[AMRadio] Screwiest Elmac problem ever

[sparky52 at cox.net]

Hello
Need a little more information ,has this unit been modified for class b modulation ,does it have the original bias battery . Has it been converted with 6ag7s . I certainly would check the mic and connectors ,then make sure you have enough drive off the 12au7 . If I remember correctly, it has been awhile but I thought it was 500 ohms not 5000 on the output ,but I will check. It was great rig in its day. Certainly there are enough old timers on this board to get this thing up and running.

John ac7xh

> On May 15, 2021 at 8:30 AM w5jo at brightok.net mailto:w5jo at brightok.net wrote:
> 
> 
>     Hummmm! maybe a microphone, cord or connector for a start?
> 
>     Jim
>     W5JO
> 
> 
> 
>     -----Original Message-----
> 
> 
>     Maybe a couple of you follow the Elmac emails, but Gary, K3OS has had is
>     AF67 do something weird. He is a regular check in on the Old Friends group
>     that meets on 75 meter 3 times a week here in the Upstate SC area. It was
>     working just fine, then the mod fell off to a very low level. It does have
>     a new modulator interstage transformer from Hammond, which was installed
>     long prior to this problem, the rest original. He is getting 40 watts out
>     in CW and AM, the modulator has been checked end to end, including
>     terminating the output transformer with a 5K load where he read 300 volts P
>     to P across the secondary. When you hook it all back up, you get 10-20% mod
>     max. Voltages, components, all check good, she just won't modulate. Any
>     ideas?
> 
>     Charlie, W4MEC in NC
> 
>     ______________________________________________________________
>     Our Main Website: http://www.amfone.net
>     AMRadio mailing list
>     Archives: http://mailman.qth.net/pipermail/amradio/
>     List Rules (must read!): http://w5ami.net/amradiofaq.html
>     List Home: http://mailman.qth.net/mailman/listinfo/amradio
>     Post: AMRadio at mailman.qth.net mailto:AMRadio at mailman.qth.net
>     To unsubscribe, send an email to amradio-request at mailman.qth.net mailto:amradio-request at mailman.qth.net with
>     the word unsubscribe in the message body.
> 
>     This list hosted by: http://www.qsl.net
>     Please help support this email list: http://www.qsl.net/donate.html
>     Message delivered to sparky52 at cox.net mailto:sparky52 at cox.net
>