[R-390] Still deaf below 8 Mc

[Tony Casorso]

I think he said R-390 not A. Chucks fix is for R-390a. Not sure if it 
applies.

Tony

----- Original Message ----- 
From: "Walter Wilson" <wewilsonjr at gmail.com>
To: <r-390 at mailman.qth.net>
Sent: Saturday, October 27, 2007 3:55 PM
Subject: Re: [R-390] Still deaf below 8 Mc


>I always replace C327, especially if signals below 8MC are a problem:
> See http://r-390a.us/R-390A%20Restoration%20Checklist%20v2.htm for a
> more detailed checklist.
>
> Chuck Rippel's site also has this listed as a common problem:
> http://r390a.com/Commonfail.htm#I%20was%20finishing
>
> Walter - KK4DF
>
>
>
> On 10/27/07, Jim Green <jagreen3 at sbcglobal.net> wrote:
>>  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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