My 1st Predicta

[DaveWM]

I will check them out, thanks Andy.

I may just plug in the CRT and use a .002 for the time being on the vert plate cap. I can at least see if I get a raster, and know the fly is ok.

runing out of time though since the hamfest is today so may not get to it tonight.

The cabinet is red and looks pretty good, but the inside is covered in surface rust, the outside has one or two spots of rust (not bad just enough to mess up the paint), overall the paint looks very nice.

So If I get it running I will have to decide if I want to keep the orig paint or get it stripped, get rid of the surface rust on the inside, and then repained.

The bright work is the same not bad not pefect. I will get some pics later.

Not that I am trying to make this thing an investment, but I dont want to do something dumb like refinish it if that is big mistake. any comments on this please. For me if I get it working I would like it to be finished so it would look the way it did when new.

[DaveWM]

we got HV, we got raster, we got intermittant damper tube socket and intermentant vert osc tube socket.

At least I know the fly is working, 17kv on the anode

I just laid the crt on the side and hooked it up.

I am hoping its just loose pin contacts, when I tested the resistance I did it with the tube out so its possible they are just not quite touching the pins with the tube in.

Breaking out the pick for some more work. I hope the damper tube socket is not covered, I know the HOT is but not sure if the damper was.

[DaveWM]

checked the tube socket solder reflowed but it looked ok before, same deal, I think the problem maybe some other part that is being affected by the movement of the tube (it takes quite a bit of force to get it to work) causing the pcb to flex. I will turn the brightness all the way down and get a wood chop stick to it and see if I can prob some other parts on the board to find the problem. Damper seems ok now that I have tightned up the filament pin sockets.

[Charlie]

Dave, I remember having the same problem with my damper tube socket. In fact, i don't think I ever fixed it.... just wedged an empty tube box between the damper and the HV cage. I remember getting fed up with it and finally said screw it! It's been a while since last time I turned mine on... but I remember that was the deal... make sure the empty tube box was wedged in there just right to make it play. Once that's done, it plays really nice.

[DaveWM]

found it, the vert tube socket had a micro fracture at the pin socket, I tested ok for resistance since I would touch the prob to the pin socket, which in turn pushed it down and closed the fracture. With the tube installed the push was gone and the fracture would open up.

I found it by using my tube test socket, and cliipping on to the test point rather than pushing it with the prob, bingo it opens right up.

I think I have a pcb mount 9 pin mini AND this is an easy to get at one, so I plan to just remove the socket. I tried to bridge over the fractrue, I may try that again I just have to get a small file in there to clean the metal so the solder will stick. the damper seems ok for now.

I am not sure if its a socket or pcb issue with the damper, I will play with it some more, but like Charlie says I may just move it to the sweet spot and be done with it.

I need to check the HOT current next to see how that is doing.

I have a buddy that does vacuum forming I may get him to mold up a new cover for the CRT, mine is ok but I would like a crystal clear one it I get this working right.

[DaveWM]

well there were two fractured pins, looks like a design flaw in the socket there is a stress riser right at joint from the pin socket to the down leg that is soldered to the board. I am sure I will replace this now rather than just tacking on a quick fix since even if I did get it working there is a good chance of another fracture. Charlie the damper is acting up again....

[DaveWM]

I think I have a technique the fix the fractured pin joints. Good thing to since after fixing two on the vert osc, another on its filament opened up. I will keep at it regardless, I would like to see how durable my fix is, before resorting to socket replacement. Dog gone damper is still fighting me. I tried tightening up the pins again, I will see if I can inspect the bottom.

[DaveWM]

Good thing I checked the HOT K current, 200ma, range should be 100-140.

I adj the screen voltage to get the current down to 110ma, of course I lost some HV and screen brightness but better that than the fly.

My guess is the higher line voltage translates into more voltage at the B+ (duh I did not check that yet) in which case the screen dropping resistor in series with the screen pot (width) is simply too low a value, that is I would think that if the pot was set to zero thee dropping resistor would set the max at no more than say 160v. Of course perhaps the idea is this is supposed to be set at the factory and hopefully the owner would not mess with it (but it is exposed at the back).

Well 1st things 1st, I will go back and check that B+ if its high I may up the resistance of the fusistor to try and compensate for the higher line voltage, then go back and check that screen/K current.

[Charlie]

On the damper... is the bad connection in the socket or the pcb trace itself? Perhaps you follow the trace to the previous point, solder a wire there, then run the other end to the bottom of the socket of the damper.

[DaveWM]

Thats what I did Charlie, it was the trace for the ground pin (looks like someone had already done it for the 6v trace). I was able to get some wire in there and follow the trace with a bent up solder gun tip.

I think I got it licked, going to see if I can get it to go out now by wiggling.

[DaveWM]

progress...

1st screen shot off tuner input.

still a long way to go, Pretty sure it needs some new tuner/IF tubes, maybe a video amp tube.

[Charlie]

Awesome!

Looks like that CRT has some good life to it!

[DaveWM]

Cleaned the tuner, much better contrast now, better sync lock, volume is still a bit lower than expected, but I have not tried a new preamp tube.

has this odd whitesh line in the vert, I can tune it out, but at the expense of not as sharp a pic. IIRC an earlier poster said this may be a part of the color signal.

I have not yet hooked up the IF sweep gen to take a look at the band pass. I will prob do that just to see what it looks like.

that darn damper is acting up again, Geez I see what you mean Charlie, it's a real PITA...

[DaveWM]

think I finally really really got the damper figured out, I could not understand why it was still not grounding even with the wire along the track, then I realized the stake that pops up though the pcb and is then bent over and soldered to the stake that is part fo the chassis was moving, the joint was not solid. I cleaned it up fluxed and got out big beartha to resolder that stake. Now I cant wiggle the damper off no matter what, whew, that was getting to be a pita.

there is a lot of little tricks on these predicta's...

[Charlie]

Are you using the coxial connection straight from an old VCR/DVD combo? Or does your source go thru a seperate 20 dollar RF modulator?