[R-390] Parts Needed, new R-390A owner & questions...

[Flowertime01 at wmconnect.com]

Steve,

Welcome to the group of owners.

On the IF deck caps. Once you start you may as well do the whole deck.
As long as you have to get some caps you mite as well get enough to do them 
all.
Once you start getting the iron hot you may as well do them all.

You do it once in the receiver and you are done with it for life.
Do use a good 600 volt cap on the mechanical filters. It is just cheep 
insurance.

Good 250 volt or better are OK else where in the receiver.

Do change the 8 uf C609 cap in the audio deck. A larger value helps. it 
only needs to be 30 volts or so. You do not need the high voltage model the 
military used to have a common in stock part.  A 30 volt 10 or 20 uf works nice.

There are a couple of BBOD under the RF deck. Someday you may want to 
change them.

You should pull the RF deck at least once and do an inspection and over 
haul.
Do change the BBOD under the RF deck.
Do perform a good visual inspection and alignment of the RF band switch.

The goal is to make sure you get as much metal to metal contact in each 
wafer section of the switch in each of the six band switch positions. It is a 
six variable equation and best done by eye. Look to see if in the past the 
switch has been poorly adjusted and has some metal corners burnt off. If the 
switch section contact area is not large enough for the current, the metal 
get burnt. Then there is less metal to adjust and make contact with. No need 
to burn out RF band switches from poor adjustment.

Do the mechanical alignment a couple times to get it good.

Check the tubes and do the RF alignment a couple times back to back. 
A second pass and third pass will yield improvements.

The BBOD are .1uf and .05 uf (5000 PF) once you start putting in new caps 
two things happen.

There is a lot more room under the deck. You find shorter closer points to 
ground the caps to. Along the way unbolt and rebolt the ground lug hardware. 
This just cleans up any crud under the ground points and gets you a good 
mechanical connection for the next 50 years.

Once you start the process, you quit wondering and just know you are going 
down the right path of least resistance as a once in a life time experience. 
You should be able to recap the whole IF deck in a weekend.

Think $15.00 in parts. 10 hours plus at 25.00 an hour and know you just 
about double the value of the receiver with just the labor dollars you have in 
the receiver.  A good semi PM where you test the tubes and do an alignment 
can be done in 4 hours. Likely 6 to 8 for the real owners. And again at 25.00 
an hour you have added a 100 or 200 in value to the receiver.  You do this 
because you love these old receivers not because you can make money at it.

I hope you are getting some direct to you offers for the parts you need.

Many of the Fellows have some odd parts and will make you an offer.
But you have to ask for what you need. We do not just put up parts as it is 
a waste of effort. But ask and you shall receiver offers. Just the way the 
reflector works.

The Fellows you get offers from are good guys. If you get a bad offer, you 
will let everyone know about it with a post here. This process also culls 
out the bad offers.

welcome Aboard

Roger Ruszkowski AI4NI