test-drb November 2014

test-drb@ccmp.vtda.org

200 participants
279 discussions

Reading a CD that has no reflective layer

by spacewar＠gmail.com

On Tue, Nov 18, 2014 at 7:45 AM, John Foust <jfoust at threedee.com> wrote: > The CM100 apparently only works on PC and XT era hardware. I saw > mentions on the web that even a 25 Mhz PC is incompatible. I have some CM100 drives, which may or may not work at this late date due to a combination of age and poor environmental conditions in storage. I do not have a CM153 interface card. The interface consists of three or four RS-422 pairs. At one time I reverse-engineered the 8051 firmware in the drive and understood the details of the interface quite well, but I've forgotten them and cannot currently locate my old notes or the service manual. Still, if a CM100 is useful to you, let me know.

10 years, 1 month

11/73 (ba23) bringup after 12 years in deplorable storage conditions

by jnc＠mercury.lcs.mit.edu

> From: Robert Jarratt > There is no printset that I am aware of the for the H7864 PSU. Really? Wow. With all the machines that used BA23 boxes (both -11s and uVAXen), you'd think that the printset for _one_ of them would have included the H7864. That was common DEC practise; the print-set for the 11/xx system as a whole usually included the prints for the 'standard' power supply for that machine. (That's how we have the prints for the H786 BA-11N power supply - as part of the prints for the 11/23 - someone kindly pointed that out to me.) So I'd check out all the machines that came in a BA23, and look for the print sets for them, and see if any has the H7864 included. (If anyone finds them, do let us know if you succeed - I have a feeling I'll be needing them before too long! :-) Noel

10 years, 1 month

dec rainbow claimed

by jwest＠classiccmp.org

The dec rainbow was claimed yesterday by a listmemeber. J

10 years, 1 month

The Whetstone Benchmark

by mark＠wickensonline.co.uk

This is an interesting read about the history of the Whetstone benchmark and a good summary of vintage performance: http://www.roylongbottom.org.uk/whetstone.htm Mark.

10 years, 1 month

PET 6540 ROM operating temperature

by derschjo＠gmail.com

Hey all -- A quick one -- what's the normal operating temperature for the old MPS6540 ROMs used in the original Commodore PETs? I noticed last night after running mine for ~30 minutes that the ROMs were very hot, to the point of being painful to touch. The machine is running fine as far as I can tell -- though I haven't verified the contents of the ROMs, BASIC runs without any apparent issues. Voltages are normal (just a shade under 5V). I've not experienced ROM chips that run so very hot -- is this normal? Thanks, Josh

10 years, 1 month

equipment available

by jwest＠classiccmp.org

DEC Rainbow, working. No shipping - local pickup only, Colorado Springs area. Email me off-list if interested. J

10 years, 1 month

11/73 (ba23) bringup after 12 years in deplorable storage conditions

by jnc＠mercury.lcs.mit.edu

> Roe Peterson roeapeterson at gmail.com > I would remove all the boards, blow it out, insert the minimum board > set, (CPU, memory, DL console, maybe bus terminator depending on > backplane) and just turn it on. That long in storage, I think that I'd probably go for powering it on with a dummy load first. It's not _that_ much more work, and it could save some expensive/rare electronics. It you don't have any QBUS Minimum Load Modules, get a couple of high-wattage resistors (down at Radio Slack, if necessary) and rig the equivalent. The M7556 MLM draws 1A of +5V, and I like to run two for testing. RS sells 10-Ohm/10-W resistors (ISTR they had smaller ones too, but I needed to test a 12V supply, hence the 10-W), so buy four... Probably a good idea to throw a 'scope on the DC power, too, check for ripple, etc. Noel

10 years, 1 month

old DEC boards

by sales＠elecplus.com

NC won't save by PN, but they will save by general description, like the ones with the purple or white tabs on the ends, they can pull those easily enough. If these are still wanted, can people please send me some pictures? What will probably be sent is a box of x number of boards weighing x pounds that have purple tabs, or white tabs, or whatever is asked for. Also need to know what people want to pay. Cindy Croxton Electronics Plus 1613 Water Street Kerrville, TX 78028 830-792-3400 phone 830-792-3404 fax sales at elecplus.com AOL IM elcpls

10 years, 1 month

PDP-11/23 Debugging

by jnc＠mercury.lcs.mit.edu

> From: tony duell > Err, isn't the first question 'Do you have a logic analyser?' Depends on who you're talking to... :-) > From: Ben Sinclair > I did find a Sigma brand M8043 equivalent on eBay for a decent price > (via a make best offer). Is using non-DEC hardware just adding more > variables, or are they generally okay? There are 3 factors to consider in using non-DEC boards these days, I find. #1 - Can you get documentation? (In this case, yes. I have some where the answer is a resounding no, e.g. a Clearpoint DCME/Q4E 4MB PMI memory card.) #2 - Can you get the cables/etc? I don't know the answer in this case; I will note that this apparently doe not use the same cable as a DLV11-J - it uses a 40-pin header - _but_ you may be able to plug your DLV11-J cable into it. There's an page that talks about it a bit: http://www.avitech.com.au/pdp-11-03/ba11nc.html#SCD-DLV11J/8P although note that there seems to be something wrong with the URL for the image of the board on that page, this works: http://www.avitech.com.au/pdp-11-03/pictures/SCD-DLV11J-8P_640X480.jpg and according to that page, you can plug a 10-pin shell into the 40-pin header. Seems slightly dubious to me, but maybe it'd work! #3 - How good were the boards when they were new? Reliable, flaky, etc? In this case, Sigma mostly made pretty good stuff, although I have no experience with this particular card. Your call! Noel

10 years, 1 month

PDP-11/23 Debugging

by jnc＠mercury.lcs.mit.edu

> From: Ben Sinclair > It doesn't seem to work on mine, so maybe I am having an interrupt > problem on the DLV11! Definitely an interrupt problem of some kind! But this is a big step; knowing we have a specific problem, we can try and track it to its lair. > I have V6 jumpered, V7 jumpered, and V5 on X to 0. According to the > manual, that's the factory setting. Is that how you have yours setup? Yes. So the first question is 'do you have a spare DLV11-J you can swap in'? I'm assuming the answer is 'no'. :-) Where are you located? Noel

10 years, 1 month

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test-drb November 2014