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  • jackrubin's Avatar
    Today, 09:36 AM
    jackrubin replied to a thread VC8E point plot 74xx replica in DEC
    Here's a link to my folder on the KV8I, a bit more elaborate implementation using the TEK 611 but also supporting a joystick. The cabling and 611...
    13 replies | 331 view(s)
  • m_thompson's Avatar
    Today, 04:20 AM
    How about a quad board with a KT8A and 128kw of RAM, and other peripherals.
    13 replies | 331 view(s)
  • m_thompson's Avatar
    Yesterday, 04:01 PM
    m_thompson replied to a thread PDP-9 at the RICM in DEC
    Looks like the S107 module in the TC02 inverts two of the device address bits from the processor. One of the inverted bits is inactive, so the next...
    58 replies | 6438 view(s)
  • MattisLind's Avatar
    Yesterday, 12:17 PM
    I have a bunch of Signetics N8X305 that I am unlikely to ever use. Pulls from circuit boards. Give me an offer to consider!
    7 replies | 73 view(s)
  • jackrubin's Avatar
    Yesterday, 05:01 AM
    jackrubin replied to a thread VC8E point plot 74xx replica in DEC
    Re the M8650, I've got several of them with DL1 (30 ns delay line) either broken off or missing altogether; I expect others do as well. A small...
    13 replies | 331 view(s)
  • m_thompson's Avatar
    Yesterday, 03:58 AM
    Roland, An combination I/O card that included RTC, two serial, Centronics printer port, memory, and bootloader would be really great. It would...
    13 replies | 331 view(s)
  • m_thompson's Avatar
    June 23rd, 2019, 03:50 PM
    m_thompson replied to a thread PDP-9 at the RICM in DEC
    We connected up the I/O cables from the PDP-9 processor to the TC02 and borrowed the indicator display cables from the TC59 controller. When...
    58 replies | 6438 view(s)
  • m_thompson's Avatar
    June 23rd, 2019, 03:49 PM
    m_thompson replied to a thread PDP-9 at the RICM in DEC
    I could only find Dialight 507-397-1475-600 replacements. The originals are flush with the front panel. The replacements stick out about 1/8".
    58 replies | 6438 view(s)
  • jackrubin's Avatar
    June 23rd, 2019, 06:31 AM
    jackrubin replied to a thread PDP-9 at the RICM in DEC
    What bulbs does the panel require? Were you able to find present-day replacements or are you using old spares? I've got a couple of TC02 panels to...
    58 replies | 6438 view(s)
  • m_thompson's Avatar
    June 23rd, 2019, 05:34 AM
    m_thompson replied to a thread PDP-9 at the RICM in DEC
    The original power supply in the I/O cabinet for the TC59 Magnetic Tape controller didn't have enough power to also feed the TC02 DECtape controller....
    58 replies | 6438 view(s)
  • jackrubin's Avatar
    June 22nd, 2019, 07:58 PM
    I was actually looking at the MC8/I, which uses a 3-bit IF/DF for the full 32K words of memory on the 8/I, rather than the MC8/L. Either way, you're...
    115 replies | 10471 view(s)
  • jackrubin's Avatar
    June 22nd, 2019, 12:03 PM
    jackrubin replied to a thread VC8E point plot 74xx replica in DEC
    I expect there's a whole lot of people who would say we're all 4 bits short of a word. Keep calm and carry on (at least 'til October 31) ...
    13 replies | 331 view(s)
  • jackrubin's Avatar
    June 20th, 2019, 11:39 AM
    A member of another mailing list pointed out this 24K memory expansion box for the 8/I -...
    115 replies | 10471 view(s)
  • jackrubin's Avatar
    June 20th, 2019, 06:23 AM
    The boards look great, but I'd still vote for SMD bypass caps. 0805 parts are easy and a nice way to transition toward that technology. Maybe rev 2?...
    115 replies | 10471 view(s)
  • jackrubin's Avatar
    June 19th, 2019, 12:23 PM
    My set of Logic Boards is here! I guess I'll start inserting bypass caps while I wait for daver2 to finish up the front panel. :>) Marty, would...
    115 replies | 10471 view(s)
  • MattisLind's Avatar
    June 18th, 2019, 10:31 PM
    Hello Volker, Do you have an oscilloscope? I would use that to have a look on the signal from the serial cards. To me it looks like there is a...
    0 replies | 353 view(s)
  • m_thompson's Avatar
    June 17th, 2019, 03:56 PM
    m_thompson replied to a thread RK05 fan blower motor in DEC
    As a separate project we should determine why the blower motors are going bad. I have three of them where the internal connection between the start...
    17 replies | 695 view(s)
  • m_thompson's Avatar
    June 17th, 2019, 03:44 AM
    m_thompson replied to a thread PDP-9 at the RICM in DEC
    Yes, it would be interesting to see how yours is wired.
    58 replies | 6438 view(s)
  • MattisLind's Avatar
    June 17th, 2019, 03:29 AM
    Yes. You are absolutely right. I have been contemplating the idea of bringing home the second one and see if it behaves the same or differently. But...
    11 replies | 293 view(s)
  • MattisLind's Avatar
    June 17th, 2019, 02:33 AM
    There is an extremely noisy fan in the VR12 to cool the deflection amplifiers. I have to unplug it temporarily to hear any electrostatic discharges....
    11 replies | 293 view(s)
  • MattisLind's Avatar
    June 16th, 2019, 07:14 AM
    Checked all capacitors on amplifiers boards for capacitance and loss factor. All of them were in good shape. DEC used quality capacitors! I had to...
    11 replies | 293 view(s)
  • m_thompson's Avatar
    June 16th, 2019, 06:39 AM
    m_thompson replied to a thread PDP-9 at the RICM in DEC
    Yesterday we wired the DC power to the TC02 DECtape controller (thanks Charles Lasner) and the two TU55 DECtape drives that we recently installed in...
    58 replies | 6438 view(s)
  • m_thompson's Avatar
    June 16th, 2019, 05:46 AM
    m_thompson replied to a thread What is DB08? in DEC
    it is an interprocessor buffer to interconnect two PDP-8 systems, or maybe your PDP-9 and a PDP-8. You need to find the 08-H8PA-D PDP-8 DB08...
    1 replies | 132 view(s)
  • MattisLind's Avatar
    June 16th, 2019, 04:33 AM
    Thanks for the input! Actually I think part of the problem was me not understanding "switched mode" operation of the G912 amplifier. I was under...
    11 replies | 293 view(s)
  • jackrubin's Avatar
    June 15th, 2019, 03:44 AM
    I bought my DM-2's from Halted/HSC before they went out of business (they closed in early 2019), where they were listed as G797-1. This is also where...
    11 replies | 431 view(s)
  • MattisLind's Avatar
    June 15th, 2019, 03:27 AM
    I am in the process of repairing a VR12 point plot display. It has two power amplifiers which drives the deflection coils. The first thing I...
    11 replies | 293 view(s)
  • MattisLind's Avatar
    June 15th, 2019, 02:03 AM
    I think the difference between DM1 and DM2 is the maximum reverse voltage and maximum amps rating. Vince lists DM1 and Solitron G797-0 and DM2 as...
    11 replies | 431 view(s)
  • jackrubin's Avatar
    June 14th, 2019, 04:39 PM
    I've been through my box of DM-1 and DM-2 diodes and can't really see any difference between them. I'm still trying to find specs on them, but no...
    11 replies | 431 view(s)
  • jackrubin's Avatar
    June 14th, 2019, 07:05 AM
    jackrubin replied to a thread SerialDisk sans BSW in DEC
    That would be great - please send copies to me and Kyle. Thanks!
    2 replies | 120 view(s)
  • m_thompson's Avatar
    June 14th, 2019, 04:24 AM
    m_thompson replied to a thread SerialDisk sans BSW in DEC
    Charles modified the handler so it would run on the RICM PDP-12, so it should run on your 8/I. I believe that Kyle has a copy of the...
    2 replies | 120 view(s)
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About m_thompson

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About m_thompson
Biography:
Volunteer at the RICM. Working on a PDP-12, PDP-8/I, 8/L, 8/e, PDP-9, 11/34a, and 11/44.
Location:
Rhode Island
Interests:
Vintage minicomputers.
Occupation:
Engineer

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Member of the Rhode Island Computer Museum
http://www.ricomputermuseum.org

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