test-drb June 2014

test-drb@ccmp.vtda.org

187 participants
157 discussions

TD Systems Inc Viking QTO / QDO conversion. QBUS.

by mattislind＠gmail.com

I have a TD Systems Viking QTO MSCP emulating SCSI tape QBUS controller and I found a manual for that one one the net: http://manx.classiccmp.org/collections/antonio/chrisq/TD_Systems_Inc_-_900-… But I rather have a disk controller rather than a tape controller. Or a combined tape and disk. An old post from '99 ( https://groups.google.com/forum/#!topic/alt.sys.pdp11/2XddHq03SQI) indicate that the web address is www.tdsys.com. Accessing this webpage just informs me that the company doesn't exist any more. But someone is paying the domain fee. I tried to email but hasn't got neither a bounce nor a reply yet. I would guess that it is all up to the EPROM and the PAL chip to decide how this card is working. QDO, QTO, QDT, QDD or QDA. The PAL is a simple 16L8 so it is most certainly only used for address decoding and should be pretty simply to change. The EPROM contents is a problem though. I dumped it and did some initial checking with a Z80 disassembler and simple operations like "strings". There are a lot of strings in there. Some of them seems to relate to tape drives, like "EXABYTE", "WANGTEK" and "space forward". But also others that seems to be disk oriented like "Booting from DU0", "Disk common command set" and "Fomat unit". A couple of years ago a someone sold such a controller on Ebay but also included an EPROM and a PAL to convert it. I contacted this seller but never go a reply. Does anyone have this controller? Know anything about it? Has anyone converted it from tape to disk?

10 years, 1 month

DEC8271 shift register

by mattislind＠gmail.com

> On Thu, Jun 19, 2014 at 2:18 AM, Marco Rauhut <marco at familie-rauhut.eu> > wrote: > > > i have here a PDP8/E with a defective M8300 Mayjor Register board. The > > problem is a DEC8271 shift register that is used for bit 0 - 3 in program > > counter register. > > Do anyone know a modern equivalent for the DEC8271? > > > > It's a Signetics 8271. The full Signetics part number is N8271B for > plastic package or N8271E for ceramic, or "S" prefix rather than "N" for > -55C to +125C temperature range. > > There is no "modern equivalent". The 74LS395A has similar functionality > except that it has a single clock input and a load/shift control, whereas > the 8271 has separate load and shift clocks. And the pinout is completely > different. > > If you can't get an 8271, you could program a PAL to do the same thing, > though it's possible that the much higher speed of the PAL could cause > problems. > > I wouldn't advise trying to substitute the Intel 8271. I just recently repaired a DEC TU60 tape drive. It contained N8271 chips in the CRC logic. One of them was bad. I replaced it with a 74179 which I bought on EBAY. As far as I understand they are identical. http://www.datormuseum.se/computers/digital-equipment-corporation/pdp-11-04

10 years, 1 month

The Mac inspired loyalty - was Re: Least PC-Compatible MS-DOS machines?

by seefriek＠gmail.com

> > AU/X for PowerPC would have given them a contender > AU/X was a pretty awful Unix cobbled together to meet a narrow market need unrelated to the markets Copeland was intended to address. It's singular grace was it let Apple say with a straight face "yes, you can run Unix on our hardware" (and to a lesser extent, say "and see, it looks pretty like a Mac"). It wasn't a contender in the Unix market, much less the "platform to take Apple to the next level" market. KJ

10 years, 1 month

VAX 3100/38 memory error

by mark.kahrs＠gmail.com

So, the memory fails when booting up and the result of a test 50 is as follows: ?? MEM 0010.0200 01000000 According to the M38 manual, there SHOULD (not yelling, really) be a second address of the failure after the memory size on the second line. As you can see, there isn't. What's up with that? Where do I begin? I think the biggest hint is the 0200, but alas and alack, that isn't in the manual (at least the one that I have). My offhand guess is that this is a problem w/ the on board memory on the processor card --- but then you'd still expect an address. Comments?

10 years, 1 month

Handspring Visor with a ton of accessories $150 plus shipping

by shawn＠thekompany.com

Hi, I've got a very nice, and working, Handspring Visor with various cases, the docking station, the 'eye' module camera and the Targus folding keyboard as well as all the accompanying software. Shipping in the US is $15, for international I'd have to check based on country. Let me know if you are interested, I can take Paypal or an echeck. I can send pictures if interested. Thanks, Shawn

10 years, 1 month

Unknown console/computer

by billdeg＠buzz1.com

> While digging through a local estate sale yesterday, I found an unknown (to me), unmarked system. From what I know of the late owner, the system may be related to the aircraft industry, as many of his tools and bits and bobs were from Boeing surplus. > As for the unit itself, it is a yellow desk, with a tinted glass slide-down screen, a complex keyboard. It had two Canon 5.25" floppy drives mounted behind the screen, next to a USi Pi3 amber monitor. <snip> Others may have said something similar, but here is my 2 cents....The USi Pi3 monitor was sold as a package by Protecto along with the liquidated Commdore B-128 computers in the mid 80's. They bought the remaining stock. Assuming the monitor came with the terminal, one could deduce that this smart terminal is also from the mid 80's as well. Bill

10 years, 1 month

Thinkpad 750C

by chuck.mcmanis＠gmail.com

I've got my original IBM Thinkpad 750C (486SL version as I recall) with a docking station (it has slots in it) which I cannot justify keeping around any more. I need the space. Anyone here interested in it? I believe I have the original install disks as well but finding those might be more of an issue. It has Windows 3.1 on it and one corner of glorious 640 x 480 color display is not working (like maybe 15 - 30 pixels out of the corner with issues. --Chuck

10 years, 1 month

So I Got This Old Sun

by silent700＠gmail.com

Hoping to bring some knowledge out of the woodwork here...I have acquired what is, in any case, quite a relic, but I suspect there is much more to learn about it: http://silent700.blogspot.com/2014/06/leads-always-follow-them.html In short, I stumbled upon a Sun-1. It's the rackmount version, the 1/150, but it has a strange model name on the ID plate which appears to be "RM-CC" or "RM-0C." It has a very early serial number but I can't determine if that was its first number or the result of an upgrade or refurb. It appears to contain a Sun-2 CPU board so, according to what I've read, should be ID'd as a 1/150U. I've read nothing about re-assigning a serial, however. I was told that Sun-1 serial numbers began at 013, due to there being 12 employees at the time. Again, I have no idea if this machine's serial number is original or not. It was sold to the University of Chicago, who I believe were among the first purchasers of Sun products. They are said to still have S/N 13 (in theory the "first" Sun made) in their posession but I have no first-hand knowledge. I am supposed to be put in touch with the original curator of this machine, from which I hope to learn a lot more about its history. For now, enjoy the pics and please share whatever info you may have... - jht

10 years, 1 month

Lilith CRT flyback failure

by jdr_use＠bluewin.ch

During preparation of the machine for VCFE i had a failure in the CRT's high voltage part. Yep, flyback burnt.. The high voltage winding was potted as a separate unit, enabled my to rewind the flyback's primary (was burnt). Then after replacing 2 transistors, 2 resistors and 1 diode I got a brief few seconds of live out of the display again. The hisses accompanying this would indicate the maybe the flyback HV isolation is not good anymore, however i did not see sparks flying... Current working assumption is that the secondary potted winding is also compromised. I will also replace the HV voltage diode, is the HV capacitor something that fails regularly ? It is a 17 inch white monochrome Ball HD17-type monitor. What are my options : repair again, looking for a generic flyback ( is there such a thing ?) , or dumping it into lake Zurich, which is my current mood.... I am not averse to putting some modern solution in place ( to generate the HV that is ) Jos

10 years, 1 month

DEC H7140 issues

by b4＠gewt.net

All, I have an (untested) H7140 here with the bias/interface module from my dead one...took me a bit to get it in...apparently the aligning rails got knocked loose. Now, it comes up ad the DC OK light blinks (there is no load, I haven't done voltage checks and I'm not ready for a load yet). However...the fans don't spin and I measure 0VAC there. Last night the wires had gotten caught on something, cut a bit and ended up shorted together...I hadn't noticed as the tag covered up the damage...but I fixed that today. I wouldn't imagine there was protection missing there...I never heard arcing, anything frying, and I didn't see current draw shoot up. Any ideas? I don't want to put ANY load on this until I have the fans working...not even a dummy load. -- Cory Smelosky http://gewt.net Personal stuff http://gimme-sympathy.org Projects

10 years, 1 month

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test-drb June 2014