I just completed the very nasty job of downloading the operating system and a few BASIC programs to my "new" PDP8, which is built from Robert Armstrong's design. It only draws about 5 watts, so it isn't a problem to keep on all the time, unlike others that people on this list might own! sloboyko.home.mindspring.com/pdp8e.htm

--- Loboyko Steve <sloboyko(a)yahoo.com> wrote: the "new" design... Nice job. I've done some wire-wrap projects. Nothing that large for, I'm sure you can see why, obvious reasons. One question - I noticed the large soldered "wire" running around the outside of the board. From the way it looks like it goes, doesn't that cause ground-loop problems? The books I've read on electronic design and layout have substantially different geometry. Cool. BTW, your link to www.sparetimegizmos.com has a typo in it - you need to put an "http://" in front of it. The way you have it, it's a relative link to your own page. -ethan BTW, where'd you get the rack-mount case? __________________________________________________ Do You Yahoo!? Yahoo! Greetings - send holiday greetings for Easter, Passover http://greetings.yahoo.com/

Being a hardware guy - I want to know - did you (or Mr. A) fully emulate a DEC drive (RK05??) or other drive with a microcontroller ? or did you write a device driver to support the IDE drive under OS8? Either trick would be very slick indeed ;) Regards and congratulations on getting your baby running. Once and a while you see these Intersil 61xx chips appear on ebay.. maybe others could duplicate your efforts.. Cheers, Heinz Re: From: "Loboyko Steve" <sloboyko(a)yahoo.com> Subject: "New" PDP-8 the "new" design. to the PPI

Pics, if interested, are at: sloboyko.home.mindspring.com/pdp8e.htm

Well, no, it isn't. Because the cost of getting a PCB made is less than the cost of a good electronics technician, I think it started to die in the late 80's. And, of course, its practically impossible to WW BGA chips, etc. I get stuff from: Jameco More expensive than they used to be. Still the best (non-mindbogglingly expensive Augat)sockets, but have gone up in price a lot. Marlin Jones (www.mpja.com) Pretty good blank boards. BG Micro (www.bgmicro.com) Some good stuff! Digi-key Outrageous prices, but they have...well...everything, and they deliver. Unicorn Electronics Good supplier of older chips. Incredibly, I still use a hand WW tool from Radio Shack. It's cheap, it works! New England Wire Prep has the best prices on wire wrap wire itself. I've found Jameco's to be strangely hard to work with, never mind expensive. Ebay - learn to work the search engine and you can get some real deals no one else has found! WW sockets are getting more expensive. I won't use anything but machine tooled pin sockets, which are even more expensive. Buf going nuts and wasting your precious free time over a flaky socket is really, really expensive.

...The board will be about 8" x 7" and $175 canadian for two prototype boards. Wire wrap sockets/wire/protoboard would cost me $100...

from other projects when I already _have_ a working PDP-8. With that

While I can recommend a real PCB if the setup costs and the per-sq-in costs are not killing you (price an Omnibus or Unibus-sized 4-layer board, complete with gold fingers!), personally, my WW overhead isn't terrible: I rescued all the prototype hardware from my former employer when they went bust - I probably have three lifetimes worth of WW sockets. When I do a project, the only part I have to spend money on is the wire.

My last project is a good case-study for expense vs. time. I wanted to replicate a scoreboard from a Dragon's Lair/Space Ace. I tried to find one on ePay, but they only come up occasionally (every couple of months). I decided to build one. I started with a couple of digital pictures, a parts list and a schematic. Since the board was approx 6"x9", it would have been somewhat expensive for a commercially-made PCB. There are still plenty of surplus units out there that sell used for under $50 when they are available, so it would be cheaper to wait for a sale than to have a professional PCB created unless the new PCB added value somehow. I had the blue perfboard (from when the MicroCenter got rid of all of their prototyping hardware at 80% off list!), the wire and the discrete components. I had to purchase the LEDs ($0.65 each) and the driver chips (a few bucks each). Total out-of-pocket expense was <$25. I probably pulled about $15-$20-worth of supplies out of my parts bins. Construction took place over several evenings, watching the sci-fi channel, tacking down point-to-point connections (didn't have the vertical clearance for socketing the LEDs). I'm pleased that it worked the first time! - pictures at http://penguincentral.com/retrocomputing/retrogaming/ under the "LED Scoreboard" link. Mostly, it's pictures of the glow of the LEDs, but there's one out-of-focus, flash-burned picture of the perfboard and yellow wire in there (the Apple QT150 has about a 24" min focal distance without the strap-on lens).

The upshot was that if this were being done for anyone but me personally, it would have been an economic disaster. Nobody would have paid me a reasonable amount for that much work - it would have been much cheaper to go to an arcade service company and *buy* a used scoreboard than spend 10+ hours wiring up a board. It would have been much cheaper than that to wait out the next wave of offerings on eBay (which I accidentally did - the project took so long to complete that I _did_ pick a real one up for around $30, after I was 95% finished with my replica. The good news is that it made a nice functional benchmark to prove that mine worked). So I chose to trade my time for semi-instant gratification. I would have loved to have done a PCB, but I chose not to spend the time with layout tape and a blank board, and I chose not to pay to register a demo-ware layout package so I could make a 6"x9" board.

If I were to make the new PDP-8 design that kicked off this whole thread, I'm not sure if I'd get professional boards (~$200/set, in small quantities, according to the designer, for a couple of 4-layer boards) or I'd point-to-point it.

In terms of $$$/hour, even $200 for a board set is cheap. In terms of a discretionary hobby, $200 is a lot to divert from other projects when I already _have_ a working PDP-8. With that kind of money, I could start trolling for a Qbus SCSI controller!

Back to the initial topic, though, I'd love to get a good buy on a dozen or so spools of kynar-coated wire. I'd prefer an assortment of colors, but I'd take it in whatever I could get - yellow, red, white... Anyone have a lead on any surplus places that have it for a few bucks a spool?

--- Ben Franchuk &lt;bfranchuk(a)jetnet.ab.ca&gt; wrote: Here in a city of 10E+06 people, about all we have left is Rat Shack, too. When I was a kid, there were lots of surplus places and new parts places to shop at (c. 1978). They've all gone mail-order and shut up their sales floors for cost reasons. I do most of my component shopping online these days (BG Micro, Mouser, Digikey, Allied...) Simple upload, yes, but for larger designs, it starts to get pricey again until you make things in quanity. I did several runs of a two- layer Zorro-II board (GG2 Bus+) - q. 100, they cost around $15-$20 each, including spreading out the setup charges. That's with a lot of gold (100-finger Zorro edge, plus a full 16-bit ISA edge), and a foot-long PCB. If only I hadn't ordered that last run of boards... :-( At q. 25, they were significantly more expensive. At q. 5, ISTR they were over $50 each.

I think you missed my point... yes, the demoware packages let you lay out a 3"x4" board for free.

If you increase the size of the board and keep things under 8MHz, 2 layers (and a sensible layout) will probably be fine. A 1MHz 6502 design will probably not require multi-layer unless you want it the size of a pack of playing cards.

That would have been fun.

True. I already know how to make a front panel pulse the lights. Driving a TTY is a lot more fun.

Yep. Been a happy customer for years. Thinking of placing an order this week.

--- Ben Franchuk &lt;bfranchuk(a)jetnet.ab.ca&gt; wrote: > ...The board will be about 8" x 7" and $175 canadian for two > prototype boards. Wire wrap sockets/wire/protoboard would cost me

While I can recommend a real PCB if the setup costs and the per-sq-in costs are not killing you (price an Omnibus or Unibus-sized 4-layer board, complete with gold fingers!), personally, my WW overhead isn't terrible: I rescued all the prototype hardware from my former employer when they went bust - I probably have three lifetimes worth of WW sockets. When I do a project, the only part I have to spend money on is the wire. My last project is a good case-study for expense vs. time. I wanted to replicate a scoreboard from a Dragon's Lair/Space Ace. I tried to find one on ePay, but they only come up occasionally (every couple of months). I decided to build one. I started with a couple of digital pictures, a parts list and a schematic. Since the board was approx 6"x9", it would have been somewhat expensive for a commercially-made PCB. There are still plenty of surplus units out there that sell used for under $50 when they are available, so it would be cheaper to wait for a sale than to have a professional PCB created unless the new PCB added value somehow. I had the blue perfboard (from when the MicroCenter got rid of all of

prototyping hardware at 80% off list!), the wire and the discrete components. I had to purchase the LEDs ($0.65 each) and the driver chips (a few bucks each). Total out-of-pocket expense was <$25. I probably pulled about $15-$20-worth of supplies out of my parts bins. Construction took place over several evenings, watching the sci-fi

tacking down point-to-point connections (didn't have the vertical clearance for socketing the LEDs). I'm pleased that it worked the first time! - pictures at http://penguincentral.com/retrocomputing/retrogaming/ under the "LED Scoreboard" link. Mostly, it's pictures of the glow of the LEDs, but there's one out-of-focus, flash-burned picture of the perfboard and yellow wire in there (the Apple QT150 has about a 24" min focal distance without the strap-on lens). The upshot was that if this were being done for anyone but me personally, it would have been an economic disaster. Nobody would have paid me a reasonable amount for that much work - it would have been much cheaper to go to an arcade service company and *buy* a used scoreboard than spend 10+ hours wiring up a board. It would have been much cheaper than that to wait out the next wave of offerings on eBay (which I accidentally did - the project took so long to complete that I _did_ pick a real one up for around $30, after I was 95% finished with my replica. The good news is that it made a nice functional benchmark to prove that mine worked). So I chose to trade my time for semi-instant gratification. I would have loved to have done a PCB, but I chose not to spend the time with layout tape and a blank board, and I chose not to pay to register a demo-ware layout package so I could make a 6"x9" board. If I were to make the new PDP-8 design that kicked off this whole thread, I'm not sure if I'd get professional boards (~$200/set, in small quantities, according to the designer, for a couple of 4-layer boards) or I'd point-to-point it. In terms of $$$/hour, even $200 for a board set is cheap. In terms of a discretionary hobby, $200 is a lot to divert from other projects when I already _have_ a working PDP-8. With that kind of money, I could start trolling for a Qbus SCSI controller! Back to the initial topic, though, I'd love to get a good buy on a dozen

so spools of kynar-coated wire. I'd prefer an assortment of colors, but I'd take it in whatever I could get - yellow, red, white... Anyone have a lead on any surplus places that have it for a few bucks a spool? -ethan __________________________________________________ Do You Yahoo!? Yahoo! Greetings - send holiday greetings for Easter, Passover http://greetings.yahoo.com/

--- Ben Franchuk &lt;bfranchuk(a)jetnet.ab.ca&gt; wrote: While I can recommend a real PCB if the setup costs and the per-sq-in costs are not killing you (price an Omnibus or Unibus-sized 4-layer board, complete with gold fingers!), personally, my WW overhead isn't terrible: I rescued all the prototype hardware from my former employer when they went bust - I probably have three lifetimes worth of WW sockets. When I do a project, the only part I have to spend money on is the wire. My last project is a good case-study for expense vs. time. I wanted to replicate a scoreboard from a Dragon's Lair/Space Ace. I tried to find one on ePay, but they only come up occasionally (every couple of months). I decided to build one. I started with a couple of digital pictures, a parts list and a schematic. Since the board was approx 6"x9", it would have been somewhat expensive for a commercially-made PCB. There are still plenty of surplus units out there that sell used for under $50 when they are available, so it would be cheaper to wait for a sale than to have a professional PCB created unless the new PCB added value somehow. I had the blue perfboard (from when the MicroCenter got rid of all of their prototyping hardware at 80% off list!), the wire and the discrete components. I had to purchase the LEDs ($0.65 each) and the driver chips (a few bucks each). Total out-of-pocket expense was <$25. I probably pulled about $15-$20-worth of supplies out of my parts bins. Construction took place over several evenings, watching the sci-fi channel, tacking down point-to-point connections (didn't have the vertical clearance for socketing the LEDs). I'm pleased that it worked the first time! - pictures at http://penguincentral.com/retrocomputing/retrogaming/ under the "LED Scoreboard" link. Mostly, it's pictures of the glow of the LEDs, but there's one out-of-focus, flash-burned picture of the perfboard and yellow wire in there (the Apple QT150 has about a 24" min focal distance without the strap-on lens). The upshot was that if this were being done for anyone but me personally, it would have been an economic disaster. Nobody would have paid me a reasonable amount for that much work - it would have been much cheaper to go to an arcade service company and *buy* a used scoreboard than spend 10+ hours wiring up a board. It would have been much cheaper than that to wait out the next wave of offerings on eBay (which I accidentally did - the project took so long to complete that I _did_ pick a real one up for around $30, after I was 95% finished with my replica. The good news is that it made a nice functional benchmark to prove that mine worked). So I chose to trade my time for semi-instant gratification. I would have loved to have done a PCB, but I chose not to spend the time with layout tape and a blank board, and I chose not to pay to register a demo-ware layout package so I could make a 6"x9" board. If I were to make the new PDP-8 design that kicked off this whole thread, I'm not sure if I'd get professional boards (~$200/set, in small quantities, according to the designer, for a couple of 4-layer boards) or I'd point-to-point it. In terms of $$$/hour, even $200 for a board set is cheap. In terms of a discretionary hobby, $200 is a lot to divert from other projects when I already _have_ a working PDP-8. With that kind of money, I could start trolling for a Qbus SCSI controller! Back to the initial topic, though, I'd love to get a good buy on a dozen or so spools of kynar-coated wire. I'd prefer an assortment of colors, but I'd take it in whatever I could get - yellow, red, white... Anyone have a lead on any surplus places that have it for a few bucks a spool? -ethan __________________________________________________ Do You Yahoo!? Yahoo! Greetings - send holiday greetings for Easter, Passover http://greetings.yahoo.com/

What I've encountered more and more is the inconvenience associated with trying to use current-generation components in wire-wrap. I'm always having to build adapters that make a DIP out of a TSSOP or the like. The adapters in a prototype often exceed the cost of a PCB. It's much easier to build small boards, about the size of a typical playing card, and that's enough space to house a microcomputer of reasonable capability, comparable with any "classic" 8-bitter of the '70's and '80's, including its I/O, memory, video, and mass storage interfaces. After I get the current task off the table, I'll take a closer look, but it seems to me that it's easier to put a system on a playing-card sized board, and cheaper too, using current technology, than to recreate the old stuff using parts that are increasingly scarce and boards that are needlessly large and costly.

> Is wire-wrap still a common prototyping technique?

Does anyone know how to park(lock) the heads on RK07 drives for moving? Thanks, Mitch