test-drb December 2021

test-drb@ccmp.vtda.org

114 participants
75 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

DEC RF30 Integrated Storage Element Service Guide

by robert.jarratt＠ntlworld.com

I am looking for the service guide for the RF30 DSSI disk. It is not on Manx and not on BitSavers. Does anyone know of a copy? The part number is apparently EK-RF30D-SV. Thanks Rob

2 years, 11 months

Testing a H744 Regulator on The Bench

by robert.jarratt＠ntlworld.com

Hello All, Following a discussion on resurrecting a PDP 11/45 I have started looking at the regulator bricks in the PSU. I have started with a H744. I reformed the three big capacitors, although they seemed to be fine as they charged up >from my DC bench PSU and then had zero leakage so I didn't reform them for very long. I then moved on to powering the whole unit from my DC bench PSU and it seemed to run fine. I am using a panel mount 1R resistor, so drawing 5A of the rated 25A. It drew just under 2A from the PSU which was set at 20V. I didn't run it for very long as I wasn't sure how hot to allow the load to get. Is there any sense in measuring ripple when powering this from DC? There does seem to be some ripple: https://rjarratt.files.wordpress.com/2021/12/h744-ripple.png hard to say if that is OK? Also, the indicator light does not work (as expected). I have seen the suggestion to replace it with a CM7381. It looks like these can be sourced <https://www.mouser.co.uk/ProductDetail/?qs=N8%2Bk0S5zvCZ7dMEMH2XU9Q%3D%3D> with relative ease, but I wondered if there might be a better LED-based longer term solution? I was also advised that OL-6003BP is good for the 15V regulators, but these seem to be hard to find, any suggestions there? Thanks Rob

2 years, 11 months

PDP-11/44 gas struts

by Flash688＠flying-disk.com

Mark J. Blair <nf6x at nf6x.net> wrote: > When I need gas struts and cannot identify a source for exact original > replacements, I usually look at McMaster-Carr first: > https://www.mcmaster.com/gas-struts/ Thanks for the McMaster-Carr suggestion, I should have thought of that. I removed the gas struts from my PDP-11/44 and found the following markings: Gas Spring Corp. Colmar, PA 1216166-0-0 22/81/3 (the "1" might be an "I") I measured them, and found a compressed length of about 9.8" and an extended length of 15.25". The threaded studs are 5/16"-24. I can't find the company, and Google turns up nothing with either of the number strings. Nor do the numbers seem to indicate what the specifications might be. Perhaps someone with better Google skills than I have might find something. It is, however, an almost perfect match for McMaster-Carr P/N 4138T55. The big unknown is the extension force. After cleaning and oiling them, one of the bad ones measures about 12 pounds, and the other is about 23 pounds. The 4138T55 is available in 15, 20, 30, 40, 50, 60, 90, and 120 pounds. I made a wild random guess and ordered two of the 30 pound struts, which should be delivered Wednesday (12/29/2021). The 40 pound ones have a seven week lead time, and a pair of 50 pound ones seem way too high. When they arrive, I'll let you know how well they work. Worst case, I will have wasted $20.29 each, plus shipping, and have to wait seven weeks for the 40 pound units, or go whole hog and try the 50 pound ones. Thanks for the help and suggestions. Alan Frisbie

2 years, 11 months

New mailadress

by pontus＠Update.UU.SE

Hi I've been using this adress for many years: "pontus at update.uu.se". But the club is now at risk of loosing the domain name. I'm therefore moving over to "pontus at dfupdate.se" Sorry if this is of topic but I have made many acquaintances on this list that might not find out otherwise. Regards, Pontus.

2 years, 11 months

New mailadress

by pontus＠Update.UU.SE

2 years, 11 months

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb December 2021