blue flashes on roundie - Videokarma.org TV - Video

DaveWM · #1 06-04-2010, 08:39 PM

this is the late model last of the roundies a philc ford hybrid.

I finally got it off of the bench and put the legs back on it (metal cabinet, screw on legs).

the pic is good but I get flashes of blue some times a lot of the screen some times just a few lines.

I am guessing a flaking out tube in the color circuits, I will check the blue driver, thinking a shorting tube?

Or maybe I just need to let it play for a while and see if it settles down, I had it on for about an hour, did not seem to change.

ctc17 · #2 06-04-2010, 09:15 PM

noisy flaky drive or screen pot, flaky drive tube or socket or crt.

move the pots and tube around and tap on the neck of the crt.

DaveWM · #3 06-04-2010, 10:17 PM

I will give all those a shot tomorrrow am.

I hope its not anything wrong with the CRT (like a shorting grid).

freakaftr8 · #4 06-05-2010, 12:25 AM

second that alond with Ctc17. I have a CTC-17 that did that with green. Mine turned out to be a bad ground on the B/Y amp area. Check grounds and solder connections on the B and Y amp tube sockets along with those screen pots.

fujifrontier · #5 06-05-2010, 09:15 PM

I have a philco ford roundie that will display snow but blacks out when you apply a signal. any guesses?

DaveWM · #6 06-05-2010, 09:28 PM

BY amp had a loose resistor, tapping the tube would cause a flash then I noticed a 47 ohm resistor that was floppy on the PCB right next to that same tube. My bad, I am pretty sure I had desoldered it while checking it out (it was in circuit P with other stuff IIRC). Any way I am sure thats it, I will pull the chassis tomorrow and correct.

Vert was also a bit jumpy, 6lu8 tube was changed, no help, but a 1 watt resistor that is right next to that tube would settle it down when hit wit some cool juice. It will get replace while I have the chassis out.

I am looking forward to getting it worked out cause it has a very nice picture. Cateract free (has the separate saftey glass lens not bonded to the tube)

I cleaned up all the tar and nicotine that was ALL over it. really gross, mixed it with dust made for big chunks of black goo as well as the brown junk everywhere. It clean up very nice.

I got some plastic and fabbed up a door (missing) over the controls. It even has the same kind of finish. I dont know how the orig stayed up and down I cant see any catches,spring mounts or overcenter type pivots. I was thinking of using some small magnets but its very close to the screen.

Maybe the pivot points were tilted in such a way as to operate over center.

I will mess with it and see.

ctc17 · #7 06-06-2010, 03:53 AM

Quote:

Originally Posted by fujifrontier

I have a philco ford roundie that will display snow but blacks out when you apply a signal. any guesses?

Check the AGC, Check the AGC pot for shorts to ground internally. Tin whiskers grow from the case to the leads and short

jeyurkon · #8 06-06-2010, 01:16 PM

Quote:

Originally Posted by ctc17

Check the AGC, Check the AGC pot for shorts to ground internally. Tin whiskers grow from the case to the leads and short

Those whiskers have always amazed me! They can get really long. I'd love to understand how they grow.

colorfixer · #9 06-06-2010, 04:52 PM

Tin whiskers are going to be the achelles heel of "Lead Free" electronics:

http://nepp.nasa.gov/whisker/

DaveWM · #10 06-06-2010, 06:15 PM

soldered that loose resistor back and replaced a 68k 1 watt resistor in the vert circuit. No more flashes of blue and no more jumpy vert

I am letting the chassis cool down and will then button it up for I hope a long time. Its got a very nice picture, I am looking forward to getting some time on it.