Sinclair mtv1

[jr_tech]

I don't see how PIN switching diodes can be used as varactor (or varicap) diodes ... a real head scratcher... I assume MPN3404 is indeed the correct number for the diodes that you found

jr

[timmy]

Originally Posted by jr_tech

I don't see how PIN switching diodes can be used as varactor (or varicap) diodes ... a real head scratcher... I assume MPN3404 is indeed the correct number for the diodes that you found

jr

Well all I can hope for is get the rest out and test and maybe find a bad one. Any clues why this tuner stopped oscillating. I don't think the IF- video board would have anything to do with the tuner oscillator, well I hope not as I don't have another. There is nothing more I can check on the tuner board relating to changing the battery's.

[jr_tech]

You have certainly gone where I have not gone before. Could you perhaps post a pix of the inside of the tuner box? I have not had the guts to take one apart yet.

jr

Question: Are you working on the UHF tuner module box or the VHF tuner (under the low shield cover).

[timmy]

Originally Posted by jr_tech

You have certainly gone where I have not gone before. Could you perhaps post a pix of the inside of the tuner box? I have not had the guts to take one apart yet.

jr

Question: Are you working on the UHF tuner module box or the VHF tuner (under the low shield cover).

Yes I was working on the vhf the short box and yes it's like brain surgery I would not recommend anyone do this. I hooked up a DVD player and got a picture and was able to see what it was so while I had the chance I used a very thin flat screw driver to adjust the focus, and attempted to lower the line amp because of horiz lines and it turned out that where the pot is , is almost impossible to get between without touching the other and the worst happened as careful as I was it touched the other pot next to the line amp pot and the pic flickered and now I have bearly and brightness, I can see the pic but with the light off. So this project is probably going on the shelf and maybe if I find another I could use this for parts. Well live and learn I'll know better with another one.

[jr_tech]

Ouch! sorry to hear.
These sets are a real pain in the rump to work on, and apparently somewhat fragile.
Is the -45 volt supply still working ok?

jr

[timmy]

Originally Posted by jr_tech

Ouch! sorry to hear.
These sets are a real pain in the rump to work on, and apparently somewhat fragile.
Is the -45 volt supply still working ok?

jr

As a result of me trying to be careful the 45v supply is now down to 26v .