[R-390] R390 from Newbie

[flowertime01 at wmconnect.com]

Jerry,

Welcome,

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I am just getting around to begin to use it and have found some things
not working right. Would appreciate a 'starting' point in helping me
know where to start looking

http://mailman.qth.net/pipermail/r-390/  R390 archives
http://r-390a.net/Y2K-R3/index.htm R390 frequently asked questions.

http://www.r-390a.net/  R390 home page.

Find a copy of the Y2K manual, much more readable than the original TM.

Find a copy of TM 11-5820-358-35P also a PDF file on line at R390

Read on the freq ask question to start on the alignment testing procedures.
Do read the pearls of wisdom.

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2) antenna trim seems to have very small effect in peaking any signal

This is mostly an antenna marching problem. But other statements you make 
lead to a bad antenna relay.
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1) receiver sensitivity not anywhere as good as my (unrestored) EAC
390A.

Tubes and alignment. Likely as always with tube receivers, it needs some 
new tubes. Just because it test good on a tester does not make it a tube you 
want in a R390/A.

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3) only small movements in the carrier meter in response to tuning
signal and/or antenna trim knob. 

More clues you need some tubes and alignment.

____________

4) all signals much louder when function switch moved from AGC to
Calibrate

OOPS, there should be no signals when in cal. You expect only cal tones. 
These may or may not be loud, depending on many things. If you really have 
"signals" while in calibrate you have an antenna relay circuit problem.
--------

 Calibrate tone OK on all 100Kc spots but compared to my 390A very low
output so when bandwidth switch down to 2, or 1 cannot hear it anymore.

This is an alignment problem BFO and VFO are collectively more than 2Khz 
apart.

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Time to read the Y2K manual and get started on an alignment and tube 
swapping.

You only need a signal generator and volt meter to get the receiver 
aligned. More stuff is good and can make the job easy. (freq counter comes to mind).

If you do not have a tube tester then find a shop that still has one and 
sells tubes. This is not an easy thing to do. Any cheep tester you can find 
will test the tubes in an R390 for shorts and conductivity. This is as good as 
needed.

Real tube testing comes by swapping tubes into the same socket of the 
receiver and comparing them to each other. Read some Pearls of wisdom for 
procedures on getting this done.

You can tune WWV at 9+000 and 10-000 and check the VLF band over run or 
under run. You expect it to be exact, but may find it off by 3 or more Khz. 
This is not your most important thing to try and fix first. Let the VFO go 
until you get the sensitive and alignment up to par.

Look under the cover of Z501 and ensure there is a 455 crystal in there.

Hang a DC volt meter on the diode load.

Hang a 600 Ohm 1/2 watt resistor (2ea 1200 1/4 watt resistors in parallel) 
on the local output terminal board. 

Then hang an AC volt meter with a DB scale on the same terminals. If the 
meter does not have a DB scale no problem, you just get to do some math. Go to 
radio shack and look at a meter with a DB scale you will see the meter just 
takes the math out of the process.

Start with 455 into the RF deck at E211, walk the generator into the 
crystal with the IF band width set to .1.

You can then zero beat the BFO against the generator.

You need to set the IF gain mid scale and back the generator down until you 
get about -7 volts on the diode load. 

You should have just under 1/2 watt out on the audio with the generator 
modulation turned on and set to about 30%.

Set the IF band width back to 2KHz. 
Set the BFO off.

Turn the modulation off so you just have CW.

The diode load will not change.

The audio output needs to drop 30 DB.

If the receiver will not do this, its time to start swapping IF deck and 
audio deck tubes until you do get at least 26, 27 or more DB and the meter 
lays nice and still on the low end. If its bumping up, you still have a pop 
corn noise tube or tubes to find and get swapped out. Just do the best you can 
with what you have on hand today and go on.

If you have good generator you need to put 150uv into the IF deck using the 
adapter and short cable. Then you are looking for exact numbers. Li put 
this all in the Pearls of Wisdom. Its in the TM very messy to follow.

Once you get the IF deck and Audio deck working well 30 DB signal to noise 
and 1/2 watt out. the you can move back to the RF deck.

The Y2K manual will walk you through all of this.

Roger AI4NI</HTML>