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 ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ R-390 mailing list Home: http://mailman.qth.net/mailman/listinfo/r-390 Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
