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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Mon 23, 2020 9:12 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1668
Location: Phoenix, Arizona
Once addicted there is no stopping.

I bought a new capacitor from AES. It arrived in the mail about 24 hours after I placed the order and is mechanically identical with the old can electrolytic.

I don't believe I could had re-stuffed to old can as it had three of the four mounting lugs soldered directly to the chassis.

I used my monster soldering iron and soaked up as much solder as possible from the lugs and then brute force removed the old can

For the new can I just twisted the lugs and added a ground wire just in case.

The chassis is a bit corroded, I don't plan to make this perfect although I may repaint the transformer.

The new electrolytic is 30 -30 - 30 - 30 @ 475, I only needed three sections, The original was 20 - 20 - 30 @350, however I will utilize the remaining section and ge rid of another tubular electrolytic.


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Mon 23, 2020 11:59 pm 
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Joined: Jan Thu 16, 2020 12:29 am
Posts: 486
jimmc wrote:
Once addicted there is no stopping.

I bought a new capacitor from AES. It arrived in the mail about 24 hours after I placed the order and is mechanically identical with the old can electrolytic.

I don't believe I could had re-stuffed to old can as it had three of the four mounting lugs soldered directly to the chassis.

I used my monster soldering iron and soaked up as much solder as possible from the lugs and then brute force removed the old can

For the new can I just twisted the lugs and added a ground wire just in case.

The chassis is a bit corroded, I don't plan to make this perfect although I may repaint the transformer.

The new electrolytic is 30 -30 - 30 - 30 @ 475, I only needed three sections, The original was 20 - 20 - 30 @350, however I will utilize the remaining section and ge rid of another tubular electrolytic.


Its great you used the new twist lock cap.

I thought it was also interesting on these sets how they rotated the power transformer to minimize magnetic interference on the CRT beam, the MU-Metal shield on the CRT also helps. The original transformer also has a copper flux band, the replacement transformer on my set didn't have one, but it was still ok. There was still, despite the shielded enclosure, a trace of interference visible from the EHT RF power supply as slightly tilted closely spaced horizontal lines in the image, but its very subtle on my set. If you take the shield box off, the interference is extreme.


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Tue 24, 2020 12:34 am 
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Joined: May Sun 07, 2017 11:35 am
Posts: 840
Location: Belrose, NSW, Australia
I've found that NOS twistlug cans need careful reforming else they will heat up and you risk undoing all your good work!

_________________
Wax, paper, bitumen, cotton, high voltages - what could possibly go wrong?


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Tue 24, 2020 12:45 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1668
Location: Phoenix, Arizona
Before I did plug and smoke, I applied B+ slowley with a powersupply.

Good point to mention.

It appears they make quite a variety of these cans and we should find varieties that wil work in most sets.

Getting the clutter glob from under the chassis helps a lot.

Jim


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Tue 24, 2020 12:52 am 
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Joined: Mar Sun 01, 2009 10:27 pm
Posts: 5256
Location: Ann Arbor, MI
irob2345 wrote:
I've found that NOS twistlug cans need careful reforming else they will heat up and you risk undoing all your good work!

The caps from AES are NNS (new new stock).
NOS caps should not be used. Using a reformed NOS cap is not really different from reforming the old cap already in the set. You can't count on it lasting very long.

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Tom


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Tue 24, 2020 9:18 am 
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Joined: May Sun 07, 2017 11:35 am
Posts: 840
Location: Belrose, NSW, Australia
Well if I'd known they were NOS I wouldn't have bought them!

They did come up OK in the end though. Time will tell.

Where I come from, there were two main brands of electros in the 50s and 60s. One of these brands will nearly always reform successfully, the other, hardly ever. I'll usually put a chassis on the dim bulb overnight or sometimes for a day or so just to see if it is worthwhile.

_________________
Wax, paper, bitumen, cotton, high voltages - what could possibly go wrong?


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Tue 24, 2020 4:22 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1668
Location: Phoenix, Arizona
The can Electrolytic I installed is new manufacture.

Someone posted a you-tube of this guy who has the original machinery from Mallory, I believe.
He manufactures the can electrolytic as they were made originally using the same materials.

They are not a modern Asian capacitor stuffed in a can.

It appears the capacitor is wound in layers then they impregnate it in the secret sauce and seal it up in the can. They Form it at working voltage.

Antique Electronic supply is a distributer and they stock quite a few varieties.

They seem to be more into the Gituar Amp business and this is what seems to be favored.

They will make custom orders in large quantity.

I used a stock 30 - 30 - 30 - 30 @475V to replace a 30 - 30 - 20 @ 350V in my TV.

Fits perfect and works perfect.


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: Mar Thu 26, 2020 1:38 am 
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Joined: Jan Thu 16, 2020 12:29 am
Posts: 486
jimmc wrote:
The can Electrolytic I installed is new manufacture.

Someone posted a you-tube of this guy who has the original machinery from Mallory, I believe.
He manufactures the can electrolytic as they were made originally using the same materials.



I have been using these new manufacture capacitors (NNS) in my restorations for at least 15 years, or more. I have been buying them from AES the whole time and having them Air posted to me in Australia and it really surprised me that quite a few TV & radio restorers in the USA did not seem to know about these and the use of the original Mallory manufacturing equipment. So these re-makes are every bit as good as originals when they were freshly made. They are far preferable to reformed NOS electrolytic caps.


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 Post subject: Re: Admiral 19A11S & Faudell & White's brilliant circuit.
PostPosted: May Sun 10, 2020 8:26 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 1668
Location: Phoenix, Arizona
Among the interesting circuits used in this little TV set, I find the combination Audio Output, 145 Volt voltage regulator rather interesting.

The 6AS5 Audio Out tube has the 250 volts primary power supply applied to its plate through the speaker transformer.

The control Grid of this tube has a fixed bias of 140 volts supplied by way of two resistors connected in series from the 250 volt primary B+ to ground. They form a voltage divider biasing the control grid at about 140 volts. As this is the audio output, audio is coupled through a .001 MFD cap.

The Cathode is connected to a 40 MFD electrolytic cap and a typical filter circuit so no audio is present on the cathode.

Theory is if the cathode voltage rises higher than the control grid, the tube cuts off. Cathode falls somewhat below the control grid and it starts to conduct. It thus regulates the cathode to 145 volts which supplies the Tuner and IF section.

So after several Re-Caps and fixes, I have been watching morning news on this set and aware of an occasional cracking in the audio.

Someone on this forum had suggested checking resistors and today I replaced the 560K and 470K 5% original resistors that form the voltage divider and now no crackle.

The voltages I mention above are higher than stated in SAM's, maybe due to higher line voltage these days. I had already replaced all the cap's and the 6AS5. The parts for this section are very tight in the chassis and require surgical procedure to remove old and not damage a 7 Pin tube socket.

I looked at the regulated voltage supply and there is no noise, audio. nothing on the output of the filter circuit feeding.

Jim


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