Binatone Monovison 01/9909

[Richard_FM]

My latest addition to my collection was from someone who was clearing out his Dad's house & selling off the things he didn't need but had some value.

When I picked it up I was given a quick test of the usual screen of snow but it wasn't until I got home that I could give it the usual shakedown.

I connnected it to my modulator & powered up, after tuning to the right channel I could get some decent sound but not much of a picture, but I could tell from the patterns that the horizontal hold was out of alignment.

After a minute or so of turning I got something approaching a meaningful picture, & a quarter of a turn gave me a fairly clear image.

I adjusted the brightness & contrast to improve things, & a quick check with tbe Transdiffusion Start Ups Volume 2 DVD helped with getting the settings even better.

Considering this would have been a bottom end set when new electronically it's working well, with no obvious problems apart from the pots needing a little cleaning.

Cosmetically it needs some work, with marks on the top of the case, which has yellowed slightly. Two of the knobs have lost their centre discs, the power / volume should have a red one. Some of the raised lettering needs some white paint, & it's Solid State badge has been lost.

I would have guessed it was from late 1970s by the style, but one of the sites with service data says it's from 1983.

[Richard_FM]

Just a little update:

I've given the set a "creative soak test" watching The League Of Gentlemen (not the Royston Vasey one!) on it.

It performed well, & I managed to get the brightness & contrast fine tuned.

I've found the test cards I have on DVD don't have enough dark on dark segments, I get a set of display a card just fine, but when I've watching something with a lot of shadows they all look like silhouettes & I have to adjust the settings to make them look right.

I have the case a wipe down with anti bacterial spray, which I find is good for removing grubby stains, & doesn't leave any residue.

[hamid_1]

Originally Posted by Richard_FM

I've found the test cards I have on DVD don't have enough dark on dark segments, I get a set of display a card just fine, but when I've watching something with a lot of shadows they all look like silhouettes & I have to adjust the settings to make them look right.

That's probably because the TV does not have a black level clamp circuit. The black level will vary with the average brightness of the picture. On dark scenes, black will go grey. It's very noticeable in advert breaks or when a scene changes, the picture does not go completely black. On bright outdoor scenes, some of the grey areas will go too dark. This can force you to turn the brightness up, which only makes things worse when the next dark scene occurs. Thus the brightness and contrast settings will have to be something of a compromise.

Colour TVs always had black level clamp circuitry, otherwise the effect would be too noticeable in colour. However, most of the TV manufacturers did not bother adding a black level clamp to their monochrome sets. Philips were a notable exception. If you have a Philips-made monochrome TV from this era, put it side by side with the Binatone while viewing the same programme. You'll notice the difference.

It is possible to add a DC restorer / black level clamp circuit, using only a few additional components. There was an article about this in Television magazine many years ago - I'm sure it's been posted here. A search should find it.

[AJSmith625]

Just adding to what Hamid 1 said, except for the Bush/Murphy A640 chassis and the Philips 210/300 mono sets I cannot remember any other UK mono TV having black level clamp/DC restoration. Certainly no mono portables had it as far as I know. When colour arrived it was a necessary feature. For any one who has fitted one of those LEDco replacement solid state CDA panels into a PYE 693/697 colour set you soon noticed the difference. A night time scene with a grey overall background, but with bright colours showing eg- a red London bus just did not look right.

Alan

[Richard_FM]

Thanks for letting me know about black clamps, I sometimes notice the same with my Pye which uses a Philips TX chassis.

Why did the late mono sets have no black clamp, easy enough to do.

[kan_turk]

Originally Posted by merlinmaxwell

Why did the late mono sets have no black clamp, easy enough to do.

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