Philco Predicta Pedestal
 

Ive always wanted a Philco Predicta pedestal and one popped up at an auction near me last weekend! It's the blonde version which is in great shape. It has the 2.68v CRT and it tests good. Looks like I'll have another Predicta to restore after I finish the Debutante I'm on now...

It took a lot of elbow grease, but I finally got the CRT cover clean and polished. Couldn't stand looking at it the way it was.

Awesome! I electronically restored one - also a rare blonde version and also minty original over last winter and its a real nice player. Resist the temptation to skimp with the capacitors-get all of them before powering up. Then do an evaluation and continue your work from there. As long as the CRT is good and the flyback, you can expect a nice player. These are fun TVs to own and enjoy!!

George

I have an un-restored blonde version setting here too. Mine has the UHF tuner option. I'm not so sure that the blonde is more rare than the mahogany finish. Considering the time these were manufactured I'd of thought the blonde was the more popular finish of that time. :dunno:

I put this set up on the bench and it looks like the last guy added wires everywhere around the main electrolyric. I may need help figuring out which wires go to which section of the main electrolyric. Not sure what happened here...

Wow! Perhaps someone was strapping external caps in parallel with cans, in an effort to troubleshoot...
Very nice looking set. My mom still has a near mint blonde table top Predicta she bought new. I still remember watching The Outer Limits on it when the show originally aired and being quite scared, ha! I restored it for her about 20 years ago, and also restored two other identical sets after that one. They use the same chassis as the pedestal model. If you don't already have a SAMs for the set its well worth picking up.

That cap job is a persuasive argument as to why one should not let children under 5 years of age change caps unsupervised...

Ok,

I've got the electrolytics hooked back up to the original. I fired it up under a variac and I still cannot get the tubes to light. My fusible resistor is in and all of the tubes test good. I even jumped the on/off switch as I know they're often faulty. Of course I've gotta go through all of the resistors and caps as usual, but any thoughts why I'm getting none of the filaments to light?

Series string heaters: if one is open none light...And if anything else in the string such as tube sockets, board traces, solder joints, or wire is bad the same problem will occur.....You basically have to ohm out the whole heater string till you find the open, or voltage test it.

You might reflow the solder connections on all the PC board tube socket terminals. I usually add just a tiny bit of solder while doing this to help the heat to conduct and to bridge any cracks/breaks in the soldering. As mentioned above you should check the entire filament string with a meter, including continuity of the each tube filament too with a little expected resistance there of course.

Page 3 of the SAMS on this shows the filament string detail. Here is a link to the entire 21 page PDF:
http://www.earlytelevision.org/pdf/P...Sams-439-1.pdf

Ok, so I checked continuity through each filament string and couldn't find a problem. Then I got to thinking, the string includes the two tuner tubes, which I left unplugged in the cabinet. I plugged in the tuner and the entire filament string and dial light came on! I didn't get a raster, but no suprise with original electrolytics in. Now I will make a wiring diagram of all connections and begin removal of the board.

This article has a board connection diagram that I made when I restored my Predicta pedestal some years ago:

http://antiqueradio.org/philc12.htm

You're welcome to use it, although I'd still recommend checking to make sure all of the connections are the same and the labels make sense to you.

Regards,

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

I changed out my fusistor and I did get a slight raster only on the far right of the screen. At least the flyback is good!

Thanks Phil, my wiring color layout is exactly the same. That'll save me done time. Here is my unrestored board, ready for me to go through everything.

While I'm waiting on new caps to arrive, I thought it would be a good time to clean the chassis and get all of the sticky goo off all of the wire. Looks like new again.

A clean chassis is a happy chassis!

You did the inside of the HV cage too, right? Rubbing alcohol is good for removing any sooty coating from there. Leaves no residue.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

That cleaned up really nice!

Thanks. My parts order came in today so I finished replacing all of th caps on the main board. Now the main board is complete and ready to be reinstalled. Time to finish the caps on the rest of the chassis and replace all of the electrolytics.

I got the set completely recapped and have it a fsow power up on a variac. The horizontal has a high pitched whine, and when I adjust the horizontal controls it doesn't get better and you can hear brief arcing from below. What is going on here? I cannot get the whole screen to light up, just strips or opposite sides.

If you can hear arcing and can't get the whine to go away quickly, you could be destroying your flyback.

Looks like your yoke may have slipped off the back of the CRT. It could be shorting out.

Bob, good call on the yoke being loose. The clamp screw was very loose and it was sliding on the neck. I tightened up the yoke and got it straight, but my problem still persists. Any other thoughts on what to try next?

I checked the yoke and took off the black cover, hoping to find a snapped off lead or something, but everything like old ok. There was a couple cold folder joints where the ceramic capacitor is, so I touched those up.

this is with just a raster, no signal correct?
I would scope the video lead to the CRT cathode/Grid look for a horz rate blanking signal.

next I would look a the boost voltage filter cap, make sure you have the right value and its not open, scope the boost voltage (use a 10x prob), see if its clean at the screen grid of the CRT. I don't have that model but my predicta show boost 400v at the CRT screen grid, and uses reduced boost voltage to control the brightness, if you don't have well filtered boost there perhaps that could be an issue.

something is blanking a the horz rate, it has to be the grid/cathode/screen of the CRT. should be easy to locate if you look there.

Ok,

I'll give that a try. I've been busy at work and haven't had much time to get back to it.

I haven't got s chance to dig out my oscilloscope, but I did take find voltage checks.

CRT
Pin 2-6 (420v) I get 470
Pin 7 (35v) I get 69v
Pin 4 (0) I get 0

6CG7 horiz mult
Pin 1 (175v) I get 190v
Pin 7 (-15v) I get -10v
Pin 6 (175v) I get 155v
Pin 8 (6.5v) I get 6-7v

My boost voltage is supposed to be 435v and is 460v

9BR7 horiz AFC/sync
Pin 8 (3.5v) I get 2v
Pin 7 (-0.5v) I get 0v
Pin 1 (55v) I get 59v
Pin 2 (-2v) I get -3v

I'm not trained in electronics but enjoy this hobby and know the basics. Do these readings throw up any flags to any of you guys? Maybe a couplate causing these issues? I've checked all of the resistors and caps I put in and do not see any errors.

Thanks
Scott

The brightness and contrast also seem to have no effect. I also tried hooking up a DVD player to see if any video got through and it also had no effect.

Bandersen suggested that maybe the CRT, which filters the hv, may not be grounded properly. That got me thinking, why not try the CRT that works in my holiday. It's a 6.3v CRT, but should work anyway. I hooked it and it has a full raster! So what's going on with my CRT that came with it? Anyway, I hooked up video and see some signs of life, but no images yet...

Was it JUST the CRT or the CRT and yoke you switched? If the yoke got swapped too I'd suspect that.

Both got swapped, so I don't know what's wrong with it yet.

I've got a yoke/flyback transformer, but I've never tested a yoke before. Any tips on how to test this yoke? The CRT tested ok on my tester, so I'm thinking there's something wrong with my yoke.

Do you mean a yoke/flyback tester?

If it's a vintage tester, you can find many equipment manuals at BAMA:

http://bama.edebris.com/manuals/

Regards,

Phil Nelson

I think I may switch the CRT from my holiday to my barberpole since it's worth the most. I'll search for a new 21fdp4 for my holiday and hopefully find another some day. My barberpole I play on having and watching in my living room too.

The wire that connects the grid cap to hv rectifier broke off at the flyback...I had an nos one so I dug down a little and soldered it on. The flyback has to be recoated anyway and I have rtv 4165 I believe. Is that suitable? I believe when I bought it, it was rated for 15k+ volts.

I did a google search for RTV 4165 and came up empty. Are you sure that's what you have ?

I'll look and see, I may be wrong. A 1 watt resistor in the tuner also over heated, not sure why. I got the video to work, but now I only have a white raster. Not sure where my video is lost or maybe my tuner is bad?

It is Dow Corning 3145 rtv sealant.

This is what I'm getting now with a DVD player. Like I said above, I had pretty good video earlier. What happened?

Forgot the image...

After a little help from another Predicta restorer, I found out that the black plug from the tuner to the main chassis, can be plugged in more than one way. Only one way works right! I've got my video working again, but now I'm trying to figure out where my interference is coming from?