Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Jan Mon 22, 2018 8:59 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 735 posts ]  Go to page Previous  1 ... 29, 30, 31, 32, 33, 34, 35 ... 37  Next
Author Message
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sat 25, 2017 11:57 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
Hi guys. Today I ran the set after it sat for a few weeks and it works pretty well. The picture is good, and the sound is perfectly synchronized with the picture. I have no problems with video/sound synchronization, and never have. The new adapter I got (pic below) for the video took care of the copy protection lines on "The Day the Earth Stood Still". When first on the sound is strong and pretty clear.

There is one problem left that I would definitely like to fix:
- after running for about 20 minutes, the sound goes "bzzt" and drops off to a fuzz. This is not a new problem, it's been around since I've ever been able to run the set.

There are several lesser issues that are "nice to haves":
- slight retract lines on darker screens
- sometimes it "flashes" or judders a bit
- the sound, even when first on and working well, has a lot of fuzz in it. It's run before without that, maybe when it was in a good mood, so I *have* heard it crystal clear. It's just not that clear any more.

I'll be trying to track these down in the coming days. I'll be even more cautious now since I was at this point at the start of December, then I started testing, replacing, and poking at things, and ended up destroying R100.


Attachments:
Video Fixer.jpeg
Video Fixer.jpeg [ 14.76 KiB | Viewed 1693 times ]
Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sun 26, 2017 12:28 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 3779
Location: WI 54812
I can't remember what all you've tried, but you could start over by measuring the DC voltages on the pins of your audio output tube, to see if anything changes significantly when your sound acts up or drops out. The first thing I'd look at is the plate voltage that gets fed to the plate through the primary winding of the output transformer.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sun 26, 2017 3:20 am 
Member

Joined: May Thu 14, 2015 4:15 pm
Posts: 579
Location: Dallas, TX
sdyer wrote:

What I've found is that if I adjust so that the sound is good, strong and clear with little buzz, the picture is grainy. If I adjust the picture so that it is clear, it and the sound are very dim. Shouldn't these be more "aligned" - i.e. good together, or bad together, not so separately?

Often I find that some of the better results require things like the contrast, volume and other controls to be turned almost all the way clockwise. Shouldn't the set be able to operate without them being so "maxed"?


sdyer, I think you misunderstood what I meant before. Not sound/picture synchronization, but getting both good at the same settings.
It might be a minor problem but the controls shouldn't need to be at one extreme. This might be corrected if you end up fixing something more major, like the sound thermal problem.
The jumping or gliching that happens occationally may be caused by the high voltage 'jumping' to ground somewhere.
BYW, a couple of months ago I went to an estate sale. This sale included a TV like yours. I seem to recall it had a spot on the top of the cabinet that was very dark like something had caught fire there.
I don't know where these sales get there idea of pricing. Unrestored it was marked $400. I didn't give it a second look.

_________________
Tim
"Excellent!" I cried. "Elementary," said he. - Sherlock Holmes


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sun 26, 2017 3:38 am 
Member

Joined: May Thu 14, 2015 4:15 pm
Posts: 579
Location: Dallas, TX
By the way, what schematic and other info are you using? That is, where did you get them? I'm asking because SAMS, Riders and the factory info usually identify the parts differently. C10 on one might be called C65 on another, etc. Also sometimes there were more that one version of a model.
I looked at a Riders manual on the Early TV museum site and it looks like this TV uses 'split sound'.

_________________
Tim
"Excellent!" I cried. "Elementary," said he. - Sherlock Holmes


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sun 26, 2017 2:58 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7781
Location: Cleona, PA
Checking the sound problem: you can determine whether the audio first tube, output tube, output transformer and speaker are OK by doing this: wait until the sound drops out, then turn the volume up and touch your plugged-in soldering iron to the center terminal of the volume control: should give a healthy buzz in the speaker. If it does, everything from the volume control to the speaker is OK and the trouble lies before that point, see next paragraph.

One thing that was suggested before, I have not seen reported as having been done: that was using freeze spray. This will test whether a component has changed characteristic by heating up. If you don't have specific freeze spray, you can use a can of computer keyboard "air" turned upside down. Wait until the audio drops out. Then go one by one on the resistors and caps in the audio IF, detector, and amplifier chain. Spray a resistor, wait a few seconds, if the sound comes back, replace that one. If no change, go on to the next component.

_________________
Reece


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sun 26, 2017 3:05 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
wrnewton - I will try the soldering iron technique. I did use freeze spray - two cans of it - to no avail. I'm going to order some more and try it again.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Feb Sun 26, 2017 4:16 pm 
Member

Joined: May Thu 14, 2015 4:15 pm
Posts: 579
Location: Dallas, TX
In the mean time you can check the voltages. I would measure the voltages around the audio tubes and also the voltages on the resistors you replaced R100 with. These would be with respect to chassis ground. Compare the measurements with the ones in your documents. The voltages across the R100 resistors will show if something they are connected to is drawing the wrong current.

_________________
Tim
"Excellent!" I cried. "Elementary," said he. - Sherlock Holmes


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Tue 11, 2017 2:51 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
Brief update - the "thermal problem", where the sound fades away and stays that way, seems to be gone. I've played the set many times for many hours over the last month and that doesn't happen. So I'm going to consider that solved. What did it, I think, is adjusting all of the little screws on top of the cans on the chassis - you know, the ones that everyone told me to never ever touch :o . Only the ones in the tuner and audio circuits, though. That seemed to get things torqued around so that the performance is generally good.

I may do some more fiddling. I'd like to see if I can get the picture completely clear - there is a bit of snow and such sometimes that I'd like to try to eliminate. Also, some of the main controls are not really centered, but way off one way or the other to make things happen. I can live with that, but may take some risk to see if I can get things to where they are centered.

BTW - after 2 years working on his thing, I just got my first shock recently :shock: . My hand got too close to the top of the high voltage tube. It was - stimulating.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Tue 11, 2017 6:09 pm 
Member
User avatar

Joined: Nov Thu 08, 2007 2:44 am
Posts: 2730
Location: Martha's Vineyard, Mass.
sdyer wrote:
BTW - after 2 years working on his thing, I just got my first shock recently :shock: . My hand got too close to the top of the high voltage tube. It was - stimulating.


It was...inevitable.

Welcome to the club.

Lee 8)

_________________
“You can always count on the Americans to do the right thing after they have tried everything else.”


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Fri 14, 2017 10:39 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
I'm now looking at the resistors in the RF circuit. The TV works and works pretty good, but I'm looking to maximize how good it works. At the same time I don't want to do a bunch of useless or tedious work (the RF circuits are really packed into a tight space) and risk breaking something, which I've done on this set before. Below is the info I have on my in-circuit measurements on the RF resistors. Any suggestions on which would be the most beneficial to try replacing first? Also, why would I start with some over others? I'm curious how the circuit works.


Attachments:
RF - tight quarters.jpg
RF - tight quarters.jpg [ 205.84 KiB | Viewed 1378 times ]
RF - map.jpg
RF - map.jpg [ 107.7 KiB | Viewed 1378 times ]
RF - schematic.jpg
RF - schematic.jpg [ 142.38 KiB | Viewed 1378 times ]
File comment: Note: the percentages are quick ballparks. I did not do the math.
RF - hi resistors.jpg
RF - hi resistors.jpg [ 127.55 KiB | Viewed 1378 times ]
Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Fri 14, 2017 11:04 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5164
Location: Woodinville, WA USA
I think usual practice is to stay out of the tuner unless you have the right equipment and experience to realign it (I sure don't).

Do you have any specific symptom that you would attribute to a tuner problem?

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


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Fri 14, 2017 11:43 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
I'm sure it's unaligned by now - I've fiddled with the screw adjustments in the RF and audio circuits, as well as the little screw on the front of the tuner module. All this has resulted in pretty good picture and sound. The specific issues that remain are:
- bands of "snow" that slowly move up the screen - not horrendous, but noticeable
- controls are not centered - I get the feeling that I've torqued all of the controls, little screws as well as the knobs on the front, to make it work. I'd think it should be possible to get it all set so that the controls are basically centered, so they can be adjusted either way.
- sound vs. picture - when I coil up the antenna wire, the picture gets very clear, and the sound goes way low. I'd like to get the clear picture somehow, but keep the sound

These are not killer problems and I'd be happy to run the set without them fixed. But a clearer picture would be nice.


Last edited by sdyer on Apr Sat 15, 2017 3:33 am, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Sat 15, 2017 1:17 am 
Member
User avatar

Joined: Feb Thu 17, 2011 11:27 pm
Posts: 10856
Location: Long Island, N.Y.
Reading these posts so reminds me of the times I had early Philco TV's in my collection. As I stated earlier, they're great looking sets, but very finicky and cause a lot of frustration. A friend has a 48-1002 for sale and every time he gets it working, something else soon fails!


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Sat 15, 2017 1:03 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
Decojoe67 - working with this old set has made me thoroughly appreciate a) the ingenuity that made TV happen, and b) how far we have come.

The old sets like this seem to be an endless series of knobs and adjustments to account for all the variances and drift. But they got it to happen in an economically viable way which is a feat.

New sets are amazing - big, brilliant and with virtually no futzing. They don't drift, don't have 45 little screw adjusters inside - they just work. Of course they take as much time to boot as the old sets took to warm up...


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Sat 15, 2017 2:07 pm 
Member
User avatar

Joined: Feb Thu 17, 2011 11:27 pm
Posts: 10856
Location: Long Island, N.Y.
sdyer wrote:
Decojoe67 - working with this old set has made me thoroughly appreciate a) the ingenuity that made TV happen, and b) how far we have come.

The old sets like this seem to be an endless series of knobs and adjustments to account for all the variances and drift. But they got it to happen in an economically viable way which is a feat.

New sets are amazing - big, brilliant and with virtually no futzing. They don't drift, don't have 45 little screw adjusters inside - they just work. Of course they take as much time to boot as the old sets took to warm up...

I totally agree. As frustrating as these early TV's can be to make work properly, in that is the challenge and fun of owning one. I used to want my vintage TV's playing rock-solid like a modern set, but that is rarely the case. Actually you need to let one of these work for at least 15 minutes before you even bother making adjustments. These days I'm forgiving with them and often make adjustments throughout the time I'm watching them. The old sets are a very cool experience to watch a classic movie/show on, but in the evenings when I settle down, it's the modern flat-screen TV.
Continued success with your set. One day get a period Admiral and you'll be impressed at how simple and reliable they are compared to the Philco.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Mon 17, 2017 5:10 pm 
Member
User avatar

Joined: Nov Thu 11, 2010 6:03 pm
Posts: 664
Location: Pewaukee, WI
If it was not for the static I'd advise you to steer clear of the tuner....I'd still advise you to look for other sources of the issue first (Internal and external baluns, signal source, local interference, etc.).

Osc. adjustments on the tuner and sound stage IF adjustments are about as far as can safely be gone without messing up the tricky video IF alignment.

In your shoes I'd either coil that wire for clear picture and try to get sound back, or replace the off tolerance resistors 1 by 1 powering up between each change to see the effect (and know which steps to reverse if your work messes it up). Be mindful of lead dress...Try to keep it similar. Up in the TV spectrum you can literally change the alignment by changing lead dress.

One advantage of the early sets is that often the alignment info has an alternate procedure that does not require a sweep generator (still need a regular RF generator though) so it should be possible to align it....The disadvantage of that is that often the non-sweep procedure does not yield as good of results.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Mon 17, 2017 7:19 pm 
Member

Joined: Jun Thu 25, 2015 3:21 am
Posts: 1219
when i worked on tvs they had specialized shops for tuner repair. if you needed tuner repair you would pull the tuner and send it out for repair. if the customer would pay for it you could also replace the tuner with a new or rebuilt one. what i was taught and everything i read said dont touch tv tuner repair yourself send it to a shop that specializes in tuner repair.

does anyone know if they still have tuner repair shops out there?

yes in the rf stage lead dress is critical. if u do attempt this replace parts in the exact same position or as close as possible. keep leads as short as possible consistent with original lead dress. good luck.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Mon 17, 2017 7:36 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 3779
Location: WI 54812
If your inclination is to maximize your nostalgic TV watching pleasure, then you may want to look into installing composite video and audio input jacks. Keeping a vintage set in reliable operation from the video amp to the picture tube becomes a much less demanding experience, and it pretty much eliminates the need for specialized alignment test equipment. As an aside you'll benefit from the best video and audio quality possible from the technology. The front panel controls will still operate as expected(other than the channel knob which you're not utilizing anyhow). No one other than yourself will give it a second thought why the set appears so reliable in operation.


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Mon 17, 2017 7:54 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5164
Location: Woodinville, WA USA
Re the tuner: I think it's a bad idea to shotgun a bunch of tuner parts in hopes of a miracle cure. As thomas13202 mentioned, back in the day, even experienced TV repairmen didn't try to fix tuners themselves. They sent to the tuners out to specialists, and the last I heard, there are no such specialists anymore.

Before messing with the tuner, I would investigate and rule out ALL other possible causes for your symptoms.

Re injecting video and audio: this article shows how I built a simple A/V adapter for my Admiral 24C15:

http://antiqueradio.org/A-V_AdapterForVintageTVs.htm

Note: my Admiral isn't identical to your Philco, so some changes might be required. Also, if you want to permanently modify your TV to use direct video and audio, that's a simpler job than making the adapter switchable as I did.

Just my $0.02.

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


Top
 Profile  
 
 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Apr Mon 17, 2017 11:08 pm 
Member

Joined: Jan Sat 31, 2015 10:06 pm
Posts: 404
Thanks Phil. you know, I read that article of yours last year, several times, in detail. I very seriously considered doing that. Ultimately I came down on the side of keeping the set as original as possible. Back in the day they watched it via the tuner, so I figured I would leave it that way, warts and all. Plus I couldn't easily figure out where to inject the video signal. :)
I may yet try something like this. The cabinet will take a while to finish (colder weather is coming, so refinishing stops dead), so the electronics will be on the bench for a while.


Top
 Profile  
 
Post New Topic Post Reply  [ 735 posts ]  Moderators: 7jp4-guy, Mr. Detrola Go to page Previous  1 ... 29, 30, 31, 32, 33, 34, 35 ... 37  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: irob2345, thomas13202 and 6 guests



Search for:
Jump to:  






















Privacy Policy :: Powered by phpBB