test-drb September 2013

test-drb@ccmp.vtda.org

168 participants
203 discussions

by shadoooo＠gmail.com

Hello Holm, I hope you find some part to repair your tape system! If the NEC disks you found have SMD interface (two flat cables, one is wider) and you don't need it, I would be glad to buy it. Thanks Andrea

11 years, 2 months

PDP-8/L current loop -> RS232 help

by derschjo＠gmail.com

Hi all -- I'm attempting to get my 8/L talking to the outside world. It's outfitted with the typical Teletype interface, which I'm attempting to connect to a PC via acurrent loop to RS232 adapter. Specifically, I've got one of these: http://www.bb-elec.com/Products/Serial-Connectivity/Serial-Converters/Curre…. At the moment I have it configured (per the manual) assuming the 8/L is an active loop device (i.e. the converter's transmit lines connect to the 8/L's receive lines, and the 8/L's transmit lines connect to the converter's receive lines). With this configuration I'm able to get the 8/L to send data to the PC successfully. I'm not having much luck getting the8/L to receive anything from the PC, however. If I put my multimeter in the loop, I see a current of about 40mA, which drops to between 30 and 37mA when the PC is sending data (depending on what data's being sent). However, I'm not getting much of anything onpin "E" of the W076 (Teletype Connector) board -- this is supposed to be the "Logic Output" and I'm assuming that should be the TTL-level data signal, correct? I do see a very, very tiny signal (in the millivoltrange) on pin "E" that matches up with the data being sent from the PC, but it's obviously nowhere near the correct level. I've gone over the W076 board and checked the related diodes and resistors for anything open/shorted. And I actually did find a bad diode (fell apart when I desoldered one leg to test) but replacing it made no apparent difference. At this point I'm wondering if the loop configuration I have is incorrect. I thought this was supposed to be a 20mA loop, but I'm getting 40mA. I know very little about the fundamentals of current loop stuff, so I could be way off here. Anyone have any advice? Thanks, Josh

11 years, 2 months

military computer on ebay

by brianlanning＠gmail.com

Terrible price, but interesting nonetheless. http://www.ebay.com/itm/1991-C3-Military-Field-Combat-IBM-PC-Working-Condit…

11 years, 2 months

Does anyone know what the functional differences are between models of Sony OA-34V floppy drives for early Macs?

by ethan.dicks＠gmail.com

Hi, All, Tangential to my Mac128K repair, I now have an OA-D34V-22 drive but my Mac128K board came with -A ROMs, as I have mentioned previously. I have found pictures of various models of this drive, and I know about what models work with what ROMs, but what I haven't been able to find out is what changed that old firmware doesn't work with newer drives. For search terms (and later documentation of this topic), here's the matrix... Original rev 64Kbyte ROMs, P/N 342-220-A / 342-221-A OA-D34V works OA-D34V-22 does not work OA-D34V-02 does not work Later rev 64Kbyte ROMs, P/N 342-220-B / 342-221-B OA-D34V works? OA-D34V-22 works OA-D34V-02 works >From my reading, it seems to have something to do with the stepper motor, but I haven't turned up any details. My guess is the original stepper pulse frequency or pulse width doesn't drive the motors on the newer drives correctly, but does anyone here know what the changes are and why? My solution to what hardware I have is still going to be to replace the -A ROMs with -B ROMs, but I just wanted to learn more. Thanks, -ethan

11 years, 2 months

Friday night deals at VCFMW/ECCC

by slandon110＠gmail.com

Im bringing a 12 foot trailer full of goodies out to VCFMW. Friday night ill let everyone raid the trailer, deals will be made so I dont have to haul it all inside. So get there early and get some good deals.

11 years, 2 months

Torx HDD screws

by dgriffi＠cs.csubak.edu

Does anyone here have any clue where I can find 6-32 1/4" screws with torx heads of the sort one would use to secure hard drives? The only source I know is scrouging HP stuff and I'd really like a better source than that. Philips screws annoy me to no end.. -- David Griffith dgriffi at cs.csubak.edu

11 years, 2 months

Subject: Torx HDD screws

by elson＠pico-systems.com

David Griffith <dgriffi at cs.csubak.edu> Subject: Torx HDD screws Does anyone here have any clue where I can find 6-32 1/4" screws with torx heads of the sort one would use to secure hard drives? The only source I know is scrouging HP stuff and I'd really like a better source than that. Philips screws annoy me to no end. McMaster-Carr and MSC are some places that come to mind. If you need a lot, there are fastener companies that specialize in these things. Check your local phone listings. Jon

11 years, 2 months

NEC DKU 743 Disk drive?

by holm＠freibergnet.de

Hi, a frienbd of mine phoned me, he currently is at the facility from a electronics recycler, looking at what a previous guy has left over from a Nixdorf Targon/35. (desoldered the cpu(s) with an hot air gun) He pulled the cipher M891340 9 track drive and is looking at the disk bays now. There are "NEC DKU 743" drives, couldn't find anything with google. What kind of drives are that? Interface? Kind Regards, Holm -- Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe, Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583 www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741

11 years, 2 months

N8 PCBs are here

by LYNCHAJ＠YAHOO.COM

Hi!? The reordered N8 boards have arrived! These are the all-in-one retrocomputer boards based on the Z8S180 CPU plus a full suite of IO peripherals. http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&param=ECB%20N8%20prev iously%20known%20as%20the%20Home%20Computer The PCBs will be $20 each as per the usual arrangement.? Shipping in the US is $3 for a single PCB and $2 for each additional PCB.? Shipping internationally is $10 for a single PCB and $3 for each additional PCB.? This is for the bare basics USPS first class postage with no tracking or insurance.? The builder assumes all risk of delivery as per usual arrangement. Please send a PayPal to LYNCHAJ at YAHOO.COM and I will send your board(s) right away!? Please contact me if you have any questions.? Thanks and have a nice day! Andrew Lynch

11 years, 2 months

6x0x host processor and 6x0x IO mezzanine PCBs are here

by LYNCHAJ＠YAHOO.COM

Hi! At long last the 6x0x host processor and matched 6x0x IO mezzanine boards have arrived! These can be used on the ECB backplane as a 6502, 6809, or 6802 coprocessor or as a standalone SBC. They can even host their own ECB backplane as bus master with the 6x0x ECB backplane PCB. http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&param=ECB%206x0x%20Ho st%20Processor http://n8vem-sbc.pbworks.com/w/browse/#view=ViewFolder&param=ECB%206x0x%20IO %20Mezzanine The PCBs will be $20 each as per the usual arrangement. Shipping in the US is $3 for a single PCB and $2 for each additional PCB. Shipping internationally is $10 for a single PCB and $3 for each additional PCB. This is for the bare basics USPS first class postage with no tracking or insurance. The builder assumes all risk of delivery as per usual arrangement. Please send a PayPal to LYNCHAJ at YAHOO.COM and I will send your board(s) right away! Please contact me if you have any questions. Thanks and have a nice day! Andrew Lynch

11 years, 2 months

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test-drb September 2013