[R-390] Still deaf below 8 Mc
Walter Wilson
wewilsonjr at gmail.com
Sat Oct 27 18:47:37 EDT 2007
Sorry, I missed that.
On 10/27/07, Tony Casorso <canthony15 at msn.com> wrote:
> 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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