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101090 discussions

(DiscFerret): First prototype built, photos available!

by classiccmp＠philpem.me.uk

Hi guys, The parts for my soldering iron finally arrived this morning, thus I spent the day playing with solder paste and SMD stencils. I've got one working DiscFerret built on a 0J28 board, using the same 2C8 FPGA and Cypress RAM chip I used on the previous two prototypes. The key difference here is that this unit is RoHS-compliant, built entirely with lead-free parts, and was assembled using a modified Argos mini-oven. The extent of the modifications? I installed an eCAL E6C PID controller and a Crydom EZ480F18 solid state relay. After a few hours spent reading the "concise operator's manual" for the PID controller, I finally got the Kester Pb-free and SnPb profiles loaded, and the thing is as happy as a pig in muck! (Oh, it turns out Multicore RA15 and 318LF work fine with the Kester profiles... for anyone who cares). Here's the Hardware Overview I've just written: http://www.discferret.com/hardware/ And, for the impatient, here's the 1280x712 photo of the very first DiscFerret: http://www.discferret.com/hardware/discferret_pcb.jpg This board has been allocated the serial number "GB0K1801", which decodes as: GB: "Great Britain", i.e. "Made in England," of course :) 0: 0 years after 2010 K: 11th month, i.e. November 18: 18th day of the month 01: First unit built on that day The plan is to clear out my stocks of 2C8 FPGAs, which should (in theory!) leave me with six saleable units in total, based on the stock of parts I have available. Tomorrow should be fun. It took me four hours to make this one board. If I can scrape together enough table space, I should be able to paste-and-place three or four boards at the same time, then oven-bake them in turn (which takes 5-10 minutes a piece). The fun part is, as always, clearing up all the solder bridges :( -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

15 years, 5 months

MEK6800D2 restoration

by wim＠hackbox.be

I'm in the process of restoring a Motorola MEK-6800-D2 evaluation kit. The kit was adapted and has its RAM on a separate board through an EXORciser backplane. After putting everything together and verifying that all looks good, I've applied +5V from an ATX power supply. The '-' prompt appeared, the JBUG monitor program is working and I even dumped the ROM and some EPROMs over the cassette port and decoded them on a PC :) So far so good, but to do anything cool I need the RAM board going. The problem is that this (custom wire-wrapped board) is using 16 MCM4116 chips. They need also -5V and +12V. Ok, these are available on the ATX power supply but I'm affraid of doing anything stupid that might blow up something. What would you check before applying these additional power levels ? I've been verifying a bit with an ohm meter that the -5V and +12V leads are not by accident connected to anything they shouldn't but not sure if that's a good way. I also read in the datasheet that you need to apply -5V before the others and removing it after the others. How would you do that ? I was thinking on having the -5V and GND permanently connected. So after switching on the power supply it will have -5V right away. Then manually connect a additional cable having GND, +5V and +12V. On power off do the reverse. Is that a good idea ? Not very handy but if it works I'll live with it. Thanks for any advice, Wim. -- hackbox dot be slash museum

15 years, 5 months

1103s

by tshoppa＠wmata.com

> They had non-multiplexed addresses I think. Later DRAMs had multiplexed > address inputs. of course. Was there a good reason for this other than to > save package pins? I wouldn't call it a necessity but the RAS/CAS/refresh coordination works out very nicely when address inputs are multiplexed in this way. So much so that I can't think of a DRAM since the 4116 that hasn't used this scheme. SRAM's almost always have the concepts of "row" and "column" select internally but rarely is it obvious from the outside. Tim.

15 years, 5 months

OT: Bluetooth

by evan＠snarc.net

Totally off-topic .... it's 3:20am EST here and I need to test something on my new headset .... anyone awake so I have someone to call for the test? (Please reply off-list. evan at snarc.net) Thanks.

15 years, 5 months

RF31s available

by binarydinosaurs＠gmail.com

Folks, Before I send a DEC R400X expansion box to the recyclers does anyone want the RF31s contained within? There's 5 plus a single DSSI variant of the RZ26. All are in the later pluggable backplane type enclosure and I need to know by next tues (23rd). Shipping isn't a problem as long as you pay for it :) Cheers -- adrian/witchy Owner of Binary Dinosaurs, the UK's biggest home computer collection? www.binarydinosaurs.co.uk

15 years, 5 months

Ebay Sperry Unisys Boards (leaknoil)

by jonas＠otter.se

Some kind of US Military Standard Electronic Module, see http://www.tpub.com/content/MIL-SPEC/MIL-M/ (the marking M28787 is the MIL-M number) Referred to here: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.129.4343&rep=rep1&… No idea what they are/were used in. If you Google for M28787 there are dozens of surplus supply outfits selling these. /Jonas

15 years, 5 months

1103s

by tshoppa＠wmata.com

Tony writes: > Tim writes: >> Having worked with 1103's I would argue that by modern standards >> Even the "cream of the crop" were little above floor sweepings. > Was it that a lot of new 1103s were DOA, oe what there a problem with > them fialing in use, or what? > The reason I ask is that I have several old HP calculators full of 1103s, > and AFAIK all are original (and gettign on for 40 years old). So far, > otuch wood, I've not had any problems with the RAM in these machines. How many hundreds of 1103's are in each HP calculator? :-) In the early minicomputer 1103-based memories (say 16Kbytes, so 128 1103 chips) it was, um, optimistic to expect a lot of stability. In the bigger "supermini" systems (say 128 Kbytes, so over a thousand 1103 chips) ECC was a necessity and continual scrubbing helped a lot with stability - but that was a lot of work and power consumption just to brag that you had semiconductor memory, and the advantages over core were not all that obvious. I'd expect that smaller systems probably didn't have ECC or scrubbing but also didn't have high expected uptime. Were 1103's in the HP 9830? I had a couple but they usually worked fine enough that I never had to go rummaging through the insides. My feeling is that in the 1103 era (which preceded my direct involvement but I inherited several 1103-based systems), DRAM chips were not quite ready for prime time. By the time the 4116 came along things had settled down and a lot had been learned from the 1103 and DRAM really was ready for prime time. Tim.

15 years, 5 months

Legacy Binary File Editor

by Hollandia＠ccountry.net

Will someone direct me to a good binary file editor that will function on legacy machines? Thanks, Kurt

15 years, 5 months

Looking for a Depraz mouse.

by h.marien＠telenet.be

Hi, I don't know if this tread is still valid, but I have such a mouse with a blue cover and white buttons. The mouse was especially made in this color combination for our long gone firm. It's a quadrature mouse but I have a special developed serial interface card for it too. It served to couple the mouse to a Digital PRO350/380 (personal PDP11) computer. Regards, Hugo

15 years, 5 months

Legacy Binary File Editor

by Hollandia＠ccountry.net

My request was apparently a little hazy. The machine I refer to is a Packard-Bell 486SX running DOS 5.0 and Windows 3.1 By "legacy machine" I meant a machine that was "slightly behind the times". 8D Thanks, Kurt

15 years, 5 months

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