Recent content by anders_bzn

Wow, nice!

Well, I ended up with replacing about 1/3 of all IC's in the machine. And not only the IC's where a problem, I had to replace quite some transistors since the legs rusted of. Espescially the TO-5's that where mounted with a plasic spacer between the board and the package. Mine 8/L had been...

I have also restored a PDP-8/L computer. It's already ten years ago. I made this: https://www.pdp-9.net/docs/pdp-8-l/modules/index.html Which might be helpful.

I have restored a PDP8/L, its about 10 years now. I did this litte web-page to easier find my way around the schematics for the modules: http://www.pdp-9.net/docs/pdp-8-l/modules/index.html

Sure, I realized that there are no pull up/down resistor to measure the current thru. This is also not the version that matches the board. I'll do more changes...

I have made this so far. A prototype of a levelshifter, to 3.3V logical levels. Two channels of I/O. Tolerant to +/-15V in case of faulty modules. Releays are for galvanic isolation. Three holes in top is ground and connections to the pins of the tested board for clipping on oscilloscope probes...

Which components fails usually? How do they fail? I'm trying to understand what a tester must be able to find.

Is there someone here that has changed bearings in a RL01 drive? The bearings in the disc spindle in one of my drives sounds bad and generates vibrations. From what I can see the belt pully is pressed on the axis. I guees heat, a puller and a hydralic press is good tools to have. It seams like...

Roland Huisman solved the problem with the RK05 to RK8E cable, which is great (which is the one I use, thanks Roland). I'm trying to do the same for TD8E to TU56 (and even TU55) cable. I have drawn replacement boards for M961 and M960. The "M961" board also includes the five G888's. The...

I had my RK05 working, but now it wan't pass the MAINDECS anymore. It fails the "drive control test" at address 3277: http://svn.so-much-stuff.com/svn/trunk/pdp8/src/maindec/08/dhrkb-e-d.pdf As I understand it all data written to the disk and is verified in the test before. The test that fails...

0 Fire (Red) 1 Rotate L 2 Rotate R 3 Thrust (Green) 4 Yellow 7 Yellow 8 Fire (Red) 9 Rotate L 10 Rotate R 11 Thrust (Green) My idea was to change the code so that the yellow triggered hyper space, but I never came to it. In the implementation I have hyper space is triggered by pushing both...

I found some proper DEC connectors so I ordered a custom board. No hard gold unfortunately, so lets see how long it will last.

Well, what should I say? THANKS! Finally I got something to print on the 3D-printer at work. An Ultimaker 2+ for those that might be interested.

A friend of mine got parts to build a small PDP-8a/100 with MOS memory. After some time he figured out that the limited function panel didn't work, it was for a core memory machine! I draw a new one, it should be possible to move the components from a core-board to this new one. I built mine...

I used those: https://eu.mouser.com/ProductDetail/80-R60EW61005000K 100uF/100V I should really print some holders to those...