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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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21st Mar 2019, 11:46 am | #21 |
Dekatron
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Re: PIL - Colour fringing
GEC-McMichael C2089 series of television receivers are equipped with a Hitachi chassis using 560EGB22 and 510VSB22 CRTs. From the service manual information about the purity adjustments on these PIL tubes.
DFWB. |
21st Mar 2019, 12:14 pm | #22 |
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Re: PIL - Colour fringing
Thanks David.
I knew there was at least one Hitachi PIL crt that was setup has explained in the GEC instructions. I don’t know if the CTP 213 set uses a similar set up or the scan coils are fixed when manufacturered. I think the advice about leaving well alone is the best.
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21st Mar 2019, 2:10 pm | #23 |
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Re: PIL - Colour fringing
Despite the lack of specific convergence instructions, it's often possible to converge such a set better, but you will need to study and practice instructions for similar tubes and possibly have to use permalloy assy's from scrap monitors or trinitron sets.
Edit: the two posts above also mention instructions for similar tubes. I think we're all on the same track here. |
21st Mar 2019, 6:41 pm | #24 |
Dekatron
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Re: PIL - Colour fringing
From experience I don't think you'll improve on the existing setup. If you can, select a red raster and if it's not blotchy the purity's OK. Converging a tube on a picture is virtually impossible. Early sets with real controls you could twiddle are capable of excellent results and can be better than they were on leaving the factory as forum members have proved (hi Tas!). However the early PIL tubes were always something of a compromise to set up. I won't be the only one to have thought I could improve on the settings and many hours later realising the tube was at the limits of its tolerance and I was getting nowhere. If you must adjust things, make sure you mark the rings first as you may well need to return it to where it was.
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21st Mar 2019, 7:04 pm | #25 | |
Pentode
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Re: PIL - Colour fringing
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Re. discharging: I'm not a qualified engineer myself, just a former engineers' assistant (in radio) and a lapsed tinkerer. It would be best for you to get further advice from a better source than myself, ideally an engineer near you who either restores vintage TVs or used to be in the trade. Or could other members here help? You may find some TV servicing guides from the relevant era at your local library. If it hasn't been closed, that is! There's a servicing guide by Eugene Trundle, a well-regarded author, on Amazon: https://www.amazon.co.uk/gp/offer-li...3189576&sr=1-3 If you're interested in technical information generally, there are old issues of the magazine 'Television' on http://www.americanradiohistory.com Loads of other technical documents on that site. It's a goldmine! Have fun! |
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21st Mar 2019, 9:04 pm | #26 |
Heptode
Join Date: Jan 2008
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Re: PIL - Colour fringing
I once had a good set with a defective PIL-tube. I couldn't get a correct replacement. I had a tube where the yoke had different impedance but the "glass" was the same. I tore off the yokes and swapped them. I put the yoke against the wedges and the picture was perfect. I might have been lucky...
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22nd Mar 2019, 12:31 am | #27 | ||
Octode
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Re: PIL - Colour fringing
Would it be possible, if you had the time and patience to do so, but get an almost perfect convergence, if not perfect? Of course I don't know the full ins and outs, but I'd have thought if you could adjust the positioning of the DY/Scan coils, couldn't you get perfect convergence?
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The purity seems to be OK. I was watching Film 4, and the bright red ident was solid, I didn't notice any blotches, that's the closest I can get to a solid Red, green or blue, until tomorrow. Of course it's not too much of an issue as the colour fringing isn't noticeable when on a full screen, but when something has the black bars down the sides and a graphic, like BBC, or ITV is when it's noticeable, but of course, that's not the focal point. I think I'll take other people's advice and leave it alone, it's good enough as it is, I'm just being a little OCD with it, after all. Thanks Quote:
I'll have a look at the links and have a read, thanks for linking them! Thank you for your help, It's appreciated! |
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22nd Mar 2019, 11:18 am | #28 |
Octode
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Re: PIL - Colour fringing
I have found the static and dynamic set up instructions for pre converged PIL tubes.
In order to give you as much information as possible, I will need to scan from several documents; no problem just takes a little time. In respect of the wedges, these are unlikely to have sagged, it could be the CRT is being driven harder to compensate for reduced emission or just that the original alignment was a question of compromise. You will though need a cross hatch picture before any adjustments are made because,as stated earlier, trial and error is a recipe for disaster. Chris |
22nd Mar 2019, 3:16 pm | #29 |
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Re: PIL - Colour fringing
There are lots of "TV Test Pattern Download"s on the internet, simply burn to a DVD and play.
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22nd Mar 2019, 5:43 pm | #30 | |
Octode
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Re: PIL - Colour fringing
Quote:
Are you sure, I don't want to cause any trouble for you. I'm very grateful but I don't want to put you out in any way. Of course, i don't know how the set performed back in the 70s when it was new, so i cannot compare it. It's very bright when the brightness is turned all the way up, so it doesn't seem to reduced emission, or not a great deal anyway. But this is my guess. I will have to find some blank DVDs, as Merlinmaxwell said, to burn onto from the internet. There is no rush for the instructions, as i will need to get the DVDs from somewhere. (I've been looking around for a while and cannot find any?? Will probably have to order some online) Thank you for your help, i really appreciate it! |
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22nd Mar 2019, 6:14 pm | #31 |
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Re: PIL - Colour fringing
As an aside, I do remember a good delta tube and convergence circuits could be aligned to within one phosphor dot and straight and level. Took ages to do and was rather satisfying.
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22nd Mar 2019, 6:31 pm | #32 |
Octode
Join Date: Jun 2018
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Re: PIL - Colour fringing
I bet it's very satisfying when it's perfectly aligned, with the nature of CRTs. I hope I can improve mine, if even slightly.
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22nd Mar 2019, 11:10 pm | #33 | |
Dekatron
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Re: PIL - Colour fringing
Quote:
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23rd Mar 2019, 1:06 am | #34 |
Heptode
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Re: PIL - Colour fringing
The 20 AX had to be converged and was "fully adjustable". I used to swap these tubes in the Telefunken sets with Philips tubes. The Telefunken and Philips tubes had different yokes. I swapped the yokes and adjusted them up. Didn't take long set these up and get a good result.
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23rd Mar 2019, 11:28 am | #35 |
Dekatron
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Re: PIL - Colour fringing
You could often get surprisingly good results swapping yokes. Very often 30AX types that had been regunned came back with convergence rings added. Results were often mediocre, though, as a good regun wouldn't need them.
I used to swap yokes from those Orion 14" TVs - the ones with the wedges that ate through the copper wire and damaged the winding beyond repair. I had a load of broken Philips tubes and with some adjustment they could be made to work. |
23rd Mar 2019, 1:07 pm | #36 | |
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Re: PIL - Colour fringing
Quote:
This also explains that reguns sometimes came with external multipole magnets, as the integral multipole would have been part of the gun. |
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26th Mar 2019, 10:27 am | #37 |
Octode
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Re: PIL - Colour fringing
Attached are instructions for adjusting static and dynamic convergence of a PIL CRT similar to the one used in the Hitachi CTP213.
The use of a cross hatch is preferred but you might be able to use the Freeview Test Card, a wide screen Test Card F, as described in the sticky note "Displaying a test card on Freeview". You will note that the dynamic (yoke) adjustments described adjusts the position of the red/blue convergence at the crt circumference. To make this easy, for this prceedure, the green video output is disabled. I am not famiiliar with the inside of the Hitachi and so you you will need to either remove the "green" video by disconnecting the video out Tr852 on the crt base, turn down Green Background R859, having noted its position or short the base to emitter connection on this transistor. Whilst, quite correctly, attention has been drawn to the high voltage on the yoke, it was after all adjusted during manufacture by a human being. I wear cotton gardening gloves when doing this, take note of the connections and keep my hands clear of them. Good luck Chris |
26th Mar 2019, 3:32 pm | #38 |
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Re: PIL - Colour fringing
Instead of turning off guns you could use coloured glasses.
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26th Mar 2019, 3:41 pm | #39 |
Dekatron
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Re: PIL - Colour fringing
If you can get hold of a working ZX Spectrum or BBC Micro, I could easily recreate my old "convergence test" program in an emulator and post the BASIC here. It was necessarily fairly quick to type in.
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26th Mar 2019, 5:15 pm | #40 | ||
Octode
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Re: PIL - Colour fringing
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Quote:
Thank you so much for attaching the instructions, I shall get to reading right away! I'll have to find a suitable pattern, as I have a "YouView" box and cannot get Test Card F on it, unfortunately. However, if I could take up Julie's offer of the BASIC programme, please? I'd be grateful as I could use "Beeb Emulator" to programme it in and I'll get a suitable adaptor/cable to connect my PC to the TV. I was thinking about wearing gloves, myself actually. Would dish washing gloves be okay, being thick-ish rubber? I could get some gardening gloves easy if need be. Thanks all for your help! I really appreciate it! |
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