[R-390] Problem !?

[Al Parker]

Hi Pete,
	Like Todd says, check related capacitors.  I've been muckin with an 
R-390, off & on, for the last cupla mo.s, after setting it aside 6 yrs 
ago, and I've found several bad mica caps in the RF deck coil cans, and 
elsewhere.  The cans are easily removable, and, IIRC, you can ck for 
shorted/leaky caps without even opening it, tho' in some cases you have 
to open it to decide which of 2 might be bad.  (and you'd open it then 
anyhow.)
	50+- yr old micas are going bad with some frequency nowadays.
73,

Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 11/19/2011 1:39 AM, Pete Williams wrote:
>   G'morning...
>
> Process of  aligning a R-390A...The 1st variable IF calls for 1.2 Mhz to
> tune cores  and 7.6 Mhz to tune trimmers .
> No matter what combination of core and trimmer settings I use. peaking 1.2
> Mhz on  L232 always results in the core almost fully in  and out of  thread
> ..  Have struck this on RF section in past too but it always comes good
> Why is it  so ?
> The Diode load voltage is also much higher at that frequency than at the
> 7.6Mhz end but that may be a function of the sig.gen input which is
> connected to the balanced antenna input.
> I maybe  suspect the 51 pf cap open below the  deck but haven't had the
> strength of mind-yet- to take the deck out  for  look.
> Cores have been changed with no improvement.
> Suggestions  welcomed .
> Cheers
> Pete VK3IZ
>
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