my newest project - Videokarma.org TV - Video

radotvguy · #1 03-11-2009, 05:31 AM

Here is my newest project . A rca kca72a . Sams 184. Looks to be a real top of the line black and white tv . I replaced all wax caps, elemenco caps , bumble bee caps and electrolytics . Close to 50 caps have been replaced . It was a job . It has no high voltage still . I even replaced the damper tube, rectifier tube and horz output tube . Still dead with no high voltage or nothing on screen , just sound . So i am just poking around checking all resisters in horz , high voltage section and i hope its just something silly like a open or way off value resister . The flyback looks ok , no melting or cracking on it . The crt in this tv was replaced in 1955 with a 21ap4. It came with all receits and owners manuel . The bonus was it even came with the optional 45 player which plugged into the back of the chassis . Pretty nice find for 30 bucks at a house sale .

Ampico-kid · #2 03-11-2009, 12:36 PM

WOW!!!! There's a lot of orange in that set isn't there?? Looks like quite a bit of time went into that recapping job. It should have a great picture when it's done.

Good luck with it!

Bob.

bgadow · #3 03-11-2009, 02:00 PM

How's the horiz osc circuit? A flaky tube has thrown me off a few times.

Tubejunke · #4 03-11-2009, 11:52 PM

Quote:

Originally Posted by radotvguy

Still dead with no high voltage or nothing on screen , just sound .

Are you certain that there is "no high voltage", or just "nothing on the screen?" Not trying to be a smart a**, just making sure that you are on the right path. There is a lot that can cause "nothing on the screen." Most commonly an intermittently open c.r.t. plug. Is the heater in the c.r.t. lit up?

Also a mis-adjusted ion trap would be another common fault, especially in a set that has recently been taken apart. Again, are you sure that there is no high voltage?

Tubejunke · #5 03-12-2009, 12:05 AM

Hey radotvguy, I just noticed that you are the same person in another post asking about a sub for a 21AP4. In that thread you mention having damaged the "bakelite crt socket." Is this the same project that we are talking about in this thread? Are you sure that the damaged plug is working properly and not just cosmetically repaired?

radotvguy · #6 03-12-2009, 06:57 AM

YES i am certain there is no high voltage . The second anode test dead with high voltage probe and usually you can even hear high voltage and there is nothing . THe crt filiment does light up . The whole set has been recapped . All electrolytics, wax and bumble bee caps . The only caps not replaced are the mica caps . The horz output, damper and rectifier tube have been replaced with new ones . The crt has a crack on the side of the bakalite plug but no damage to the tube or electrical connections . Its still on there pretty tight and secure . I tested the crt with the beltron . Its ok , comes up a bit slow but its ok . In one of my other posts i was just curious if there was a sub being a have a bunch of new old stock tubes in my attic that i could use if needed but unfortunatly they dont sub . No big issue the one i have i believe is good but would have loved to use one of these new ones i have being the tubes take up half of my attic and i am cramped for room . Anyhow i began testing some of the resisters and thats where i am at . The horz oss tube and frequency tube are a 6sn7 and test good . I have not tried swapping them out yet with new ones becuase i dont think thats the issue but i might go ahead anyway and try it . Well hoppefully tonight i can dig a little more into this set .

7"estatdef · #7 03-12-2009, 07:45 AM

Don't forget the fuse in the HV by the HO tube.
Terry

radotvguy · #8 03-12-2009, 07:52 AM

checked both fuses there

bgadow · #9 03-12-2009, 11:31 AM

I have a Philco that is real picky when it comes to 6SN7 horiz oscillators. I had to try 3 or 4 before I found one that worked. Do you have any equipment which can inject the horiz osc pulse?

radotvguy · #10 03-12-2009, 12:25 PM

No i dont

roundscreen · #11 03-12-2009, 07:15 PM

Pull the plate cap lead off the horz output tube and connect your volt meter to it. See if you get b + through the flyback. It could be a resistor opened up somewhere or a broken wire somewhere on the fly back.
I have two sets like yours but they don't have the doors on them. The chassis will work good when you get the problems fixed and they have a clear bright picture.
Good luck
Ed

radotvguy · #12 03-19-2009, 12:33 PM

Well after days of checking this over and the help of a friend i got high voltage and a picture . One of my caps i soldered in was the wrong value. Replaced it and got my high voltage up . Next was the picture , it was not that all great . The tuner was definitly dirty . Took that apart and cleaned it . Also found both tuner tubes a bit weak and one IF tube weak . Replaced those and firied it up . Picture comes in and locks in very nice . Have a few more adjustsments to make being the picture is a little smeared but it looks pretty good otherwise . Will post some pictures shortly .

*zenithfan1* · #13 03-19-2009, 11:15 PM

Good job on the recap, I like to see those orange drops. I'm looking forward to the pictures of it up and runnin'.