Alpha 77 bridge rectifier assembly to replace the original Alpha 77Sx 77Dx high voltage board. It is adaptable to the Alpha PA-77.  See pictures of actual installations.  PA-77 installation photos complements of Mike, WA5MTT. 

Design is complete with high voltage multiplier resistor for metering and protection diode.  Fully tested... includes detailed installation instructions. Uses 36 1N5408 diodes to form the 9 kV, 3 Amp bridge rectifier. This assembly is a drop-in replacement for the original board. 

Unit is designed to accommodate old and new style filter capacitors.  The assembly is designed to mount directly above the oil-filled filter capacitor (see photo). Capacitor is not included.

If you are upgrading your Alpha with a new transformer and capacitor, you will need to upgrade the original high voltage board as well.  The original diode bridge rectifier components have very limited voltage and current headroom.

Please note that this HV board can be put to use as a stand-alone HV bridge rectifier for refurbishing ANY Ham linear amplifier.  See pictures that illustrate this approach from Clark - KE7TRP who used this board in his upgraded BTI amplifier.

If interested, I do offer this assembly as a kit for a reduced price.   Contact me via QRZ.