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Thread: PDP-8 wanted

  1. #1
    Join Date
    Sep 2020
    Location
    Perth in Western Australia
    Posts
    74

    Default PDP-8 wanted

    I am looking to buy a complete and working DEC PDP-8 series in good cosmetic condition.

    Specifically the following models in this order of prefence:

    PDP-8/F
    PDP-8/E
    PDP-8/L
    PDP-8/I

    I would also consider non-working machines which can be fixed with moderate effort, but not beaten up machines with damaged or missing front panels.

    Could you please let me know if you are aware of anyone willing to sell such a machine to a good new home.

    I am happy to pay a reasonable price and would take care of pickup and shipping.

    Thanks and best regards
    Tom Hunter

  2. #2

    Default

    hi Tom,

    PDP-8s are quite rare these days and quite scattered around the place. I think you will find it hard to get one in Australia and let alone ship it. PDPs weigh a ton 41 kilos stock (for an E) but very easily could weigh more a PDP-I weighs well over 100 kilos and are reasonably delicate. it might be fine before shipping but after you might need to look for a new front panel and a few switches!

    I wish you luck on your search but Ebay is probably the best place to and work somebody down to a price you are happy with. But be prepared to shell out a lot of cash for it.

    Al

  3. #3
    Join Date
    Sep 2020
    Location
    Perth in Western Australia
    Posts
    74

    Default

    Thanks Al,

    The PDP-8s - in particular the later models (/E, /F, /M and /I) - have been made in very large numbers - in their 10s of thousands and they were very affordable machines for the time. I am sure that many have been destroyed or "recycled", but I suspect that there are still many lurking in garages, sheds and other forms of storage - waiting for a rainy day which never comes.

    I am hoping to find one in reasonable condition, complete and with a front-panel in good cosmetic condition. There was one for sale just a few days ago, but sadly the front panel was badly damaged.
    The later model PDP-8s are all 7400 series TTL based which are readily available so repair is definitely possible without having to chase rare parts.

    I am happy to pay a reasonable price for the right PDP-8, so a seller won't be disappointed.

    Best regards
    Tom Hunter

  4. #4
    Join Date
    Nov 2013
    Location
    Bristol, England
    Posts
    310

    Default

    Quote Originally Posted by thunter0512 View Post
    There was one for sale just a few days ago, but sadly the front panel was badly damaged.
    The later model PDP-8s are all 7400 series TTL based which are readily available so repair is definitely possible without having to chase rare parts.
    Rod "Panelman" Smallwood over on ClassicCMP makes very accurate replicas of the panel glass for various PDP-8s, so providing the PCB and switches are good that may be an option for you.

    The later 8s are indeed 7400 series for the most part, but there are some hard to find Signetics chips. I believe they can all be replaced with 7400 series with the use of a daughter card though.

    One place they did frequently show up in was CNC machines - you may have some luck finding one in Australia if you're willing to trawl through CNC spares dealers and mis-listed eBay items.
    Wanted: VT100, Altair 8800 CPU card, KD11-A, KE8E (M8340 M8341), memory for 11/40.
    Available for trade: AlphaStation DS10, DS15, IBM 5150, XT, Numerous PC ISA, PCI, and VLB boards and motherboards from the 5150 to P4 era, DEC Storageworks HDDs, misc DIP ICs, QBUS cards, 8080/85/86/88/Z80 CPUs, Misc radio valves (vacuum tubes), C64, Amiga 1200, Sinclair ZX Spectrum/+/QL, Mac Classic + Classic II.

  5. #5
    Join Date
    Apr 2011
    Location
    Brisbane, Australia
    Posts
    581
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    Default

    G'day Tom,
    I'm also in Australia (Brisbane) so I'll relate my experiences, but for PDP-11's instead of 8's.
    Firstly it goes without saying I've run searches looking on Oz eBay and Gumtree for a number of years and sadly not found any. I'm sure you do this too.

    Perhaps I've just missed them but sadly we in Oz aren't really party to the amazing finds that our US and European listmember friends have, where they also have the advantage of mind-bogglingly cheap postage and freight logistics.

    But, as the saying goes, 'never say never or always'. I lucked onto a rebadged PDP-11/15 and drove the round trip Brisbane to the Hunter Valley and back to collect it and some other bits.
    Another time I went to a local Brisbane Hamfest with a WANTED sign taped to the back of my shirt. On this A4 page was a photo of an ASR33 teletype and below that a photo of a DECwriter II.
    It worked - comments I got from total strangers led me to post a Wanted query on a ham radio Buy/Swap/Sell web page, and would you believe it, a bloke in Sydney saw it and had both an ASR33 AND a DECwriter II for no cost!
    That subsequently involved another Brisbane-Sydney-Brisbane weekend trip (~2000km) to collect them.

    All my other PDP-11's and peripherals are US or European imports. My full-height 11/05 (weighs about 40kg) came in with a friend importing a WWII amphibious jeep in a container, I then had to get it shipped interstate from there.
    That was the good end of the shipping. Another, a slimline PDP-11/05 (about 24kg) came from US eBay, shipped internationally with nothing more than a piece of cardboard taped around it...
    I've shown this picture here before, but here it is as I collected it from the post office:
    PDP11_05_as_it_arrived_1.jpg

    I had assumed a seller would always pack an old machine with care, but sadly this isn't always the case. It had suffered a cracked plastic front grille and some other minor damage, since repaired.

    Another 11/05 came from right here on this forum. The seller and I agreed on a price, I paid him including shipping but it took months for him to get to it. After a number of emails and pithy responses from him I finally resided to mentioning I would be invoking legal action if he did not send it. At that point it was promptly posted and with a complimentary bunch of extra flip chip modules for a QBus machine.
    I did not have a QBus chassis at that time so found a PDP-11/03 4-slot chassis on eBay from 'efi' a great stateside DEC reseller, who takes reasonable offers on their listings (I can definately recommend them, have bought a few items from them and they are nice to do business with and do not bat an eyelid about shipping to Oz).

    I found a pair of DEC H960 racks on eBay, but they were in Melbourne. I immediately went onto Gumtree and found a furniture removalist who could backload them from Melbourne to Brisbane for $200 all up, as long as I was prepared to wait up to two months. That was fine with me, they arrived about four or five weeks later.

    So, given the situation you're probably leaning heavily toward US or European eBay. After you factor in the shipping to Oz, and then the exchange rate, and then the GHT (Gerry Harvey Tax) you're sadly not going to get out of it cheaply.
    You should get yourself an account with a US-based reshipper if you've not done so already - I use MyUS.com and they have been very good for me. For most of this year I have been handling my foreign purchases with care, washing my hands thoroughly after opening and leaving them to 'air out' for a week or so, given their situation in US/Europe.

    In summary: you may be lucky, who knows - so keep looking!

    Steve.

  6. #6
    Join Date
    Sep 2020
    Location
    Perth in Western Australia
    Posts
    74

    Default

    Quote Originally Posted by 1944GPW View Post
    G'day Tom,
    I'm also in Australia (Brisbane) so I'll relate my experiences, but for PDP-11's instead of 8's.
    Firstly it goes without saying I've run searches looking on Oz eBay and Gumtree for a number of years and sadly not found any. I'm sure you do this too.

    Perhaps I've just missed them but sadly we in Oz aren't really party to the amazing finds that our US and European listmember friends have, where they also have the advantage of mind-bogglingly cheap postage and freight logistics.

    But, as the saying goes, 'never say never or always'. I lucked onto a rebadged PDP-11/15 and drove the round trip Brisbane to the Hunter Valley and back to collect it and some other bits.
    Another time I went to a local Brisbane Hamfest with a WANTED sign taped to the back of my shirt. On this A4 page was a photo of an ASR33 teletype and below that a photo of a DECwriter II.
    It worked - comments I got from total strangers led me to post a Wanted query on a ham radio Buy/Swap/Sell web page, and would you believe it, a bloke in Sydney saw it and had both an ASR33 AND a DECwriter II for no cost!
    That subsequently involved another Brisbane-Sydney-Brisbane weekend trip (~2000km) to collect them.

    All my other PDP-11's and peripherals are US or European imports. My full-height 11/05 (weighs about 40kg) came in with a friend importing a WWII amphibious jeep in a container, I then had to get it shipped interstate from there.
    That was the good end of the shipping. Another, a slimline PDP-11/05 (about 24kg) came from US eBay, shipped internationally with nothing more than a piece of cardboard taped around it...
    I've shown this picture here before, but here it is as I collected it from the post office:
    PDP11_05_as_it_arrived_1.jpg

    I had assumed a seller would always pack an old machine with care, but sadly this isn't always the case. It had suffered a cracked plastic front grille and some other minor damage, since repaired.

    Another 11/05 came from right here on this forum. The seller and I agreed on a price, I paid him including shipping but it took months for him to get to it. After a number of emails and pithy responses from him I finally resided to mentioning I would be invoking legal action if he did not send it. At that point it was promptly posted and with a complimentary bunch of extra flip chip modules for a QBus machine.
    I did not have a QBus chassis at that time so found a PDP-11/03 4-slot chassis on eBay from 'efi' a great stateside DEC reseller, who takes reasonable offers on their listings (I can definately recommend them, have bought a few items from them and they are nice to do business with and do not bat an eyelid about shipping to Oz).

    I found a pair of DEC H960 racks on eBay, but they were in Melbourne. I immediately went onto Gumtree and found a furniture removalist who could backload them from Melbourne to Brisbane for $200 all up, as long as I was prepared to wait up to two months. That was fine with me, they arrived about four or five weeks later.

    So, given the situation you're probably leaning heavily toward US or European eBay. After you factor in the shipping to Oz, and then the exchange rate, and then the GHT (Gerry Harvey Tax) you're sadly not going to get out of it cheaply.
    You should get yourself an account with a US-based reshipper if you've not done so already - I use MyUS.com and they have been very good for me. For most of this year I have been handling my foreign purchases with care, washing my hands thoroughly after opening and leaving them to 'air out' for a week or so, given their situation in US/Europe.

    In summary: you may be lucky, who knows - so keep looking!

    Steve.
    G'day Steve,

    Thanks for reaching out and all the useful info.

    I am trying all possible avenues to make known to possible sellers that I would like to buy a PDP-8. Unfortunately I am very late to this game. I have spent the past 18 years obsessing with CDC 6000 series and CYBER series mainframes including writing a full system emulator for the family of mainframes: For more info see my website: http://www.control-data.info/

    I am very new to the DEC and specifically the PDP-8 world. Somebody pointed me to the nice RaspBerry Pi based PiDP-8/I which runs the PDP-8/I emulation built into SIMH coupled with a very nice acrylic front-panel, switches and lights (yellow LEDs). Here is a link: https://obsolescence.wixsite.com/obsolescence/pidp-8

    I bought the kit (it is only US$165) and assembled it and got hooked. I am fascinated by the elegant architecture of the original system. I wrote a few exploratory programs on it and had lots of fun with it. A new love affair started so I am now hunting for one of the following PDP-8 models:

    PDP-8/F
    PDP-8/E
    PDP-8/L
    PDP-8/I
    PDP-8/M

    I have a few leads but nothing too solid yet. As I found out during my 18 year "CDC 6000/CYBER phase" the most important thing in this game is patience (sadly not one of my virtues).

    As to Ebay in Oz or USA - I have not seen a complete PDP-8 even if you search for "sold" machines which implies that nothing was on offer for at least 6 months - the period after which old Ebay listings are deleted. I am trying local government departments, schools and industry hoping to eventually stumble across something.

    I am not expecting cheap, but something which is cosmetically good and repairable/restoreable. All the PDP-8s I listed above are made with standard 7400 series TTL logic most of which is readily available. Apparently there are a few exceptions but there are workarounds for those.

    Could you please put out the word in your community of enthusiasts that some nutcase over in the west is looking for a good PDP-8?

    Thanks and best regards
    Tom Hunter

  7. #7
    Join Date
    Mar 2011
    Location
    The Netherlands
    Posts
    1,018

    Default

    Quote Originally Posted by thunter0512 View Post
    I am trying all possible avenues to make known to possible sellers that I would like to buy a PDP-8.
    I do the same when I'm searching for a machine... When you don't ask, nobody knows...

    Quote Originally Posted by thunter0512 View Post
    PDP-8/F
    PDP-8/E
    PDP-8/M
    PDP-8/L
    PDP-8/I
    Remember that an 8/i needs a H960 rack. It is not a machine which you can easily put on your desk...
    The machine does not have a case from itself and has a separate power supply. The 8/L itself is limited to 4K.
    I'm working on an expansion for that model. But things are quite time consuming... (And just 24h in a day)

    The /E /M and /F (and also the /A) are omnibus systems. These are the easiest expandable machines.
    Expansion cards can be found on Ebay quite often, and there is also a list of replica board you can build.

    But ask yourself what you want to do with an PDP8...

    Regards, Roland
    WTB: Case for Altair 8800 ...... Rolands Github projects

  8. #8
    Join Date
    Sep 2020
    Location
    Perth in Western Australia
    Posts
    74

    Default

    Quote Originally Posted by Roland Huisman View Post
    I do the same when I'm searching for a machine... When you don't ask, nobody knows...

    Remember that an 8/i needs a H960 rack. It is not a machine which you can easily put on your desk...
    The machine does not have a case from itself and has a separate power supply. The 8/L itself is limited to 4K.
    I'm working on an expansion for that model. But things are quite time consuming... (And just 24h in a day)

    The /E /M and /F (and also the /A) are omnibus systems. These are the easiest expandable machines.
    Expansion cards can be found on Ebay quite often, and there is also a list of replica board you can build.

    But ask yourself what you want to do with an PDP8...

    Regards, Roland
    Thanks Roland,

    I did not know about the 8/I needing a special rack - nevertheless it is a nice machine because you don't have to play around with a knob to see the different CPU status values (PC, MA, MB, AC and MQ).
    I knew about the 4K limit on the 8/L.
    My "shopping list" was ordered by preference so the 8/F would be my first choice.

    As to what I would do with a PDP-8 - I am fascinated by the architecture, so after playing with the SIMH based PiDP-8/I I would like to explore it more on a real hardware implementation which is accessible. All the models on my "shopping list" use mostly 7400 series TTL chips which are readily available. The boards are nicely spaced out and with an extension board you can probe around with a scope or logic analyser. The PDP-8 is extremely well documented and schematics and diagnostic are available for it. I think this is fun system to go back to basics.

    There is the "Spare Time Gizmos" beautiful SBC6120 and FP6120 which is effectively a PDP-8/E clone based on the Harris 6120 LSI chip. I have bought one of these already and can't wait for it to arrive in the mail, but you cannot hook probes to the guts of the 6120 chip to get a better understanding of how it works. On a PDP-8 implemented in TTL I can learn much more about the internals and the various tricks DEC engineers used. Admittedly I could just look at the schematics, but it is not quite the same.

    Thanks again.
    Tom Hunter

  9. #9

    Default

    Hi Tom (and g'day Steve - we haven't spoken for a while!)

    Tom - great to see your enthusiasm for chasing down a PDP-8. I've also seen your postings on cctech.

    They are around (mostly in the U.S.) but yes, they rarely come up. I bought my 8/e (actually an Industrial and 8/f both through eBay in the U.S. Both systems were not cheap, and were acquired approx 5-8 years ago. Without looking up the prices I paid, I'd say it was roughly US$5K for the 8/e and US$3.5K for the 8/f. Both came with a reasonable amount of peripherals (including 2 x ASR33s) etc. It cost about another AU$5K to have the 8/e crated, freighted to the west coast, then shipped to Melbourne. I got a better deal on shipping for the 8/f, but that's because I travelled to the U.S., crated it myself, and incorporated it into someone else's larger shipment. I don't regret paying those prices - they've given me a lot of enjoyment since, and were free of corrosion, rodent damage, etc.

    I agree with Steve that the chances of finding them locally are low (but not zero). I have seen some systems available in Aus, but the asking price was really no better than U.S. prices and mostly had non-DEC peripherals and racks (and so not worth big $ in my opinion). Keep looking, keep networking. You'll find one.

    Malcolm.

  10. #10
    Join Date
    Sep 2020
    Location
    Perth in Western Australia
    Posts
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    Hi Mal,

    Thanks for your encouragement. I am hopeful that my search will yield some result.
    Just a couple of days ago I managed to buy a "Spare Time Gizmos" SBC/FP/IOB-6120 kit (a PDP-8/e clone using the Harris 6120 CPU chip) which is actually much rarer than a PDP-8 with only a small number ever made.
    Real PDP-8 were relatively abundant. Of course many years have passed since they were made.
    Should you decide that you don't really need a PDP-8/E and a PDP-8/F and I would happily take one of you and pay a fair price for it and organise pick-up and shipping. Hint, hint ...

    Best regards
    Tom Hunter

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