Using Drake AC3 PS in place of AC4 - problems, warnings, etc please.

Discussion in 'Ham Radio Discussions' started by K5FRH, Jan 31, 2020.

Tags:
ad: L-HROutlet
ad: l-rl
ad: L-MFJ
ad: Subscribe
ad: abrind-2
ad: Left-3
ad: Left-2
  1. K5FRH

    K5FRH Ham Member QRZ Page

    Can I use an AC3 PS on T4/TR4 Drake gear ? I am sure there is a thread on this somewhere, so if there is, please point me to it. Otherwise, I would appreciate your comments. Thank You, Rod K5FRH
     
  2. KD8DEY

    KD8DEY Ham Member QRZ Page

    Yes
    There is a thread about it on the Facebook group, along with a video someplace...
     
    Last edited: Jan 31, 2020
  3. N2EY

    N2EY Premium Subscriber QRZ Page

  4. KD8DEY

    KD8DEY Ham Member QRZ Page


    14 min into the Video...
     
    Last edited: Jan 31, 2020
    K5FRH, NQ8J and WA7PRC like this.
  5. NQ8J

    NQ8J Ham Member QRZ Page

    I used an AC-3 with a TR-4C for a few years. That was back in the early 90's. Make sure it has been re-capped. The bias supply is also used for part of the circuit that controls RX/TX switching. A shorted bias supply capacitor will cause loss of bias and in turn, the rig will go into transmit mode, and your output tubes can be ruined as there is no negative bias on the power tube grids. A bias pot with an open wiper will cause this too.
     
    WA1GXC likes this.
  6. WA1GXC

    WA1GXC Ham Member QRZ Page




    Drake AC-3 and AC-4 power supplies are electrically equivalent in performance. Both are

    the factory-delivered P.S. from early 4-series T-4X thru last TR-4CW. Slight differences are

    essential physical.

    Do yourself a favor and without fail replace e v e r y diode with a brand-new production one -

    1N4007 is super-cheap. The semiconductors from the 60's and 70's are inferior to todays devices.

    Replace the filter caps also -- they are waiting to fail and new ones will give you full B+ and

    stiffer voltage regulation.

    As N2EY points out, invaluable and 100% flawless info on WB4HFN Drake site. Also equally

    authoritative VE3EFJ Drake site. These are 2 super-smart guys.

    Enjoy your beautiful radio.

    "Rich hams buy Collins. Smart hams buy Drake"

    Apologies to Glen.

    73
     
    K1LKP and N2EY like this.
  7. K5FRH

    K5FRH Ham Member QRZ Page

    THANK YOU TO EVERYONE FOR YOUR INFORMATIVE RESPONSES....JUST WHAT I WAS LOOKING FOR.
     
  8. K5FRH

    K5FRH Ham Member QRZ Page

    This video is very very good and a great listen for any Drake enthusiast. I learned a lot. Thanks for posting.
     
  9. WB3EGK

    WB3EGK Ham Member QRZ Page

    Both Harbach Electronics and The Heathkit Shop sell upgrade kits for the AC-3 (and AC-4) that will replace capacitors and diodes. The kit is a little bit of work, but can be done in an afternoon. As stated above, if you lose your bias voltage from an old capacitor, you may very well lose your sweep tubes in the final, and these tend to be expensive.
     
  10. K1LKP

    K1LKP Platinum Subscriber Platinum Subscriber QRZ Page

    YES,,,, YES,,, HARRY AND NQ8J ES WB3EGK ARE CORRECT.

    IF YOU DON'T UPGRADE YOUR POWER SUPPLY YOU COULD
    END UP WITH A NUCLEAR MELTDOWN.

    IF YOU HAVE TO POWER UP THIS SUPPLY B4 YOU HAVE AN OPPORTUNITY TO UPGRADE IT,
    NEVER LEAVE THE RIG UNATTENDED.

    HAVE FUN AND WORK SAFELY,


    yea weekend.gif
    73 CARMEN.jpg

     
    Last edited: Feb 1, 2020

Share This Page