[R-390] R-390/URR

[Bob Camp]

Hi

Check your PTO for bad lubrication. The spring on the Oldham coupler  
can only deal with a limited amount of torque. The same thing is true  
of the screw driving the tuning core. Since the PTO is sealed they  
often do not get a regular clean and lube treatment. The result can be  
concrete where there used to be lubrication. You also may have  
everything so tight that the PTO is binding up as it rotates.

Bob


On Oct 28, 2007, at 1:58 AM, Bob Young 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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