My Attempt at Predicta Restoration

[PredictaNoob]

Originally Posted by Sandy G

Curiosity killed the cat & all, but...Did you find this Predicta there in Germany, or did you ship it in from America ? If that was the case, I bet it set you back a small fortune in shipping charges...An' you're lucky it got there in 2 big pieces...(grin)

I bought it from a guy in the States. I paid peanuts for the tele, but he swindled me on the postage (paid for priority x 2 boxes (each double boxed). He sent 2 boxes via parcel post (painfully slow and rough handling) and single boxed them. So I forked out about $100 for postage, and he spent about $55. Chiseler.
I guess I am lucky that there was only one small crack in the CRT cover. Could have been a lot worse.

[PredictaNoob]

I've got a question about the electrolytics. I've read where certain sections of these TVs require exact component replacements. I had to go with a little higher rated caps on two stages on the 4-stage E1, and the single stage E1. The original ratings were 80mf at 350v (I used 82mf at 450v), and the other two were both 200mf at 150v (I used a 220mf at 160v). Are these eletrolytic stages required to be exact, or will the ones I have listed work?

[Phil Nelson]

The caps you listed will work. The difference in value is probably equal to or less than the manufacturing tolerance, in any case.

It's generally OK to go somewhat higher in capacitance with electrolytics, but don't go nuts. Don't substitute 100mfd for 22mfd, for instance. There's no advantage to using the 100mfd cap and it will be larger/more expensive.

Ditto with voltage ratings.

Phil Nelson

[PredictaNoob]

Originally Posted by Phil Nelson

The caps you listed will work. The difference in value is probably equal to or less than the manufacturing tolerance, in any case.

It's generally OK to go somewhat higher in capacitance with electrolytics, but don't go nuts. Don't substitute 100mfd for 22mfd, for instance. There's no advantage to using the 100mfd cap and it will be larger/more expensive.

Ditto with voltage ratings.

Phil Nelson

Thanks Phil. That's the procedure I normally follow with radios, but I had read somewhere that at least one section of these Predicta's requires exact value replacements. But I can't seem to find that website now, and I can't remember which section nor exactly which capacitors where involved. Dang!

[PredictaNoob]

I'm trying to replicate the control labels on the back of the cabinet top. It dawned on me that someone here might know the font that Philco used on these sets? Here's what I've got, so far. It isn't exact, but I'm rapidly losing concern about it...


This is Haettenschweiler 24 font size with a 4 point character spacing.

[batterymaker]

Originally Posted by PredictaNoob

I'm trying to replicate the control labels on the back of the cabinet top. It dawned on me that someone here might know the font that Philco used on these sets? Here's what I've got, so far. It isn't exact, but I'm rapidly losing concern about it...


This is Haettenschweiler 24 font size with a 4 point character spacing.

Another close-fitting font is Alternate Gothic No. 2.

[DaveWM]

ok duh, its the height pot, schematic say 3 meg pot. Still dont get the big resistor, it should be connected to a 1.5 meg resistor that goes to the plate of the 6DR7

[DaveWM]

check the resistance of pin 6 to the 275v source should be around 3.9 meg

[DaveWM]

what is the value of that big sand resistor tacked on?

[PredictaNoob]

Originally Posted by DaveWM

check the resistance of pin 6 to the 275v source should be around 3.9 meg

If you mean the 275 from the VOT, I can't get a good reading. It starts around 18M and climbs beyond what my VOM can handle. Or should I be checking from another location?

[PredictaNoob]

Originally Posted by batterymaker

Another close-fitting font is Alternate Gothic No. 2.

I don't have selection in Power Point. Could you send me an example?

[batterymaker]

Originally Posted by PredictaNoob

I don't have selection in Power Point. Could you send me an example?

I'll have to get my portable hard drive and post an example.

[DaveWM]

Bob and progress, it has been more than 8 days...

[PredictaNoob]

OK, so I'll let this thread rest a bit while I work the board loose from the chassis and start swapping caps, electros and resistors, and nailing down cold solder joints. Its going to take me a bit since we've got some events coming up. I'll try to pop up a picture or two when I make some progress.

[PredictaNoob]

I did want to report that I have definately decided to pull the main board. I replaced 4 caps last night in and around the audio section, since they appeared to be 'low hanging fruit". But even these fairly accessible caps weren't "a snap".
I won't actually pull the board, just "loosen it up", meaning I'll free it from the grounding stakes, but leave the wires connected. I calculate that I'll be able to lift the board about 5-6 inches away from the chassis. That should allow me easier access to most everything.

BTW, I finally found some solder braid at a different hardware store yesterday, yippee! They even had the HCL I was needing to etch some PCBs I'm building, and the water-soluble temporary spray adhesive for neat decal -pressure transfer system I'm putting together (for the control text on the back of this cabinet, as well as a good looking substitution for the silk-screened, reverse painted dial scale which is broken from my 1936 Blaupunkt KW741!)

On a related topic, I see that the previous repairman did not concern himself with lead dress. The Philco Service Manual dedicated an entire page to lead dress, so I suppose it is important enough to follow thier recommendations. I'll re-do the ones that are suspect.

I do see why people recommend NOT choosing a Predicta for you first tv restoration. I am having a blast though, and suprising enough, my wife remains positive about the whole project.
So, for today: Life, 'tis good!