Educate me on the Predicta?
 

I'm starting to contemplate going after this unit. I don't usually mess with TVs, but there is something extremely cool about a Predicta. I know this one is the 4242 with the 21" tube. http://springfield.craigslist.org/clt/2010305739.html

What do I need to know before taking the plunge?

Tricky to disassemble. Some of the tube housings have a bad smell. Flybacks are frequently an issue. Printed boards can be somewhat fragile. And, you'll have a real conversation piece and a set that holds its value!

That one needs major cosmetic work but does appear to be complete.

At that price, I'd grab it. One that came out of a barn all rotted and rusty sold for like $135 on the bay in Milwaukee a few months ago. I don't think you can go wrong on this one.

I'd go for it too. The 21" don't seem to show up as often as the 17".

You might enjoy this video I made on the issues with restoring a Predicta: http://www.youtube.com/watch?v=hFghaXEjSak

$50? I'd grab it. They aren't too hard to restore, they just have issues with unobtainium parts, as well as gremlins that can creep up in bad traces on the boards.

I believe that's the same chassis used in my barberpole.

http://antiqueradio.org/philc12.htm

Predictas are like the girl in the nursery rhyme, the one with a curl on her forehead. When she was good, she was very, very good, and when she was bad, she was horrid.

$50 is a good price and Predictas are well known. There will probably be some cussing before you finish the project, but you'll have no shortage of armchair quarterbacks.

Phil Nelson

There is of course the issue of the CRT. Predicta CRTs had a very poor lifetime, and very frequently are found to be dead. Rebuild was a great solution for them (the new gun is better than the original), but it's getting harder to find an affordable rebuilder.

I had my Predicta CRT rebuilt by an outfit in Los Angeles 15 years ago or so.

Your CRT enclosure and screen cover look very good. If you ask around a bit, you may find someone with a better lower cabinet but a trashed screen cover. Combining parts could result in one very nice Predicta.

Harder to find is putting it mildly. The last CRT rebuilder in the US has gone out of business and the ETF rebuilding project is still in early days.

Phil Nelson

Hi Phil,

Clinton Displays is still doing it, but it will cost you more.

I think it's a good buy at $50. I'd shoot for it and ask questions later! These sets are popular enough to have quite a following so I'm pretty sure there's more than a few guys here at VK who could steer you in the right direction. Knowing me, I'd probably tackle the cosmetics first just so I'd have a cool-looking Predicta to admire until I got around to tackling the electronics.

Is the lower cabinet photofinish or real veneer?

Lower cabinet on these is photofinish -- that's why I mentioned possibly trying to combine with another Predicta with a better lower cabinet.

Might make a nice victim for a transfusion of real veneer...

Well, guys...$40 later, I've joined you in the vintage TV world. Unless I trip over an early RCA color model cheap, it ends here, too. ;)

Plastic parts are in great shape except for the center of the lower knob - it's broken. The plastic has some light scuffs and a few discolored marks on the back, but no breaks, cuts, decay or nasty smells. The metal parts have some corrosion, they'll take a bit of work to bring back. I haven't looked at anything inside yet.

I would check the CRT, careful on the filament voltage, not sure what it is.

You could prob do some resistance at the fly to see if it seems good. Dont worry about how it looks, I have had flys that you would bet on as bad that work out fine.

IMHO on the fly try not to touch it. I know some folks like to recoat them if the wax is damaged. I dont think I would ever try that, besides the possilbe physical damage that could result from applying the stuff, I would be worried about how it may react with the wire isulation. I would just leave it alone.

I'll have to find someone with a picture tube tester. My Triplett emissions tester has the instructions for a TV tube adapter, but no actual adapter. The tube doesn't look like it's ever been touched - drat, I was hoping to find a nicely rebuilt tube in there. :D

It's a VHF-only unit, the mounting points for the UHF antenna connections are blank. I have most of the antenna, though I wouldn't mind finding the block-off plate as it will never be receiving analog TV signals again.

http://i928.photobucket.com/albums/a...Predicta_1.jpg

http://i928.photobucket.com/albums/a...Predicta_2.jpg

Front controls, broken button visible:
http://i928.photobucket.com/albums/a...Predicta_3.jpg

http://i928.photobucket.com/albums/a...Predicta_4.jpg

http://i928.photobucket.com/albums/a...Predicta_5.jpg

I have a feeling that the power switch and speaker on the back cover aren't original...
http://i928.photobucket.com/albums/a...Predicta_6.jpg

Paging Dr. Vacuum!
http://i928.photobucket.com/albums/a...Predicta_7.jpg

http://i928.photobucket.com/albums/a...Predicta_8.jpg

Indeed, be careful, my GE tube manual says that the 21EAP4 has a 2.34 volt 600 ma heater.

jr

looks like the adams family moved into the cabinet.

Pretty sure its a series string set, so be careful.

I would start by pulling the chassis, use some compressed air to blow out most of the dust, then use q tips and your fav solvent to clean the rest.

after that you can asses how to tackle the recap (above board or pull the board).

Since its your 1st one, I would recommend going with above board j hook or pig tail, so as not to disturb the wiring.

After a basic recap of all the papers, I would check the filters, they maybe ok if so you can try a slow power up with the HOT and VOT tubes pulled out of the sockets, check the filter cans for heat and watch the input current on the ac line. I like to start out slow, maybe 10-20vac and check the b+ if each B+ leg is looking good, then go up to 40vac and keep an eye on it. again watching for heat/current on all the filter caps and B+ rails.

Dont go much over 60vac since with out the HOT there will be no load on the B+ and it can go too high.

you can also just check the resistance at the B+ (power off of course) to look for shorts. Just a WAG but I would think 10k or more. If its a lot less then I would suspect a short (it should rise some as the filter cap charges from the current in the ohm meter).

I just went thru this with another set, one of the lower B+ legs was 240 ohms to ground. It had taken out a big dropping resistor. Traced the short by disconnectig the B+ until I found where the short was (the B+ daisy chained around, so you could unhook a section and see if the resistance popped up, if finally did, turned out to be a shorted disck bypass cap).

anyway if your B+ resistance checks ok, and the filter caps dont heat up at 60vac line voltage, and the current was low at the line (no other shorts), then I would let everything cool down (all the tubes since they would be warmed at athe 60vac) plug in the HOT and VOT, and do another power up. This time go right to 115vac relatively quickly (seconds) keep an eye open for filaments and monitor the the B+ if you can.

Series string stuff scares me and come to think of it , the other tubes prob will not be warmed up since you pulled the HOT and VOT, but the B+ should still be there during the testing phase since I am sure it just uses a SS doubler.

Thanks for the suggestions! I have a few tube audio projects that need in line in front of the TV, so I'll have some time to accumulate info before digging in. This might be my first television, but I've been slinging solder for a while and I've been into tube audio for a year or so now. I'm not afraid of pulling the boards to do it right. :thmbsp:

Part of me is itching to drag the Variac over and see what I'm dealing with...

Gave it a spin with the Variac. Nothing doing. The pilot light came on, but I couldn't see any glowing tube filaments through the grilles, and the picture tube didn't do anything. I would assume that at least one tube is shot, I should have spares for all of them.

If anyone has a complete "shotgun" list of parts for the Predicta Holiday, I'd greatly appreciate it. My feeling is that 52-year-old carbon comp resistors are probably due for replacement, and there is no need to futz around taking the boards in and out. Fix it once, get it over with.

These things have a soft start thermistor as well, it's likely that went open, and that would kill the filament string as well.

Below is a rare thing to find online-a free Sam's Photofact folder for your set (no affiliation):

http://www.nappepin.com/predicta/predicta.htm

ETF also has Schematics posted for this set, and others. http://www.earlytelevision.org/tv_sc..._diagrams.html

Thanks, guys! Anyone know of any errors in the Sams parts list for the G4242?

I didn't notice any errors, but I didn't replace every resistor.

Phil

There is probably a fusible resistor in there; mine was pretty ugly/corroded and was keeping the set dead. You could hunt around for a replacement (Workman sold them, among others) or make up something with a wirewround.

IIRC, my barberpole had both a thermistor, aka "surgistor," on the AC line and a fusible resistor, aka "fusistor," somewhere near the flyback (although I don't remember exactly what it connected to).

For a thermistor, I have used either CL-90 or CL-60 on various sets. For that fusible resistor, I wired a fuse in series with a power resistor of the needed value.

Phil Nelson

What exactly does that dual concentric knob on the front do? Volume and power? I assume something is wrong with the power switch, as one was grafted onto the back.

Center control is off-on-volume, outer control is contrast.

Is it a push on/off, push-pull, or turn type of power switch? From futzing with mine, I would guess that it's push on/off, and the retainer is busted.

Most are push-push for off-on. Some TVs that used the same configuration are rotate off-on. Depends on the year. Either will work fine. Getting the correct knobs to fit the shafts is most critical.

Your TV is a '59 model. It uses the reworked '58 "Seventeener II" portable chassis.

It's a push on-off switch. Whatever broke the knob may also have damaged the switch. You may be able to fix it if you get inside and look at the control itself.

(Oops, I didn't see the above post on the next page when I replied...)

I might pull the chassis in the next week or so to do a parts inventory. If I do, I'll investigate the on-off switch further. Then start looking for a new button.

watch out for frozen speaker wire bullet connectors at the audio transformer, dont try to hard to pull them out.

Blech, you're right. Neither of the Sams folders I downloaded has the right tube list. Do you know if there was a Sams folder issued for this version of the Holiday? Is it better or worse than the 58 version?

Still haven't found any references to this second edition of the Holiday. :(

Ummmm, don't be too sure about that; it can become addictive! :)

Sam:

Better or worse is a judgement call. The ’58 Seventeener II portable version was prone to fire risk from routing the yoke wires around the filament dropping resistor, an underrated B+ shunt resistor, IRC sync diode and sound buzz.

The ’59 version fixed most of the bugs. A tube, 2EN5 or 9BR7, replaced the phase diode, improved IF can for sound, higher wattage resistors, etc.. It was then jammed into a tighter space so it runs hotter. The long CRT leads make for touchy sync if not dressed properly. The chassis was also used for the low end, conventional 21” models.

The ’60 version was a much better, all new design using a power transformer and improved tube line up. The ’58 series string chassis was dropped all together. (It may have been used for a few 1/2 year carry overs or motel specials, but certainly gone by Jan, 1960.)

I do not have Sams literature. I use Philco or Beitman’s, which is a copy of the Philco. I find Sams makes some errors when redrawing the schematics. Can you see a chassis and run number? It should be something like 9H35/9H38 and run number 121, 122 etc...

The tube line up should be the same for all ’59 versions. The only variables I remember are some tube numbers (locations and functions remained the same) and a optional UHF tube and CRT number. Any schematic for that chassis number should be OK. Late engineering modifications and service bulletins may show up in the TV since they were incorporated after the manuals were printed. Documentation may be in the batch of Service Bulletins that followed the product release.

Thanks for that info. Do you know where the Philco or Beitman's service information might be located?

From your description, I take it that this model used the reworked and less fire-prone version of the chassis?

Here's the tube list from the position chart inside the cabinet:
1G3
2AF4A
3BN6
3BZ6
4BL8
5AM8
5X8
6AW8A
6CG7
10DE7
12CA5
12DQ6A

Boy hidee, ain't THAT th' truth ! (grin) One day, you'll be stumblin' around a Antique Emporium, an' one o' them Tres Cute l'il 8" PT-Somethin'-or-Others from '56 will look atcha & wanna go home w/you REAL bad...Or one of the Oriental marvel 1.5" Panasonics from the '80s...Or a Sony Watchman...Or a big ole fusty Zenith Roundie...Worser than me 'n' Guns...(grin)