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Old 09-05-2010, 03:38 AM
Eric H's Avatar
Eric H Eric H is offline
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Philco 48-2500 Restoration Blog

Since this is probably going to be a long drawn out affair I thought I'd start a thread where I can post some notes and pictures on the progress of this set.

As many of you probably know I bought it on eBay for $37.00 and picked it up near Garden Grove CA in Orange County.

It came with a "Certificate of Authenticity" from The Hollywood Entertainment Museum", this means absolutely nothing except it was owned by them at one time for some purpose, maybe it was in a display, maybe not.

I wish it had been owned by Humphrey Bogart but then I probably wouldn't have gotten it so cheap.

The cabinet is somewhat rough, some Veneer will probably have to be replaced to get rid of some of the defects, it's all flat surfaces so if matching veneer can be found it shouldn't be too hard to do.

Looking through the lid I could see a lot of tubes were missing, I thought the seller had perhaps kept them for himself but when I pulled the back off I found a little surprise.

There is a narrow door on the right side (from rear) to access the chassis bolts, when I opened it there was a small box taped shut and labeled "Tubes out of Philco 2500" inside were all the missing tubes!

The first thing I did after removing the chassis was take apart the projection barrel and look at the concave mirror, it's not perfect, it has some scratches and a few spots of corrosion but overall it's still highly reflective and should work fine for the time being.

The trapezoidal mirror that reflects the picture on to the screen however is pretty much shot.

The chassis is in really good condition, very clean and rust free for the most part.

The CRT looks like it has a million miles on it, the Phosphor has turned dark brown in the area where the picture is scanned, it's trapezoidal in shape because it's scanned in that shape, it's reflected off center on the concave mirror to a trapezoidal mirror in the cabinet and comes out on the screen in a rectangle.
The setup procedure for the optics looks like it could take the better part of a day to complete!

Here are some pics of the CRT , the one on the right is from this set, the center tube is from a previous 2500 I owned but scrapped, the tube on the left is I hope, NOS or near to it, it has no burn at all so it either is very low hours or possibly defective.

the two tubes that I know came out of sets have similar inspection markings on them, some numbers and the letters OK with a squiggly underline, the "New" tube doesn't have these markings so I'm hoping it's a later replacement tube.


This is a long post, if anyone's still reading at this point I will post more pictures in the future.

The cabinet is at my work, the chassis is in the back of my truck here at home. Capacitors have been ordered but I have other projects in front of it.

I planned to work on it during my lunch hour at work but I'm off till at least this Thursday due to ripping a muscle or tendon in my arm this past Wednesday.
Attached Images
File Type: jpg coa.jpg (37.9 KB, 67 views)
File Type: jpg tubebox.jpg (28.8 KB, 61 views)
File Type: jpg tp400.jpg (17.4 KB, 133 views)
File Type: jpg tp400-2.jpg (22.9 KB, 75 views)
File Type: jpg tp400-3.jpg (23.8 KB, 66 views)
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Old 09-05-2010, 05:52 PM
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Tom Albrecht Tom Albrecht is offline
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I've got several TP400 CRTs for my set as well. Will be interesting to find out if you see a huge difference between the new one and the two with darkened phosphor. None of mine is new, and they show varying degrees of darkened phosphor, although none quite as dark as the two you show. Somewhat to my surprise, however, all of my CRTs work about the same, regardless of how much darkening of the phosphor there is.

Curious what solution you'll find to fix up the front-surface trapezoidal mirror. Mine is OK, but could probably benefit from a better reflective surface.

Good luck with the set! This one has about as many capacitors to replace as a TV can have...
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Old 09-05-2010, 09:07 PM
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ChuckA ChuckA is offline
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Eric,

Don't worry to much about the front mirror, as long as you can see a reflection it will work. The spherical mirror in the barrel is the real key to a good picture, and of course with the Philco, the reflective screen.

If the flat mirror is really gone just use the thinnest regular mirror you can find and use a thin back board to make it the same thickness as the original.

Chuck
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Old 09-05-2010, 09:27 PM
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Has anybody here taken one of these tubes apart? I am wondering if the phosphor is brown from electron bombardment, or perhaps the glass is brown from X-rays?... or perhaps a little of both effects?
jr
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Old 09-05-2010, 11:08 PM
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Eric,

Those projection sets are a lot of fun to work on. The spherical mirror can be resilvered (aluminized), and front surface mirrors can be bought off the internet for not too much money. Having good surfaces on both mirrors will result in optimum brightness. While you can use an ordinary mirror for the flat one, it will produce some image degradation, dut to reflections from both the front and back surface of the mirror.
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Old 09-06-2010, 02:48 AM
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Eric H Eric H is offline
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Interesting info on this site: http://www.myvintagetv.com/philco_48-2500.htm

It claims the first 25 Field Test units of the 48-2500 were Blond sets, now I can't really hope that I lucked into one of those but it would be cool.
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Old 09-06-2010, 10:13 AM
mbates14 mbates14 is offline
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you might have... just never know. look at the serial numbers.
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Old 09-06-2010, 10:22 AM
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Phil Nelson Phil Nelson is offline
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Well, it looks to me like the finish was originally blonde, not stripped and refinished.

If this is a field trial set, I wonder who typically got those? Company execs? A magazine likely to write a glowing review? I presume that (at least) some of the lucky testers would be engineers, so the company could get some educated feedback.

Should be an interesting project in any event. I think you have already gotten at least $37.77 worth of fun out of it!

Phil Nelson
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Old 09-06-2010, 01:50 PM
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ChuckA ChuckA is offline
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Quote:
Originally Posted by Phil Nelson View Post
If this is a field trial set, I wonder who typically got those? Company execs? A magazine likely to write a glowing review? I presume that (at least) some of the lucky testers would be engineers, so the company could get some educated feedback.
Phil Nelson
Phil,

All the prototype and field trial Philco sets I have found or known about, (15" color prototype, 3 prewar field trial sets, and an "Apple" prototype), have all been in the hands of retired Philco engineers. The 48-2500 field set also was from a Philco engineer.

I guess the execs had no interest in them.


Chuck
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  #10  
Old 09-06-2010, 02:38 PM
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Eric H Eric H is offline
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I got the answer here: http://www.antiqueradios.com/forums/...c.php?t=145288

I knew I couldn't get that lucky but it was worth checking.

Phil, the Blond is original on this set, the Dark Anti Reflective color inside the lid was applied over the outside finish.
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Old 09-08-2010, 07:16 PM
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John Folsom John Folsom is offline
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Philco upgrade kit for code 125

Here is an interesting Philco tidbit. Philco made this kit to convert your 48-2500 projection set to a code 125 model. This is a 1X2 based tripler HV power supply sub assembly. I assume it is intended to replace the older 1B3 based tripler.

In addition to installation instructions, they have a sheet of service tips. Of interest is the suggestion that the DC restored tube be removed. This improves the focus performance in changes from light to dark scenes. They state the improvement in focus will more than offset the disadvantages of not having DC restoration
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Old 09-08-2010, 09:03 PM
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Eric H Eric H is offline
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That's an interesting item.

I wonder how many made it out with the 1B3 system?

Both of my chassis use the 1X2 I think, the tube chart on the HV cage of this set had 1B3 printed on it but it was crossed out and 1X2 was written in by hand.

There's another tube chart pasted on the hardboard back of the set, I'll have to see what it has for HV Rectifier tubes.

I like the automatic discharge safety lever inside the cage, designed to keep you from getting whacked with 20 kv if the cover is off.
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File Type: jpg tube1x2.jpg (49.4 KB, 61 views)
File Type: jpg hvbox.jpg (39.8 KB, 65 views)
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Old 09-08-2010, 09:29 PM
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The DC resto mod is interesting. I had a friend who owned a 40's projection set, and he said adjusting focus was a constant problem, in fact, that is why he got rid of it. I can easily understand why one would want an in focus picture even if it meant getting rid of DC restoration. Note that the RCA Berkshire had a wired remote that was simple a focus control rheostat.
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Old 09-08-2010, 09:50 PM
Don Lindsly Don Lindsly is offline
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Quote:
Originally Posted by ChuckA View Post
Phil,

All the prototype and field trial Philco sets I have found or known about, (15" color prototype, 3 prewar field trial sets, and an "Apple" prototype), have all been in the hands of retired Philco engineers. The 48-2500 field set also was from a Philco engineer.

I guess the execs had no interest in them.

Chuck
I recall doing a service call to the Board Chairman's home in 1957. He was watching a 1957 Diamond D. I doubt he would have put up with a TV 123 color with its reliability. The engineers surely did not want him to experience the failure rate of the early color TV.

I recall another executive was watching a cheap 16 inch RCA in a metal cabinet.

Don
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Old 09-08-2010, 10:20 PM
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Eric H Eric H is offline
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Does anyone here have a complete 2500 Field set or know where one can be seen?

It would make sense that the Engineers would be watching them, the bean counters wouldn't be able to give good feedback about failures or bugs.
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