Philco 48-2500 Projection set
 

Looking for some info on this set.

There is a number 483 stamped into the top rear edge of the cabinet, is that the cabinet model or the serial number?

How many of these sets were made?

The round plastic cover that goes on top of the barrel and around the neck of the CRT has 4 small lines etched into it at 90 deg intervals, what are these for, some type of adjustment I presume, and do they show up on the screen?

I've been thinking of fixing mine instead of parting it out, (yes, it's really hammered :( ) spent some time this week cleaning the chassis and projection assembly and it all looks pretty good.

Eric

Eric,

That number may be year and month of manufacture. I had one of those and it made a small raster. I pulled the chassis in thoughts of recapping it and groaned. Too expensive! I sold it to finance the acquisition of an RCA 9PC41 which IMO is a way better projection set. The TP-400 CRT in your's is hard to find replacements for also. If the cabinet is trashy I wouldn't bother.

Hi Eric:

I have a 15 page manual that Philco put out describing how to adjust the optics of the 48-2500. I can send you a copy if you are interested. The scribe lines on the plastic cover are for alignment.

Steve

Eric,

If you decide to restore the set, I have an extra chassis if you need parts.

If you decide to junk it, I could use the reflector screen. I made the mistake of cleaning mine, it is nice and bright now but viewing angle is completely screwed up only one narrow spot can you see an almost complete picture, I believe there is a coating on top of the screen that is necessary for it to operate correctly.


Chuck

Chuck,

I think those screens and the aluminum ones that came with the Advent Videobeam projectors with the external curved screens in the 70's had a micro etched surface finish that would be polished flat if one touched them even gently with a cleaning cloth. The only way to clean these screens was with a type of soap gently sprayed on and a clear, warm water spray rinse. Fantasic, the spray cleaner works great (no physical brushing or rubbing) and dissolves smoke resins that get on this equipment in Bars and taverns. The same treatment works great on the front surface mirrors in the projection schmidt optics (provided the mirror is overcoated with vacuum deposited silica).

You may be able to revive your screen with very delicate glass bead or sand blasting. I think the Philco screen is aluminum overcoated stainless steel formed sheet

The screen on mine is shot too.

Rob, I believe you are right, it's aluminized stainless.
Someone told me that plain grey primer makes a decent screen coating in a pinch, havent tried it but I might if I get this thing working.
I suppose you could have it re-aluminized too for a price :eek:

I wonder if aluminum foil, using the dull side, would work?

Eric,

If you sold aluminum foil for a living I'm sure you wouldn't talk like that! ;)

I don't think you could get the concave shape without major wrinkling.

How about a dusting of aerosol aluminum spray paint?

Hi Rob,
I have what is probably a NOS TP-400, I was just going to get the chassis running well enough to test the tube but once I started I sort of got the crazy idea of fixing this set :nutz:

I took the projection assy to work yesterday and cleaned it up and repainted it. Haven't tried to fire the chassis up but I suspect it will need filters before it will do anything except smoke.

The cabinet is beat but pretty solid, it could be refinished but reskinning it might be a good idea, I could do it in Oak for a more modern look :)

I really hate to scrap any set this old if it's at all possible to fix, not saying I can do it all in a week but a little at a time might be OK.

Eric

there are pictures of it on this site here: http://audiokarma.org/forums/showthr...ghlight=482500

Chassis works, kinda.
 

Powered it up tonight, first through a big bulb then full power with an ammeter in the line, draws about 1.9 amps.

I was concerned about burning a line in the screen if the set had no vertical sweep so I fired it up with the controls all turned down.

With the old CRT I got a dim horizontal line, and as I figured, no vertical sweep, the brightness control had no effect one way or the other but at least I know the chassis is functional.

With the new? CRT I had nothing at all on the screen, till I switched the set off then it lit up brilliantly, so much so I was afraid it would damage the tube! (the old tube does pretty much nothing when switched off, it also has a really burnt screen so I would guess it's about used up)

I decided to try again and by playing with the brightness I can get a line to flash across the screen for a second or so.
I 'm guessing the new tube is good but the much higher emissions may be dragging down the tired chassis.

I seem to also recall reading somewhere that some projection sets would cut the beam off if the sweep stopped working?? can anyone verify that?

Eric,

The Philco doesn't have the sweep protection circuits.


Chuck

Philco Proj. Set
 

I picked one of these up last year at a garage sale. Everything's in nice shape but when I pulled the chassis, figured it'll cost me about as much as a low-milage Yugo to buy the number of caps this thing has.

What was Philco thinking?

I got part of a raster on the CRT but something started sounding very, very bad around the power supply when I got the Variac up to about 90V, so...

Hell's supposed to freeze over around 2010, so I've purchased a good used(?) CRT in anticipation of restoring this set at about that time. Until then, if I buy 3-4 caps a week, I'll just about have what I need.

I've got the complete manual on this set so if anyone needs the Schmidt alignment info, etc., please let me know and I'll be glad to mail you copies with an SASE; please email for an address.

Thanks,
Michael