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Title: Bauer 707 Repairs Post by: ka4koe on January 10, 2022, 08:26:37 AM Working again on my Bauer 707 which was a gift from Liz K4GHT (now SK) back in 2017. The transmitter was successfully converted to 75m and in use when it had a major failure early 2018. I was then diagnosed with cancer and was distracted for a few years. Back on repairs and hopefully will have it back on the air for the AM Rally in February.
See video at https://youtu.be/iDE8Ud-DEZE I am eventually going to a grid drive arrangement as the current configuration that modified the driver tube to a TGTP configuration borderline works; the design was taken from ER Magazine. Not stable (TGTP is usually associated with oscillators) and will spew out garbage up and down the band if it is not tuned just right. Fleep KA4KOE Title: Re: Bauer 707 Repairs Post by: kc4mne on January 14, 2022, 07:59:17 AM I have one in S FL. Have not fired it up in a while. Know what you mean about barely working and garbage up and down the band. Mine has that behavior as well.
Title: Re: Bauer 707 Repairs Post by: ka4koe on January 14, 2022, 08:06:37 AM One should not go straight from repairing Valiants to broadcast transmitters like I did. But, I'm fully vested and going to see this project thru.
Title: Re: Bauer 707 Repairs Post by: flintstone mop on April 03, 2022, 07:19:47 PM Well Fleep
This cancer journey is catching. I just got through another bout with my cancer from 2015 trying to make a come-back. But they have newer more dangerous drugs that don't make your hair fall out; and it did put the cancer back into remission. Your thread is about modifying a B'cast TX grid drive?? There are ways to get it to a point where you can use your transceiver and antenna tuner to couple energy to the B'cast transmitter grids. Something needs to be done on the grid side of the circuit to make it reliable and easy on the tuner. I see this is an old thread. I can scan an input circuit for a PA final using a 4CX1500A. And attach here. I'll keep watch for any reply Fred Title: Re: Bauer 707 Repairs Post by: ka4koe on April 04, 2022, 07:42:32 AM I am sorry you are ill. Cancer sucks.
I have a good design from Borgi and parts collected for grid drive using a modern radio as a 20W exciter. All I need is time. I'll get hot and heavy on a project and then run out of steam. I just needed to take a break. I started around Thanksgiving and then hit a creative brick wall in mid-January. PAN Title: Re: Bauer 707 Repairs Post by: flintstone mop on April 04, 2022, 06:02:59 PM My recent bout with cancer in DEC 2021 was about 3 mos of treatment. Me and my wife were out of work, because of possibility of seizures. Never had a problem but was not worth the chance of driving a school bus and something going wrong. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
I had a Raytheon RA 250 that someone used a high power 50 ohm resistor to terminate my plastic radio and it also took about 20 watts going into a coupling cap to the grids of the 2............810 PA finals. It was ready for 160/75. I never tried it out. Too busy on 75 . Fred |