test-drb

test-drb@ccmp.vtda.org

101090 discussions

by jacob.ritorto＠gmail.com

Hi, Man. I'm becoming concerned that I can't fit any of the significant features that I want in my 11/45 without making uncomfortable sacrifices. The first 25 slots are for an initial "unibus a" terminator, cpu, floating point and memory, which, since I only have one bipolar matrix, is an enormous waste of like ten slots (they're wired for weird voltage and would presumably explode other boards installed there, right?). So then there are three slots available at the end, 26, 27, 28 that are also marked "non-standard voltage." I guess that means that putting normal boards in there is right out, too. Anyway, the unibus out and bridge 9200 jumper that connects unibus a and unibus b are supposed to go there. That's it for the main backplane. The next three small backplanes are core. They take up the rest of the chassis. I don't want to give up my core because core is cool, right? So this means I've nowhere to put the hex boards I need to run. I need to install more memory (planning to use MS11 (124KW M7891)), ethernet, some sort of hex height SMD disk controller (SC21,etc.), possibly an RL11, and a DZ11. That's at least four, maybe six hex-height boards I need to accommodate. I'm going to duck after asking this, but would it be at all feasible to rewire the main 11/45 backplane to get rid of the weird voltages in those bipolar slots so they'd accommodate normal boards like these? Short of that, what can I do? I definitely don't want another chassis. I guess I have to sacrifice my core to make way for a second "normal" dd11-type backplane to house the modules I need to run. So sad. <duck> jake

11 years, 6 months

11/23 clock issue

by jnc＠mercury.lcs.mit.edu

> From: Tothwolf > Before I forget again, did you check for +5V on pin 1 (enable) when you > were testing your existing oscillator? Wow. Never thought to try that. Then again, I don't look for +5V on your average 74xxx when I'm debugging, either! :-) I mean, it's a trace, the solder on the pin looks good, that's as far as I go, usually! And there's nothing shown as connected to that pin on the circuit diagram. So I looked, and... it's at ground (or floating). The only pin that has anything is 14, at +5V (expected). But I looked online for some datasheets for similar oscillators, and some of them say 'pin 1 - N/C'. Are yours tri-state? (That's the enable pin on the tri-state ones.) I suppose even if yours are tri-state, I can still use them; a quick ohmmeter check shows that pin 1 isn't connected to either power or ground, so I can probably tie it high (via a resistor, which in addition to being normal practise, will prevent a major disaster in case I'm confused - a state I'm often in :-). Noel

11 years, 6 months

Radio Shack

by evan＠snarc.net

So ..... Radio Shack is (more or less) finally dead. There are still plenty of RS stores open for business. (Although I read this morning that they're not getting new shipments, which makes them essentially clearance stores.) Apparently the company is legally allowed to close a maximum of 200 stores per year. Or something like that. Horn-tooting: the Wall Street Journal interviewed me about RS back at World Maker Faire last fall. They published the story online today and it'll be in print tomorrow. http://www.wsj.com/articles/strategic-confusion-put-radioshack-at-the-mercy… Scroll aaaaaaaaaaaall the way down to the bottom. (LOL, yeah, I'm important!)

11 years, 6 months

Differences between PDP-11/83-84 M8190-AB/AC and AD/AE CPU cards

by jnc＠mercury.lcs.mit.edu

> From: Jerome H. Fine > for the PDP-11/83 (usually in a BA23 or a BA123), the backplane is > wired so that the PMI memory is activated correctly WHEN the first > memory board is in slot 1 and the CPU follows the memory boards. That's an artifact of the way Qxx/CD backplanes, and PMI CPU cards, are wired. (And you probably already knew this, but just to be explicit... :-) For the backplanes, with few exceptions, pin nQm2 (where n is the slot #, Q is C or D, m is A-V, in the DEC alphabet) is wired only to pin (n+1)Qm1 - i.e. pin Qm1 is not wired through to all slots. In other words, the CD bus is not carried _through_ a slot, only _between_ slots. The PMI bus on the CPU is only wired to the top (i.e. 1) pins. So if you plug a PMI CPU into a normal Q22/CD backplane, the only slot that receives the PMI signals is the slot _before_ the CPU. Hence the requirement to plug memory cards in _before_ the CPU when using a Q22/CD backplane for PMI. The 11/84 backplane is different; per the backplane prints in EK-PDP84-TM-PR2, the 1-side pins on the Q22/'CD' portion of the backplane _are_ all bussed together. (Note: from what I can see in the backplane prints in EK-PDP84-TM-PR2, none of the other CD bus pins are bussed together; in particular, the staggered connections from nCA1 to n+1CC1, nDA1 to n+1DC1, etc found in the real Qnn/CD backplane don't seem to be there in the 11/84 backplane. So it's not _real_ Q22/CD - it's probably better to call that section of the 11/84 backplane Q22/PMI. PMI _can_ run over a normal Q22/CD backplane, though.) >> Would a KDJ11-A board even work in an 11/84 backplane? > I meant the KDJ11-BD board or the M8190-AC. > ... > it seems reasonable to hope that the PDP-11/84 can also use the > KDJ11-BD instead of the KDJ11-BF Ah. My guess (having not looked at the 8190-AC in detail) is that to the extent the M8190-AC implements PMI, it should work fine in an 11/84. Noel

11 years, 6 months

Differences between PDP-11/83-84 M8190-AB/AC and AD/AE CPU cards

by jnc＠mercury.lcs.mit.edu

> From: Noel Chiappa > (I suspect, but have yet to verify, that this is in part because bus > grant lines are run directly from that slot to the UNIBUS adapter slot.) So it turns out I was half-wrong, but half-right. I was paging through a copy of EK-PDP84-TM-PR4 (PDP-11/84 Technical Manual) which I recently acquired: in section 2.1.14 "Backplane (H9277-A)", pg. 2-6, the following sentence appears: Bus signals BDMGI (pin AR2) and BIAKI (pin AM2) for slots 2 & 3 are jumpered on the front of the backplane. (This is not in any other version of EK-PDP84-TM, of which I have several.) So I got out my spare 11/84 backplane, and sure enough there are two jumpers, W1 and W2. The traces connected to them are, luckily, on the surface, so it's possible to see where they go: one end runs to a trace connected from slot 1 to slot 2, and the other to a trace connected from slot 3 to slot 4. EK-PDP84-TM-PR2 actually contains (pp. D-4 to D-8) prints for the backplane. Unfortunately, they are very low-res, and only partially readable, but one can see, on the bottom of the first print (D-4), the two jumpers. The associated traces do indeed connect to AM2 (BIAKI), AN2 (BIAKO), AR2 (BDMGI) and AS2 (BDMGO). In other words, when the jumpers are in, the CPU's BIAKO/BDMGO pins are connected directly to the UNIBUS adapter's BIAKI/BDMGI pins; when they are out, those signals are routed through the two 'memory' slots, in the normal QBUS manner. What this strongly suggests to me is that those two slots _can_ function as real QBUS slots. Otherwise, why arrange so that the grant lines can run through them? I haven't examined all the other pins, to make sure they contain the full set of QBUS signals - in part because I don't want to pore over those poor images! (Speaking of which, does anyone have a copy of either 11/84 Field Maintainance Print Set - MP-01955 or MP-02536? Neither one seems to be online - at least, as best I can tell, from some Googling, although others may have better Google-fu than me - and it would be fabulous to have access to them.) But I do strongly suspect they can function that way; at some point, when I have an /84 running, I'll actually try them out. As to why DEC put this capability in, and then didn't document it or use it - who knows? Maybe they though it would introduce extra complixity in the user instructions, or something. Anyway, I think we are close to cracking this particular puzzle... Noel

11 years, 6 months

Differences between PDP-11/83-84 M8190-AB/AC and AD/AE CPU cards

by jnc＠mercury.lcs.mit.edu

> From: Jerome H. Fine > With regard to the MSV11-JD in the PDP-11/84, was this board placed > after the KDJ11-AE board or before it? After. The CPU _has_ to go in slot 1 on the 11/84 backplane. (I suspect, but have yet to verify, that this is in part because bus grant lines are run directly from that slot to the UNIBUS adapter slot.) > Also, has anyone ever used a KDJ11-AC board with the 15 MHz crystal in > the PDP-11/84 backplane? I can't see why it should not work, but just > maybe the PDP-11/84 backplane and a simple KDJ11-AC board are not > compatible. Would a KDJ11-A board even work in an 11/84 backplane? It wouldn't (couldn't) do the special PMI (actually, we ought to distinguish between 'QBUS PMI', such as in the 11/83, and 'UNIBUS PMI', as in the 11/84; the second is a superset of the first, I believe) protocol, so it wouldn't work with the UNIBUS adapter. See also Micronote #39, "Differences between KDJ11-A and KDJ11-B". Noel

11 years, 6 months

Sharp PC-1600 keyboard issues

by derschjo＠gmail.com

Another day, another project (the DAP will wait until I have the wiring to support it...). This week a bunch of "Refurbished" Sharp PC-1600s showed up on eBay for cheap and I snagged one; it arrived this evening. It looks like the unit is effectively new-old-stock; it doesn't seem to have been used since Sharp refurbished it back in the day -- it arrived with the original Sharp-branded batteries in the compartment. Amazingly, only one of the four batteries leaked, but only a tiny bit and there's no obvious corrosion anywhere from it (whew). The PC-1600 powers on and mostly behaves normally after an "All Reset" but the keyboard is having trouble; here are the symptoms: - Keys A-K on the 2nd row of the QWERTY section do not function ('L' does). - The "Shift" key doesn't work properly -- hitting it doesn't cause the "Shift" annunciator on the LCD to light up. However, it does seem to do *something* in that if you hit Shift+another (working) key, nothing happens at all (for example, Shift+5 should result in a left curly brace but does nothing at all.). - The "SML" key does not put the machine in lowercase mode, instead one of the Kanji (i believe) annunciators gets toggled. This has no other obvious effect (uppercase letters are still produced from the working letter keys...) - Hitting the "KB II/Click" key (farthest right under the LCD) turns "Key Click" mode on even though Shift is not being depressed. (Or maybe this is normal behavior -- I can't find this key described in the manual...) Otherwise, the thing seems to be working OK, it'll calculate fine and I can enter/run small programs (that don't use the home row for entry...) I've found the Technical Drawing set here: http://www.sharp-pc-1600.de/Schaltpl%8ane%20A3/Technical_Drawing_DINA3.pdf which makes it obvious that the dead home-row keys are related to the KIN3 line from the keyboard matrix; I note that the keyboard signals are brought to the edge of the PCB and connected to a membrane layer which contains additional circuitry, including what looks to be an IC that does the keyboard decoding. My first guess would be dirty contact between the PCB and this membrane (esp. since the lines in question are close to a hole in the battery compartment where the aforementioned 30-year-old batteries were...) but I'm a bit nervous to disassemble and clean this without knowing how it's held together. Anyone have any experience here? Any tips? Thanks as always, Josh

11 years, 6 months

Differences between PDP-11/83-84 M8190-AB/AC and AD/AE CPU cards

by jnc＠mercury.lcs.mit.edu

> From: Henk Gooijen > Maybe a few PALs have to be a faster version, but I do not expect that. > The 15 MHz to 18 MHz is not that big of a difference. I did wonder about that, but they boards use parts from a number of different chip companies (both the PALs, and the PROMs), so since I don't know how to read those parts for speed variants, I couldn't say. > From: Johnny Billquist > The 11/84 variant is pretty much a PMI bus all the way, but I seem to > remember a couple of signals defined differently even in the 11/84 > compared to the 11/83. If you run across where you saw that, I'd be curious. The 84's use is, as you point out, different, since it includes the CPU<->UNIBUS adapter protocol for UNIBUS cycles. But I would have assumed that it was a plain superset of the 83's (not that I have read much about 11/83's... :-). > From: Jerome H. Fine > The MSV11-JB (1 MB) and MSV11-JC (2 MB) are used in the PDP-11/84. The > MSV11-JD (1 MB) and the MSV11-JE (2 MB) are used in the PDP-11/83. Err, not sure this is correct: I got an 11/84 with an MSV11-JD in it. As someone pointed out in a later message, the difference between the B/C and D/E is that the B/C only work as PMI memories, their QBUS functionality has some issues (IIRC, something to do with QBUS block transfers not working correctly). > In addition, for at least the PDP-11/83, the PMI memory must be placed > into the backplane ahead of the CPU for the memory to function as PMI > memory. That may be the only position allowed for the memory for the > PDP-11/84. The 11/84 backplane has two special Q22/CD slots after the processor slot which the memory goes in, with the CD sections wired to through-connect the PMI pins. I have this sneaking suspicion that the Q22 portions of those two slots aren't _real_ QBUS slots (so you can't plug a QBUS device into them if you aren't using them for memory :-), because I suspect they didn't run BIAK and BDMG to those slots, but rather piped them directly to the UNIBUS adapter slot. My reasoning for that is that if you don't plug in a memory card in one of those slots, you don't have to plug in a grant continuity card, so.... Anyway, I have a spare 11/84 backplane, and one day I'll get around to poking at it with an ohmmeter to verify that suspicion. > I seem to remember that when two memory boards are used, they should be > the same. Really? That would surprise me. Noel

11 years, 6 months

Differences between PDP-11/83-84 M8190-AB/AC and AD/AE CPU cards

by jhfinedp3k＠compsys.to

Does anyone know why DEC would have MSV11-JC boards for use ONLY with a PDP-11/84 and the MSV11-JE boards which could be used with BOTH the PDP-11/83 and the PDP-11/84? It seems inconsistent. >Glen Slick wrote: >>On Wed, Feb 4, 2015 at 7:09 PM, Jerome H. Fine <jhfinedp3k at compsys.to> wrote: > > >>Longer explanation: The PMI memory used in the PDP-11/84 is sufficiently >>different >>from the PMI memory used in the PDP-11/83 that the magic smoke might be >>released >>if the incorrect PMI memory is used. The MSV11-JB (1 MB) and MSV11-JC (2 >>MB) >>are used in the PDP-11/84. The MSV11-JD (1 MB) and the MSV11-JE (2 MB) are >>used in the PDP-11/83. >> >The MSV11-JD and MSV11-JE are documented as being compatible with both >the PDP-11/84 and Q-bus systems. The documented restriction is that >the MSV11-JB and MSV11-JC are only compatible with PDP-11/84 systems >and incompatible with Q-bus systems. > >http://www.bitsavers.org/pdf/dec/qbus/oemMicronotes.pdf > >uNote # 028 >MSV11-Q/M/J MEMORY COMPARISONS > >MSV11-J >------- >The MSV11-J has four versions, the MSV11-JB and the MSV11-JC which are >used in the PDP-11/84 UNIBUS systems and the MSV11-JD and the MSV11-JE >are used in either the MicroPDP-11/83 Q-bus systems, or the PDP-11/84 >UNIBUS systems. All four modules use ECC memory for error correction, >as well as using 256K bit MOS RAM parts on either a half for fully >populated quad size module. > >NOTE: >----- >NONE OF THE FOUR MSV11-J MODULES CAN BE PLACED IN A Q/Q BACKPLANE >SLOT. IF THIS IS ATTEMPTED PERMANENT DAMAGE WILL BE DONE TO THE BOARDS >AND TO THE SYSTEM. > >The MSV11-JB (M8637-BA) is a half populated quad size PMI memory >module containing 1MB of memory. The second version of the MSV11-J is >the MSV11-JC (M8637-CA), this is a fully populated MSV11-JB quad size >PMI memory module containing 2MB of memory. These two module can not >be used in a Q-bus system due to gate array incompatibilities, and can >only be used in the PDP-11/84 systems which use the UNIBUS/PMI bus >interface (KTJ11-A). The third version of the MSV11-J is the MSV11-JD >(M8637-DA) which is a half populated quad size PMI memory module >containing 1MB of memory. The last version of the MSV11-J is the >MSV11-JE, (M8637-EA) which is a fully populated MSV11-JD quad size PMI >memory module containing 2MB of memory. These last two modules can be >used with either the MicroPDP-11/83 system which uses the Q-bus/PMI >bus interface or the PDP-11/84 system which was mentioned above. > >Although the MSV11-JD and MSV11-JE are PMI memories they can be used >in two other Q-bus configurations. >(more details follow...) > THANK YOU for the correction. After 20 years, the memory becomes a bit hazy. Also, I have only the 2 boards which are both 2 MB, so there must have been some confusion when I was told that a 1 MB and a 2 MB board should not be combined. It is good to know that is also not true. Does anyone know why DEC would have both MSV11-JC boards for use only with a PDP-11/84 and MSV11-JE boards which could be used with both the PDP-11/83 and the PDP-11/84? I have never worked much with Unibus systems and never with a PDP-11/84. Also, thank you for confirming that these memory boards MUST NOT be used in a Q/Q backplane. At one point, the MSV11-JE memory boards were equally priced with other 2 MB Qbus memory boards since most individuals thought they could be used only as PMI memory. I have no idea what the current prices are. Jerome Fine

11 years, 6 months

When to re-condition electrolytics

by jnc＠mercury.lcs.mit.edu

So, I'm about to bring up an old 11/10, and step a) is going to be getting the power supply up. So this means probably reconditioning some old electrolytics. So my question is 'should I _always_ recondition old caps, or is there some way to tell if they are still OK'? E.g. if they check out OK on an ohmmeter (no dead shorts), and also on a ESR meter, does that mean they are good to go? Or should I just always recondition them? I ask because this power supply (H750) seems to be a switching supply, and so I can't use the simple VARIAC hack, I'm going to have to do each capacitor individually. (For you experienced hardware guys, this is probably No Big Deal, but I'm mildly terrified... :-) Noel

11 years, 6 months

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