[R-390] R-390 rack slugs question

[Roger Ruszkowski]

Frank,

You are right slugs do not mix and match well.

Put a request up here for the slug and or other parts you need.

Some of the Fellows have some spare parts and will get back to
you as direct mail and make you an offer.

The RF deck has 8 octaves. as
.5- .999  1.00 - 1.99 2.00 - 3.99 4.00 - 7.99 8.0-15.999  16.00 - 31.999

plus two IF slug sets.

Each slug set has a front middle and back can.

Just ask for the slug you need by the RF band octave and position (front, middle, back)

Actually there are only a few types of slug in each receiver.
But rather than worry about it at this time just keep it simple.

Divide that receiver in half.

Inject 455 into the IF deck at about 150 uv. 0.00015 volts. CW

You set the receiver band width to .1 KHz and rock the signal generator into
the crystal used for the band pass. No exact signal generator of level needed here.

Set the RF gain adjust on the IF deck for -7 volts on the DC load.
With no modulation and no BFO.

Turn on the generator modulation at about 30%.

You should get almost 1/2 watt of local output on the back panel across a 600 ohm resistor
( 2 ea 1200 ohm 1/4 watts work as a load.)

There is a check list on the R390.net page that will step you through all of this.
There is a Y2K manual there that will help a lot even though you have an R390.

The original TM's are there also as PDF files. R390 TM 11 5820-357-35

You need a 30 :1 difference through the IF deck and Audio deck with the 455Hz injection
between CW and modulation. 

There is stuff on the R390.net page and in the Pearls of wisdom that will walk you through
all of this with an AC volt meter and 600 ohm resistor with tables that convert all
the power levels to AC voltages if you do not have an AC meter with DB scales.

If you can not get the 30:1 in the IF audio chain you will never get 20:1 through the 
receiver. 

You can have lots of tubes test good on the tester but still have a high noise level 
that will be unacceptable. 

Once you get the IF audio up to par you can start on the RF deck.

In the RF you can loose under over 8, one two three 1 mega hertz bands due to a poor
crystal in the second oscillator, or loose an octave due to slugs, cans, plug in contacts on the cans
a bad / dirty cap in one of the cans.

You get to use some logical deduction to decide the frequency span of the problem and 
what small number of parts could be involved.

You can save this receiver and restore it to full sensitivity and enjoy it for years to come.

Please do tell us what you find in your receiver that needed fixing.
Ask for help if you need it.

We do not live on line so it may be days before we read your mail and get back to you.

Who ever happens on you mail first and several others will jump in with help.

Some will come direct some will be reflected. It's just the personal choice of the Fellows.

Make your request for parts public here on the reflector.

The responses to sell you parts will be direct and private.

Roger Ruszkowski 33C4H   AI4NI