User manual HARBACH ELECTRONICS RM-220

[. . . ] RM-220 RECTIFIER & METERING BOARD INSTALLATION INSTRUCTIONS PART S SUPPLIED WITH T HIS KIT : (1) RM-220 Rectifier & Metering Circuit Board Assembly To start the installation, read these instructions very carefully. Now unplug the am plifier and remove any input, output and control cables that may be connected to the back of the amplifier. Place the amplifier on a book, front panel up, and remove the bottom screws holding the feet and case in place. [. . . ] () Connect the RED wire coming from the high voltage transformer to hole "D" on the new circuit board and s older. 1 () Connect the HEAVY BLUE wire coming from the high voltage feed-through insulator on the left to hole "J" and s older. Connect the BLUE wire coming from the bottom of the capacitor bank (the + wire) to hole "H" and s older. Connect the BLACK wire coming through the grommeted hole in the chassis (from the relay contact) to hole "E" and s older. Connect the ORANGE wire coming from the meter switch to hole "G" and s older. Connect the YELLOW wire coming from the meter switch to hole "F" and s older. Connect the BLACK wire coming from the plate meter to hole "C" and s older. Connect the RED wire coming from the plate meter to hole "A" and s older. Connect the BLACK wire coming from the top of the capacitor bank (B- w ire) to hole "B" and s older. Connect the bare wire of the 0. 001µF 6KV capacitor to hole "K" and s older. Carefu lly inspect all solder joints to be sure that both the joint is good and that there are no solder bridges which could short components together. Attach the RM-220 circuit board to the tapped spacers using the previously saved (4) 6-32 x ¼" screws. Place the front panel back in place and loosely put in the 2 Phillips-head screws on the left side of the front panel. Loosely reinstall the nut and washer holding the band switch to the front panel. Place the right side panel in position and hold it in place with the 4 previously removed sheet metal screws. [. . . ] You may notice a slight reduction in the idling plate current of your SB-220. This is becaus e the new board produces 6. 8V of bias for the 3-500Z tubes, rather than the 5. 1V provided by the original Heathkit design. This will lower the heat produced by the amplifier during voice lulls, but will not materially affect the linearity at high power levels. RM-220 RECTIFIER & METERING BOARD PARTS LIST D1 & D2 D3 ­ D6 D7 R1 R2 R3 R4 R5 5-1N5408 (3A 1000 PIV) 1N5408 (3A 1000 PIV) 8-1N4005 (1A 600 PIV) 1 3W 1% 3600 ¼W 1% 0. 82 3W 5% 14-1M ¼W 1% IN SERIES 5600 ¼W 1% HARBACH ELECTRONICS Jeff Weinberg ­ W8CQ 468 County Road 620 Polk, OH 44866-9711 (419) 945-2359 http://www. harbachelectronics. com info@harbachelectronics. com 3 [. . . ]