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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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18th Mar 2012, 10:31 pm | #41 |
Pentode
Join Date: Jul 2006
Location: Bedfordshire, UK.
Posts: 211
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Re: Philips CP90 Chassis Service Info
Some feedback from my initial testing and visual inspection.
The voltage measured across C2663 (+280V) is about 325V. So I guess that is OK. The voltage across C2696 (+95V) with the linescan connector M6 unplugged and a 60W lamp connected was initially too high. Maybe because I had some other loads disconnected or it was in standby. Anyway it has now settled down and seems to be regulated at 95.4V. From my visual inspection it appears to my untrained eye that the line output transformer has probably failed. There seems to be a split in the casing with some of the innards spilling out. See the attached photo. So before I go too far with my investigations, how easy or otherwise is it likely to be to obtain a suitable replacement transformer. Also I have failed so far in my attempts to release the EHT lead from the transformer. I tried to prize up the clamping ring with a screwdriver as described in the service manual, but it seems to have split rather than extracting and the EHT lead is still stuck firm! Any ideas what I can do about this? Note: I have removed the lead from the tube end OK. Richard |
18th Mar 2012, 10:37 pm | #42 |
Retired Dormant Member
Join Date: Feb 2008
Location: Croydon, London, UK.
Posts: 408
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Re: Philips CP90 Chassis Service Info
You should not have to take the leads from the transformer, as a new one comes with the leads already pushed in. Sometimes taking out the leads risks breaking the plastic clips.
Try CHARLES HYDE AND SONS for a transformer. |
18th Mar 2012, 10:40 pm | #43 | |
Nonode
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
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Re: Philips CP90 Chassis Service Info
Hi Richard,
Post the numbers, from the label on the transformer. Quote:
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18th Mar 2012, 11:00 pm | #44 |
Retired Dormant Member
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Location: Croydon, London, UK.
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Re: Philips CP90 Chassis Service Info
Not having a diagram to hand, is C2700 a non polarised electrolytic?
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18th Mar 2012, 11:13 pm | #45 | |
Nonode
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
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Re: Philips CP90 Chassis Service Info
Quote:
No, C2700 is just a normal electrolytic, it decouples the gate of the thyristor used for overvoltage and overcurrent etc., it is part of the trip circuit. C2703 decouples part of the set ht network, and can cause all sorts of symptoms, ranging from patterning to int. tripping. edit: it may also pay to replace C2671 3.3uF on the primary side, this decouples part of the optocoupler on the primary side.
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19th Mar 2012, 12:50 am | #46 | |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,562
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Re: Philips CP90 Chassis Service Info
Quote:
Basic Teletext 8188 mask code Fastext 8189 mask code. My original service manuals for the CP90 and CP110 only mention the 8188 mask code for the microcontroller but a later supplement describes the 8189 version for the Fastext decoder. I would guess the Fastext version was introduced around 1988. ISTR converting a CP90 which had basic teletext by replacing the microcontroller with the 8189 coded version and simply plugging in a Fastext decoder from a scrapped CP110. There was definitely a through hole component version Fastext decoder that could be fitted to both sets providing the set had the 8189 microcontroller. The Fastext decoder had it's own microcontroller, an MAB8461 for recognition of the control codes from the main microcontroller ic. Symon. |
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19th Mar 2012, 12:57 am | #47 | ||
Nonode
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Location: Sunderland, Tyne and Wear, UK.
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Re: Philips CP90 Chassis Service Info
Hi Symon,
Quote:
I have already had one 'blonde moment' today, see my earlier mistake in post#37, and correction in post#40, it's an age thing!, and it is quite a while since I last repaired these sets. Quote:
If you had the wrong micro/text panel combination, you just got no text.
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19th Mar 2012, 12:58 am | #48 |
Hexode
Join Date: Mar 2012
Location: Liverpool, Merseyside, UK.
Posts: 453
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Re: Philips CP90 Chassis Service Info
That LOPTX is the usual classic failure, I wish I could remember the Alba/Bush chassis that I used to salvage these from. The Bush ones were always 14 inch portables that always suffered flashovers at switch on (or it sounded like it) which corrupted the MDA2062 EEPROM. I never found a cure, and it was always the portables, I suspect poor CRT's or some design fault. The same chassis was used in 20 and 21 inch sets which were much better.
Anyway they were a great source of transformers and BU508A's. Lots of memories here |
19th Mar 2012, 1:06 am | #49 |
Hexode
Join Date: Mar 2012
Location: Liverpool, Merseyside, UK.
Posts: 453
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Re: Philips CP90 Chassis Service Info
Just stirred my memory, the Bush models used the Indiana 100 chassis, I believe the portable was a 2114. If I'm correct the LOPTX from these goes straight in, though you may have an easier time getting the Philips one now.
The 17 inch FST CP90 gave one of the best colour pictures I can remember at the time! |
19th Mar 2012, 1:07 am | #50 |
Hexode
Join Date: Mar 2012
Location: Liverpool, Merseyside, UK.
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Re: Philips CP90 Chassis Service Info
Correction it was the 2514 not the 2114
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19th Mar 2012, 1:12 am | #51 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,562
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Re: Philips CP90 Chassis Service Info
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19th Mar 2012, 1:14 am | #52 | |
Nonode
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Re: Philips CP90 Chassis Service Info
Hi Clyde,
Quote:
I do remember writing off a stock CP90, by inadvertantly fitting a similar Lopt from a Toshiba set that someone had put back in the wrong box! The tube heaters flashed brightly, and promptly went O/C, the transformer fitted physically, and was the same grey type, except the heater winding used different pins, and IIRC, the Tosh one had the Video supply pins where the Philips heater pins should have been, thus feeding 160 plus volts to the heaters , Damn! Luckily (or unluckily) it was a stock set.
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19th Mar 2012, 1:25 am | #53 |
Dekatron
Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
Posts: 7,484
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Re: Philips CP90 Chassis Service Info
As I mentioned briefly in an earlier post:
21ce1251/16B - early grey boxy one, Uses HR7503 LOPTX I think this was the only transformer I ever fitted for those 21" sets, last one I bought about 4 years ago cost me 12 Euros. HTH
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19th Mar 2012, 1:31 am | #54 |
Nonode
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Re: Philips CP90 Chassis Service Info
Hi ben,
CHS has not got the HR7503 listed, in fact Iam not sure they have many Lopts listed at all nowadays. I mainly fitted the Philips original replacement Lopts, because at one time I could get them far cheaper than the HR Diemen equivalent (about 1/3 the price !). But later I did fit the HR types hence the wrote off set above in post #53 Richard is trying to source one though, so any Info. is helpful.
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19th Mar 2012, 1:39 am | #55 |
Dekatron
Join Date: Aug 2006
Location: Madrid, Spain / Wirral, UK
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Re: Philips CP90 Chassis Service Info
The place down the road from me here in Madrid probably still has 'em, so if all else fails I can buy it here and send it over next time someone comes out to visit me, probably within the next few months. But first we'd need to double check the reference, just in case. the HR7503's I used to buy for the 1251 series, don't think I've changed one in the 1558.
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19th Mar 2012, 2:13 am | #56 |
Hexode
Join Date: Mar 2012
Location: Liverpool, Merseyside, UK.
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Re: Philips CP90 Chassis Service Info
I guess I just used to get lucky with my attempted LOPTX replacements that looked the same. I know with the Bush transplant I just noticed that it looked the same and to my surprise it worked! I subseqently did the same on many CP90 sets as we had a lot of Indiana 100 scrapped chassis.
Any other attempts on other chassis with transformers that fitted physically usually resulted in the HT supply being grounded, I guess your Toshiba LOPT transplant shows the danger of this method. |
19th Mar 2012, 2:39 am | #58 |
Nonode
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Location: Sunderland, Tyne and Wear, UK.
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Re: Philips CP90 Chassis Service Info
Hi ben,
Probably because Vestal etal. bought all end of production line stock from various manufacturers, and made TV's out of the bits and pieces. Still it is very useful to know, Thanks for that. When Clyde first mentioned it, it stirred some memories, but without the Lopt numbers was impossible to confirm. Besides this, when these repairs were commonplace, there was no need to try to source via alternative model numbers, as parts were readily available by the model or lopt number, and as I said in a previous post, Philips had at one time priced these much cheaper than the alternatives, about £6 odd + Vat Trade at the time IIRC. I cannot ever remember Philips using alternative/different Lopts in the CP90 chassis, as far as I know the lopt was the same across the range. Having said that, I saw very few of any of the smaller screen size sets other than the 21" variety of this chassis, I maybe saw a couple of the 17" sets, but this was unusual and a rare occurrence. I don't know why we never saw many of the smaller screen variants, but all of my stock was ex-rental, so if the rental companies never put these smaller sets out for rental, then we wouldn't see them either. But that does not explain why I did not see many of them in for repair via private repair customers.
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I don't suffer from Insanity. I enjoy every minute of it. Last edited by Red to black; 19th Mar 2012 at 3:08 am. Reason: additions |
19th Mar 2012, 2:39 pm | #59 |
Dekatron
Join Date: Dec 2007
Location: Haarlem, Netherlands
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Re: Philips CP90 Chassis Service Info
Probably not because of an end-of-stock condition, but because this transformer was promoted by Philips parts as a standard solution. Vestel e.a. weren't so much buying end of stock parts and pieces, but they were taking datasheets and appnotes very literally (you can build a working tv set just by looking at datasheets and appnotes, but it will never be as good as a set designed by someone who actually knows what they're doing). It might well be the single most common loptx.
I agree on the cable being non-detachable since it would be glued in place. This might have also been mentioned in the service manual. It could be useful to cut it off though, if you ever need the rubber cup or other parts to replace a failed one. Regarding the look-alike transformers with different windings and connections: They're all AT2079's, so attention should be paid to the either or both the stroke number following AT2079 and at least the first four of the last five digits of the 12NC article code. This is what distinguishes between variations. Last edited by Maarten; 19th Mar 2012 at 2:47 pm. |
19th Mar 2012, 2:48 pm | #60 | |
Nonode
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Location: Sunderland, Tyne and Wear, UK.
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Re: Philips CP90 Chassis Service Info
Quote:
As other posters have already said though, there is no need as the replacement transformer usually comes with it attached.
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