More NC-270 Progress

[Fuqua, Bill L]

There is nothing wrong about using a 6BA6 for a product detector just as long as you have enough BFO voltage swing and it is biased is right. No need to change it. I have a NC-270 which has a few minor problems but have not gotten back to it. Mostly with the AGC and S meter.

73
Bill wa4lav


________________________________________
From: Boat Anchor Owners and Collectors List [BOATANCHORS at LISTSERV.TEMPE.GOV] On Behalf Of Steve [stever2k at MCHSI.COM]
Sent: Saturday, August 18, 2007 1:47 AM
To: BOATANCHORS at LISTSERV.TEMPE.GOV
Subject: Re: [BOATANCHORS-TEMPE] More NC-270 Progress

Hammer and a punch???  Wow that must be rather tricky to retighten them that
way but I can think of no other.  How do you do this without wacking
something of value and creating more problems?  Did you make some special
tools of some kind?

Right now I am fighting some distortion under the presence of moderately
strong signals for some reason.  Also the audio on SSb is rather muddy too.
This radio uses a 6BA6 for a product detector which seems a bit uncommon to
me since most of the designs I see are based on the 6BE6.  The radio also
sounds very raspy on the stronger signals when I tune close to zero beat, as
the audio gets lower and lower it is worse, it gets better when I tune it to
a beat note like 900 or 1Khz.  Any ideas on these kinds of problems will
help.

I did try one fix that helped a lot with the spurs or birdies and that was
to decrease the hfo drive into the 1st mixer, that fixed almost all birdies
that I had.  It used a 68 pf coupling cap in series with a 68 ohm resistor
to couple the HFO into the first mixer, I decreased the value of the
coupling cap to 30pf and things got way better.   Was this a reasonable
thing to do?  Or should I have increased the 68 ohm resistor value instead?

Any discussion would help me understand what I did and if it was the right
thing to do, I did not notice any decrease in sensitivity.

Steve NU0P

-----Original Message-----
From: Boat Anchor Owners and Collectors List
[mailto:BOATANCHORS at LISTSERV.TEMPE.GOV] On Behalf Of Glen Zook
Sent: Wednesday, August 08, 2007 5:01 PM
To: BOATANCHORS at LISTSERV.TEMPE.GOV
Subject: Re: NC-270 Progress

Try tightening all of the machine screws, nuts, etc.,
that go through the chassis.  All of the grounds in
the unit are made through these.  If there are rivits
instead of machine screws holding the tube sockets,
terminal strips, etc., then you are going to have to
tighten them using a hammer and a punch.

I "fix" well over 90% of the "strange" problems in
boat anchor equipment that I repair for others by
getting all the grounds working again.

Glen, K9STH


--- Steve <stever2k at MCHSI.COM> wrote:

I put a 3 wire plug on and grounded it but it didn't
make any difference with the scratchy noise I get when
I touch the chasses with a screwdriver, still don't
know what to do about that one.









Glen, K9STH

Website:  http://k9sth.com



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