[R-390] Mystery Component

[Jacques Fortin]

Wow, hold it !
Renée, R554 is 2.2k ohms in the part list !
Why do you state it have to be 470 ohms ?
There is a published modification order for that ??

73, Jacques, VE2JFE in Montreal

-----Message d'origine-----
De : r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> De la part de Renee K6FSB
Envoyé : 13 octobre 2024 23:13
À : Barry <n4buq at knology.net>; R390A List <R-390 at mailman.qth.net>
Objet : Re: [R-390] Mystery Component

this should settle the mystery  470 Ohm 1W ..I however do not know why the schematics show 2.2K unless a different tube was used ie 6ba6 or 6au6.. at some point in the past Renée

On 10/13/24 7:57 PM, Renee K6FSB wrote:
> oh R553 is 47K 1/2W all the way at the bottom...umm top?  hard to see
> - next to chassis and  connected to G2 then to B+ Renée
>
> On 10/13/24 7:48 PM, Renee K6FSB wrote:
>> it is a 1 W resistor.....old style molded.....most likely what was in 
>> stock......
>> I just pulled my 390 deck....all the pictures I saw it appeared to be 
>> brown..however I could be wrong! the 6 decks I measured was ~500 ohms 
>> I just lifted mine yep looks maybe ORAnge or Brown...more brown...1w 
>> Thanks for making me look again Real hard.....to verify The meter I 
>> am using says 0.474K . if it was 47K or 470K the AGC would not work 
>> at all, I still think Brown especially for a 6JB6...that makes sense 
>> anything else no.
>> i have been following you and AGC issues and no matter your agc is 
>> not working so put in a 470 Ohm 1W make sure Z503 is good and not 
>> open fried.
>> 500K is pretty much open for that application.
>> plate voltage would be way too low if R is too high and no AGC action.
>> Renée
>>
>>
>> On 10/13/24 6:46 PM, Barry wrote:
>>> I measures just a bit over 500k.  I'm pretty sure it's yellow, 
>>> violet, orange.  I just don't get why it's a molded style like that.  
>>> There doesn't, though, appear to be a 2.2k between it and Z503.
>>>
>>> Thanks,
>>> Barry - N4BUQ
>>>
>>> --------------------------------------------------------------------
>>> ----
>>>
>>>     *From: *"Renee K6FSB" <k6fsb.1 at gmail.com>
>>>     *To: *"Barry" <n4buq at knology.net>
>>>     *Sent: *Sunday, October 13, 2024 7:46:12 PM
>>>     *Subject: *Re: [R-390] Mystery Component
>>>
>>>     looking close at the picture (btw your picture is in the AGC
>>>     area) it IS a 470 ohm resistor and IS R554. one side to B+ the
>>>     other side to Z503...just like mine.....I did a lot of research
>>>     looking at IF decks and the R554 is 470 for R390....for the A it
>>>     is 2.2K
>>>     put a meter across it....and in My schematics shows 2.2K which
>>>     is incorrect.. all the units I have seen it is 470 Ohms per
>>>     chassis visuals about 25 units...
>>>     Note R390 IF Schematics are wrong shows 2.2K....btw mine
>>>     measures 474 Ohms
>>>     you are over thinking this it is fine. just an older style
>>>     molded R,  Yel Vi Brn 10%
>>>     Renée
>>>
>>>     On 10/13/24 4:50 PM, Barry wrote:
>>>
>>>         Hmm.  I could see it could be a 47k (last stripe being
>>>         orange but it's kind of hard to see much of the stripe to
>>>         tell for sure).  If so, then its likely R553; however, if
>>>         that's the case, then R554 seems to be missing (or I just
>>>         can't see it).
>>>
>>>         Thanks,
>>>         Barry - N4BUQ
>>>
>>>             That is a 470 Ohm resistor same as in the AGC B+ circuit.
>>>             Renée
>>>
>>>             On 10/13/24 3:14 PM, Barry wrote:
>>>
>>>                 Maybe not really a “mystery” but I can’t identify the dark brown cylinder with one yellow and two brown(?) stripes in the AGC time-constant compartment in my R-490/URR. A 410-ohm resistor?
>>>
>>>                 If those are actually violet stripes then I’m even more confused.  Anyone know?
>>>
>>>
>>>                 Thanks,
>>>                 Barry
>>>
>>>
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>>>
>>
>

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