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  #31  
Old 07-02-2007, 09:03 AM
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Originally Posted by tritwi View Post
Il numero di chi???
Your number, mister!
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  #32  
Old 07-02-2007, 02:57 PM
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For Gianni

347/3585521
There you are! You can call now!
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  #33  
Old 07-16-2007, 03:05 PM
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Update...

Hello everybody! After a lot of work and even more study at the schematic diagram (which was really not easy...) I finally discovered what the problem was with my Zenith "pal modified" 24MC32,model 5304U (The Buchanan). I changed the cristal quartz (4,43Mc) and the odd colors left finally place to more normal colors. I then grounded pin 2 of the 4,43Mc and then I tuned the reactance coil for steady color bars. The results were amazing especially thinking it is a tv more than forty years old! Ok, there are more things to fix, the focus control must be set fully counterclockwise to get a decent picture, there are few retrace lines on top of picture and the hue control must be set to its position were you normally get pink colors to achieve normal flesh tones.
Here are few pictures of the set...
I must admit I'm really happy!
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File Type: jpg DSC00109.JPG (57.7 KB, 74 views)
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  #34  
Old 07-16-2007, 04:02 PM
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Awrite, Tritwi !! Lookin' GOOD !
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  #35  
Old 07-16-2007, 04:55 PM
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Way to go!
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  #36  
Old 07-17-2007, 02:48 AM
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Quote:
Originally Posted by tritwi View Post
Hello everybody! After a lot of work and even more study at the schematic diagram (which was really not easy...) I finally discovered what the problem was with my Zenith "pal modified" 24MC32,model 5304U (The Buchanan). I changed the cristal quartz (4,43Mc) and the odd colors left finally place to more normal colors. I then grounded pin 2 of the 4,43Mc and then I tuned the reactance coil for steady color bars. The results were amazing especially thinking it is a tv more than forty years old! Ok, there are more things to fix, the focus control must be set fully counterclockwise to get a decent picture, there are few retrace lines on top of picture and the hue control must be set to its position were you normally get pink colors to achieve normal flesh tones.
Here are few pictures of the set...
I must admit I'm really happy!
I am happy too!
Is there a PAL delay? There is a hue control, i see.
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  #37  
Old 07-17-2007, 06:33 AM
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There is a coil that will allow you to adjust the hue range. Set the hue control to mid position and adjust the coil for natural flesh tones. The location of the coil should be identified on the schematic. That's a great picture by the way. That's a lot like the way mine looks. I love the deep reds these sets produce.
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  #38  
Old 07-17-2007, 07:26 AM
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Hue control

Hi Gianni, the set has a tint control (useless with our Pal system) but no chroma delay line. Hello compucat, thank you for your advice! Do you remember what the coil you mention is? The flesh tone is achieved only with the control fully counterclockwise. Turning it even just slightly makes flesh tones go completely off (blue skin tones). I think I also need to replace few tubes here and there... You're right. The reds are deep,really amazing!
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  #39  
Old 07-17-2007, 04:42 PM
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Interestingly, this set has no PVA cataracts...

Francesco
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  #40  
Old 07-18-2007, 11:56 AM
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Some of those tubes do not use PVA but instead have the safety glass seperate with a rubber gasket. I have a couple like that, including a 25MC30 Zenith, but have not had them apart to see just how it fits. It may have only been done on the standard models; maybe the anti-glare tubes were bonded?
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  #41  
Old 07-18-2007, 12:10 PM
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Quote:
Originally Posted by tritwi View Post
Hi Gianni, the set has a tint control (useless with our Pal system) but no chroma delay line.
I believe this set is fitted with simple PAL circuits. Simple PAL has no delay line but a tint (or hue) control.

- Eckhard
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  #42  
Old 07-18-2007, 07:16 PM
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Quote:
Originally Posted by bgadow View Post
Some of those tubes do not use PVA but instead have the safety glass seperate with a rubber gasket. I have a couple like that, including a 25MC30 Zenith, but have not had them apart to see just how it fits. It may have only been done on the standard models; maybe the anti-glare tubes were bonded?
I'm wondering why American CRTs used separate or PVA bonded safety glass lenses until the late 60s, while most European sets made after 1964 had CRTs with the modern "tensioned rimband" type of integral implosion protection and did away with any kind of safety glass in front of the actual CRT's face...

Maybe the separate or bonded safety glass was a legal requirement in the US back then?

Francesco
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  #43  
Old 07-18-2007, 07:58 PM
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Think you're right, Francesco. Also dimly remember a health scare going on in the mid-60s about X-rays from color TVs...There was a big yah-yah about it, the "consumer" movement was in its infancy then...
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  #44  
Old 07-18-2007, 09:47 PM
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I don't think there was any particular requirement for safety glass vs. rimband - the tube or tube/faceplate combination just had to meet certain limits on impact strength and dispersion of glass when imploded, I think. It's possible European color tube factories went to rimband directly when first opened, while the U.S. factories had to be adapted to the process.
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  #45  
Old 07-19-2007, 05:31 AM
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Quote:
Originally Posted by yagosaga View Post
I believe this set is fitted with simple PAL circuits. Simple PAL has no delay line but a tint (or hue) control.

- Eckhard
Yes.

Somebody, in this forum, affirmed there are no simple PAL TVs from industrial factorys ( not from craftsmen ), apart from Kuba and Telefunken sets with 11SP22 cathode ray tube.

Actually, according to Argeo Deotto, simple PAL was a flop, then following TVs adopted PAL delay; therefore there ARE some simple PAL TVs and Marco's set proveS that.

According to Marco, his PAL Portacolor makes some Hannover bars, more visible on yellow images; but we see two good rasters from his "new" PAL-Zenith, without Hannover bars, only some retrace lineS on the raster from "Cultura moderna" broadcast ( not the young lady ); therefore, supposing both the TVs are connected to the same aerial, pheraps the little one needs some adjustements ( synchro demodulators? ).
I have the schematic and some instructions for the technicians, with regard to the "Telecolor" ( a Telefunken simple PAL TV, pheraps made in Milan, with some writings meaning: "Volume", "Luminosità", "Colore", "1/2" on the VHF/UHF switch knob and Italian VHF channels "A,B,C,D...", and having 11SP22 cathode ray tube; in my opinion it is possible that it resembles Marco's simple PAL Portacolor )

Quote:
Originally Posted by Sandy G View Post
Think you're right, Francesco. Also dimly remember a health scare going on in the mid-60s about X-rays from color TVs...There was a big yah-yah about it, the "consumer" movement was in its infancy then...
1) Yes, in a lot of Italian TVs from 50s there is a safety-glass who increaseS the contrast too; even in some European sets from 70s there is a similar device, a "plastic glass", almost black (!)
My parents had one of these TVs until 1982 ( a Siemens hybrid TV, with push - buttons tuning and four slider potentiometers, one of them for tone adjustement; now it appears only in a lot of photos).

2) ...Is there in English any neologism as "consumIST" or sIMILAR?
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Last edited by Gianni; 07-19-2007 at 07:26 AM. Reason: When i find out some HOrrors in my messages, i correct them using CAPITAL TYPES, in order to make every future search...>>>>>
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