[Boatanchors] Multi-Elmac AF-68 and AF-68A

[aerosmithl]

You can purchase all the 22 1/2 volt batteries from China with fast shipping. Check E-bay. I bought two for my Elmacs.

Sent from my iPad

> On Feb 21, 2019, at 11:41 AM, D C _Mac_ Macdonald <k2gkk at hotmail.com> wrote:
> 
> Hi, Gary.
> 
> I could not find anything through Google about the differences.  However, the originals had two known problems:  1) Modulator driver transformer quickly went bad, frequently replaced. 2) Negative 22.5 Volt Bias for 6L6 modulator tubes derived from a 22.5 Volt battery with short life (try finding one today). Build voltage doubler from 12.6 VAC filament supply and then hand-select Zener diode(s) to get to 22.5 Volts.
> 
> The "A" model MAY have fixed one or both of those problems.
> 
> 
> 73 de Mac, K2GKK/5​
> Since 30 Nov 1953​
> Oklahoma City, OK​
> USAF, Retired ('61-'81)​
> FAA, Retired ('94-'10)
> 
> ________________________________
> From: boatanchors-bounces at mailman.qth.net <boatanchors-bounces at mailman.qth.net> on behalf of Gary H. Harmon, Jr. <gharmon at idworld.net>
> Sent: Thursday, February 21, 2019 09:46
> To: 'BOATANCHORS2 LIST'
> Subject: [Boatanchors] Multi-Elmac AF-68 and AF-68A
> 
> Looking for a schematic or manual for a AF-68A in order to determine the
> differences in the two.
> 
> 
> 
> Thanks in advance.
> 
> 
> 
> Gary H. Harmon, Jr. - K5JWK - HAM Radio and ATARI Archaeologist
> 
> 6003 Archwood
> 
> San Antonio, TX 78239-1504
> 
> (210) 657-1549 <home>
> 
> (210) 884-6926 <cell and text>
> 
> (210) 657-1549 <FAX with prior notification>
> 
> gharmon at idworld.net
> 
> 
> 
> "Retirement = Every day is a Saturday except Sunday"
> 
> "Real radios glow in the dark"
> 
> "Too many projects, not enough time"
> 
> 
> 
> https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.grissomroadcoc.org&amp;data=02%7C01%7C%7Cf393b397c91f48af153e08d69813be04%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636863607887130052&amp;sdata=N0EqIM3sEfOdEgl4mBy3%2FpV0SbqyqbvrTngWwUkW85M%3D&amp;reserved=0
> 
> 
> 
> ______________________________________________________________
> Boatanchors mailing list
> Home: https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailman.qth.net%2Fmailman%2Flistinfo%2Fboatanchors&amp;data=02%7C01%7C%7Cf393b397c91f48af153e08d69813be04%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636863607887130052&amp;sdata=vW5%2FuPDY%2BsR7BdO4fzXIJ3%2BA2ozs%2FV5WH%2FEdUsrrhb4%3D&amp;reserved=0
> Help: https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailman.qth.net%2Fmmfaq.htm&amp;data=02%7C01%7C%7Cf393b397c91f48af153e08d69813be04