[R-390] RF deck removal

[Norman Ryan via R-390]

Alan,
Check these websites:
militaryradio.com/r390a-rfdeck-geartrain.html
http://militaryradio.com/R390A/R390RFDeck/
Take photos of your own.  Take notes and make sketches.  Place gears, shim washer, etc., in zip-lock bags and number the bags with a Sharpie  --  reference the numbered bags to your notes and sketches.
Take your time.  Geartrain is intricate, but reassembly is not impossible with constant attention along the way.
If you take the split gears apart for cleaning, gently file any burrs off gear faces prior to reassembly.  Do NOT dub gear teeth!
Lube sparingly with synthetic oil such as Mobil-One 90W.  (90W is a guess from memory.)

When engaging gears during reassembly, pre-load split gears just enough (no more!) to eliminate lash.  These techniques will contribute to silky smooth single finger KC change operation.
Have fun!
73,Norman


 

     On Monday, October 13, 2014 2:55 PM, Alan Victor <amvictor at ncsu.edu> wrote:
   
 

 Hi Roger, agree. However, the panel I was referencing is the gear train
front panel, not the main frame front panel. All of the items you mentioned
in this post are mainframe front panel items and I agree, those require
attention in the process of getting to the RF deck. Now to investigate the
intermittent gear and the MHz switch alignment, not sure if the gear case
front panel needs removed. Is it possible to view proper MHz switch and
intermittent gear alignment by looking at the BOTTOM front of the gear
train? As well the 2 front lower CAMs when the KC dial is set to 7+000. If
all those items seem reasonable as well as the contact points on the MHz
wafer switch,  then I may initially clean the gear case in tact with
liberal WD40 and paint brush.

Alan

On Mon, Oct 13, 2014 at 1:52 PM, Roger Ruszkowski <
flowertime01 at wmconnect.com> wrote:

>
> Alan,
>
> You wrote, ----------------------------
> I am going to have to pull the front panel off the gear train. This
> requires removing the veeder root counter and some small gears etc.
> ---------------------------------
>
> Not true.
>
> The bezel (black box with micro scope glass slide as a window) comes off
> with the front panel.
> The veeder root counter and its gears are mounted to the front of the gear
> train.
> You do not have to undo any of the counter parts to remove the panel.
>
>
> But some more things to look at.
>
> You do have to loosen the dial lock and rotate it.
> First time around just take the knob off the dial lock and remove the
> bushing nut
> on the dial lock and let it fall loose. As you drop the front panel it
> will fall out.
> Then you get a look at what's going on so you can loosely hand the dial
> lock back into
> the front panel for reassembly.
>
> One of the Fellows pointed out that you also have to pull a wire harness
> clamp loose on the bottom
> in front of the audio deck near the local line pot from the front to back
> frame panel between the
> VFO and the audio decks. This is where you reach in with the long #1
> Philips screw driver.
> You will need this slack. Do this first then,
>
> If you are going to pull the RF deck also remove the spring to the VFO
> Oldham coupler.
>
> Use a couple blocks of 2x2 or 2x4 under the side rails to prop the front
> panel off the bench.
>
>
> Two big knobs.
> Dial lock.
> Antenna trim knob.
> IF band width switch extension shaft clamp.
> BFO pitch extension shaft clamp.
> Dial lock.
> Wire harness clamp.
> five 8 x32 face plate bolts three under BFO band width knobs, two more
> between line gain and KC knob.
> Eight 10 x32 four down each front rail. Again the slender Philips screw
> drive lets you reach around the guard rails (not handles, used as handles)
>
>
> If you have a burr on the KHZ or MHZ shafts and the panel bushings will
> not slide over the burr, you can take the nuts
> off the bushings and leave the bushing on the shaft until you have time to
> hone the burr off the shaft.
> On reassembly you loosen the bushings and re center than as needed.
>
> There are also three green screws along the back of the RF deck with tight
> clearance that must be loosened, they are captive.
> The long 6 - 10 inch small diameter Philips screw driver is the preferred
> tool for this task.
>
> Total time to drop a front panel under fifteen minutes with beverage.
>
> Roger AI4NI
>
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