90s Philco-branded Philips 13" - Very dark screen
 

I have rescued a 13-inch Philips (Magnavox) CRT TV set, probably built in the mid-90s (build date is obscured by wear on the label) from an abandoned motel. I kept it mostly because of the curiosity of the set being branded Philco, despite that brand having ceased television manufacture decades prior. After thoroughly cleaning the TV and checking for any obvious signs of trouble, I plugged it in and powered it on. All seems well, but the picture is extremely dark, to the point of being almost totally black. I tried adjusting the flyback G2 control, and although this did produce a picture, it was very washed out, as though something before the flyback is keeping the picture dark. I also tried adjusting the sub brite control on the board, to no avail...I am out of ideas. I returned the flyback to its previous setting, to avoid any undue wear.

Model number? Sams doesn't yield without that or a chassis number.

Philco existed as a elcheapo badge into the DTV transition...Those magnavox DTV converter boxes were also sold in white plastic with Philco brand on them.

Sorry about that, I should have thought to mark that down! The model number is P1321R C403. Chassis number 13Y401-00AA. Label says it is a Philips set. The more and more I stare at what's left of the manufacturing year, it looks like it could be 1993.

Yeah, I think Philips might still have the rights to use the name. I have seen at least one 'Philco' DVD player...

Post the CRT voltages & its easy to nail down the bad stage.
With its history its probably a dead CRT.

73 Zeno:smoke:
LFOD !

My late Grandmother in Athens had a knob tuned Philco set from that era. Was a reasonably basic model that screen size or a bit bigger. Had a nice picture. Ad slogan from Knoxville, "Philco, What A Picture, What a Price". Also, they used "Philco, Your Better Buy".

The CRT is very much alive, the onscreen menus are bright and sharp. It's just the picture itself that is almost black.

Could be a bad eeprom. They weren't nearly as much trouble as the Thomson RCA/GEs, but we used to stock them. Unfortunately, I tossed all my Philips parts many years ago.

I may have the SM for the Y series. I'll take a look when I get to work.

John

I have an RCA CTC185 table set (Thomson/RCA) which still works every bit as well as when it was new (it was my first new TV after I moved here in 1999). I never had one problem with it, with the EEPROM or anything else, save for having to replace the antenna connector after about six months (under warranty). Other than that, the set still works, but I don't use it anymore (or at all) since getting a flat screen TV about two or three years ago.

I figured I'd try to take some photos and show what I'm dealing with. (Hard to take images that accurately show the dark screen, but I promise you, Super Mario doesn't usually look this satanic.) As you can see, the onscreen menus and OSD are fine...it's the image itself that is dark.

A service manual (rather it be a Sam's Photofact or factory manual) will be a big help. It could be something as simple as a dried out electrolytic capacitor in the video chain.

As far as the Philco name, Ford bought them in, I believe, 1961. Then, Ford sold Philco to GTE (who already had Sylvania) in 1974. At that point, Philco and Sylvania TV's were basically the same inside; but, the Philco-branded sets were the "loss leader." In '81, NAP (who already had Magnavox) bought the Sylvania and Philco brands from GTE. I believe NAP still owns the rights to the Philco name; but, they have licensed the Philco, Magnavox, and Sylvania brands to Funai and other outfits.

Hard to tell, but it looks like the picture is all chrominance and no luminance. Turn the color control off and see if the image disappears. With a scope, this would be very easy to find but I realize that not everyone has one.

Depending on the year, it could be a delay line of sorts or a rudimentary comb filter issue.

Some TVs had a service switch of sorts on the CRT module. It will be a small three position switch if it has one. Some had a similar switch on the chassis somewhere, but those were mostly imports. If you can find one, try all three positions.

John

Will do some more tinkering and troubleshooting tonight. I DO have a scope, but don't really know how to use it.

I think the details that do show are too sharp to be chrominance. So, there is something wrong with the luminance level (brightness/black level/DC level, whichever you want to call it).

Adjusting the color control has no noticeable effect on brightness. I pored over the entire board and could not locate a service switch anywhere, which actually surprised me, given I usually do find one. All other controls work as they should, just...a really dark picture. Menu is fine, as is blue screen brightness while auto channel searching.

EDIT: It's doing something else I hadn't noticed before. Almost like clockwork every 7-8 seconds, the image will get slightly fuzzy (like someone tuning away from the center of the channel on a knob tuner) and then 'snap' back into focus. Weird. I thought maybe it was some outside interference but nothing I can think of is running nearby.

Something that cycles so slowly is suspiciously like a beat note between vertical rate and the power line. Usually this means a power supply problem.
A schematic sure would help here.

Not sure if its this chassis or an older one. They were had lots of
bad micro IC's. They came with a sheild. The micro was right
under the CRT & the board was cut out for a shield. Seems they
left them out to save $$ & it bit them in the ass.
When they go almost anything can happen including strange charicters
Japanese & other symbols.
You can try different settings for the AFT searching. Norm, CATV, HRC.
ICC SPSL etc.

73 zeno:smoke:
LFOD !

That's true, but the chroma seems to be about 90 percent of the available brightness. The color seems normal but there is indeed a little video on the screen.

John

Not sure if this helps at all, but here is a scan of the circuit diagram that was affixed to the inside of the cabinet.

Try to turn the sub bright up and see what happens.

Pretty sure this is NOT the chassis with the micro problems.
Control functions are done one of 2 ways.
1) each control ( color, tint, brite etc) goes from the micro to the
jungle IC on separate lines. They will show a changing DC voltage
as you change the setting. The easy & better way IMHO.

2) data & clock lines come into the jungle IC. Its decoded within the
jungle IC. All you can do it watch for activity ( on scope) on the data line when adjusting controls. Bursts of activity may happen even when not changing controls. This is the "modern" way of doing things. Like energy star
better to avoid it at all costs !!

In any case I would say its a video problem for sure. OSD shows
a strong looking CRT & eliminates easy problems. Time to dig in.

enuf fer now
73 Zeno:smoke:
LFOD !

BTW I probably have the training manual for this set if you go further.....

I think I might have the Magnavox Version of this set if you need some assistance with what things should look like. Mine does work properly and does have its original remote. :yes:

That was one of the first things I tried, right after G2. Barely any difference at all, so I put it back where it was.