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


It is currently Sep Thu 20, 2018 2:53 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 94 posts ]  Go to page Previous  1, 2, 3, 4, 5  Next
Author Message
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Dec Thu 28, 2017 2:07 am 
Member

Joined: May Thu 14, 2015 4:15 pm
Posts: 948
Location: Dallas, TX
Crist Rigotti wrote:
I'm going to add the retrace blanking circuit that Phil shows on his website. It shows a 250pf 1Kv cap and a 22K resistor. What type of cap should I use? A ceramic, mica, other?

https://antiqueradio.org/Admiral19A12Television.htm

I'd probably go with mica, although I think 270 pF is a more common value. Ceramic would be OK too.

_________________
Tim
It's not the Destination, It's the Journey.


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Dec Fri 29, 2017 1:41 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 12413
Location: San Jose, CA USA
Best to go with a 1 kV voltage rating on that cap. I usually use ceramic, since I have a bunch of those, but 1000 V micas should be OK. Plate voltage can be quite high on vertical output tube, if that’s where you’re grabbing the signal.

_________________
Tom K6VL


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Dec Fri 29, 2017 7:03 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
Yeah, I did get some 1Kv caps for that circuit.

I've ordered the HV caps, 630V caps, and picked the other stuff up from Mouser. They are only a 20 minute drive away! Will Call so there is no shipping. :D

Working on stuffing the 3 section E-Cap C1. Pics to follow.

_________________
Crist


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Dec Fri 29, 2017 6:25 pm 
Member
User avatar

Joined: Mar Sun 01, 2009 10:27 pm
Posts: 4546
Location: Ann Arbor, MI
Crist Rigotti wrote:
I've ordered the HV caps, 630V caps, and picked the other stuff up from Mouser. They are only a 20 minute drive away! Will Call so there is no shipping. :D

Wow! Am I ever jealous of you!

_________________
Tom


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Fri 05, 2018 3:53 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
Been busy over the holiday. Things have settled down a bit.


Attachments:
File comment: I re-stuffed C1 with 3 Nichicon 10k hour caps in the usual manner that I do.
100_8943a.JPG
100_8943a.JPG [ 89.77 KiB | Viewed 1685 times ]
100_8946a.JPG
100_8946a.JPG [ 97.68 KiB | Viewed 1685 times ]
File comment: Then I labeled all the components like I usually do.
100_8956a.JPG
100_8956a.JPG [ 139.09 KiB | Viewed 1685 times ]
File comment: I noticed that the 3 wires coming from the HV coil going to the Osc. 6V6 tube were hard and the insulation just crumbled away. So I'm in the middle of replacing those wires along with the HV wire going to the plate cap of the 1B3GT. That wire was cracking too.
100_8978a.JPG
100_8978a.JPG [ 81.27 KiB | Viewed 1685 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Mon 08, 2018 6:53 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
An update of my progress. The HV caps came in so I started with the HV section. I replaced all the caps and resistors, and thouroughly cleaned all surfaces. I removed the phenolic board and pots and cleaned them too.


Attachments:
100_9005a.JPG
100_9005a.JPG [ 107.42 KiB | Viewed 1621 times ]
100_9006a.JPG
100_9006a.JPG [ 99.94 KiB | Viewed 1621 times ]
File comment: I then installed a fuse holder in the AC line going to the ON/OFF switch. I used an existing holes and just removed the wire from the interlock and folded it back to the fuse holder and installed a new brown wire from the fuse holder to the interlock.
100_9007a.JPG
100_9007a.JPG [ 103.5 KiB | Viewed 1621 times ]
File comment: I then installed C1 and wired that.
100_9008a.JPG
100_9008a.JPG [ 98.44 KiB | Viewed 1621 times ]
File comment: Then C2 was replaced with a terminal strip and 2 E-Caps. The ground terminal was soldered to the chassis like all ground terminals are. The terminal strip was placed in the same location as the clip was for C2. The wires were then just tacked in place so I could do a power up.
100_9009a.JPG
100_9009a.JPG [ 91.43 KiB | Viewed 1621 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Mon 08, 2018 8:39 pm 
Member
User avatar

Joined: Aug Thu 12, 2010 6:25 pm
Posts: 182
Location: Durham, NC
With the lovely work you are doing that TV is going to be better than new when you're done.

_________________
Mark Nelson
A collector of TV signal boosters and UHF converters -- God help me!
tv-boxes.com


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Mon 08, 2018 11:29 pm 
Member

Joined: Oct Thu 23, 2014 5:15 pm
Posts: 95
Awesome work! How do you get the chassis of a 70 year old set to look like it's new?


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 2:40 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
aj2x wrote:
With the lovely work you are doing that TV is going to be better than new when you're done.


Thank you Mark.

_________________
Crist


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 2:42 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
stuben wrote:
Awesome work! How do you get the chassis of a 70 year old set to look like it's new?


I scrub the outside with 50/50 CLR and water using a soft brass bristle brush from Harbor Freight. On the inside I use a cut down acid brush and acetone. Then some Q-Tips to get into the crevices.

_________________
Crist


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 2:44 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
I'm replacing the components in the Horizontal and Vertical sections right now. I thought that I would include a picture of how I arrange things when I'm doing a section of the chassis.
First thing I do is take some close up pictures of the area. Then using some lined notebook paper and a pencil, I draw out what is connected. For example let's say a tube we'll call V12. I draw a circle and place the key way and 8 dots which represent the terminals. I then draw a resistor going from pin 1 and the other end of the resistor I list where it goes like #3 V13, and so on. I also draw in what ever is connected to that terminal like wires, coils, etc.

Then I clip out the components that I'll be changing out. I lay then next to the chassis then I measure the resistance of the clipped out resistors and record them on my spreadsheet. I then get a new resistor and measure that and again record it on my spreadsheet. I dig out the the new caps too. I placed the new components next to the old ones. I then clean up the terminals and clean them using an acid brush and acetone. I then make any repairs needed to wiring etc.

Then I start to install the new components. It's like building a kit now! After soldering, I again clean the terminals with acetone.

Then take a break.


Attachments:
100_9015a.JPG
100_9015a.JPG [ 103.62 KiB | Viewed 1581 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 2:54 pm 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
The Horizontal and Vertical sections are finished. Today I'll power it up and see my progress.


Attachments:
100_9017a.JPG
100_9017a.JPG [ 126.72 KiB | Viewed 1564 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 11:07 pm 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
I did the audio section today. Here are the before and after pictures.


Attachments:
100_9025a.JPG
100_9025a.JPG [ 97.14 KiB | Viewed 1543 times ]
100_9028a.JPG
100_9028a.JPG [ 89.24 KiB | Viewed 1543 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 11:18 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 163
Location: madison,wisconsin
Crist Rigotti wrote:
I did the audio section today. Here are the before and after pictures.


Nice Neat work !
you even cleaned off the old Flux, after power up will you be aligning the I.F stages?

Terry


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Tue 09, 2018 11:31 pm 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
wiseguy wrote:
Crist Rigotti wrote:
I did the audio section today. Here are the before and after pictures.


Nice Neat work !
you even cleaned off the old Flux, after power up will you be aligning the I.F stages?

Terry

Thank you.

Yes, I'll align the IF stages and audio.

_________________
Crist


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Thu 11, 2018 4:57 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
Today I worked backward through V9 the Ratio Detector, V8 the sound IF, V7 the Video Amp, V6 the video detector, V5 the 3rd Video IF, and V4 the 2nd Video IF. All that's left is V3 the 1st Video IF and the Tuner.


Attachments:
100_9038a.JPG
100_9038a.JPG [ 95.29 KiB | Viewed 1473 times ]
100_9039a.JPG
100_9039a.JPG [ 107.53 KiB | Viewed 1473 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Thu 11, 2018 4:58 am 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
BTW, I got a original Sams Photofact for this TV. It's Sams 59-2. I scanned it and sent Steve at ETF a compressed pdf copy that is much better than what's up there now. Looks like Steve did some further compression and the copy isn't all that good.

Never fear. I've uploaded the full resolution pdf in my dropbox. You can enlarged it at least 400X and it is still very readable. Here's the link. Caution large file @16Mb.

https://www.dropbox.com/s/o0f1yge36vw1h ... 2.pdf?dl=0

_________________
Crist


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Thu 11, 2018 5:13 pm 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
OK, I have a concern that I need cleared up. There are these ceramic capacitors used in this TV, mostly in the IF stages. I call them "Hot Dog" caps because they look like hot dogs. Seeing they are ceramic I haven't paid too much attention to them when I do a recap. On this chassis I'm down to the last tube, tube V3, and decided to check some of these caps because they were already disconnected while I'm replacing the resistors. Well, to my amazement the 5 I checked were well out of tolerance......I think.

According to the the Sams parts list, C12-C16 (the ones I checked) can use Aerovox 1468, Cornell-Dubilier 1W series which both are mica caps. I looked in the 1951 Allied catalog and the C-D mica caps have a tolerance of +/- 20% while there was no tolerance listed in the Allied catalog for the Aerovox caps.

In the picture of the schematic below I have penciled in the readings I get for each capacitor. They are:
C12 - 1623pf
C13 - 1431pf
C14 - 1931pf
C15 - 1707pf
C16 - 1230pf

Should I check all of those hot dog caps and replace them too? I've never replaced those before because I've always thought they were good. Now I'm not so sure.


Attachments:
100_9044a.JPG
100_9044a.JPG [ 103.4 KiB | Viewed 1458 times ]
100_9041a.JPG
100_9041a.JPG [ 99.96 KiB | Viewed 1458 times ]

_________________
Crist
Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Thu 11, 2018 5:26 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 12413
Location: San Jose, CA USA
Since those are all bypass caps, a capacitance that is a bit too high should be no problem. I'd leave them in place. I'm surprised they are out of tolerance -- I don't expect that from ceramic caps.

Have you confirmed that they are free of leakage current?

_________________
Tom K6VL


Top
 Profile  
 
 Post subject: Re: Scored an Admiral 19A11
PostPosted: Jan Thu 11, 2018 5:51 pm 
Member

Joined: Jan Sun 18, 2015 5:01 am
Posts: 1149
Location: Waxahachie Texas
Tom Albrecht wrote:
Since those are all bypass caps, a capacitance that is a bit too high should be no problem. I'd leave them in place. I'm surprised they are out of tolerance -- I don't expect that from ceramic caps.

Have you confirmed that they are free of leakage current?

No I didn't check for leakage? How do I do that? Do I use my vintage Solar cap checker for that?

_________________
Crist


Top
 Profile  
 
Post New Topic Post Reply  [ 94 posts ]  Moderators: 7jp4-guy, Mr. Detrola Go to page Previous  1, 2, 3, 4, 5  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 4 guests



Search for:
Jump to:  
























Privacy Policy :: Powered by phpBB