[R-390] Guided discovery on the RF deck

[jkharvie]

 Jacques, perhaps this was a manufacturing efficiency, such that the "identical" assembly could be interchanged between position "1, and position "2" during assembly.  I was surprised to discover this detail on the non-used pins. 

Yes - I have now completed replacing all "bumblebee coded" leaky caps (these measured >1% leakage), the picture was before component level work started.
I have also completed the resistor drift change out, and I have installed the new "high-Q" dipped silvered mica capacitor (C327) across the primary of T207 (retaining the old just in case).
making progress!

John



    On Wednesday, July 10, 2024, 3:09:59 PM EDT, Jacques Fortin <jacques.f at videotron.ca> wrote:   

 John, these non-used pins are linked to the fact that the Z201-1 and Z201-2 are identical, and etc. for the other Zxxx.
These are non-used pins when they are in position "1" but used when they are in position "2".

>From the picture you sent, I see three "bumblebee coded" PIO caps in there.
Did you plan to change those ??
All the ones I had were found leaky....

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 jkharvie via R-390
Envoyé : 10 juillet 2024 13:46
À : R-390 Mailing List <r-390 at mailman.qth.net>
Objet : [R-390] Guided discovery on the RF deck

While in the RF-subschassis process of cleaning and reassembly I noted that only 2 of three pins are plugged in and active on 

Z201-1Z202-1Z203-1Z204-1Z205-1Z206-1
as per the electrical schematic, but something I never specifically noted or thought much about previously.

This got me thinking that the non-used pins might serve as a source of spare pins if/when needed.
Attached graphic shows top view of the RF subchassis awaiting cleaning, a three pin "can" of which two pins are used, a bottom view showing mounted cans with no connection to the one pin in highlighted red box, and the RF subschassis schematic showing all of this.  

One of the "tools" I made was drilling out the end of a bamboo chopstick with a #35 drill (0.110") to hold 1/2 of cotton tip applicator swab.
Best regards,

John (N3JKE)