Boots MTV5 & crosshatch generator

[djrm]

    Today Ive been sorting stuff out and tried this portable TV with my old crosshatch generator. At first I didnt get a signal and it took a while to find the battery snap had failed open circuit where it is rivited together.

Ive never used the TV on anything bu an old TV tennis game which I bought it with some time ago.

I cant now remember making it but it looks as if I made the PCB myself, on the bottom it has my name and 'ETI crosshatch 1978' drawn into the ground plane.

I tried the generator on another portable colour TV but I couldnt get the sync to lock, I suspected it was overloading but it now looks as if the clock frequency is a bit off, there is supposed to be a timing adjustment potentiometer but its missing and replaced with a fixed resistor, so I'll try adding one.

David

[peter scott]

David, You have induced me to bring mine down from the loft too. Note the thick layer of dust on the top of it but it still works without intervention after lying dormant for 30 years.

I built mine in the clam shell case of a Hewlett-Packard 5300 counter. I had even put copies of my schematics in the case although I took them out for the photo.

       

Peter  

[ppppenguin]

Peter, I wonder if some of the parts for your crosshatch came from the spares box at HP

I built my crosshatch generator c1974, when I first got an ex-rental colour TV. I think the design was in either WW or PTV and was even simpler than either David's or Peter's. It took H and V sync from the TV and gave a video output which I injected into the TV. Cobbled together on a bit of Veroboard. All very easy with a Thorn 2000. Power was probably a 4.5V battery.

My 2nd crosshatch generator was a lot more sophisticated. I was working at BBC Research Labs, between school and uni. Somebody had replicated a Labgear crosshatch and colour bar generator PCB and had a batch made in the PCB shop. I acquired one and built it up. Used a TBA520(?) as the modulator. I think I still have it, including the nice white painted case that was put through the BBC workshops as an unofficial job. Known as a "home office job" at the time.

Other "home office" projects of that time include a TV line selector (based on a PTV design) and an EHT probe. I still have both in regular use.

[peter scott]

Peter, I wonder if some of the parts for your crosshatch came from the spares box at HP

I confess that everything you see in the photo came from HP labstock except the case that was being scrapped from a development that didn't get to production.

My design was just basic TTL. Nothing clever.

Peter