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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Tue 29, 2016 3:44 pm 
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Yes, there are caps shown inside the audio IF cans on the schematic. I don't know if they are the exposed type prone to failure though. I do know that opening up an IF transformer can be tricky business. One slip and a delicate coil can be damaged. Also keep in mind that if you do replace those caps it will throw the alignment off and will require some test equipment and careful adjustments to restore.


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Tue 29, 2016 8:05 pm 
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bandersen wrote:
Yes, there are caps shown inside the audio IF cans on the schematic. I don't know if they are the exposed type prone to failure though. I do know that opening up an IF transformer can be tricky business. One slip and a delicate coil can be damaged. Also keep in mind that if you do replace those caps it will throw the alignment off and will require some test equipment and careful adjustments to restore.


I was hesitant to even bring up the subject because of the severity of the diagnosis and repair. But at this point in the game it seems like a real possibility. I agree completely to proceed with extreme caution, and within the realm of ones experience level and available resources. This most certainly has been an amazing and inspiring restoration effort.


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 12:42 am 
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Location: Conway, Arkansas
thomas13202 wrote:
joernone...has allot of bad habits and advises things that should never be done such as ignoring lead dress taking the screw out of trimmer condencers and removing the mica sheat to clean. soaking a chassis in evaporust. taking every part off a chassis then trying to rebuild it. all these things can cause real problems.


Allow me to enlighten you...it's called "restoring". After applying all my so-called bad habits, every item that's been restored continues to function very well to this day. Since you seem to know it all, how about providing a link to a step-by-step restoration you've accomplished...minus the bad habits, of course.

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 1:03 am 
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bandersen wrote:
I don't know if they are the exposed type prone to failure though. I do know that opening up an IF transformer can be tricky business.
This article has a section titled "Replacing Mica Capacitors in Audio Transformers" that may be informative:

http://antiqueradio.org/Admiral24A12Television.htm

That TV was an Admiral; I don't know offhand what style of IF transformers your set has, or what's inside them. In some TVs, such as that Admiral, it is not terribly difficult to remove the can so that you can see what's inside. In that TV, the mica caps are the "exposed type" that Bob mentioned -- little naked slabs of mica with electrical connections. Those are more likely to go bad than the more conventional "domino" type of mica cap.

As explained in the article, there are different ways to install the new caps: either in the same position as the old ones, or underneath the transformer, attached to the appropriate terminals. Here is another article with a section about replacing mica caps in audio IF transformers:

http://antiqueradio.org/Admiral24C15Television.htm

If you are not set up to do an audio alignment, I would not replace those caps just for the heck of it. As the old service books advise, always eliminate the more obvious, simple causes before attempting a trickier solution.

Regards,

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

Image

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 4:12 am 
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Allow me to enlighten you...it's called "restoring". After applying all my so-called bad habits, every item that's been restored continues to function very well to this day. Since you seem to know it all, how about providing a link to a step-by-step restoration you've accomplished...minus the bad habits, of course.[/quote]

i accept your chalange. bring your cam and i will be happy to show you how to get a radio working the way the text books and experts of the day taught you to do it. when i was working in electronics repair for 20 years that is the way i always did it. no cam though. for that matter no digital either or internet. i have probably repaired more tvs in a month than you did in your entire life.

allow me to enlighten you the reason for observing proper lead dress is to prevent feed back or interference. the original designers arranged parts the way they did for a reason.

taking trimmers apart should never be done because the mica sheats can be broken. the alignment is way out when you put it back together. yes it can be brought back to normal condition but you are making more work for nothing. also the conventional wisdom at the time was the alignment adjustments should never be touched unless components were replaced that cause alignment problems or some idiot was in there playing with the adjustments. or do you think ghirardi markus nri to name a few were idiots.

takeing every part off a chassis. the more you take off the more chance of damaging something and the more chance of human error putting it back together. dont do it. i had a radio i had to replace every wire due to crumbling insulation. i did it one wire at a time. no way do you take every wire out then put it back together. yes you can figure out what wire goes where from the schematic diagram but do you remember the correct lead dress. this is not shown on a schematic.

i could go on but i wont because we are hijacking someone elses thread.

back to the philco and sorry for the interuption in your thread.


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 4:27 am 
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If you are not set up to do an audio alignment, I would not replace those caps just for the heck of it. As the old service books advise, always eliminate the more obvious, simple causes before attempting a trickier solution.

very good advice phill. i agree 100 percent.


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 4:48 am 
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.................................

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Last edited by badrestorer on Nov Wed 30, 2016 3:32 pm, edited 1 time in total.

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 5:04 am 
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badrestorer and thomas13202 - STOP IT. Please do not use this thread to air your differences.
Edit: Thank you.


Last edited by sdyer on Dec Wed 14, 2016 5:05 am, edited 1 time in total.

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 5:43 am 
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Has anyone mentioned the use of freeze mist to troubleshoot problems that only show up when the set warms up? With the set warm you start cooling various parts with the freeze mist until it starts working again. That will often find the bad part.

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Nov Wed 30, 2016 5:50 am 
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The freeze mist would also keep my soda cold while I work. :)


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Fri 02, 2016 12:20 am 
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After much glueing, clamping, and screwing, the cabinet is now structurally sound. Now on to the refinishing.
Attachment:
Structurally sound at last.jpg
Structurally sound at last.jpg [ 115.02 KiB | Viewed 1402 times ]


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Fri 02, 2016 12:47 am 
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For a complete set of clamping/gluing pics as well as more pics of the cabinet in its current state, see the thread in the cabinet restoration section:
http://antiqueradios.com/forums/viewtopic.php?f=7&t=307372&start=20


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Sat 03, 2016 3:04 am 
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Excellent progress.

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Quote: (Antique TV collecting) always seemed to me to be a fringe hobby that only weirdos did.


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Sun 04, 2016 7:12 pm 
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Joined: Jan Sat 31, 2015 10:06 pm
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I was able to capture the audio problems in a video which I just posted to https://www.icloud.com/sharedalbum/#B0f5n8hH4m5dr7. It's a Match Game '78 episode, fyi. The light gray line going up the screen and the exposure changes are an artifact of filming with my iPhone and aren't a problem with the TV. The TV's picture looks pretty good - just a little juddder every now and then.

Attachment:
Audio Issues Captured.jpg
Audio Issues Captured.jpg [ 33.57 KiB | Viewed 1329 times ]

At about 2 minutes:
- sound begins to fade, buzz increases
- then there's a zap and the sound fixes itself
- sound fades again
- I move to show the speaker and the now heavier buzz, though some sound still gets through
- I change the tuner away and back, and the sound is fixed

After I stopped the video the sound eventually faded again, and changing the channel away/back did not restore it. I turned the set off.

I've still got to go through all of the audio and IF resistors, and I haven't tried swapping the audio or IF tubes. All of that I'll work through. But if anyone has a likely place to point me to, many thanks.


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Sun 04, 2016 9:52 pm 
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sdyer wrote:
- I change the tuner away and back, and the sound is fixed
Have you ever cleaned the contacts in the tuner?

Phil Nelson


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Sun 04, 2016 11:04 pm 
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There is a component somewhere with a marginal internal connection, most likely a metal to metal contact that is just barely making contact. The switch contacts in the tuner are one place where you can get such marginal connections, but if it were in the tuner contacts then you should always be able to get the sound back by wiggling the channel selector. What I think is happening is that by changing the tuner away and back you are creating a very slight voltage surge that is arcing over the bad contact and re-establishing the contact temporarily. Similar to the way I could fix my mothers radio by turning on the room lights. One place you can get such marginal connections is between the tube pins and the tube socket. So with the audio gone try gently wiggling all of the tubes in the tuner, IF strip and audio amp. Another place, as mentioned earlier, is in the caps inside the IF and sound detector transformers. You might try gently tapping the various cans and see if there is one that will bring the sound back when tapped. An alternate to tapping is freeze mist.

sdyer wrote:
The TV's picture looks pretty good - just a little juddder every now and then.

The way your set is designed, that is to be expected. Most sets newer than the late 40's used a circuit that was some variant of a phase locked loop. Such circuits take the average of the last dozen or so sync pulses to sync the horizontal. In your set each sync pulse syncs one horizontal scan line. It doesn't take much interference to affect the sync. The tuned circuit made by that coil you had so much trouble with helps to smooth things out a little

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Mon 05, 2016 5:26 am 
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To verify that the audio amp and audio output tubes are not the noise source, you can inject a audio signal directly into the lug opposite the grounded end of the volume control. Probably should pull the audio IF and ratio detector tubes to make sure those don't interfere with the test. For an audio source use the audio out from your DVD player, or whatever your video source is. In fact you might get to liking the way that sounds and add an external audio in jack.


Last edited by Kevin Kuehn on Dec Tue 06, 2016 5:42 am, edited 2 times in total.

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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Tue 06, 2016 1:57 am 
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Tom Schulz wrote:
try gently wiggling all of the tubes in the tuner, IF strip and audio amp.
And if you find any intermittency there, try cleaning (or even re-cleaning) that socket and its tube pins:

http://antiqueradio.org/FirstStepsInRestoration.htm

If you have never cleaned any of the tube pins/sockets, don't stop with one. They should all be cleaned, on every TV or radio that you restore.

Regards,

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


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Wed 14, 2016 5:00 am 
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The picture is really pretty good, but it get blurry out from the center. What would cause this?
Attachment:
Blurry Edge.jpg
Blurry Edge.jpg [ 46.37 KiB | Viewed 1211 times ]

Here's a quick update on other matters:
- Sound - in working on the sound I broke the 6J6 tube, replaced it with a 6J6A, now sound is all buzzy all the time, much worse. I've ordered a replacement 6J6A (it seems 6J6 does not exist to be bought), hopefully the NOS tube I had is just a dud.
- Sound - tested most resistors in circuit, many are high. I hesitate to dive in and unsolder and test out of circuit, and then replace, as I suspect that the sound problems are a tube (thermal) or IF circuit problem.
- Cabinet - going to haul it to a cabinet maker to determine what kind of veneer it is once and for all


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 Post subject: Re: Philco 48-1000 Complete - how to restore?
PostPosted: Dec Wed 14, 2016 8:30 am 
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if you have a thermal intermittent in a tube wait for the sound to go out then tap each tube gently with a pencil. i had a problem like that in a radio i owned where the filament would open when the tube became hot and the way i discovered the bad tube was exactly that. when i tapped the tube with the intermittent the sound came back on.

any resistor that is out of tolerance by 20 percent should be replaced.

the nos tube that caused buzz could have grid emissions. that can cause problems for sure. also the tube could be microphonic. did you check the pin out on the 6j6a and is it identical to the 6j6. if the 6j6 is a metal tube pin one will be grounded to the metal tube envelope. on a glass tube this is not the case. in some cases replacing a metal tube with a glass tube can cause a problem due to no shielding on a glass tube. to see if that is the case shield the tube by wrapping aluminum foil around the tube. ground the aluminum foil to the chassis. if the buzz goes away you know that you need to find the metal tube. usually the tube number with nothing after it is a metal tube with a g after it would be an early style glass tube envelope and gt after it would be the later style glass envelope.

poor focus can be caused by a weak crt low high voltage or misadjusted focus control.


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