test-drb November 2021

test-drb@ccmp.vtda.org

118 participants
73 discussions

by a.carlini＠ntlworld.com

I have three AlphaServer 2100 systems in storage in the UK (Oxfordshire). The storage, however, is due to be demolished (soon, but no fixed date). I won't have room to store these three systems, so if anyone would be interested in offering them a home, then please get in touch! I can probably get some pictures in the next day or two. These systems were SMP Alphas and could sport as many as 4 CPUs. I'm not sure of the configuration of these systems but I can probably find that out soon. They have not been run since ~2003 so they may be in need of some TLC. OTOH they are not rusted to death so you have a chance of getting them back to life. Just so you know what you might be dealing with these systems are about: 700mm H x 430mm W x 810mm L. I can't find the weight in any of my references right now but they are very heavy. Three people can move them up a slight slope with some effort but you would not successfully lift it into a car (assuming that it would fit). I'm planning to dismantle them to move them (i.e. remove PSU/PSUs etc. until they are light enough to move). A tail-lift would probably be the sane way to go (and is, indeed, how they got to their current location. I'm hoping that someone can step forward and offer one or more of these machines a new home. Please contact me off-list (once you're sure you understand what you are getting into :-)). Antonio -- Antonio Carlini antonio at acarlini.com

2 years, 8 months

H7821 power supply in MicroVAX 3100, SCSI disk enclosures and others

by cctalk＠beyondthepale.ie

The recent discussion on BSC protocol prompted me to dig out my Microvax 3100 with DSH32 synchronous serial interface. It had been idle in storage for several years and it wouldn't power up, only giving a brief flash on the diagnostic LEDs and a quick twitch of the fans. There was a slight smell, like the stale air that comes out of a deflating tyre. I took out the H7821 power supply and found that five identical brown 1800uF 25V electrolytic capacitors on the output side had leaked. The SCSI disk enclosure where the machine's system disk lives required several power cycles to get it to run at all and it died as soon as the disk tried to spin up. It turned out to also contain a H7821 power supply which had a similar issue with the same five brown capacitors, although not as extensive as in the main unit. I found a second disk enclosure which had seen little use and grabbed the power supply out of that to put in the MicroVAX. It worked well enough to test with but there was a ring of goo around the bottom of one of the brown capacitors which was worst affected in the other units. Time to order a batch of replacement capacitors and figure out what else has been damaged. While it is not the worst I have seen, access to these power supplies for repairs is quite difficult and it is really difficult to debug them safely while they are running with the cover off :-( If anyone has anything with H7821 power supplies in them, I suggest checking on these capacitors. If anything with these power supplies is in storage, I suggest ensuring it is stored the normal way up as this should limit the ability of the goo to escape and spread around the power supply. And there I was thought I was being safe enough by removing the nicad battery packs some years ago... Regards, Peter Coghlan.

2 years, 10 months

Applesauce FDC

by nospam212-cctalk＠yahoo.com

I've recently picked up a new Applesauce floppy disk controller and have been playing with attaching various different drive types and imaging different Apple II, Atari, TI and other floppy disks with it. So far I've mostly imaged unprotected disks and run them in various emulators just fine. I've since added a sync sensor to one of my older Disk II drives and started to make some flux images of protected disks. These too seem to run fine in the emulators I've tried. The documentation on the device is limited at the moment, particularly the software, and while it is slowly being updated I was wondering if anyone else here had any experience with the setup. Any hints, suggestions, best practices, "do this to get the best copy", etc, to pass along would be appreciated. For example I read you can try to recover borderline disks by having it do multiple passes of the bad sectors. I see how this is done on the Fast Image option and has helped a couple of times but don't see any way to do something similar via the Flux Image option. Does it not work/matter with those? Also I see sometimes it reports a file as bad if I do one image type but if I do the other it comes back as okay. So I tend to play with both when I can. There is a lot of options and functions in the Flux Image option that I just really don't know how it works or what to do with it so far that any info would be great. I know it can image non-Apple II disks as well and I've done a few. It works great on Apple II protected disks but wonder how to deal with protected disks from other systems? Or is that more an issue of other emulators and such not having something like the .woz format being used with the Apple II? I bought this for my Apple II collection and it was a nice surprise to learn it could work with other systems too, just looking for more info about them as well. So far I really love the device and it has been worth the long wait for new units to come back into production again. Especially as it is a new design that allows for attaching PC floppy drives now as well. I've noticed the doc on the site being updated, just hope that they can find time to update more, particularly in regards to the client software. Best, David Williams www.trailingedge.com (http://www.trailingedge.com)

2 years, 11 months

The Prolok Saga (Was: Applesauce FDC

by marvin＠west.net

Another thing Prolok did was produce a small 3 disk set of sample disks with the Prolok protection. Somewhere around here I still have a set of those disks. As I recall, a program was included on each disk to copy the program to be copy protected to the special disk.

2 years, 11 months

Apple I auction

by shumaker＠att.net

Another Apple I on the auction block: https://www.liveauctioneers.com/item/114629733_the-chaffey-college-apple-1-… Steve

2 years, 11 months

What happened to control-data.info and controlfreaks.org?

by jim＠deitygraveyard.com

Is anybody able to access these sites? I just get redirected to Google. Jim

3 years

Looking for someone in London (UK) to read 2 9 track tapes

by cclist＠sydex.com

Hey list, I received a note today from a fellow in London who has 2 9-track tapes that he'd like read. Brands are CDC and BASF, so media shedding should not be a problem. Dates are '92 and '93, so likely 1600 or 6259. The tape seal on one (the other has no seal) is IBM-style, which may be the system that produced the tapes. Any takers? Let me know if so, I'll put you in contact and you can take things from there. All the best, --Chuck

3 years

PDP-11/70 Boards

by jnc＠mercury.lcs.mit.edu

> From: Ed Cross > I'm currently restoring a PDP-11/70 system and need the following > boards to complete the CPU: FP11-C >From your mention of the FP11-C, I gather your -11/70 has a KB11-C (later) CPU, not the KB11-B CPU of the earlier PDP-11/70's (prior to 1976 - the difference between the two was whether they took the optional FP11-B or FP11-C FPP). Not that it makes a big difference in your case; the 4 cache cards are the same in both. There used to be a seller on eBait (on the mid-East Coast - Baltimore, IIRC) who was selling -11/70 CPU cards (I bought a whole spare set from him) but alas he seems to have gone away (or sold them all; a quick search, both on eBait, and in my email, didn't turm him up; I can institute a deeper search if need be). >From the blog of someone who got a KB11-A working, you'll really need KM11 cards; dunno if Guy Steele still has those clones he was selling. There are definitely some versions of Unix which will run fine on -11/70's without the FP11 (e.g. V6). The system binary is different for the with/without versions, though: in the assembler code which saves the state of one process before switching to another, there is code like: stfps (r1)+ which will probably get an illegal instruction trap in kernel mode on a machine with no FP11, and is therefore conditionally assembled (depending on if the particular machine the system is being built for has an FP11). Perhaps the later BSD versions look for the FP11 on startup, and adjust their behaviour appropriately, but I'm not familiar with them. V6 as distributed contains system binary for an -11/40, which will run on _any_ -11 UNIX will run on, and can be used to build appropriate system binary. (Diversion: I've never found out whether the KB11-B and KB11-C of the -11/70 used/could use the same backplane or not. By examining the prints for the boards of the FP11-B and FP11-C, and seeing on which pins they exchanged signals, and what signals they exchanged with the rest of the CPU, and on which pins, it should be possible to work it out. Ditto for the M8133 ROM and ROM Control of the KB11-B, replaced with the M8123 in the KB11-C.) (Interesting factoid: the M8123 is the only card shared between any variant of the -11/45 and -11/70: both the KB11-C and KB11-D use it. Of course, I think we're still missing a wirelist for the -11/70 backplane, of any variant; and the ECO history. There appears to have been at least one poorly documented upgrade; see here: http://gunkies.org/wiki/MK11_memory_system#CSR_Access for more.) Noel

3 years

Looking for tips debugging DEC TC01 controller

by derschjo＠gmail.com

Hey all -- I picked up a TC01 in trade (for a TC08) a couple of weeks back and this past weekend I got it hooked up and powered up with my PDP-8/I + TU55 transport. I've been debugging it and have solved a couple of issues but the current one has me stumped and I'm looking for advice, hoping I overlooked something obvious. At this point the PDP-8/I can talk to the TC01 and use it to control the TU55 without issue. I've mostly been using MAINDEC-08-D3BB to exercise the hardware (see: http://svn.so-much-stuff.com/svn/trunk/pdp8/src/dec/maindec-08-d3b/maindec-…) and issuing FWD/BACK commands via the "Basic Motion" routine the tape runs >from one end of the tape to the other, stopping at the endzones correctly. The tape comes up to speed properly, the COUNTER register increments, and in general the various status lights on the panel do what I expect them to do. The root symptom I'm seeing now is that DECtape operations (like SEARCH) don't complete, and I've traced this back to the MK BLK MK signal not getting asserted. This signal is generated by a large AND gate (see p. 112 of http://bitsavers.trailing-edge.com/pdf/dec/dectape/tc01/DEC-08-I2AB-D_TC01_…). This gate ANDs together a pile of signals from the WINDOW register and the counter, looking for a specific bit pattern on the mark tracks; this AND gate is never satisfied because the WINDOW register's MSB (W1) is stuck low. On the scope it's a completely flat line, no glitches or anything noticeable. Despite my best efforts I cannot figure out why this is. Here's what I've looked at and what I've discovered thus far: 1) The inputs to the W1 flip-flop (pins U (clock) and V (data) look to be correct -- U is identical to the TP1 signal being passed to all the other flip-flops in the chain, and V is identical to the data coming out of W2 -- levels all look fine. 2) The outputs of W1 (pins T and S) are not being pulled up or down by anything external. I've gone so far as to completely disconnect T and S >from the backplane (with some tape over the card fingers) and the outputs are still a flat line. 3) The output of pin T goes to -3V when 0->WINDOW is de-asserted (when tape is in motion), returns to 0V when 0->WINDOW is asserted after the tape stops. (S is the inverse of this, as expected.) (As an aside, the schematic drawing suggests that 0->WINDOW ought to be a pulse given the arrow symbol; this does not appear to be the case. Other flip flops in the chain seem to behave properly, regardless...) 4) The backplane connection to the R203 flip-chip that the W1 flip-flop is on is fine. I've beeped this out and there's no significant resistance between the backplane pins and the connection to the card in the slot. 5) W1 is not affected by the state of the two other flip flops on the R203 (also tested by disconnecting all pins other than power/gnd and pins R/S/T/U/V with tape). 6) Swapping in a different, working R203 shows no change in behavior. 6) Sometimes, randomly, W1 starts working. Last night I noticed that the solder side of R203 was rubbing against the top of the "flip chip" packages on the R107 next to it and even though those shouldn't be conductive, I stuck a piece of cardstock between the two. W1 started working! I tested things for about a half hour in this state (interrupts were still not occurring, much to my annoyance) and this morning I powered it up and it was still working. Pulled the cardstock out and W1 stopped working; this would seem to causation. Put the cardstock back in... still won't work. Backplane connections all test out fine (see (4) above). Put the R203 on an extender (to completely avoid interference with neighboring cards) and still no go. Possibly the insertion of the cardstock flexed the board or the connection with the backplane slot ever so slightly to make things work but if so I've been unable to replicate it. All of this still sounds like a bad connection somewhere (backplane, cold solder joint, broken trace) but the evidence seems to be against it (checked, double-checked, triple-checked backplane, swapped R203s around, etc...) Anyone have suggestions? I'm going to start looking at things on the board itself (which is going to be a pain given how things are currently arranged in the chassis) but curious if I've missed anything here... - Josh

3 years

Datapoint 2200 on ebay

by sieler＠allegro.com

Noticed a Datapoint 2200 on ebay.... https://www.ebay.com/itm/275043446827 They're asking $48,000 I want one...but not for that price! :)

3 years

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test-drb November 2021