I’m using a Heathkit SB220 since 1995. I bought it used. It has been built in 1980 by an Italian Amateur. This year I wanted to modernize it to keep it at a good level of performance.
Ho deciso di usare il kit RM-220 della Harbach Electronics. Il kit permette di sostituire completamente il sistema di retificazione e i circuiti di misura del PA.
I decided to use the RM-220 Harbach Electronics kit. It allows to sostitute the entire rectifier system and the meters circuits.

We continue the renovation of the Heathkit SB220 Power Amplifier.

Remove the 15 sheet metal screws that hold the perforated cover in place and remove this along with the top rear plate cover. Save the screws in a safe place. Be careful not to remove the screw that supports the insulating spacer that shorts to ground the positive high voltage, for safety reason, when the top cover is removed. The photo shows the small isolating spacer tied up the cover.

.We can disassemble the old rectifier circuit board. Remove the four screws holding the old rectifier circuit board to the tapped spacers on the capacitor bank bracket. Put the four screws in a safe place. Unsolder old wires from the boad. It don’t require remember the positions. The wires’s colors will help us reconnect them on the new circuit board.