re the AGC in the R-725
I just gutted my entire AGC in my R-725 and installed a modified version
of Clark Hatch AGC....further testing is required however it so far is
great!!!
I will let ya'll know later.
re the caps I machined a "new aluminum" container with a lid for the
caps and installed whatever I wanted...same for R390A I used film caps
currently only one in use R725 and has .47 uf 250V Panasonic film
Renée , K6FSB
On 11/9/24 2:47 PM, David Wise wrote:
Thanks, Jordan, multiple radios with one cap each didn't occur to me.
The op-amp circuit and the V506A AGC Time Constant tube will work fine
regardless of meter resistance. If you add 18 ohms, you'll need more meter
gain, that's all. Gary Biasini and I worked that all out when developing our
own meter retrofit mod.
Dave Wise
________________________________
From: Les Locklear <[email protected]
Sent: Saturday, November 9, 2024 2:22 PM
To: David Wise <[email protected]>; Larry Haney <[email protected]>; Geoff
Brozny <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: [R-390] R-725 AGC quits working after 1 hr.
LED’s + 1 why not?
Les Locklear
Get Outlook for iOS<https://aka.ms/o0ukef>
________________________________
From: [email protected] <[email protected]> on behalf of
David Wise <[email protected]>
Sent: Saturday, November 9, 2024 2:49:14 PM
To: Larry Haney <[email protected]>; Geoff Brozny <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: [R-390] R-725 AGC quits working after 1 hr.
Jordan,
"film caps" plural? Do you mean that you did the partial-mitigation for moment
of silence mod that uses one cap for LONG and another cap for MED?
If I were to do it again, I would do Charles Steinmetz's moment of silence mod,
placing the caps behind the front panel, and abandon the original C551 in
place. Once you've committed to removing the panel, you can also illuminate
the frequency readout with LEDs, and install Jan Skirrow's universal carrier
meter circuit if you don't feel like doing mine and Gary Biasini's.
Dave Wise
________________________________
From: [email protected] <[email protected]> on behalf of
Geoff Brozny via R-390 <[email protected]>
Sent: Saturday, November 9, 2024 10:22 AM
To: Larry Haney <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: [R-390] R-725 AGC quits working after 1 hr.
On 11/9/2024 1:09 PM, Larry Haney wrote:
Geoff, the minimum voltage for that cap is a good quality 250 vdc or
more (200 vdc on the plate of the 'time constant' tube). You might find
one 2mfd cap that will work.
Regards, Larry
Thanks Larry, I appreciate it. Hopefully I can get it back up and
running this next week.
Thanks,
Geoff
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