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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Sun 04, 2018 2:03 pm 
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Joined: May Sun 17, 2009 10:08 pm
Posts: 332
Location: Massachusets, 02019
I have brand new Philco crt in the original early Philco box still sealed if you want original. Also have rebuilts from Hawkeye 4 of them if you dont trust people with used ones. I do have good ones no junk.


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Sun 04, 2018 2:29 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
I would be interested the tubes, tvdude11. The new-in-box philcos sound interesting - do they have the magnets and metal frame and cables and all? I'm certainly interested in a good tube that will hopefully last a while. Even if I can get the current tube working again, it would be good to have a spare as these will only get rarer. Let me know what you have and how they test, and the price, and we'll see if we can make a deal.


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Sun 04, 2018 6:27 pm 
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Posts: 4548
Location: Ann Arbor, MI
sdyer wrote:
After a couple of months of being very focused on my new job, I took some time tonight to work with pin 11. I tinned some 30 gauge wire, heated the pin - which was indeed very hollow - and inserted the wire. I soldered the end up. When it was cooled I snipped off the wire and sanded of some bits of excess solder. I'm not sure my tinning technique was adequate - the 30 gauge wire is very thin, and I ended up with solder along it for an inch or more - the length it fit into the pin. It was not even, more globby. The end of the pin, though, is soldered over as before. The 30 gauge wire definitely made contact - before I soldered up the end I pulled on it and it was anchored deep inside by the solder in there.

I turned the set on, and no change. The set runs. The sound is good. The picture is there, but very dim. Contrast and tuning etc. knobs all function. Brightness knob does nothing.

While it was running I tried rapping on the end of the picture tube with a screwdriver handle as someone suggested above, but no change. The picture didn't even flicker.

Next I may re-try the tinned wire to see if I can do it better. I'll let you know.

While you are at it, do the other pins too. It does not sound hopeful, but it's not going to take a lot of time to try it.

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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Sun 11, 2018 8:46 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
Today I did the following:
- replaced R101, which was reading atop 70% or more high in circuit.
- tinned/wired/soldered the remaining pins on the CRT (see picture below). I used 24 gauge wire, had used 30 on pin 11. I stuffed another 30-gauge wire not pin 11 for good measure.
- banged on the picture tube with a screwdriver handle, in a variety of locations, while the set played
None had any effect. Still very dark picture, Background has no effect everything else functioning normally.
Next up is to get a new picture tube.


Attachments:
File comment: Of course, the wires were trimmed and excess solder cleaned up before I hooked it back up.
Tinned, soldered.jpg
Tinned, soldered.jpg [ 99.78 KiB | Viewed 1140 times ]
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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Mon 12, 2018 3:52 am 
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Joined: May Sun 17, 2009 10:08 pm
Posts: 332
Location: Massachusets, 02019
I may have a spare frame also


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Mon 12, 2018 4:59 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 704
Location: Crystal Bay, NV
What is the crt cathode current? You can measure the voltage drop on the cathode resistor (R344, I believe). A current of 80 microamps (typical) will cause a voltage drop of 8 volts, using a FET voltmeter or a VTVM. Not sure where this will lead, but knowing the crt current is useful knowledge. The main thing is to make really sure the CRT is bad before you buy another. Perhaps there is somebody nearby (where are you?) who could loan you a test CRT or put your CRT in their set.
=====
Ron


Last edited by TahoeTV on Feb Sun 25, 2018 9:03 pm, edited 1 time in total.

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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Mon 12, 2018 5:47 am 
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Joined: May Sun 07, 2017 11:35 am
Posts: 387
You could use my tester:

viewtopic.php?f=3&t=331576

But frankly, looking at the symptoms, i.e.

The picture on the screen, i.e. very poor LF response
The fact that the set uses G1 not the usual cathode drive,
The brightness control has no effect even though its voltage varies, and
Looking at the circuit,

I can be pretty darned certain that the CRT has an O/C cathode. The only reason you can see any picture at all is because of heater-cathode capacitance/leakage.

My tester will reveal a very low cathode current, if anything at all.

Use clip leads to connect direct to the pins, as in the diagram. That at least bypasses the tube socket. If it still reads close enough to zip, then it's bad like I said.

Pity the neck tapping didn't help. It doesn't always work in my experience.....

Oh BTW, the Thomas tubes that I used to see with O/C cathodes in the 60's, when you looked closely at the gun through the glass, there were TWO connections to the cathode. They must have been expecting trouble!


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Sun 25, 2018 8:12 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
Does anyone still rebuild CRTs? Hawkeye and Clinton Electronics are names I've seen come up when I search the forums.

I'd be happy to pay to have the one I have fixed up.


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Sun 25, 2018 8:21 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5300
Location: Woodinville, WA USA
The last CRT rebuilders in the world went out of business years ago. This part of the ETF website details their project to start rebuilding CRTs again:

http://www.earlytelevision.org/crt_rebu ... useum.html

CRT rebuilding is complex, requiring skill as well as the right equipment. Until the ETF project ramps up, collectors have few options -- either use what you have, or find a replacement. Fortunately, your TV uses a 10BP4, just about the most common vintage CRT, so replacements can be found if you need one.

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Feb Mon 26, 2018 1:44 pm 
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Joined: Oct Thu 23, 2014 5:15 pm
Posts: 95
Keep an eye on craigslist and ebay for sets that use a 10BP4. There are lots of them out there. There is a 10BP4 on ebay now but he is asking too much i think. You could make an offer: https://www.ebay.com/itm/vintage-CRT-10 ... 1438.l2649

I read the thread about your restoration of the set and I am in amazed at your skill and perseverance in restoring this set. It sure looks fantastic! Best of luck in finding a new tube. If you can find one a 10FP4A is a drop in replacement that is alluminized and has a much brighter and sharper picture. Finding another set would probably be your cheapest option. I have seen several nice sets around where I live that use this tube go for $75.00 - $100.00.


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Mar Sat 24, 2018 5:19 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
Props, shout outs and many thanks tvdude211. I took the chassis and CRT down to his place last week, and he confirmed that the original Philco tube was completely dead. RIP. He set me up with a new tube and showed me how to install it in the frame and get it all adjusted. It was great to get it working again, and great to see his collection of interesting old TVs.


Attachments:
File comment: Back on my bench, working once again.
New Picture Tube.jpg
New Picture Tube.jpg [ 128.33 KiB | Viewed 789 times ]
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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Mar Sat 24, 2018 5:22 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
Before I install the new tube, I need to lengthen the high voltage anode cable. The new tube has the hole in the CRT on top, where it was down on the side with the philco tube.

--> What particular kind of cable do I need in order to lengthen it?

Should I buy a new anode/cable like this one, and then cut some length of cable from it?
http://www.talonix.com/shop/item.aspx?itemid=14357


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Mar Sat 24, 2018 6:22 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 704
Location: Crystal Bay, NV
The CRT has no particular rotational positon. Just turn the tube so the anode connection is where you want it.
=====
Ron


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Mar Mon 26, 2018 4:40 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1299
Location: Phoenix, Arizona
I second the comment.

Picture is scanned by the deflection yoke and the CRT doesn't care.

Were it an electrostatic tube like a 7JP4 it can only work one way.

Jim


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Mar Mon 26, 2018 6:55 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 13769
Location: Fernandina Beach, FL
jimmc wrote:
I second the comment.

Picture is scanned by the deflection yoke and the CRT doesn't care.

Were it an electrostatic tube like a 7JP4 it can only work one way.

Jim

"What he said"!

That is the way it works.

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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Apr Mon 16, 2018 4:35 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
There are two issues left before I can reassemble this TV:
1) there is a buzzing from the flyback when it plays. Somewhat susceptible to brightness/contrast adjustments, but never goes away much. This was not there before I replaced the CRT. It is similar to the horizontal frequency buzz I got way back when I was restoring the set.
2) now that I've rotated the tube the HV is in the proper place. BUT, the picture is now slightly off kilter in the frame. TVDude showed me what to adjust, and I'm going to give it a shot. If anyone has advice, let me know.
The buzz can be heard on the latest video at https://www.icloud.com/sharedalbum/#B0f5n8hH4m5dr7


Attachments:
File comment: Buzz doesn't sound right.
Buzz Frame.png
Buzz Frame.png [ 220.35 KiB | Viewed 573 times ]
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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Apr Sun 22, 2018 3:55 am 
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Joined: Jun Thu 25, 2015 3:21 am
Posts: 1256
i dont hear any sign of the squeal that you would get with the horizontal running way off frequency.

there is a slight noise but i cant really hear it over the audio. might be helpfull to upload a clip of the tv running with the volume control all the way down.

i dont see how changing a picture tube would cause the flyback to make noise. could something in the flyback be vibrating a loose core etc. are the mounting bolts tight.


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Apr Sun 22, 2018 4:46 am 
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Joined: May Fri 29, 2009 4:35 am
Posts: 2065
Location: Chicago, IL USA
That sounds like a high voltage arc hiss to me. Look for a blue-white arc or corona glow around the flyback and HV leads with the lights turned down. Also does the new CRT have a good dag coating on it and is it grounded ?


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Apr Sat 28, 2018 9:04 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
Posts: 413
You were right andersen - it was an HV arc. It's fixed and the set is reassembled, again. Thanks guys for all your help.
Attachment:
File comment: It was arcing to the ceramic post. There was a deposit there that it was arcing to - it wouldn't arc to ceramic alone. I cleaned it off with alcohol.
HV Arc.jpg
HV Arc.jpg [ 96.4 KiB | Viewed 451 times ]

Attachment:
File comment: The HV cable snapped off, it was always a weak solder. I resoldered it, cleaned up the leads to the resistor there, and bent the tab away from he post.
Fixed AV.jpg
Fixed AV.jpg [ 160.74 KiB | Viewed 451 times ]

Attachment:
File comment: Got the picture all adjusted real nice.
Pic Adjusted.jpg
Pic Adjusted.jpg [ 123.02 KiB | Viewed 451 times ]

Attachment:
File comment: And after about 9 months, reassembled the set. Hopefully for good this time!
Reassembled.jpg
Reassembled.jpg [ 107.84 KiB | Viewed 451 times ]


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 Post subject: Re: Philco 48-1000 - Brightness Failed
PostPosted: Apr Sat 28, 2018 9:36 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 13769
Location: Fernandina Beach, FL
Very..., Very..., Nice! Thanks for hanging in there and showing us the progress.

Thanks also to Bob Andersen for chiming in and helping.

_________________
Don


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