Pilot tv and retrace lines - Videokarma.org TV - Video

timmy · #1 05-23-2016, 02:34 PM

Is there any retrace mods out there for the pilot tv like the similar retrace mod for the Motorola with the resistor and cap ? I just read a post on antique radios that tom albrecht had posted about a retrace solution for the pilot tv and he wrote to put a 220k resistor in series with the g1 to the crt and also place an 820pf cap from g1 to the verticle output tube. I'm wondering where this cap would go on the vert tube and where would the cap go, befor the 220k or after the 220k towards the crt.

jr_tech · #2 05-23-2016, 08:38 PM

Indeed, on another forum Tom Albrecht said:

Quote:

I tried it on the Pilot TV-37 I have on the bench right now, and I can report that the fix works very well and doesn't seem to have any ill side effects. For my Pilot I found that a larger cap (820 pF) worked better than the 250 pF cited for the Motorola. Also, G1 of the CRT isn't grounded in the Pilot, but is connected to a DC restoration circuit. The modification still works fine (add a 220 K resistor in series with G1 of the CRT and add the cap from G1 to the vertical output tube). I'd recommend this fix to anyone who is irritated by seeing retrace lines whenever the picture contrast is low.

I think that this is the circuit that he is referring to (from Phil Nelsons site)

http://antiqueradio.org/art/Admiral1...ingCircuit.jpg

I would connect the cap to the CRT grid and the other end of the resistor to the dc restorer circuit. Other end of the cap to one of the plates of the vertical output tube.

jr

timmy · #3 05-23-2016, 08:51 PM

Well I'm not sure if he was saying to cut the wire from g1 because the Motorola goes to ground but the pilot goes to v9 DC restoration so that's where I'm getting confuse here. I believe he was referring to the Motorola chassis but then went on to having a pilot he tried it on with a different cap so if it means to cut g1 from v9 well that would make sense I just want to know for sure befor I do it although it probably wouldn't hurt anyway.

tom.j.fla · #4 05-23-2016, 09:59 PM

Put the 220k resistor between the crt g1 and the sync sep.- d.c. restoration tube. The 820pf cap from crt side of 220k resistor and vertical circuit. I would use a cap rated at 1kvdc in that spot. In the Motorola and Admiral sets the cap went to pin 5 of the vertical output tube. You will have to try both plates to find which one gets read of the retrace lines. It has been many years since I did this mod on a small Pilot television. All the best,Tom