Hmmm... Normally they suffer from bad bearings, although I don't think this is the problem with yours. Most fans can be dismantled. I've come across 3 main types of assembly : A cap in the centre of the rotor, on the opposite sde to the label, retained by a circlip. Remove this, then take out any felt pads/waskers and remove the small circlip from thend of the (fixed) spindle. The rotor/blades then lifts off. A similar cap in the middle under the label. Often this cap is flexible plastic and is retained by the label. After removing it, there's thee circlip as above 2 screws under the lable. In this case, free the wiring/tag block first. Then remove the screws and lift the hosing off the motor/blades. On the top of the motor, you'll see a sirclip. Remove this, then lift the stator out. In all cases make sure you know where all the washers go. Some are special types (I've seen bonded fiber/metal washers with flats on the centre hole, for example). This sounds, alas, like winding problems. I've never tried to rewind one.... IIRC, the 11/05 fans are pretty standard (unlike the 35V 70Hz fans used in te 11/44...) so you can probably get something new from a good electronics shop. The important thigns are the physcial size and the voltage rating -- IIRC you need a 115V AC fan here (even in Europe, you use 115V fans, they're run off the primary of the mains transformer acting as an autotransformer. [...] You have a console serial port built into the CPU board set. AFAIK it's current loop only (which is a bit of a pain), it's wired to the 40 pin Berg header on the back of the cabinet. AFAIK the 9th slot is just a standard SPC slot and could take either a DL11 or an RX11. Of course you can't put both in at the same time. What you can't do is take out one of the memory board sets and use those slots for peripherals. The wiring there is totally different. There was a backplane which took the CPU, one memory board set and, IIRC, 4 SPC boards. But that's not the backplane you have. -tony

On Tue, Jan 6, 2009 at 3:19 PM, Tobias Russell <toby at coreware.co.uk> wrote: Just what you've done... clean and lube (WD-40 is *not* lubricant!) If they really won't spin and they are oddball fans, you might need exact replacements (ISTR the 11/40 or 11/45 has that problem), but if you find a modern fan that's the same size and voltage, you are probably OK. I think you might still be able to get fans like that, but I haven't tried in at least 5 years. From: <http://www.psych.usyd.edu.au/pdp-11/11_40.html> Toggle in the following program and start at 001000. Note that the RUN light will go out! Location Contents Opcode Comment 001000 012700 mov #1,r0 Load 1 into R0 001002 000001 001004 006100 rol r0 Rotate R0 left 001006 000005 reset Initialise bus (70ms) 001010 000775 br .-4 Loop back to 'rol r0' I do not know if this will work on an 11/05 because of the 'reset' instruction, but it's a start. You could replace the reset instruction with an inner loop on r1 without too much difficulty if this won't work on your machine. My memory is that you can use the 9th slot for an SPC (small peripheral controller), but check the 11/05 handbook to be certain. IIRC, The RX11 and DL11 do not need NPR (but the RX211 might), but look those up in a mid-1970s handbook to be certain. I would think that RT-11 v4.0 would work nicely on an 11/05. I'm pretty sure even the newer stuff will work, but since you don't care about MSCP support or other modern niceties, it may not be a big win for you. Games and such, at least the ones I know of, should run on V4 and V5, as long as you have enough core for the app itself. Don't expect to run ADVENT without a full boat of memory, but there are plenty of smaller apps out there. -ethan