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-   -   Philips G22K550 (https://www.vintage-radio.net/forum/showthread.php?t=14837)

ekcopyephilips 15th Feb 2007 11:07 pm

Philips G22K550
 
4 Attachment(s)
Hi everyone

Thought you might like to see latest pics of my first foray into CTV restoration. I totally dismantled it, sanded down the cabinet, treated woodworm holes etc. Once stained and lacquered it looks pretty reasonable.

The convergence set up pretty well too. I did have a prob with the colour (see colour bar pic below) but a very slight tweak on the line disc balance VR3168 seemed to cure it.
A slight phase error was also corrected by a tweak on the quad adjustment VR 3392.

Apparently Philips never issued a service manual for the 550 series G8. Only service supplements were ever issued. If anyone has one on decoder alignment I would love to hear from you, as I would really like to set the decoder section up correctly.

Next on my list is to replace the two large caps on the line panel and the large 600uF on the mains/H.T. panel as even though working, look like they have vented in the past.

Mike

marcus 3500 15th Feb 2007 11:26 pm

Re: Philips G22K550
 
Well done Mike :)

While on my many trips to the various dumpit sites I've seen loads of these in VERY poor condition tube; smashed etc. Nice to see one in full working order.
WELL DONE MATE :)

Hope you enjoy using your G8 - a very nice 70's set :) :) :)

Regards

Marcus.........

Steve_P 16th Feb 2007 12:10 am

Re: Philips G22K550
 
All I can say here is the same as Marcus. Well done mate. Who needs these horrible modern things when you can have this...?

I'll have a look for a decoder manual this weekend. There must be one....

Cheers,

Steve P

slidertogrid 16th Feb 2007 12:16 am

Re: Philips G22K550
 
Hi Mike great job ! These Philips sets were very good for there time, reliable, easy to repair and had a long life, many were still going strong way into the 80s. The most troblesome part was the push button unit I would say ( a problem that the early g11s suffered from as well) Its good to see one still in working order after all these years!
well done!
Rich.

Mike Phelan 16th Feb 2007 8:51 am

Re: Philips G22K550
 
Well done, Mike. One of the later G8s. I agree fully with Rich about the pushbutton unit; they must be like hens' teeth now.

I would definitely change the electrolytics and set up the HT and overvolts pots on the PSU, and check the balance coil on the line panel so the BU205s share their current.

Check that there is a diode from chassis to one end of the BR100 diac (across the charging capacitor) to prevent HT flutter when there is no other reason for this.
Later panels had it on, I used to mod them all to prevent having to replace the diac every other week!

Looking at the colour bars, all I can see wrong is a slight purity error and the usual hum bar from photographing it - was there a reason that you were suspecting the decoder was off alignment? There isn't a lot to align apart from the RGB drives and B-Y quadrature, if the ref osc is locked OK.

Duke_Nukem 16th Feb 2007 9:12 am

Re: Philips G22K550
 
That push-button unit looks the same as the one on the B&W G20T322 I have and I can vouch for it being a real pain :(

TTFN,
Jon

G0PKH - Pete 16th Feb 2007 9:56 am

Re: Philips G22K550
 
The PB unit did always respond well to a good cleanup fortunately.

Well done, great to see one of these sets performing well again.
Brings back memories of the 80's for me, when I had a shed full of them ;D.

If only I still had one.

Pete

Welsh Anorak 16th Feb 2007 3:41 pm

Re: Philips G22K550
 
Hi
I agree with Mike P - it seems there's a slight purity error. If the set's had a regunned CRT then it's a good idea to turn off the blue and green guns (easy on a G8!) and look very closely at a red raster. If there's any discolouration the scan coils may need shifting slightly back or forward (wing nuts on the sides), then the purity rings may need a slight tweak to get blue and green OK.
The good news is the convergence will then need doing again.....
Nice to see one of these still going - and with a good convergence panel! Every other house seemed to have one in the late seventies - a sort of Ford Cortina TV!

Glyn

ekcopyephilips 16th Feb 2007 7:59 pm

Re: Philips G22K550
 
Hi Guys

It did indeed have a very bad purity error, caused by not having its posistor fitted. (i took the pics before i fitted it ). The purity error has now gone.

Mike, I wasnt sure if the decoder was off alignment or I was confusing myself.
I recently purchased a Philips PM 5508 pattern generator off a well known auction site. Its an old unit and i was very suprised to also receive the original instruction manual, which has colour photos in it of the test cards and what they look like in normal and fault conditions. When I chose to display the 'Phase' pattern, the TV showed what the book described as a decoder alignment error.

The pattern concised of four vertical bars, the upper half of the bars encoded to the PAL alternating standard, whilst the lower part contains colour infomation only on every "positive" PAL line. The latter means that only those lines with a burst phase of 135 degrees carry colour information. The burst is the normal PAL alternating burst for the entire pattern. To ensure the same colour impression of the upper and lower parts of the pattern, the upper part is generated with only half the chroma amplitude.

The manual then went on to say that, one should check the upper and lower parts of the pattern produce the same colours during the same vertical bars. If the colours differ, the chroma demodulators are not adjusted correctly.............phew

Sorry if i went a bit off topic there, but thats why i was getting interested in decoder alignment :-)

Mike

Mike Phelan 17th Feb 2007 10:27 am

Re: Philips G22K550
 
Hi Mike
If, with normal colour bars, there are no Hannover bars, especially on red and green (R-Y) then I wouldn't worry.
As most of this part of the decoder is inside the TBA520, errors will be due to tolerances including the PAL delay line, and are probably as good as any set.
If you can beg, borrow or steal a copy of Television January 1979 I did an article on decoder alignment including the G8.

HTH


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