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Old 8th Apr 2012, 7:53 pm   #81
Maarten
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Default Re: Philips CP90 Chassis Service Info

The BYD33D has higher specs, the BAV19 was probably found not to be up to the job. The BYD33 series might still be current, but I've found the UF4007 to be a good general replacement type for most fast rectifiers used in TV sets (specified at 1000V 1A 75ns).
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Old 8th Apr 2012, 11:45 pm   #82
Red to black
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Default Re: Philips CP90 Chassis Service Info

Hi Ricardo,

The BYD33D is still readily available, but if you get stuck I will be able to post you a couple, or as Maarten suggests a UF4007 should suffice in this position, as this is fed from a winding on the lopt, it is part of the 'run supply' for the micro.

This is a known fault and gives a no picture and no sound fault (no supply to the micro), this may have been due to the lopt failing, but I have had this device fail in sets where the lopt is ok too.

Of greater concern (to me anyway) is the failure of the supply to regulate properly on occasion, the diode mentioned above does also supply part of the optocoupler circuit as well when the set is running normally (line stage running), so I would still check for this problem after replacing the diode.

You may need to replace the optocoupler too, or at least check the components in the immediate vicinity , and I would also replace C2694 (100uF).
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Old 9th Apr 2012, 8:58 am   #83
Ricardo
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Default Re: Philips CP90 Chassis Service Info

Thanks for the helpful replies.

Maarten,

It is useful to know that the BYD33D has a higher spec than the part listed in the service manual. So I will either obtain one of those or a UF4007 as you have suggested.


Red to Black,

Yes, I too am concerned about the occasional lack of regulation of the +95V supply. C2694 is a capacitor that I haven't changed yet, because the dc voltage across it measured OK - however I probably didn't check it when the regulation failed. I also have my suspicions about the opto-coupler and I have one of those on order as a replacement.

What surprises me however is that the +95V rail can go as high as it does without the overvoltage circuit of D6697, D6698, D6699, C2700 and the SCR 6696 kicking in to stop it happening. Perhaps I need to check or replace the SCR as the rest of the components are OK.


Best regards,

Richard
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Old 15th Apr 2012, 7:30 pm   #84
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Default Re: Philips CP90 Chassis Service Info

Thanks to all the help received on the forum and a great deal of frustrationg troubleshooting I seem to at last have a working Philips 21CE1558 television again.

It isn't yet fully re-assembled as I am continuing to soak test it and I haven't yet checked out the teletext decoder, but here is a photo showing it displaying a test card.

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The actual picture is rather better than the photograph, but at least it shows the set in working condition once more.

Had I known the trouble it was going to cause I might not have undertaken this repair! Still I have learnt quite a lot about televisions along the way.


Best regards,

Richard
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Old 27th Apr 2012, 12:37 am   #85
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Default Re: Philips CP90 Chassis Service Info

Hi Ricardo,

I am glad you managed to repair the set, I have been rather busy of late, and not had much time to post on here, but have looked in from time to time.

Are you going to put us out of our misery, and tell us what you did to fix this set then ?
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Old 13th Aug 2014, 12:26 pm   #86
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Default Re: Philips CP90 Chassis Service Info

Hi everyone.

When I worked for Maxwells in Northallerton in the late 90s we had a large number of 21" CP90s that were ex-rental and used as loan sets for customers.

They were normally very reliable and if they did fail it was normally a straightforward and economical repair. I don't think we ever wrote one off completely. We were never stressed when we saw one come in for repair.

In addition to Philips and Pye models, we also had some Dynatron sets with a royal crest on them. They were in a slightly larger cabinet with the speaker at the side like the Pye sets (Philips had speaker at the bottom).

Anyway, if anybody is interested, I am just about to finally dispose of my own 21" Pye set. It is a grey cabinet, non-remote model, in full working order. It had a new LOPT and associated components a few years back (I liked it enough to invest in it), but my wife hates it and its not worth the hassle of trying to hang onto it any longer.
Free to a good home. Location Bradford/Leeds.

Another point to mention (haven't read all the posts so forgive me if someone already said this) is that the Philips and Dynatron sets had "FSQ" tubes (flat and square), while the Pye models only had "SQ" tubes (square corners, vertically flat, but horizontally curved).
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Old 14th Aug 2014, 2:18 pm   #87
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Default Re: Philips CP90 Chassis Service Info

Hi
That point on the tubes puzzles me - as far as I remember the Pye and Philips models were the same, differing only in cabinet design - grey as opposed to black. Earlier Philips ones had a side mounted speaker. The early thin-neck tubes could give a defocused picture, but mechanically were the same.
I'm sure Maarten would be able to give us a definitive answer.
They were good sets, only badly cracked PCBs or a severe leaky battery causing them to be written off, or a clumsy engineer taking the CRT neck out - not me, of course...
There was also a fairly rare non-remote version with 12 selectors and rotary controls which I believe was the last non-remote large screen set to be made.
Glyn
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Old 14th Aug 2014, 4:46 pm   #88
se325919
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Default Re: Philips CP90 Chassis Service Info

Hi Welsh Anorak. You may be correct that Pye and Philips tubes were the same. Having looked at some photos it seems to be the case. The Pye definitely bears the logo "SQ Vision" while the Philips famously boasted "FSQ Vision".
And the model which I am giving away does indeed have separate little electronic buttons for channel selection and tiny pots for volume, colour and brightness. Contrast is adjusted by a pot poking out of a hole at the back of the set.
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Old 14th Aug 2014, 7:19 pm   #89
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Default Re: Philips CP90 Chassis Service Info

Quote:
Originally Posted by se325919 View Post
Another point to mention (haven't read all the posts so forgive me if someone already said this) is that the Philips and Dynatron sets had "FSQ" tubes (flat and square), while the Pye models only had "SQ" tubes (square corners, vertically flat, but horizontally curved).
The latter sounds more like a description of a Sony Trinitron tube to me.
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Old 15th Aug 2014, 8:04 pm   #90
Welsh Anorak
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Default Re: Philips CP90 Chassis Service Info

Hi
I expect it was so that Philips could command a higher price - Flatter SQuarer. Of course the others called them FST - Flatter Squarer Tube, though decency forbids me to tell you what Radio Rentals decided FST stood for on the ICC5!
I had to odd customer complain that their set wasn't fastext - thinking that's what FST stood for.
If I remember, in the Philips sets the micro's suffix 8187 was basic, 8188 was text and 8189 fastext.
Glyn
PS These sets were great in that when the battery died the levels were set to zero, so no sound or picture, making a small fault appear serious to the customer. A slight adjustment out of sight of the customer proved this, then in with the new NiCad! We had a foolproof procedure for storing the settings in memory in all Philips models as they tended to vary and it saved the embarrassment of a recall.
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Old 22nd Aug 2014, 9:43 am   #91
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Default Re: Philips CP90 Chassis Service Info

Quote:
Originally Posted by Welsh Anorak View Post
Really? I only saw the G110 (or was it the GR2.1?) in B&O dress.
Sadly yes. It was made in Italy and looked OK in the catalogue, only when you got it home did you discover that it wasn't a miniaturised version of the bigger ones, just a bulky portable with a few styling similarities. It worked with the Beolink 1000 remote control though, that must have been tough to do with the 455kHz business. The MX1500 was the last B&O TV set with mono sound, but it really just is a CP90 in a fancy looking box.
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