Sigh... And CR1 cathode connects to pin 4, not pin 2... Oops; CR2 had disappeared somehow... And I probably should have used a fixed pitch font... *********** ---------- From: M H Stein[SMTP:dm561@torfree.net] Sent: Wednesday, September 30, 2009 7:56 PM To: 'cbm-hackers@ling.gu.se' Cc: 'ethan.dicks@gmail.com' Subject: RE: Static PET PSU questions Pretty straightforward: pins 1 and 5 are the ends of a center-tapped secondary, pin 3 is the center tap and Cap - pins 2 and 4 are DC returning from the board and connected together at the Cap + The 320008-2 schematic is correct for the board. If you've got ~9V DC available, just feed 9VDC to pins 2 and 3. If you're going to use a PC-type PS, I'd pull the regulators (if they're not still out) and run regulated 5V to the 4 Vcc points and drop the 12V to ~9 with a regulator or Zener and connect to pin 2. But I accept no liability ;-) X----------------- 1 ----->|------+ X CR1 | X | X | X +-----+------ 2 -------------------+-------> 9V DC to regulators and Cass drivers X | _|_ | _|_ X | _ _ C 23000/15 | /_\ CR3 X | | | | X----------+------ 3 -------------------+-------> GND X | | X | | X | | x +------------ 4 -------------+ X | X | X CR2 | X----------------- 5 ----->|------+ mike ********************************************* --------- From: Ethan Dicks[SMTP:ethan.dicks@gmail.com] Sent: Wednesday, September 30, 2009 5:34 PM To: cbm-hackers Subject: Static PET PSU questions Hi, All, Back on that 2001-8 board... it's a P/N 320008, original board. It has a 5-pin power supply connector. From the schematics, pin 3 is GND, pin 2 is unreg 9VDC, and there's a pair of half-wave diodes from pins 1 and 5 to pin 4. I want to run this board in a more modern PET chassis (so far I've been using external +5VDC through TP1 down by the internal cassette port). I've never been able to locate a chassis-specific schematic of any PET to match up the rectifiers and regulators on the board with the transformer and filter cap in the chassis. Can anyone point me to such a document on zimmers.net or anywhere else? I have the general idea of what needs to happen, but I'd rather not fry my only #320008 board trying to put it someplace "interesting" because I failed to understand some important detail. Thanks, -ethan Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2009-10-01 02:00:04
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