Which TV for RGB scart?

[3CX15000A7]

Hello all,

I am working on a retro setup, including a nice 90s (or late 80s) CRT TV. I always loved the picture of a good CRT, especially with RGB sources like retro games and DVD's. When I was younger we always had philips sets. I also own a old Philips CRT (the 21PT350/Anubis B) with has a very very lovely picture quality. So my prefference would to go with a Philips, but something a little larger, like 25" or 28." It should be 50HZ, I do not like the digital 100HZ picture, espcially with gaming.

When I search in my region, I can find (with some patient) regulary the following chassis/TV's that fits the discription:

GR2.1
GR2.2
CP110
AA5
MD1.X
A8
And a lot of later L series (L6,L9,L01)

Are there people with expierence on those sets? Which one give the best picture? Or are there types to avoid? Some that are really service friendly or not?

I'm also intersted in (old) electronics and I have some skills on this. I know the basic working principles of a CRT TV, the dangers and I did some small repairs in the past. So buying a TV that need some revision (for example changing capacitors) won't be a big deal.

[Welsh Anorak]

Personally, I'd avoid the CP110 as it's old and was never that reliable. Other than that, the main thing to worry about is the CRT. The ones with ESF in the middle of the type number are likely to be faulty. These are mainly widescreen sets, though all 29" and some 25" square screens have then fitted.
Of course, you're probably not going to be able to open the TV, so just look for one that has a bright sharp display that comes on quickly with no colour cast. Capacitors, apart from a few well known ones, aren't too much of a problem in these sets. Dry joints are, but that shouldn't be a problem. Some Matchline sets are very complicated and might be a bit more than you need.
I'm sure Maarten will give you his opinion which I'd listen to!

[ben]

Most of those are post-1990 sets and should be quite reliable. At least the A10E isn't on the list Or the G110 for that matter (shudder).

I personally have had generally favourable experiences with the CP110, the oldest chassis on your list. Generally a very good picture. There were a few common faults: couple of caps on the PSU secondary side which gave a slow warmup on the picture, the NiCad battery for the tuner and picture settings would leak, a transistor on the CRT panel which gave a flashing pic (had one with a faulty PTC that caused it to hiccup also!) but the line, frame and power stages I had few problems with (I once had to fit a PSU kit, which was a simple fix, to one set). Never had a bad line o/p transformer. But I bow to Glyn's vast experience on this one. These sets were once absolutely everywhere, but they will now have age related problems. Worth picking up only if free or cheap.

Incidentally, the CP90 had front mounted AV input (composite) but the more expensive 110º CP110 did not - go figure that one out.

[Welsh Anorak]

Vast experience? Hmmm...
However there were a few problems on the CP110 which resulted in the PSU blowing up. Eventually there were two service kits available, but the main culprit was the transformer itself. It was of an odd foil construction, and if you squeezed it gently after a repair and the picture size changed then it was likely to have caused the failure, and they weren't cheap, especially when added to the cost of the service kits. My main worry about the CP110 is the NiCad battery which will probably have leaked and damaged the board, even if it's been replaced in the past. At least the G110 didn't have that problem (however...)
Ah - the A10. A really reliable set let down by just one item, if you discount the CRT.

[Radio Wrangler]

Had a Panasonic TX25W3 in the early 90s. Good picture, great sound and rather comprehensive inputs including RGB SCART.

In 13 years the NICAM chip failed, shorting PSU, and the LOPT soldering needed redoing.

David

[John123]

I agree, a stereo 'monitor style' Panasonic FST would be worth considering. I recall they often had Philips tubes in them anyway, probably due to their joint-venture in the nineties.

If you're after a bit of flair, a Bang & Olufsen might also be worth considering..

[3CX15000A7]

@ Welsh

On some sets, the tube type is noted on the back:

For example:

25pt5304 with an A59EAK662X11
28pt5301 with an A66EAK552X11

Both are non widescreen sets

These (tubes) should be fine? If I search, EAK tubes should be very reliable and.

The A10e, G110 and also the older Panasonic sets aren't that common. There's a lot of newer (00's) Panasonics sets altough . .

[Philips210]

Hi.

My own experience of the CP110 chassis is a good one. In the 1990s, I repaired a number of Philips sets with that chassis and also the 90 degree CP90 and found them to be very reliable. The main problems were the 2.4V NiCad memory back up battery, occasional problems with the Toshiba microcontroller IC and dry joints in the SMPS and line output stages. The LOPT in the CP110 is ultra reliable but strangely the CP90's LOPT isn't so good.

My bedroom set is a 24" CP110 that has given next to no problems since new in 1989 and the 45AX CRT is still good and the auto grey scale system works well. It gets about an hours use each day so not at all bad for a set that's now 30 years old.

Regards,
Symon

[Philips210]

Originally Posted by Welsh Anorak

Ah - the A10. A really reliable set let down by just one item, if you discount the CRT.

Would that be the infamous Painter IC?

Regards,
Symon

[ben]

Originally Posted by Philips210

Hi.

. The main problems were the 2.4V NiCad memory back up battery, occasional problems with the Toshiba microcontroller IC and dry joints in the SMPS and line output stages. The LOPT in the CP110 is ultra reliable but strangely the CP90's LOPT isn't so good.

Agree. You have reminded me of a problem I once had, the uPc tended to get affected by static discharge and the fix was to add an shielding plate with a wire link to chassis. The symptoms I had were nonfunctional front panel buttons and perhaps some other things. That was always on the 90º sets though.

I also replaced several 90º LOPTX, the grey philips type that were similar to the one used in the GR1X portable. Very unreliable but the Diemen replacements outlived thr sets!

[ben]

Originally Posted by Philips210

Would that be the infamous Painter IC?

Regards,
Symon

What with that and the tube...what a lemon, but the sad thing was they had a great picture when they worked.

[Philips210]

Originally Posted by ben

the uPc tended to get affected by static discharge and the fix was to add an shielding plate with a wire link to chassis.

Hi.

Yes, the tin plate screen stuck to the microcontroller with a wire soldered to this and to the chassis. I recall it was important to replace the microcontroller with the correct suffix. From memory the software code for the uc, 8188 for TXT sets and 8189 for Fastext sets. Either type could be fitted to remote only sets.

One other thing I remember about the CP90 was a slight background buzz on some sets. There was a small PCB with a revised ceramic filter supplied by Philips that solved the problem. I can't recall if the CP110 suffered this problem.

Regards,
Symon.

[3CX15000A7]

Originally Posted by 3CX15000A7

@ Welsh

On some sets, the tube type is noted on the back:

For example:

25pt5304 with an A59EAK662X11
28pt5301 with an A66EAK552X11

Both are non widescreen sets

These (tubes) should be fine? If I search, EAK tubes should be very reliable and.

The A10e, G110 and also the older Panasonic sets aren't that common. There's a lot of newer (00's) Panasonics sets altough . .

I just bought yesterday the two sets I mentioned above. They aren't expensive and than I have something to compare.

The 25PT5304(A8) has far the best picture so far. Over RGB it is very clean and vivid colors. The tube is excellent, sharp (also on the sides) and bright.

The 28PT5301(MD1) has a little better RGB/Video bandwidth when using test patterns, but it seems the tube is a week. The edges are a bit unsharp and
the color balance is not perfect. Dark grey tones are lending to blue and bright white (snow) is yellowish Also there's some "smearing," especially on dark tones. I will upload some photo's later. Maybe I can tweak it a little better with the LOPT potentiometers/white balance . .

[Maarten]

I think the A8 is quite a reasonable choice as it is reliable. Also, 59cm tubes are often a bit better since they give the same brightness with a little bit lower beam current.

The best chassis would probably be the GFL, even if it's 100Hz. It was used in some large screen VGA monitors as well. Unfortunately it was used with some of the worst lasting tubes. Maybe it's predecessors from the FL series (also some 50Hz versions) would be a good compromise.

I would have a more detailed opinion but I don't know about the respective RGB bandwidths. I'd have a look at the GR and MD chassis as well, but not rule out the later L chassis (L6 probably not, maybe L7, L9, L01).

Also, 25" (59cm visible) and 28" (66cm visible) 4:3 are the most reliable tube sizes. Any 29" (68cm) 4:3 tube and most 16:9 tubes are of the ESF variety. Very sharp beam, but often don't last.

[Welsh Anorak]

Sorry to be a bit OT, but to complete post #12, the suffix -88 was standard text, -89 was fastext and -87 was for the curious CP90 NRC, which was commissioned by rental companies for customers who weren't allowed a remote control TV. They had 12 push buttons and rotary analogue controls on the front. There were also auxiliary input sockets with a front panel E1-E2-TV rotary switch to select these. I'd like to say I wish I had a pound for every customer who'd lost their signals because someone has turned it by mistake, but I probably had considerably more!
Back to the 66cm TV mentioned, I'd check the A1 setting on the LOPT, then leave it for a good soak test. As you say, the EAKs were good CRTs and it might wake up if the TV's been standing.

[3CX15000A7]

Originally Posted by Welsh Anorak

Sorry to be a bit OT, but to complete post #12, the suffix -88 was standard text, -89 was fastext and -87 was for the curious CP90 NRC, which was commissioned by rental companies for customers who weren't allowed a remote control TV. They had 12 push buttons and rotary analogue controls on the front. There were also auxiliary input sockets with a front panel E1-E2-TV rotary switch to select these. I'd like to say I wish I had a pound for every customer who'd lost their signals because someone has turned it by mistake, but I probably had considerably more!
Back to the 66cm TV mentioned, I'd check the A1 setting on the LOPT, then leave it for a good soak test. As you say, the EAKs were good CRTs and it might wake up if the TV's been standing.

I have used the TV a few days and tweaked a little. With the Focus on the LOPT I improved the sharpness a little around the edges. Also lowering the contrast helps. I am still impressed how much light an old CRT produces! I have to admit, the very high contrast was one of the reasons I preferred CRT over LCD for years. As main TV I now have an OLED (with is technically superior to these old CRT's) but still, the picture of these old sets impress me . .

But back to the 66 MD1. After adjusting the focus, I tweaked the white balance in the service menu (off course I noted the original values), so the blue tint on white is fixed.

One thing I can't fix with adjusting is the "smearing" and the blue tint on dark grey. Is this typically behavior of a worn tube? A theory: the blue gun is weak, and the automatic cut-off pushes the blue gun to get decent response but the linearity gets off -> Dark grey is too blue and white is still to yellow. A compromise . .

I tried to adjust the VG2, but this did not help for these problems. Clockwise turns makes the picture blue with lines, counter clockwise makes the picture more "dull" but sharper on the edges . . . I have to admin, I do not fully understand the principle behind the VG2 yet. I need to get my scope to adjust is correctly according to the service manual. For now, I adjusted it just so there are no lines visable.

Is there something I can look for on the RGB amplifier panel/Small signal board? Capacitors? Some fault in the cut-off feedback? I have to dig in the schematics.

I added some photo's (first is the A8, then two of the MD1)

@Maarten,
Maybe it's not the "most reliable" set I am looking for. It's also the fun of getting these old things alive/adjusting/tweaking/comparing. If a set gives really nice picture I will keep it. As long there are no common big problems as failing tubes or LOPT's that are rare. Those sets I will avoid where possible . . .

[ben]

Originally Posted by 3CX15000A7

Is there something I can look for on the RGB amplifier panel/Small signal board? Capacitors? Some fault in the cut-off feedback? I have to dig in the schematics.

Change the cap in the supply to the RGB stage. Typically a low value (22uf or less) rated 160v or more. That may reduce or remove the smearing and improve the consistency of the black level across the width of the screen.

[ntscuser]

I've used a 25" Philips GR2.1 (25ST1724) for many years in an all-RGB setup.

Slight drawbacks: the geometry needs adjusting fo best RGB results (internal presets).

Only one RGB-capable Scart input.

No 16:9 input of any kind (which one friend point-blank refused to believe).

[Maarten]

(later?) GR2 sets have the aspect ratio button on the remote for anamorph signals; your friend must have thought of that. What does your set do when you input 16:9 signals?

[ntscuser]

Hi Maarten, if it's anamorphic it displays a badly distorted picture. DVD players can of course be set to display a letterboxed picture but much of the screen area is wasted.

Some UK Freeview boxes can zoom a 16:9 picture to fill the 4:3 screen, others will force a letterboxed display. It varies from make to make and from one broadcaster to another.