Have you tested that cloudy tube in a tube tester? That really does not look right, but it could be just strange glass.

Have not tested it yet.
But, 1B3's are cheap and I think I will use a new one.

Carl

Recapping almost done.
Took a toll on my Capacitor inventory.
I did have enough to replace all the paper capacitors.
Still have 3 Electrolytic cans and 4 underchassis 50v 10uf and 50uf
capacitors to replace. Placed an order.

I did not stuff the Electrolytic cans and think it sure would be prettier
if I did. Thinking about using some heavy copper wire to
build a platform on the terminals of the Electrolytic cans and
use it to solder a terminal strip on to mount the can capacitors.

Then again, I like the clean look underneath with the orange and
yellow capacitors. Like to cut the tops off the Electrolytic cans
and mount capacitors topside -- but this chassis is kinda tight
getting a saw in on it. What advice would you give?


There are 5 Electrolytic Cans on this chassis - two have 4 sections.
There is a lot of Electrolytic capacitors on this chassis.
How did you guys recap yours?

I remember this set as needing a ton of capacitors -- I think about $75 worth, which is a lot!

Mine is recapped 100% under chassis, with a few terminal strips added here and there to make it all work. Not so different than what you are showing.

$75 ... yes, I believe you - maybe even more:-)

Have not decided where to mount the terminal strips.
Really like to bolt the terminal strip to the chassis but have
not decided where. Might drill new holes in the chassis.
If you or anyone have a photo showing where you mounted
the terminal strips, I would like to study it.

I stuffed the condensers when I restored that Raytheon Porthole.
That was a lot of work for two - but this set has 5.

Carl

I can't get to mine at the moment; otherwise I'd be happy to pull the chassis and take a picture for you.

Here is the story on the two versions of the HV power supply in the Philco 48-2500. It was first produced with the 1B3 tube version of the power supply. Underwriters Laboratory was not happy with the lack of safety features on the set, so Philco modified the design to comply with the requirements. They also offered a modification kit to make the original sets compliant.

Here is the Philco modification kit in its original box.



This kin consisted of a 1X2 tube HV power supply with safety shorting spring, new tube layout label, and warning sticker. It also contained two pages of instructions on implementing the changes and bring the chassis to meet the Code 125 requirements.

I assume all the Philco documentation was released before the Code 125 changes were made, so the schematics all reflect the 1B3 HV power supply.

John, that is very interesting historical information.
Thanks for sharing that with us.

Its interesting that Riders only mentions the 1B3 but it mentions the HV safety cutoff.
I also do not recall any mention of Code 125.
Maybe the kit you have is part safety (labels and Masonite cover) and the rest
circuit upgrade (replacement HV circuit using 1X2's)?

This is very interesting and because you posted it, it should be available
for future generations to ponder over.
Got any other information on this TV?

Carl

This has peaked my interest.
Did some reading in Rider TV Manual Vol 2 and noted the following
pertaining to Code 122 production runs:
Run 1 - the lid switch was changed from a mercury type to a toggle type
Run 2 - the 3 1000mmf Condensers replaced with 500mmf
Run 3 has an "S" stamp on the back of the chassis
Run 4 has an "H" stamp on the back of the chassis
Run 5 has an "O" stamp on the back of the chassis
Runs 6,7,8 have a diamond stamp mark on the back of the chassis

My TV has the toggle type switch for the lid and has 3 500mmf condensers,
but no stampings. I'm thinking I have Code 122 Run 2.

One thing that peaked my curiosity from the time I started disassembling this
TV is the white star marking on the Power Transformer:


In the above, the white star is on the Power Transformer and note
that the chassis is stamped with "Code 122" but no other markings.

Carl

Just noticed something unusual ... there is a Fine Tuning knob, but
on my TV it does nothing. This is the larger knob on the same
shaft as the Channel Selector.

How is this on your 48-2500 TVs?????

Carl

I figured it out ... the metal tab for the outer knob fell out.
Now both the inner and outer are Channel Selector and
both turn the shaft at the same time.
The larger outer knob must be there to make it easier
to change channels.

But still I do not see a Fine Tuning capability.

Carl

I believe this set did not originally have fine tuning. Mine has electronic fine tuning and an AFC with reactance tube added as a Philco-supplied modification kit. I think I have a copy of the service bulletin for that. On sets with this modification, one of the front panel potentiometers has a dual concentric shaft with two knobs to accommodate the extra adjustment.

Interesting. Mine definitely does not have
any dual shaft controls.
Every vintage TV I've seen had a way to fine
tune. Will have to see how electronic
fine tuning works.

How about everyone else - do you have a
fine tuning control?

BTW, I tested that cloudy 1B3 today -it tested bad.
I looked closely at it and noted that there is a
crack in the glass.

Getting real close to firing up this puppy.
Awaiting some capacitors and some tubes to
come in. I've tested and Deoxit'ed all the tube
sockets and controls.

I think I'll install a ground
wire between the Chassis and the Schmidt Optics
barrel - from John's posting of the Code 125 kit.

Still a little skiddish about that 23KV HV.
For testing I guess I'll leave the panel off the HV cage
so I'll have a way to ground the HV when I
remove power. I assume the best way is to use a
grounding wire between chassis and the metal around
the base of one of the 1B3 sockets?

Carl

Actually there were a number of early sets that had no end-user fine tuning. One example in my collection is a Sentinel 400TV. I've heard that very early Motorola VT-71s also didn't have fine tuning. Obviously, it became apparent quite early that manufacturers were overconfident about the stability of their tuners. Modifications were made to include fine tuning in sets that didn't have it, and all new designs beyond the first year or two of production had fine tuning.

Interesting. Did not know.
Learning something new all the time.
This is the earliest TV I have in my collection and its history is
interesting.

Carl

My Philco 49-1240 has no fine tuning control, nor do my two Motorola
VT-71s (early models). I had forgot the Sentinel 400TV, but as Tom
mentioned, those have no fine tuning control either.

Philco created an update kit to add fine tuning to the 48-1000, 48-1001, 48-1050 and 48-2500. It included a new dual
potentiometer with knobs and some components. Therefore some sets will have it and some will not. I found one of the original kits
at a show. If anyone wants a PDF of the instructions send me a PM with your e-mail address.

Tim, thanks for the PDF on the Fine Tuning upgrade.
Those 1940's TV designers might have been smoking weed and
visualized today's flat-panel TVs without Fine Tuning Controls:-)

It looks easy enough to install. Anyone have a photo of
what the knobs actually looked like on the 48-2500?

There is a lot of work to restore one of these TVs ...

Cabinet:
- blew out dust/dirt with leaf blower
- cleaned mold on inside of cabinet with bleach
- wiped down inside and outside with Spray Nine cleaner
- wiped down outside with Goop non-pumice hand cleaner
- stained outside with Red Mahagony
- stained inside with Ebony
- applied Howards Refinisher on outside
- cleaned and spray painted back cover with flat black
- home made knob for small control door

Schmidt Optics:
- disassembled
- cleaned mirrors and lens
- spray painted barrel flat black

Chassis:
- cleaned chassis, tubes, and cables with Oxi Clean
- RustOleum on rusty areas
- painted Power Transformer and HO Transformer black satin
- painted HV cage bronze
- recapped: 50 paper, 20 Electrolytic capacitors
- 4 tubes replaced: x3 1B3, 7F8
- DeOxit contact cleaner on all Pots, tube sockets, and Tuner
- tested all tubes - except the TP-400 CRT
- oiled tuner mechanism

... and I've not even powered it up yet.


Still To Do:
- install new AC power cord
- finish installing electrolytic capacitors when they come in
- install 4 tubes when they come in
- install ground wire between chassis and the Schmidt barrel
- power up and test
- evaluate if the Trapezoidal Mirror is usable
- don't break anything
- final assembly


Carl

Some of you may have seen this information but for collectors who didn't and enjoy obscure information on your 2500 read on:

The first 2500's were Code 121 there were 3 runs. These sets used a TP400 CRT non-aluminized
Major changes:

Run 2 - A filament choke was added to the 6AL5 discriminator tube.
First and second video IF couplers were redesigned

Run 3 - Changed the horizontal sweep generator circuit
Additional sound trap added
High voltage unit changed to a complete subassembly


Code 122 sets started using the TP400A CRT, the tube is slightly modified from the TP400 the HV anode snap terminal was moved closer to the front
of the tube. There were 10 runs.

Run 1 - Focus Coil, Focus and Auxiliary Focus controls changed from high resistance to low resistance type, circuit changed.
Additional sound trap added to detector input
Lid switch changed from mercury type to a toggle switch

Run 2 - No major changes

Run 3 - Extensive changes to horizontal sweep circuit, "S" stamped on rear of chassis

Run 4 - High voltage transformer changed, "H" stamped on rear of chassis

Run 5 - High voltage transformer changes, "O" stamped on rear of chassis

Run 6 - No major changes

Run 7 - High voltage unit changed to a complete subassembly, "Diamond" stamp on rear of chassis

Run 8 - No major changes, "Diamond" stamp on rear of chassis

Run 9 - No major changes, "Diamond" stamp on rear of chassis

Run 10 - Modification to remove vertical black lines


Model 48-2500-5 Code 122
This is a 50 cycle set, 3 runs

Run 1 - Added 30mf capacitor, repositioned power transformer

Run 2 - High voltage unit changed to a complete subassembly

Run 3 - No major changes


You can determine the run number of your set by examining the series of numbers stamped in ink on the rear of the chassis, the last
two digits of the series give the run number.

I have the installation instructions for this set, if there's any interest I'll scan and post it on my site.