test-drb March 2022

test-drb@ccmp.vtda.org

87 participants
62 discussions

by elson＠pico-systems.com

On 3/28/22 21:55, Jon Elson wrote: > On 3/28/22 17:22, Rob Jarratt via cctalk wrote: >> Its 600mV, but it is more of a spike than a ripple. >> > That's probably not real.? It looks like noise pickup from > the probe ground lead.? Try disconnecting the probe tip > and see if you still get similar signals.? I have seen > similar noise lots of times when measuring things with > switching power supplies.? The high frequency content is > pretty unlikely to be actually there on the power rails, > with a bunch of decoupling caps all over the boards. > > Jon >

2 years

Loss of Museum in Ukraine

by c.murray.mccullough＠gmail.com

Without getting political I was saddened to hear of the destruction of the Club 8-Bit museum in Mariupol, Ukraine. One can only hope that D. Cherepanov can rebuild his museum someday keeping classic computing in that part of the world alive. Murray--

2 years

FTGH: DEC Networks & Comm Buyer's Guide, Letterprinter 210/LA50 manuals

by toby＠telegraphics.com.au

Hi, Digital Networks & Communications Buyer's Guide 1987 April-June Also some DEC Letterprinter 210 and LA50 Printer manuals, ask for a list. For postage from Toronto Canada. --Toby

2 years

Webinar: Ethernet's Emergence from Xerox PARC: 1975-1980

by tom94022＠comcast.net

Ethernet invented in 1973-74 at Xerox PARC in Palo Alto, CA, evolved over many years. This April 13th Webinar will trace the history and development of Ethernet as a 10 Mb/s product up through the release of the DIX (DEC-Intel-Xerox) spec in 1980. This was the starting point for the ongoing IEEE 802.3 Standard activities. Speakers include Gorden Bell, Dave Liddle, Bob Metcalfe and seven other pioneers who were there for the transition. More detail at <https://r6.ieee.org/sv-techhistory/?p=1030> SVTHC website Register <https://www.eventbrite.com/e/ethernets-emergence-from-xerox-parc-1975-1980- tickets-301085664327> Tom

2 years

Installing an operating system on the 11/83 - update.

by rodsmallwood52＠btinternet.com

Hi All ????? I did find some RX50 images of the MicroRSX distribution. ???? So I fired up my DEC Celebris FX. It runs W95 and has a 3.5 inch floppy, a real RX33 5.25 inch drive and a CD-R. ?? Its accessible on my network so getting files onto it is not a problem. ??? So install putR.com , and transfer the image files. ? ? Huh! putR says the RX50 disk is write protected. Its not and the drive works normally with the disk from the MS DOS prompt. ? ?? So much for putR writes RX50's on RX33! ??? Rod

2 years

YouTube on the History of DEC

by r_a_feldman＠hotmail.com

A friend who used to work as a software trainer for DEC sent me the following link (https://m.youtube.com/watch?v=uIqlMfSCs0E), which points to an hour-and-a-half-long YouTube video from June 2021 about the history of DEC. It is a Zoom presentation from the Maynard Public Library done by a local newspaperman. It is fairly general, but was attended by a number of former employees, some of whom made comments.

2 years

FreHD

by bill.gunshannon＠hotmail.com

Here's one for the memory banks. I have a number of TRS-80's. Back when they first came out I bought a couple of the FreHD Hard Disk Emulators made by Fred Vecoven. They worked great and made life a lot easier. Then, I had reason to put everything away for a long rest. I just pulled them out and set them up again. Neither of them does anything. As a matter of fact, in my 4P they even keep the system from booting from floppies. Anybody else run into something like this? Is there something that would go dead if they sat idle for several years? I checked the CR2032 batteries and they are still alive so it's not like they ran out of power or anything. Any hints? bill

2 years

MAN-3A display

by charlesmorris800＠centurytel.net

Looking for a couple of MAN-3A (single character, seven-segment red LED display) to restore a '70's pocket calculator. One digit is missing a segment. I had another 3A in my LED drawer - and IT has a different bad segment... aargh. No luck searching the usual places online. Can anyone help? thanks.

2 years, 1 month

DEC ME11-L core memory expansion unit drawings

by jnc＠mercury.lcs.mit.edu

> From: Steven Malikoff > I have finally got around to scanning the print set for the DEC ME11-L > memory expansion unit Ah, thanks for that. The prints for the boards are available, in the PDP-11/05 Engineering Drawings (on pp. 115-137), but the MF11-L backplane was previously missing. (The -11/05 generally mounts MM11-L sets in the main CPU backplane, so the MF11-L backplane is not included in the -11/05 prints.) It is the non-parity MF11-L backplane (DEC part number 54-09959), not the parity one (part number 54-10331), though. (My theory is that the non-parity version can be upgraded to parity with an etch cut, and some added wires, FWIW.) Noel

2 years, 1 month

DEC ME11-L core memory expansion unit drawings

by steven＠malikoff.com

I have finally got around to scanning the print set for the DEC ME11-L memory expansion unit and you can find it at https://archive.org/details/dec-me-11-l-core-memory-system-engineering-draw… The quality is acceptable given that the office supplies shop where I (DIY) scanned them on an A3 scanner only allowed output as JPEG or PDF (undoubtedly wrapped as JPEGs inside) so I thought there was no point degrading any more than necessary with editing the JPEGs to another format just to re-save them. I just bundled the raw scanned pages as-is and it looks fine. There's also some miscellaneous fragments for the M7050, M715 and M840 module drawings which came with the ME11 set. Steve.

2 years, 1 month

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test-drb March 2022