't already have the service data I can scan the manufacturers service manual for you. As you can expect from Philips, its very comprehensive. Let me know if you need it.

tvette.jpg

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Posted : 02/07/2017 1:00 am
sideband
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Arranged for pick-up Thursday. Day off work and a drive to Malmesbury. Not been there since the Philips days. I could do the journey in two hours but then I had a company car and there weren't the number of revenue  speed cameras about then so I tended to floor it a bit.......

Using my own car I'll be a bit more sedate. Besides, my trusty SatNav warns me about the cameras.

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Topic starter Posted : 04/07/2017 9:29 pm
sideband
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Chris said
Hi Rich,

If you don't already have the service data I can scan the manufacturers service manual for you. 
tvette.jpg  

That would be great Chris. Thanks. I had one of these sets about 30 (actually 36...!!) years ago when I used it with my ZX81. I modified it for video input. I sold it along with the ZX81 and the manual went into the bin 'because I'll never need it again and won't be repairing one of those old things.....' Isn't it strange how attitudes change? I had no interest in vintage TV in those days since 405 was finished and Auroras didn't exist......
 

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Topic starter Posted : 04/07/2017 9:40 pm
Jayceebee
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It will be interesting to compare notes when you get it on the bench. Mine performs very well on 405, 625 is not so good with bad intercarrier buzz, pulling on whites and other sync issues. Due to a burnup on the system switch the scan coil switching contacts are permanently wired for 405 operation at the moment.

If a switch doesn't turn up I have some ideas to incorporate a couple of relays, the main problem being to ensure that scan coil switching doesn't occur with power applied to the AU103 which could cause instant destruction, the original system switch has break before make contacts in the AU103 supply to prevent this. For that I plan to use a single pole relay for the supply with a slight delay on a transistor driving the relay coil.

John.

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Posted : 04/07/2017 10:06 pm
sideband
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625 should be OK. I seem to recall that contrast was lower but adjustable but otherwise it was fine. As I said above, I used one with a ZX81 which was OK but I had better definition when I modified the set for video input....just a simple emitter follower and a switch. Think I used an AF124......

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Topic starter Posted : 05/07/2017 8:49 am
crustytv
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Service manual for the Philips 11TG190AT (T-Vette) is now available in the technical library.thumb_gif

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Posted : 05/07/2017 4:34 pm
sideband
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sideband said
Arranged for pick-up Thursday. 

...and it's here....

Watch for the next installment.....!

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Topic starter Posted : 06/07/2017 7:04 pm
sideband
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Chris said
Service manual for the Philips 11TG190AT (T-Vette) is now available in the technical library.thumb_gif  

Thanks Chris. Downloaded and ready to print!

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Topic starter Posted : 06/07/2017 7:05 pm
sideband
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Well as expected, not a lot wrong with it. Initial inspection shows that a contrast control has been bodged on to the print side of the board, other than that, it doesn't look like it's received any other attention. Based on the fact that the seller said it 'produced a white screen' when switched on, I decided to remove the CRT base, give it some mains and check the LT supply. I switched it to 405 and plugged in.....

LT measured 10.9 volts on the collector of the AD149 (important as the CRT heater is run from here), there were some encouraging crackles from the speaker and the line timebase was running with a healthy whistle (that's why I switched to 405....I can still hear it)! Next I reconnected the CRT base and tried again. The seller was right.....after about 20 seconds, a blank white raster appeared, not quite filling the screen, there was a gap at the bottom. Next I connected the Aurora and selected Channel 9 (that used to be our local ITA channel). A little fine tuning and an adjustment of the line and frame hold and I had a testcard. Some linearity and height problems but it was there and it was good.

When I switched the digi-box on, the Two Ronnies were on and on 'Discovery' there was an interesting astronomy program on so I sat and watched it for nearly an hour with no problems.

So there we are. The contrast control will need sorting, there is a crackle on sound (controllable so it's before the volume control) and the frame height and linearity need sorting. I think UHF is working as it produces a nice blank raster and shows noise when tuning through the digital channels. The only UHF modulator I have at the moment is on the Philips VCR so I'll have to fire that up at some point.

Some pictures:

js640_SAM_1323.jpg

Quite clean inside but someone has

nicked the contrast control. 

js640_SAM_1324.jpg

Side view

js640_SAM_1325.jpg

From the top

js640_SAM_1334.jpg

Initial results

js640_SAM_1335.jpg

Off air pictures.

js640_SAM_1338.jpg

Frequency gratings look good.

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Topic starter Posted : 07/07/2017 12:06 am
Jayceebee
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Well that's a promising start. I notice one of the push button is red and seen this on several pictures of TVettes, does this mean early or later production as they are all white on mine?

John.

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Posted : 07/07/2017 12:27 am
sideband
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Jayceebee said
Well that's a promising start. I notice one of the push button is red and seen this on several pictures of TVettes, does this mean early or later production as they are all white on mine?

John.  

Interesting....I've only ever seen the one's with a red button. I'll check the production date on mine....I have no idea yet if it's early or late production.

Maybe the red buttons became unavailable so were replaced with white. duno_gif
 

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Topic starter Posted : 07/07/2017 11:07 am
PYE625
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sideband said

Interesting....I've only ever seen the one's with a red button. I'll check the production date on mine....I have no idea yet if it's early or late production.

Maybe the red buttons became unavailable so were replaced with white. duno_gif
   

It's funny that red button, I mean it looks odd....would understand it if it was mains power, but not the 625 switch?

Perhaps it was a forerunner to the BBC's "Red Button"   grin_gif

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Posted : 07/07/2017 6:37 pm
Jayceebee
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Andrew, I always knew that Philips were forward thinking.rolf_gif

I'm not 100% sure but I think that sets fitted which were fitted with a red button it was usually on the battery switch not the 625 selector?

Edit. No I'm talking rubbish again, although it's greyscale the 625 button on the set on the front of the manual looks darker.

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Posted : 07/07/2017 7:21 pm
sideband
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sideband said
The contrast control will need sorting, there is a crackle on sound (controllable so it's before the volume control) and the frame height and linearity need sorting. 

 

Very quick update....it was so hot last night it prevented any serious work being done....

I re-sited the 1K preset that is fitted in place of the normal contrast control so at least it's adjustable. It appears that the corner of the PCB has been broken at some time so a proper control cannot be fitted unless I can make up a new 'corner' and fit a suitable pot.....probably not worth it. Height and linearity have been adjusted to improve geometry but the lin pot is at the end of its travel so resistors and/or caps will have to be replaced. The set is 'touchy' when tapped so either loose connections/dry joints will need to be resoldered. The crackle on sound is still there and that could well be down to AF11x problems in the sound IF stage. The line linearity is way out and needs adjusting.

All relatively simple stuff. The tube is 100% and now the contrast can be adjusted it's made a huge improvement. It will have a superb picture when all the little niggles have been sorted.

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Topic starter Posted : 08/07/2017 9:25 am
sideband
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Jayceebee said
 I notice one of the push button is red and seen this on several pictures of TVettes, does this mean early or later production as they are all white on mine?

John.  

I think it was probably to easily distinguish 625 from 405. Remember in the late 60's when these were sold, full UHF coverage had not been completed and being a portable, used for camping/holidays in different areas the user may not have been able to receive anything if the red (that new channel!) button had been pushed in during transit if they were in an area where there was no UHF.

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Topic starter Posted : 08/07/2017 9:42 am
sideband
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I was going to add more to this thread last night but then 2001 Space Odyssey was being shown on BBC2 so I sat and watched that instead even though it ended at 1:30 this morning.....

OK so back to where I left off Friday night. I said the set was 'touchy' when tapped....well that got worse with the picture fading off (like the heater going out) and touching the CRT base would bring it back. Dry joints and broken print track were the cause so very easily sorted and a few minutes with the soldering iron solved those problems.

Next a good look-over the main PCB around the LOPT and lots more dry joints found so these were attended to along with a few others dotted about the IF stages. Checking the set again showed that it was now very stable and at first even the annoying crackle on sound seemed to have cleared up. I adjusted the line linearity but now the width and picture centering needs adjustment....it looks as though someone had adjusted the line lin to stretch the picture to fill the screen......

The centering rings around the CRT neck have stuck together so at the moment I can shift it right and downwards or left and upwards. I need to separate the rings so I can shift it side to side or up and down as required. Careful adjustment of width and line lin should then produce a very good testcard.

Other than the slight tweaks needed, it's looking very good indeed and I watch 'Skyfall' with no problems.

I discovered an interesting anomaly not related to a fault on the set. I noticed that in the black-level parts of the picture, some noise was evident. It didn't look like RF noise (low gain) and wasn't quite sure what it was. Checking another TV from the same aerial splitter (but a different output) didn't show the noise. More by accident than logical reasoning I discovered that by moving the co-ax lead from the splitter to the TVette, the noise would come and go... It seems that there is considerable RF noise coming from my digibox and the aerial feeder was draped across it. Simply moving the cable away has stopped all the noise.

js640_SAM_1345.jpg

Dry joints and broken print on CRT base

Fixing those sorted out the fading picture

 

js640_SAM_1348.jpg

'M' is not fading anymore!

 

The annoying crackle returns after about half an hour and can be stopped by tapping around the IF section. Probably one of the notorious AF11x transistors. That will be one of the next jobs.

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Topic starter Posted : 09/07/2017 10:54 am
sideband
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Plagued with dry joints that are showing up at the moment. Latest was in the power supply that reduced the supply to 7.5V. 

Can someone with one of these sets enlighten me as to how the CRT earthing strap is fitted? There was a 'ping' last night and the earthing strap became loose (fortunately while the set was off....). There appears to be a plastic hook on the end of the strap and a spring. I think it locates on to a hook just under the CRT and it looks like the only way to reattach is to remove the CRT..... Earthing of the strap is achieved via a soldered lead to the timbase panel.

Thanks.

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Topic starter Posted : 16/07/2017 11:21 am
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