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Title: National NC-300 S-Meter at Max in CW Mode Post by: W1TTL on September 29, 2020, 09:25:25 PM Hi Everyone,
My S-meter has been working fine in AM mode, however, when in CW mode, it has a maximum deflection. I followed the instructions to zero the S-meter with R44 and that worked fine. As soon as I switch the mode to CW, the S-meter pegs to the max, even with the antenna terminal grounded. Any advice where I should look first? I am going to star aligning the radio and for some of the steps, it looks like I need to be in CW mode and watching the meter for max deflection. 73, Tony Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: MikeKE0ZUinkcmo on September 29, 2020, 11:01:09 PM In the manual, page 11, para 3-5
(https://photos.smugmug.com/NATIONAL/300/i-4JWZDNH/0/f6681a14/S/S%20meterCW-S.jpg) Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: K1JJ on October 02, 2020, 09:23:58 PM Only a cheap pimp would design a receiver with an S-meter circuit that doesn't work on CW.... ;D
T Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: W1TTL on October 02, 2020, 10:12:07 PM Mike,
Thanks so much! I was pulling my hair out. I missed that section in my manual so I appreciate you copy and pasting it. I would’ve NEVER guessed that you couldn’t measure CW signal strength. I wonder why National did that in such a top shelf receiver? 73, Tony W1TTL Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: Pete, WA2CWA on October 03, 2020, 12:15:05 AM Mike, ... I wonder why National did that in such a top shelf receiver? 73, Tony W1TTL Probably because it always seemed like the receiver was a "work in process". The number of service bulletins and addenda that they issued, is roughly around 14 or 15 sheets. Fortunately, many years ago, I acquired the NC-300 factory test and alignment procedure manual that National used on the manufacturing assembly line. This info was only used in the factory. They never issued it to the public. Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: Detroit47 on October 05, 2020, 10:21:06 AM [/quote] I acquired the NC-300 factory test and alignment procedure manual that National used on the manufacturing assembly line. This info was only used in the factory. They never issued it to the public. [/quote] Can you scan and post this? Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: Pete, WA2CWA on October 05, 2020, 01:57:56 PM Quote I acquired the NC-300 factory test and alignment procedure manual that National used on the manufacturing assembly line. This info was only used in the factory. They never issued it to the public. Can you scan and post this? It's been listed on my site, www.manualman.com for the last, at least, 20 years. :D Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: W2JBL on October 24, 2020, 12:07:59 AM AGC is disabled in the CW mode, and the S meter goes to the pin. If you want it to work on CW put the mode switch in the SSB position.
Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: WBear2GCR on October 24, 2020, 09:24:16 AM Quote I acquired the NC-300 factory test and alignment procedure manual that National used on the manufacturing assembly line. This info was only used in the factory. They never issued it to the public. Can you scan and post this? It's been listed on my site, www.manualman.com for the last, at least, 20 years. :D I think he was asking you to share this one with the community... Title: Re: National NC-300 S-Meter at Max in CW Mode Post by: Pete, WA2CWA on October 24, 2020, 01:59:09 PM Quote I acquired the NC-300 factory test and alignment procedure manual that National used on the manufacturing assembly line. This info was only used in the factory. They never issued it to the public. Can you scan and post this? It's been listed on my site, www.manualman.com for the last, at least, 20 years. :D I think he was asking you to share this one with the community... (https://images-ra.adoptapet.com/seo/1/mj/102_m1.jpg) |