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Old 6th Apr 2020, 10:50 am   #21
ben
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

You always have to set those up. it is very simple though.

A quick and dirty way is to start with the SCREEN control. Use a well insulated screwdriver just in case. Let the set warm up 10 mins.

Have the customer controls at minimum contrast, normal/mid-way brightness.

Turn up SCREEN until you see retrace lines, then back it off very slowly until they just disappear.

Then put up a page of teletext, an EPG or what have you and do the focus.
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Old 6th Apr 2020, 12:14 pm   #22
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Just to add to Ben's post, the focus is the top preset and the screen (A1/G2) is the lower one. You might need to do the adjustments a few times as they're slightly interdependent.
Even though the LOPT is almost certainly faulty, discharge the EHT cap as the CRT can hold a charge for ages, not that I've ever found out the hard way, you understand....
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Old 6th Apr 2020, 12:17 pm   #23
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

which ones the EHT cap?

cheers Ben and everyone else who's given me so much useful info. hopefully ill be back with good news.
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Old 6th Apr 2020, 12:44 pm   #24
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Quote:
Originally Posted by Tvnoob007 View Post
Hmm looks like 3692379/10 and bellow it 8825 possibly.
That decodes to 36923 (last digit is a minor revision and usually doesn't matter, if 36923 is not found look for 36921) and commercial type number AT2079/10. If those numbers point to the same replacement, by all means go for it. Otherwise 36923 is theoretically the most important number.

V8825 is the date code, meaning it was manufactured in the Volt facility in the Netherlands in week 25 of 1988. The set itself is likely a few weeks newer and made in Monza.
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Old 6th Apr 2020, 1:39 pm   #25
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

The shop must have had it a long time on the shelf. I bought it around 1990.
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Old 6th Apr 2020, 2:31 pm   #26
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Quote:
Originally Posted by Tvnoob007 View Post
which ones the EHT cap?
...the one that connects to the tube side cavity....it carries up to 25kV so discharge it to the CRT earthing braid, NOT the chassis. Two large screwdrivers with well insulated handles will do it....slide the blade of one under the cap and then use the other to short it to the CRT outer coating or the earthing braid. If there is EHT present, stand by for a sharp crack discharge!

It stores charge because the CRT forms a capacitor between the final anode inside the tube and the outer coating (aquadag) on the outer surface of the tube using the glass as the insulator.
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Old 6th Apr 2020, 3:32 pm   #27
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

To clarify - the EHT connector's the big rubber sucker on the top of the tube. When up and running there's around 22kV there so probably a bit more than you might be used to!
The 15" and 17" versions of the CP90 were excellent TVs. Do be careful of the tube neck (where the base CRT attaches) as it's easily knocked with disastrous consequences. It doesn't take much...
Oh - change the NiCd battery if you haven't already. Luckily this looks like a battery! Bear in mind that all the settings return to zero if you do this so you can spend ages looking for a fault that isn't there.
Ben and his rhombus mentioned this in an earlier post.
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Old 6th Apr 2020, 4:30 pm   #28
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

hehe thought it was a capacitor we were talking about.

very much doubt there is any charge left in it as the last time this set worked was in the 1990's i think.

i replaced the battery back in the 90's but the new ones leaked, so will need to clean up with some vinegar. hopefully i dont have to do any retracing with wire.

i seemed to have used a 3 cell battery last time with fly leads. but looking at the specs it should be 2.4v. will try and find a 2.4v nimh.

will fit the trany first before i buy a battery, make sure it works.
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Old 6th Apr 2020, 6:35 pm   #29
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

The very best of luck with it. I'll keep my fingers crossed. John.
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Old 6th Apr 2020, 9:07 pm   #30
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Anyone used the site:

Vintage-parts.com

Just wondering if they’ve been hit by the shutdown? Not had an email other than automated ones.
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Old 8th Apr 2020, 7:32 pm   #31
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

name doesn't even resolve here just get a "This site can’t be reachedvintage-parts.com’s server IP address could not be found.
Try running Windows Network Diagnostics.
DNS_PROBE_FINISHED_NXDOMAIN
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Old 8th Apr 2020, 7:52 pm   #32
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

It's Mark Hindes I think: http://markhindes.easywebstore.co.uk/
Still in business as far as I know.
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Old 11th Apr 2020, 12:49 pm   #33
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Yep same site.

I’ve now received the tranny. Despatch was a bit long but delivery was quick.

He could do with checking his web sites messages, as I left a couple on the contact page but never heard back.
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Old 11th Apr 2020, 3:46 pm   #34
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Perhaps with the current situation he's been a bit overrun with orders/contacts? After all, the one good thing about this virus is it's given us all a bit of extra time and motivation to crack on with the round tuit pile so likely his business is booming just at the time when he's least able to keep up with everything. (I know that I, for one, have been making more electronics orders and doing more on "back seat" projects this last couple of weeks)

Hope you make good progress now with the new LOPT
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Old 11th Apr 2020, 8:25 pm   #35
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Thanks everyone for the help so far.

I fitted the new LOPT and have progress of sorts.

It now powers up but the led is pulsing, the faint TV psu noise is also pulsing in time, and I have no full screen picture. See pic. This is with no input connected or aerial, so should be full screen of static.

Just noticed I’ve got no channel number display either. I did clean around the board where the battery leaked with white vinegar. Maybe it isn’t fully dry?
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Old 11th Apr 2020, 9:28 pm   #36
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Ok some voltages.

320v at 280v check point.
About 83v at both 95v check points.
16v at 19v cp.
10v at 12v cp.

So seems like the psu is no generating the correct voltages.

Also the LOPT that vintage sent is a Philips not a HR. It’s a 36925.
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Old 11th Apr 2020, 11:17 pm   #37
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Can the LOPT going pop take out bat11?

It’s just measuring between base and emitter, while still soldered in, in either polarity gives me about 1ohm.
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Old 12th Apr 2020, 12:32 am   #38
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Ok removed it behaves more like I’d expect.
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Old 12th Apr 2020, 12:27 pm   #39
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Does the set HT control work? If so, I'd unload the PSU and see what the HT voltage is. If it's around 95v or a tad more, load it with a lamp and see if it likes that. That way you'll know if the line stage is loading the PSU or the PSU itself is faulty.
Maarten will be able to tell you whether that LOPT is the correct one.
The B-E 'short' is due to it being across the secondary of the driver transformer. Unlikely it just half works!
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Old 13th Apr 2020, 1:27 am   #40
Tvnoob007
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Default Re: CP90 PYE 15” TV, no power led or picture. Buzzing sound

Quote:
Originally Posted by Maarten View Post
That decodes to 36923 (last digit is a minor revision and usually doesn't matter, if 36923 is not found look for 36921) and commercial type number AT2079/10. If those numbers point to the same replacement, by all means go for it. Otherwise 36923 is theoretically the most important number.

V8825 is the date code, meaning it was manufactured in the Volt facility in the Netherlands in week 25 of 1988. The set itself is likely a few weeks newer and made in Monza.
been sent a Philips 36925. has hr7503 scribbled on the box. someone on FB suggested it might be wrong and that's why my channel led isn't working also. as hes suggested that low voltage might be off a winding in the lopt.
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