Predicta Holiday restoration
 

A friend picked up this set last fall and I'm going to take a whack at restoring it. It's a 1958 Philco Predicta Holiday with 9L37 chassis. The cabinet has seen better days plus the channel knob and antenna are missing, but otherwise it looks OK.
Hopefully, the gunk on the screen will buff out.
http://farm8.staticflickr.com/7148/6...c669c874_z.jpg http://farm9.staticflickr.com/8447/7...74b5b62d_z.jpg


http://farm8.staticflickr.com/7139/7...0c937918_z.jpg http://farm9.staticflickr.com/8290/7...32fc9fdc_z.jpg

A few months ago I found a channel knob on ebay :)
The CRT has been replaced with a 6 volt version and it tests good. Not great, but good.
http://farm8.staticflickr.com/7008/6...63b03f6a_z.jpg http://farm8.staticflickr.com/7144/6...ecc616a9_z.jpg

As for the chassis, the fuse resistor had exploded and the thermistor vaporized!
I think all of the components are original.
http://farm9.staticflickr.com/8430/7...e9ed37b1_z.jpg http://farm9.staticflickr.com/8443/7...633e389c_z.jpg

http://farm9.staticflickr.com/8437/7...0ab6267c_z.jpg

I dove right in last night and pulled the main board. About half the wire wrap connections had been soldered which made it all the more fun to remove them.

One of the 7-pin sockets is damaged. Anyone know of a suitable replacement ?
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I certainly will be tuning in for this resto.

:lurk:

Yeah me too, Bob you're a brave man for tackling one of these! :yes: At least with the Philco T&C you've been slightly seasoned to Philco's chassis design and layout!:D
Cheers Glen

Hey Bob! Can you snap a close up of the bad socket for me? I might be able to get an exact replacement for you.

Hi Mark. Does this help ? I'm sure it used to look like the one on the left before it broke apart.
http://farm8.staticflickr.com/7250/7...c095a7c7_c.jpg

Yeah, the T&C was great practice. Those wirewrap posts are no longer intimidating. Good thing too - I have four more Predictas after this one :D

Yep, that helps a lot! I'll let you know asap if I find one, if I do it's NOS, not a used one.

Cool, thanks.
It turns out this set has had a few more repairs than I first realized. There's an extra electrolytic can under the chassis and a few other replacement parts scattered around.

I also found that in addition to the fusistor and thermistor all 3 sections of the filament dropping resistor as well as the pilot light are open. What the heck happened to this set ?!?
I figure one tap of this resistor was cut when the 6.3v CRT was installed.
http://farm9.staticflickr.com/8431/7...20cb2e58_z.jpg

That was the chassis that helped bankrupt Philco. Long time dealers dropped their products. They were such dogs.
IIRC, that was the only Philco that used the Zenith type gated beam audio detector.

I finished recapping the main board without any problems :)
Pulled the K4 network too as I've heard they are often faulty. The components to make a new one are in the foreground.
Maybe I should pull the K3 network too ?
http://farm9.staticflickr.com/8292/7...6650af09_c.jpg

Has anyone tried to make these networks plugable ? I'm thinking maybe reuse some PC board mount tube or transistor socket pins :scratch2:
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While I ponder the K networks and search for a tube socket, I'm moving onto the chassis underside. One electrolytic and a bunch of power resistors were replaced at some point.
http://farm9.staticflickr.com/8445/7...b386e466_c.jpg

One corner is finished so far. I've been using over spec resistors e.g. 2W for 1W and 3W for 2W.
http://farm8.staticflickr.com/7257/7...d3a20d08_c.jpg

I found one cap held in place by this nifty strap and was able to reuse it.
Very handy :yes: Anyone know where I can get more ?
http://farm8.staticflickr.com/7120/7...483c3563_z.jpg http://farm8.staticflickr.com/7258/7...c06efa67_z.jpg

How about these?
http://www.ebay.com/itm/20-8-CABLE-W...#ht_481wt_1185

OR

http://www.ebay.com/itm/100-Count-Wh...item35bf0f111d

Looks like a clean non-smoker chassis at least. The wires on my Predicta are a sticky, fragile mess that I contend with. That filament resistor is just horrible as mine was opened up/burnt at one spot as well as the leads being all covered with that green corrosion....

Those 12CA5 audio output tubes like to run hot and ruin sockets as you know!

Plugability seems low priority to me. If you build a new network, it may outlive everyone reading this post.

Phil Nelson

I was thinking it would be a nice way to test them before bothering to rebuild them.

We order them by the 100s at work. Let me know if you'd like some and I can ship em your way.

The only reliable test for those is how well they perform in the set, 'specially in regard to thermal stability during the heating/cooling cycle.

Home depot sells those straps. Called "Screw Mount Cable Ties". Look in the electrical aisle. You can get them in White or Black (UV Resistant).

We have those straps at work too, very handy but "Unauthentic" in a vintage TV. :D

Those modern Micas and Metal Film? caps are probably good for a hundred years or so. :yes: Of course, that's what they thought about Sprague Bumblebees too.

True, but the original can cap is gone. Hmm, that reminds me I have a scrap Motorola TS-23 chassis with a very similar cap. Maybe I'll restuff that one for this set :scratch2:

Sure, but I'm hoping I won't have to replace all of them. I have five Predictas to restore each with a few networks on the PCB. So I was thinking if I put some socket pins in on of the sets, I could test all the networks before bothering to replace them. Also gives me a way to test the reproduction networks easily.

The wires in this set were pretty sticky too. I cleaned them off with lacquer thinner as best I could. I wonder why they used a mix of cloth and plastic insulated wires :scratch2:

The nasty old filament resistor has been replaced :) These silicone coated Dale power resistors should hold up for a long time.
http://farm9.staticflickr.com/8425/7...65248914_z.jpg

Philco parts buyers probably found a deal on some NOS, or it was left over from an older model run. I really doubt they were worried about authenticity at the time. :D

Vendor components usually have plastic insulation. Philco parts and chassis wiring is usually cloth covered wire. Manufacturing Engineering called out the colors and sizes according to Philco practices.

Production wiring was cut and tinned weeks in advance by machine and placed on the line at the position where it was to be used. No one would have wasted time separating wires hoping to find some unused lengths for use on another product. Even tubes and parts that dropped on the floor were not salvaged. They were continuously swept up and discarded.

At the end of a production run, unused material was discarded by the ton.

Don

Thanks, Don. Pretty interesting to hear it from someone that experienced how it all played out. Sort of like having our own Philco time machine here on VK. :thmbsp:

Yes, thanks for the info Don. I see now that the main chassis wiring like for the AC line is cloth while the wiring harness for the tuner and control cluster is plastic.

I finished with replacing the paper caps and moved on to restuffing the electrolytics.
http://farm9.staticflickr.com/8308/7...a0f46f93_c.jpg

If you still need the tube socket, Surplus Sales of Nebraska has some very similar to the originals.

http://www.surplussales.com/Tube-Soc...ubeSkts-2.html

Thanks. I'll pick some up.

I managed to arrange the new caps so they'll just fit in the old cans.
http://farm9.staticflickr.com/8439/7...53cefde7_c.jpg

Nice work Bob,

i see some Low ESR caps in that lot, i am assuming all of the caps are 105 degree caps.

Looking forward to another progress video for this set.

Matt

Thanks. Yes, they are all 105C rated caps :)

The replacements tube sockets from Surplus Sales of Nebraska have arrived and are identical to the originals :)
http://farm9.staticflickr.com/8316/7...f3c5bd8c_z.jpg

Cool, are you replacing them all?

Oh no. Just the 7-pin socket that broke in the upper left obscured by my hand. I have four more Predicta sets to restore though and they have some damaged sockets too so I stocked up.

How long has the restoration took?

The first post is dated Aug. 19th so it's been about 3 weeks so far.

I popped out the K6 network to do a little testing. It's tough to do because of the internal parallel and series combinations, but I here's what I found.

There's a 47K and 4.7K in series between pins one and 2 for a total of 51.7K. I measured 70.7K.
http://farm9.staticflickr.com/8037/7...6280e91a_z.jpg

Between pins 2 and 7 I should have 3300pF but measured around 4300pF.
http://farm9.staticflickr.com/8301/7...5541c18f_z.jpg

Seems to me those are pretty far off and I should replace this network. I'll pop out K2 next and see how it measures up.

The other networks showed similar results so I decided to just replace them all. I was curious about the internal construction and dissected a couple. The resistors are just carbon powder and the caps look like ceramic cylinders.

I rebuilt the K4 network using plastic caps and metal film resistors on a little perf board. The 0.0015 uF cap is rated for 2,000 volts like the one next to it on the main board.

Parts for the other neworks will arrive in a couple days.
http://farm9.staticflickr.com/8437/7...afc5a696_c.jpg

Looking good!
 

That's looking great Bob,
You are making me want to eventually try a predicta but I will need to work up to it with some easier sets first, that I have in the wings.
I like how the networks are looking on the board.
I have my eye on one that is within driving distance if I win the auction, but I would never have one shipped.
If I win it will have to be on display for a little while until I get up the nerve to give it a go.
Tom

I like the solution to the networks, since you could not do what you did on the T&C. Looking forward to more updates as always!

I ordered my parts from Mouser as usual, but made a mistake when choosing shipping options. I usually choose FedEx Ground if I'm in a hurry (2 days) or US Post Office (3-4 days) if I can wait a bit.

This time I choose a new option - a rather generic "Standard Shipping". When I received a shipping confirmation, it turned out to be UPS. I later did a package track with UPS and discovered they had farmed it out to the Post Office with an ETA of 10-14 days!?!

If I had just chosen the Post Office in the first place, I probably would have received my parts by now. Instead, I'll be lucky to get them next week :(