Recent content by fritzm

Now that my 11/45 is up and running, I could really make good use of an RK05 rack storage caddy, as seen in the attached pic on a PDP-8. Does anybody have one of these they'd be willing to sell, or at least know the DEC part number so I could look for drawings? There seem to have been two...

Hi, I'm working on a PDP-11/34 right now, with the KY11-LB programmer's interface, and it is missing its front panel power control knob. It looks to me like the same one is used on the 11/04? Anybody happen to have a spare, or a 3d model, or willing to take some measurements? Does the stock...

Hi all, Some here may know I’ve been working on an 11/45 restoration off and on for some time now. My ’45 currently has floating point, KT11-C mem mgmt, 124 kword MS11-L, and an RK11-C with one restored RK05 drive. Last week I decided to see if I could bring up RSTS on the machine. I...

Double checked the reference on the schematic -- it is MM5240AM (the "AA0" mentioned earlier was a mistake). It seems National had a series of pre-fab parts with different fonts/encodings available, but the individual data sheets are hard to find... The one other datasheet I could find had the...

Hi Ken, Schematics on Bitsavers indicate an off-the-shelf National MM5240AA character ROM. You can find the part described starting on page 99 of the databook at: http://bitsavers.trailing-edge.com/components/national/_dataBooks/1972_National_MOS_Integrated_Circuits.pdf Here's the character...

Hi all: I'm in need of cabling and a distribution panel for a DZ11 I'd like to put in my PDP-11/45. Before I embark on building something up from scratch, I thought I'd ping here and on cctalk to see if anybody has all or part of this on hand and would be willing to work out a deal. PM me if...

Rejumpered the G740 on my RK11 for a single drive, but MAINDEC ZRKK still hangs up in hardware pole test (octal 57). It could just be that this test doesn't work correctly with less than two drives? After this had a brief detour because the machine stopped booting off the M9301 bootstrap card...

Hey folks, just a note friends here working on 11/45 restores -- I just got my first boot off an RK05 XXDP pack with my project a few minutes ago :-) It's been about two years of working on my restore off and on on weekends and vacations. I've still got a ways to go on this project, but seeing...

Success!! (Well, at least reads) Replaced the failed bus driver on my 11/45 UBC. NPG signaling was better, but still a little squirrelly... Turns out I also needed to install some jumpers on my M9301 bootstrap terminator to enable grant pull-ups, which are not provided internally on the 11/45...

Taking apart my first RK05 pack for cleaning, I was depressed to see some evil foam inside the back, around the hub (see picture below). If this is decaying like the rest of the foams DEC used, this seems like a disaster brewing. I hadn't read about foam removal inside packs before. A known...

An update on the RKCS bus timeout issue: I received my digital scope in the mails, so have been able to take a good look at the SSYN signaling. The short of it: Using the M9202 bus jumper reduced the amplitude of the timeout glitch to where timeouts were not tripped, but did not eliminate...

Attached logic analyzer probes to BUS A MSYN L, BUSA SSYN L, and UBCB TIMEOUT (1) H at the rear of the UBC board on the 11/45 backplane, with the UBC board fully seated. Set the trigger on the timeout line, and running my test program I can see that timeout glitches for about 12ns right before...

Yup, it's a beast (see pic below). I'd been carrying it around in pieces, collecting parts and spares, etc. for years -- finally got to working on the assembly and restoration over the last couple years since my kid is up and out. The whole project is blogged, with many more photos, over at...

Update after the weekend: racked, cabled, and powered up the RK11-C. Tracked down and repaired a failed gate in the RKDB register. Now getting a bus timeout in test 21 (controller reset) of the ZRKJE0.BIC diagnostic, which will be the next thing to investigate. More detailed writeup on my...

Hi folks! Kicking off a thread here because I'm just starting to dive in on the storage subsystem of my PDP-11/45: and RK11-C + 2x RK05, and I'll be wanting to take advantage of the collected wisdom and good advice here. There's been a fair amount of talk on RK05s here and on the cctalk, and...