[R-390] R-390/URR

[Joe Foley]

You need 1/32" between the parts of the Oldham
coupler.  BUT, if the shaft doesn't run true or the
mounting doesn't allow the shafts to align properly
then you will need more clearance.

You might want to check that there is some clearance
between the parts of the coupler as it turns through
360 degrees, it may be binding somewhere.

Joe


--- Bob Young <youngbob53 at msn.com> wrote:

> I'm working away on 2 390's also, got one running
> pretty well so far, it 
> really just needed a good electrical alignment, I
> need a couple of crystals 
> for it. I haven't checked the cams yet though. The
> bands are uneven. I 
> changed the PTO in the other one, I'm getting severe
> backlash, not sure why 
> yet, I think the oldham coupler is hooked up ok
> although it didn't have 
> backlash until I decided that the oldham coupler two
> sides needed to be 
> closer together after I put it in.
> 
> I'll check mine tomorrow for those readings and see
> what I get on E210.
> 
> Bob
> KB1OKL
> 
> 
> From: Jim Green <jagreen3 at sbcglobal.net>
> To: r-390 at mailman.qth.net
> Subject: [R-390] Still deaf below 8 Mc
> Sent: Saturday, October 27, 2007 3:26 PM
> I'm still plugging away with my R-390/URR (Not
> R-309A/URR). The main  
> struggle is the deafness below 8 Mc. I am following
> the Third Echelon  
> troubleshooting procedure in TM11-5821-357-35. I've
> made it to Signal  
> Substitution Part e IF sub-chassis tests Step 2
> where the procedure  is to 
> apply a modulated 2Mc signal to E-210 with the
> receiver in  standby mode. I 
> am supposed to hear a signal in the headphones. I 
> hear nothing. If nothing 
> is heard the procedure is to:
> 
> 1) check V205 (checks good),
> 2) check V701 (checks good)
> 3) check the V701 circuit components by voltage and
> resistance  
> measurements. All voltages seem within range except
> Pin 1 at -0.46  VDC 
> (should be -1 VDC to -2.3 VDC). All resistances are
> OK except Pin  1 at 178K 
> (should be 150K) and Pin 5 at 19.8K (should be 8.5K,
>  however the voltage at 
> pin 5 is right on the money at 178 VDC).
> 
> Does anyone see any major issues with these
> readings? Note I'm using  a 
> Fluke model 77 to take the measurements.
> 
> 4) Check the vfo operation by measuring the DC
> voltage at E210  (measured 
> 0.000 VDC). The manual goes on to say: The voltage
> should  be between -3VDC 
> and -11VDC. If the voltage outside these limits 
> check J223 and P723. J223 
> looks OK, but the cable P723 is connected  to has a
> kludjy splice in it. 
> When I measure the voltage from the  center pin of
> P723 to ground I get 
> 0.000 VDC. Perhaps this is OK  since it's likely an
> AC signal (I measured 
> 0.01VAC). When I measure  resistance I get a dead
> short to ground. Are these 
> measurements normal?
> 
> Jim (KG9MM)
> 
> 
>
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