As an alternative to a full kit with parts as described below, a limited time special for just $15.00 includes the PCB and the complete instruction CD with part requirements.  See PCB Special for details.  


With the advances in component technology since the work-horse Heathkit 23-series power supplies were sold, new components are now available which are smaller in size and have higher ratings than the original components.  The HP-23D replacement board replaces all the fixed resistors, capacitors, and diodes in the Heathkit power supplies with all new and mostly higher rated* components (voltage, wattage, capacitance, and/or temperature).  The result is a power supply (called the HP-23D) in which all the components which usually go bad are replaced with new components, thereby bringing your power supply back to original or better performance, maybe for another 35 years.  

The HP-23D is sold in kit form. 

The HP-23D works with any of the 23-series power supplies (HP-23, HP-23A, HP-23B, HP-23C, and PS-23). See Model Comparison Page. All the model-specific functions of your PS remain the same with the HP-23D PCB, such as ON-OFF & LV switching, adjustable bias, circuit breaker, pilot light, etc., if those features are included in your model. 

The HP-23D installs completely within the chassis for safety purposes.  The kit is supplied with all major components and hardware, including the PCB, and a CD to run on your PC containing detailed building instructions with color pictures of each step. Minor things you will need, such as solder and possibly a little hookup wire, are not supplied as you probably already have those on hand.    

Experience Level: The kit requires some degree of building and electronic experience, and some spare time.  This is not a project for a first time kit builder or someone with limited technical knowledge. The instructions are not as detailed as in most Heathkit manuals, but should be more than sufficient. If you can read schematics, have experience soldering components to a PCB, and can identify components and determine their  polarities and values from their markings, you should have no trouble. You will need to have a PC to run the instruction CD, normal electronic construction tools and solder, some hookup wire and miscellaneous items if needed, etc. No drilling new holes in the chassis is required. An understanding of the danger of high voltages and how to work with them, and the ability to make sure your finished product is constructed in such a manner that its high voltages are not a hazard to anyone or anything, is very important. 

The kit includes the PCB, components, and mounting hardware for any of the Heathkit 23-series power supplies.  Basically, you build the board, remove the old capacitors, fixed resistors, and diodes from your PS (leave the transformer, choke, 11-pin connector, etc.), and connect the PCB to the remaining components in the PS at points on the PCB which are identified on the silk screen legend on the PCB.  In most cases the leads left on the PS will be long enough to reach the proper point on the PCB for soldering, but some lead extension may be needed if they were cut short during the original construction. 

Pictures of built boards*, installed in a PS, and generalized schematic are below.  Click on pictures to enlarge.

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BONUS: The step-by-step instructional CD also includes a section with information on all the Heathkit 23-series power supplies, such as schematics, chassis pictures, and a side-by-side comparison of the similarities and differences between the various models.  

* For more on part ratings, click RATINGS.

See the KITS Page for prices and to order.

Since I have no control over the construction and use of these parts I require the acceptance of a liability waiver in order to purchase these parts.