[R-390] Update on R390A, open question regarding scope and options fir lubrication

[Jordan Arndt]

John...

Yes, I would use one of the 500V rated 100pF silver micas caps you already have...Personally, I don't see any need to replace the 500V silver mica caps with 1000V SM caps...

Have fun...73...Jordan VE6ZT
  ----- Original Message ----- 
  From: jkharvie 
  To: Jim Whartenby ; R-390 Mailing List ; Les Locklear ; Jordan Arndt 
  Sent: Thursday, June 27, 2024 8:13 PM
  Subject: Re: [R-390] Update on R390A, open question regarding scope and options fir lubrication


  Jordan,
  Roger that.  Timely and much appreciated!

  Field and Deport maintenance Manual indicates this is:
  "CAPACITOR, FIXED, MICA DIELECTRIC: 100 pF, ± 2%, 500Vdcw, MIL type CM15D1016"

  Is product CDV16FF101JO3F the proper to use?

  see
  https://www.cde.com/resources/catalogs/CD-CDV16.pdf

  I am swapping this capacitor based upon the groups maintenance recommendation to remove and replace the existing capacitor rated at 500 Vdcw with a capacitor rated at 1,000Vdcw.

  Additional space does appear to be available under the RF deck above of the primary.

  Would like to go ahead and take care this this while the RF deck is on the workbench.

  I do see that a 500 volt product is listed at
  https://www.tubesandmore.com/products/capacitor-cde-500v-silver-mica-radial-lead-5

  I do have some of these 500 volt parts in my NOS parts collection for the R390A, however if the 1,000 is the way forward I will order this.


  thank you again

  73

  John N3JKE










  On Thursday, June 27, 2024, 5:10:58 PM EDT, Jordan Arndt <outposter30 at shaw.ca> wrote: 




  John, do not replace the 100pF cap, C327, across T-207 with a ceramic cap. I 

  just went through doing that and after a great deal of advice, I used a 

  silver mica cap which solved the problem created by a ceramic cap in that 

  location. Tuned ckts of this sort require a high "Q" cap to function 

  properly...



  73...Jordan VE6ZT