[R-390] R-390A help needed

[Bob]

Thank you to all that answered my questions. It looks like I do have some
work to do. It may take awhile as my wife just had knee replacement surgery
and she can be somewhat demanding. I will post what I find, also there was a
question of which way that I aligned the IF.  Set it for 455Kc only, not the
stagger tuned method. Also there was a question about how the PTO was
adjusted. I used a freq counter to set the PTO to 2455KC at the 7Mc +000
point. I then maxed a received signal by slightly tweaking the Oldham
coupler. 

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of wb5uom at hughes.net
Sent: Friday, March 12, 2010 7:18 PM
To: Flowertime01 at wmconnect.com; R-390 at mailman.qth.net
Subject: Re: [R-390] R-390A help needed

Now THAT is some information!

David/WB5UOM

----- Original Message ----- 
From: <Flowertime01 at wmconnect.com>
To: <R-390 at mailman.qth.net>
Sent: Friday, March 12, 2010 6:28 PM
Subject: Re: [R-390] R-390A help needed


> Ray,
>
> Like all good things you start in the middle.
>
> You need to put 455Khz at about 150uv into the IF deck. If you have good
> bandwidth you can down load TM 11-5820-358-35 as a PDF file. Then start
with
> paragraph 73 adjustment of the IF gain pot. Para 73 just tells you how to
> hook things up for the test and gain pot adjustment.
>
> Never has any one told you that you need 30 DB difference at this point to
> get the receiver to work. It is not in print.
>
> To get 455 into the IF deck you remove the BNC to Mini BNC adapter from
the
> back panel and the 455KHz IF output cable on it. You use these parts to
> patch the signal generator into J513. Ignore all the TM stuff about test
> adapters. Just use a BNC cable to get from the generator to the IF deck.
If you
> coupler is missing. Just improvise a bit of wire from the coax into the IF
> deck jack and get a ground from the coax shield to the receiver.
>
> You want a good analog DC volt meter (any VTVM) on the diode load. You
want
> 600 ohms (2 1,200 Ohm 1/4 watt) across the local line output and another
AC
> volt meter across the 600 ohm load.
>
> You set the generator up for 150 uv CW into the IF deck.
> You adjust the IF gain for -7 volts DC on the diode load.
> You turn on the modulation at 30%.
> The local audio AC voltage must be about 16 Volts AC (1/2 watt, 26DB)
> across the 600 ohm load.
>
> Turn the generator back to CW. the local output should go to zero volts
> (drop down 30DB).
>
> Until the receiver will produce 30 DB change in signal plus noise to noise
> in this test, it will never provide the needed signal to noise at the
> antenna. Nothing can be done in the RF deck to compensate for an IF and
Audio deck
> that is not up to expectations.
>
> Expectations being 150 UV sensitivity, 30 DB difference and 1/2 watt of
> audio out of the local audio into 600 ohm load.
>
> The exact level of 150 is not a holy grail. You just need to be at about
> this level. You can screw the IF gain around to get -7 volts. You will or
will
> not have 1/2 watt out and you will or will not have a 30 DB change between
> the CW and modulation.
>
> Swapping tubes will get you there. Alignment helps. Z501 has a 455KHz
> crystal in it.
>
> Back up to test point E210 and inject 455 there. at 10UV you should get -7
> volts and a 1/2 watt out. you can rock the generator through the crystal
at
> .1 to get the generator to 455KHz. you can zero the BFO against the
> generator.
>
> Once you get up to where you can get WWV at 10 or 20 MHz. you can use the
> BFO zero to null WWV into the receiver. Then you can go to CAL and pull
the
> cal oscillator to null with the BFO. You can them drop the dial bezel and
> adjust the dial counter to read zero.
>
> If you have a counter and can count your signal generator the you start on
> the other end, You set the zero adjust to center. You adjust the dial to
> have equal over run on both ends (+ - 30). You adjust the cams to align at
> 7+000. You adjust the VFO to be 2,455,000 at +000 on the dial. You inject
32 Mhz
> and set the receiver to 31+000. you run the BFO to null. you set the
> receiver to CAL then you adjust the cal osc to null against the BFO.
>
> Then you can go and do a mechanical alignment of the RF deck and start
> swapping tubes in the RF deck until you get the whole receive up to par.
>
> Hope this get you going it the right direction. Check out the web pages
at.
> http://r-390a.net
> http://r-390a.net/Pearls/index.htm
> http://r-390a.net/Y2K-R3/index.htm
>
> A must read is Wei-Li's Pearls of Wisdom. He has been collecting and
> categorizing the wisdom which flows through the R-390A mailing list. The
Y2K
> manual is so much better reading than the original TM. You can pop it open
in
> sections. If you are on dial up like me, it is so much faster to access
than
> the big PDF documents.
>
> Roger Ruszkowski AI4NI 33C4H</HTML>
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