Jay, At 10:07 AM -0500 10/13/06, Jay West wrote: A timely question as several of us seem to be working on this model currently. [Thanks to Julian, Tim, Don, Al, Henk, and all others that have contributed to my own success...] Others will no doubt correct my errors but... I believe for the configuration above one H744 (position 2) IS required. I believe a H745 (position 1) IS also required. A second H744 (position 3) does NOT appear to be required based on your configuration above. I'm not clear whether or not a H754 is required in position 4. My take is that regulator is used primarily for core memory (+20, -5), though I could be wrong. Note that there are other regulators that can be used in place of the H744. John

Hi Jay, I copied your mail to my editor, to prevent a time-out on my connection to the e-mail server at work (I'm at home now). First, I can scan on Monday the manual "PDP1134A power system description" (EK-1134A-TM-002) which probably has everything in it you ask. Check if it is available on bitsavers. If not, I'll scan it ... If you look to the BA11-K box, the first PSU (at the side where the 11/34 CPU board are) is the H745 (-15V/10A). +15V comes from the "fixed" part which also has the transformer. IIRC, the H745 *needs* the +15 to operate. Every BA11-K box I've seen has the H745 in the first position. I do not know which modules need the -15V, you could look that up. The M7856 which is common as console interface (20mA current loop or EIA, RS-232) will very likely need the -15V. The 2nd PSU, next to the H745 is the +5V PSU. It can be the H744 (25A.) or the H7441 (32A.) The H744 is fine for the system that you describe. If you need to draw more power (check my website for a power calculation) you can install the H7441, but you must check the distribution panel. The power distribution board 5410864-0 is for the H744. Extra wiring is on the 5410864-YA to support the H7441. (In fact the -YA is also needed to support MOS memory with battery backup). The 3rd PSU (in the "other" half) is also a H744 or H7441. The 4th PSU (at the other outside of the box) can be the H754 (+20V/8A. and -5V/1A.) for core-based systems, or the H785 regulator for MOS memory. The 2nd PSU (+5V) delivers +5V power to the DD11-PK only. The 3rd PSU (+5V) delivers +5V to all other backplanes. This is of course if you put the DD11-PK at the right side, and connect it to the correct sockets on the power distribution panel. The DD11-PK backplane has a few jumpers to allow the MOS memory to be powered separately from the other logic. If you do have battery backup (probably not) the jumpers to +5B, +15B and -15B must be cut, otherwise they must be installed, connected to +5, +15 and -15. The jumpers short the "B" busses to the normal power rails. The power distribution panel 5410864-0 does not have the +5B, +15B and -15B connections as it was not designed for the BBU option. So that is an easy method to recognize which power distribution panel you have ... So, to summarize, the +5V PSU in position #2 is only for the CPU backplane, and the other +5V PSU in position #3 powers the other backplanes (probably one 9-slot DD11-DK and one 4-slot DD11-CK or dedicated functions backplanes like RK611 and RK11-D). The -15V PSU in position #1 and the optional +20V/-5V PSU in position #4 (or H785 BBU) deliver power to *all* backplanes. With your system (only the DD11-PK) you need the regulators in positions #1 (H745) and #2 (H744 or H7441) only. The system that had the RK11-D had probably the 3 PSUs installed. You can use that box, and remove the 3rd PSU, if you will only install the DD11-PK backplane. Remember, as soon as you install any other backplane you *must* install that 3rd (+5V) PSU. - Henk. This message and attachment(s) are intended solely for the use of the addressee and may contain information that is privileged, confidential or otherwise exempt from disclosure under applicable law. If you are not the intended recipient or agent thereof responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the sender immediately by telephone and with a "reply" message. Thank you for your cooperation.