[R-390] R390-A questions

Thu Jul 27 18:01:25 EDT 2006

Hi Cecil and others,

Your estimate was pretty close, was a little over a thousand not including 
shipping. I've e-mailed him several times since I think Monday and haven't 
received an answer yet. I think this guy is famous for taking his time 
answering e-mails though so I'm going to wait until at least the end of this 
week to see if I hear something from him. One other thing I forgot was that 
the knob on the megacycle change starting slipping from I thought oil on the 
shaft that had maybe seeped out of the joint where it goes into the radio so 
it definitely did not turn easily. I had to wipe it down and change knobs 
with the main tuning knob. I'll take the bottom off tomorrow after work and 
see if I can at least figure out which gear slipped.

I'm not going to get into it though unless I have to as I wanted one pro set 
up 390-A with which to compare others to and this thing was a mess when I 
first got it, wrong tubes and everything, had had little or no maintenance 
for probably twenty years.
The reason I use the long antenna is because I'm mainly a BCB DXer although 
I want my ham license soon. I usually have two LW's with a Quantum Phaser 
which cuts down on big signals very well but I just moved and haven't had 
time to set up proper antennas
Bob

>From: "Cecil Acuff" <chacuff at cableone.net>
>To: <n4buq at knology.net>, <r-390 at mailman.qth.net>
>Subject: Re: [R-390] R390-A questions
>Date: Thu, 27 Jul 2006 16:19:55 -0500
>
>I agree with all you guys are saying but if I had just dropped (guessing) 
>$1200 to $1500 buck for a pro rebuild I would box it back up and have the 
>rebuilder deal with the problems and pay the shipping back.  I know that 
>puts the radio at risk again because of the shipping issue but that's what 
>I would do....unless of course the owner is capable and equipped to get 
>into the gear train etc....
>
>It may require dropping of the front panel and who knows what.....why go 
>through all of that when you just paid good money to have the radio gone 
>through and it develops a problem like this right after delivery.
>
>It may turn out to be a broken gear clamp which will require 
>replacement....it just gets deeper and deeper.
>
>Bob have you talked with the restorer about the problem?
>
>I've been on both sides of these type issues having done restorations for 
>payment on R-1051's and a few R-390 series radio's.  It's no fun but I 
>would expect to have to make it right if I were the guy that just got paid 
>good money....
>
>Cecil...
>
>----- Original Message ----- From: <n4buq at knology.net>
>To: <r-390 at mailman.qth.net>
>Sent: Thursday, July 27, 2006 3:28 PM
>Subject: Re: [R-390] R390-A questions
>
>
>>If you are lucky enough to get the "driven" gear back onto the wide gear 
>>in
>>the same tooth as it was when the radio was last aligned, then you should
>>be okay; if not, you will probably have to do an alignment (or keep trying
>>to get the original teeth meshed).
>>
>>If things have slipped enough, you may have to do a mechanical alignment 
>>as
>>well to ensure the cams are where they are supposed to be in relationship
>>with each other.  It depends on which gear slipped as to whether this 
>>might
>>be necessary.
>>
>>I'm not trying to scare you, but want you to know what all might have to 
>>be
>>done to get the radio back to operating as it should.  You can do all of
>>this, but you might have to ask some more questions and feel free to do 
>>so.
>>
>>Barry - N4BUQ
>>
>>On Thu, 27 Jul 2006 15:43:58 EDT, Flowertime01 at wmconnect.com wrote :
>>
>>>Bob,
>>>
>>>The problem you describe here reads like a RF band switch alignment
>>problem.
>>>
>>>You also describe a split gear slip problem. I though Barry did a nice
>>job
>>>responding to that problem for you.
>>>
>>>The spring in the split gears need not be maxed out to get the job done.
>>A
>>>wimpy spring or a missing spring in a split gear is not a show stopper.
>>Get
>>>enough tension on the springs by rotating one of the gears against the
>>springs in
>>>the gears to get some tension on the springs. then go a bit more or less
>>until
>>>the teeth on both gears line up. Then you need to slide the gear on or
>>off
>>>the shaft until the split gear runs against the wide gear and both sides
>>of the
>>>split gear stay engaged in wide gear and the tension remains on the split
>>>gears from the split gear springs.
>>>
>>>The idea of the split gears is to remove some of the gear lash when you
>>>change directions when tuning up and down in frequency. Too much tension
>>and the
>>>whole gear train give you R390 wrist. Too little tension and the springs
>>start
>>>to fall out.
>>>
>>>The minimum tension is longer gear life and you can live with a little
>>lash
>>>in the gear train when tuning. Nothing sacred in the gear train set. Play
>>with
>>>the clamps, alignment and adjustments until you get a feel for working
>>with
>>>them and getting them to run in line and smooth. If you brake a clamp ask
>>here
>>>on the reflector for a part. someone will make you a reasonable offer to
>>cover
>>>postage and aggravation of getting it in the mail.
>>>
>>>-------
>>>But now the first two bands do not work correctly unless the megacycle
>>change
>>>knob is tuned lower than the click stop (or whatever you call it).
>>>
>>>-----
>>>This stop would be the detent.
>>>
>>>The Rf band switch changes from 999. to 1.000
>>>at 1.000 to 1.999
>>>at 2.000 to 3.999
>>>at 4.000 to 7.999
>>>at 8.000 to 15.999
>>>at 16.00 to 31.999
>>>
>>>We would call these the RF band octaves. There is one set of RF
>>transformers
>>>and a slug rack for each of these band octives in the Rf deck..
>>>
>>>You can set the Rf band switch with a meter as described in the manual. I
>>do
>>>not recommend this operation. As you tune up and down the band and change
>>>octaves the RF band switch changes. Some gears take care of this. You can
>>read
>>>about it in the manuals.
>>>
>>>Do you have a copy of the Y2K manual from the Net?
>>>
>>>The RF band switch changes as needed. It should seat the switch wafers in
>>>their centers when the detent on the MC knob hits the center seat. You
>>can adjust
>>>the detent spring in or out for more or less tension. Again less tension
>>is
>>>good. But enough so the MC knob set still when the KC knob is spun.
>>>
>>>If you have to go past the MC change point and then back up to get the RF
>>>band switch to set up and enable an octave for you, the switch is out of
>>>alignment.
>>>
>>>The RF band switch alignment is independent of the cam alignment, Zero
>>adjust
>>>and KC band over run alignments. You can do the RF band switch alignment
>>and
>>>then do the other alignments without going back to the RF band switch.
>>>
>>>A real little bit. Just enough to be a pain.
>>>
>>>The best way to set the RF band switch is to pull the RF deck and adjust
>>the
>>>band switch shaft by eye ball. Worry not about pulling the RF deck. Read
>>the
>>>manual a bit. Find a long #1 Philips screw driver to reach the green
>>screws
>>>behind the RF deck. Find a couple 2x4 blocks to rest the frame on. These
>>leave
>>>the front panel hanging in free air. Thus you can drop the front panel on
>>to the
>>>bench and pull the RF deck.
>>>
>>>Some Fellows like to stand the stand the receiver on the RF deck end and
>>>remove the front panel. It then swings like a door at the bottom of the
>>receiver.
>>>You can get at the Dial lock, Oldham coupler spring on the KC shaft, BFO
>>pitch
>>>and bandwidth switch shafts.
>>>
>>>
>>>The RF band switch is a 6 position 6 section switch. Some of the switch
>>>sections carry B+. Not all sections line up real good. Look at the
>>schematic and
>>>find the switch sections that have B+ on them. You want this switch wafer
>>to
>>>align the best.
>>>
>>>Do not try to change the wafer contacts or rotate the wafer sections.
>>>
>>>Remember, yesterday this receiver worked today it does not work.
>>Something
>>>simple fell apart and some simple action will put it back together. The
>>effort
>>>to get to that simple loose part has nothing to do with the total
>>problem. The
>>>effort to get the receiver back together after fixing the simple problem
>>has
>>>nothing to do with the problem. All that extra exercise is just a slow
>>screw
>>>job and real work takes real time.
>>>
>>>After years the switch sections do not all fully mesh and align real good
>>on
>>>each wafer and each contact. If you just do an alignment by meter without
>>>looking at the switch you can get a working receiver. But you risk having
>>a wafer
>>>section where the contacts just bearly make contact. Over time this just
>>>bearly there contact will burn. If you look at your receiver you may see
>>a contact
>>>that has been burnt from a prior alignment that was just barely making 
>>>it.
>>>
>>>Its a judgment call for best looks. Tune the receiver up through the
>>bands
>>>and down through the bands. Look and see how all the wafer sections look
>>at each
>>>change point. Loosen the clamp on the band switch and adjust it a little.
>>Run
>>>up and down the bands until the switch looks to get the best alignment
>>you
>>>can get. You want the Rf band switch to fully make at each change point
>>tuning
>>>both up the band and down the band.
>>>
>>>-----
>>>The feel of the knob is definitely not  right especially when I go from 1
>>to
>>>2 megacycles, there are two distinct clicks.
>>>
>>>---
>>>Bob, you are right on here. One click is the RF band switch moving. The
>>other
>>>is the detent hitting center. They should both occur at the same location
>>of
>>>the MC knob. OK like closer than your receiver does so the RF band
>>switches
>>>clean without cranking the knob both directions.
>>>
>>>
>>>----------------
>>>  A few of the other bands also sometimes need to be fooled with
>>>(megacycle change knob rocked back and forth etc.) to come in right. It
>>>seems to me that the space where the springs are in between the two gears
>>>comes too close together at a certain point and this is when the spring
>>>falls out. Does this indicate worn parts? Also is this a major
>>undertaking
>>>like it seems it would be?
>>>
>>>-----
>>>Bob,  Getting a split gear "loaded" so its springs do not fall out is
>>>separate from your RF band switch problem. Do fix the split gear loading
>>problem
>>>first.
>>>
>>>-------------
>>>Is it normal to have rezero the dial between bands with a newly aligned
>>>radio?
>>>----
>>>I think Barry explained this one for you. But every band has its own
>>crystal
>>>in a conversion stage. Unless two crystals happen to have the same error
>>then
>>>you have to zero adjust for every KC band. Part of normal operation.
>>>
>>>----------------
>>>And also is it normal to hear sideband artifacts
>>>on strong locals as far away as 10 khz on either side of the station with
>>a
>>>400' antenna no matter which selectivity position is used or was this
>>thing
>>>knocked back out of alignment? Thanks,
>>>
>>>Bob
>>>Millbury, Ma
>>>
>>>-------------------
>>>Bob,
>>>
>>>One hears many thing with an R390 not heard with other receivers. Some of
>>it
>>>can be alignment. Some can be mechanical filter ring. 400 foot antenna is
>>a
>>>lot of signal grabber and some broadcast band filtering may be in order
>>for you
>>>or out right attention.
>>>
>>>You may want to go to a balanced feed antenna input so you can get the
>>>antenna balance and first stage of the RF transformers to tune and thus
>>filter some
>>>of the strong near frequency signals for you.
>>>
>>>Good Luck with this.
>>>If you have any questions to my cryptic response here, please send some
>>more
>>>mail back on the R390 reflector and I will do some more details.
>>>
>>>Roger AI4NI
>>>
>>>
>>>
>>>
>>> >
>>> >
>>> >
>>>
>>>
>>>
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