Heathkit hp 23

Discussion in '"Boat Anchor" & Classic Equipment' started by AD9Y, Sep 15, 2020.

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  1. AD9Y

    AD9Y Ham Member QRZ Page

    Hi everyone i am working on replacing the caps on a heathkit hp 23 and am on c1 and c2 and a little confused at how to connect the caps ! I decided to restuff the original`s to keep the look. I have done c3 and c4 already Any tips and or pics of how you guy`s recap those two would be greatly appreciated thank you !
  2. KK6IYM

    KK6IYM Ham Member QRZ Page

    C1 is "floating" above ground. Because the metal case on electrolytic capacitors is connected to the negative lead, you must be sure not to allow it to touch the chassis or any grounds. Do not depend on the plastic cover on the outside of the capacitor to protect it, but either add insulation or keep it away from any grounds. There is high voltage on the case. This is why that can capacitor in the supply is mounted on a phenolic wafer instead of the chassis. High voltage power supplies often have this configuration because any one capacitor is not rated for the full HV potential.

    K3XR likes this.
  3. AD9Y

    AD9Y Ham Member QRZ Page

    So then all i have to do is connect the postive terminal of C1 am i understanding correctly ? and put some shrink tubing on the ground to make sure its not touching. And my other question is where do i ground C2
  4. W5RKL

    W5RKL Ham Member QRZ Page

    Don't guess at how the supply is wired, use the HP-23/PS-23 assembly manual so you wire the power supply correctly.

    You can download it here:


    Scroll down the page and click on the link to the HP23/A/B/C or PS23 power supply you have.

    Mike W5RKL
    N2EY likes this.
  5. W9GB

    W9GB Ham Member QRZ Page

    Orange County Amateur Radio Club (OCARC) of Tustin, CA

    Heathkit of the Month #26 — February 2011
    by Bob Eckweiler, AF6C
    Heathkit HP-23 Power Supply
    (HP23/A/B/C/E PS23 - circa: 1964 - 1983; Also UT-1, and HP-20)
    June 12, 1967
    Heathkit HP-23 : High Voltage Power Supply (AC)
    Service Bulletin No: HP-23-1D

    Increase Fuse Capacity

    Increase the fuse capacity from 3 Amps [PN 421-2], to 4 Amps SLO-BLO [PN 421-5].
    This will avoid needless failure in use and will not overtax the fused circuits.
    Last edited: Sep 15, 2020
    N2EY and W1TRY like this.
  6. AD9Y

    AD9Y Ham Member QRZ Page

    Thank you for the link i do have the manual though . So studying the schmatic it looks like i attach the negative of c1 to positive of c2 . So Would that mean i attach the neg of c1 to the old center tab and then run the positive lead to the positive lead coming off of c2 does that sound right !
  7. KK6IYM

    KK6IYM Ham Member QRZ Page

    No, not right. The negative of C1 goes to the positive of C2--along with one leg of the transformer secondary and four 100K 2W resistor leads. The negative lead of C2 goes to ground along with two of the resistor leads. The positive lead of C1 goes to two of the resistor leads, the striped end of a diode (cathode) and the red wire for the positive HV.

  8. AD9Y

    AD9Y Ham Member QRZ Page

    Cool thank you ! i will give that a try . Would anyone happen to have a pic of the bottom side of how they wired the new caps in ? I am just getting some ideas .
  9. W9GB

    W9GB Ham Member QRZ Page

    You said that you have the Construction (Build) Manual.
    The Picture & Pictorial you desire is in the Heathkit HP-23 Assembly Manual.

    This is the Heathkit HP-23B Assembly Manual (B model)
    There are DIFFERENCES in Models BASED on the Alphabet Suffix

    Based on your questions & comments, you are a VISUAL reassembler,
    with minimal or no ability to read a schematic diagram and Visualize/Build from that.
    Home Builders use Blueprints (same skill set translation)
    N2EY likes this.
  10. W5RKL

    W5RKL Ham Member QRZ Page

    Connecting C1 to C2 is discussed in the manual. If you can't figure out how to connect C1 to C2, look at the pictorial below,
    it shows C1 at "H" and C2 at "F".

    C1 "Floats" above ground and has an "insulating" mounting plate. C2 foes NOT float above the ground and it is mounted using
    a "Metal" mounting plate.

    You can see both pictorials in the HP-23A manual which can be downloaded here:



    The resistor connections between C1 and C2 are shown in the pictorial picture below which is also found in the HP-23A manual


    Mike W5RKL
    K8CCA likes this.

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