I have a hex-height (Omnibus) board in my junk box... M8549 "Universal
Substitute Board". It has a few 10101 (ECL??) IC's. Here is a picture
of both sides.
http://s1181.photobucket.com/user/DrCharlesMorris/library/PDP-8
Anyone know what this is for, and any schematic info? I can't find it
on any module list.
thanks
Charles
>On Sun, Feb 16, 2014 at 4:14 PM, Charles
><charlesmorris800 at centurytel.net> wrote:
>> I have a hex-height (Omnibus) board in my junk box... M8549 "Universal
>> Substitute Board". It has a few 10101 (ECL??) IC's. Here is a picture
>> of both sides.
>>
>> http://s1181.photobucket.com/user/DrCharlesMorris/library/PDP-8
>>
>> Anyone know what this is for, and any schematic info? I can't find it
>> on any module list.
--- I found the M8549 used in two places on the document found here:
https://archive.org/details/bitsavers_decpdp10KL_1264444
The classification hierarchy lists the system it's used in under:
DEC::PDP10::KL10::MF20
The MF20 document is titled, "MOS Memory." Note that the M8549 instances are shown with suffixes: YA, YB, YD.
Steve L.
On 02/16/2014 12:00 PM, cctalk-request at classiccmp.org wrote:
> Subject: PDP-8 core memory troubles
> Message-ID:<bsovf9l51pr6bp1098bii2o7nkgmkoiq94 at 4ax.com>
> Content-Type: text/plain; charset=us-ascii
>
>
> Any tips for checking currents/timing? Or should I just replace the
> G650, the H219B core stack, or both as a pair? They aren't easy to
> find these days and my small chassis only has room for two core boards
> that occupy two hex slots each - so they both have to be 16K boards,
> as ADVENT requires 32K even though OS/8 runs in 12K:(
>
>
Are there any adjustments on the boards? There could be
timing adjustments
or XY drive and inhibit current adjustments. Most of the
old DEC
core systems had a thermistor on the core plane to adjust
select current,
you might compare the two thermistors to see if one has gone
bad.
You could also swap the core planes or other boards to see
if you
could isolate the problem. From the symptoms, though, it sounds
like the problem has to be in either an inhibit driver or a
sense amp
for bit 11, as the XY select is common to all bit planes.
If it was always
the same word, that could be a marginal XY drive current or
a defective
ferrite core, but that is not the symptom you give.
Jon
For those interested...
An HD revamped review of the Dick Smith System 80. My first computer and
hence nostalgic favourite! Find it at http://youtu.be/rtMFhbl4mAU
Sorry to those who may have commented on the earlier Low-res version.
Youtube doesn't allow authors to refresh videos, just replace them hence
the old comments are gone. Feel free to comment again!
Terry (Tez)
Hey all, anyone recall if I need to be doing anything special in my code
(running under MSDOS) when writing to one floppy, changing the disk, and
then writing to another?
I'm closing open files before the disk change, but I seem to consistently
get data errors when attempting to write following the change (even if it's
the same floppy that's put back in), as though the OS is noticing the disk
change and is deliberately refusing to write to the new media.
That behavior seems quite sensible - and vital if DOS is caching any of the
FAT structure - but I've not found any documentation covering it, or what
the correct process should be (e.g. disk reset via DOS function 0Dh, or
drive reset via BIOS 13h/00h, or something else entirely...?)
cheers
Jules
Amstrad 464 Plus, the last of the CPC range:
http://www.ebay.co.uk/itm/271402903043
3dfx Voodoo 5500, their last card before the nVidia takeover:
http://www.ebay.co.uk/itm/271402852610
I also have some SCSI CD-ROMs and things; see my other items.
Apols for the spam.
--
Liam Proven * Profile: http://lproven.livejournal.com/profile
Email: lproven at cix.co.uk * GMail/G+/Twitter/Flickr/Facebook: lproven
MSN: lproven at hotmail.com * Skype/AIM/Yahoo/LinkedIn: liamproven
Tel: +44 20-8685-0498 * Cell: +44 7939-087884
> Message: 2
> Date: Fri, 14 Feb 2014 09:03:34 -0800
> From: Christian Kennedy<chris at mainecoon.com>
> To: "General Discussion: On-Topic Posts Only"<cctech at classiccmp.org>
> Subject: Re: DG Nova 1210
> Message-ID:<F2CB477E-C307-495B-B159-9F9A3AFF8B52 at mainecoon.com>
> Content-Type: text/plain; charset=windows-1252
>
>
> On Feb 13, 2014, at 1:35 PM, David Williams<dave at willomail.co.uk> wrote:
>
>> Just managed to score a DG Nova 1210 and need a little advise & help. The system is pretty basic having only the CPU board, 8k core memory and another I/O board (Graphic Systems 8400) It does not have any front panel, TTY or top cover. System is coming from the US to the UK.
>>
>> Does anybody have a spare front panel or TTY board?
> You're looking for a 4010 "basic I/O board". They tend to turn up fairly regularly on ePay in the US; if you can't find one I'm pretty sure Bruce or I can find a spare.
Thanks. Might take you up on that offer.
> Are there any schematics availiable for this system?
> Yes. I don't have a 1200 in my collection and thus haven't bothered to find prints for the 1200, but I'm pretty sure Bruce has a copy.
Yup, Bruce has already been in touch :)
>> Can the PSU be converted to 240v from 110 or would I need a converter?
> Good question. In a 1200, 800, 830 or 840 I'd know the answer to be "yes", but the 820, 1210 and 1220 use an integral power supply that I've never seen in my life. The How To Use and Abuse manual specifies input as 115 or 230 VAC, 47 to 63 Hz, but it's certainly not auto sensing -- you'll have to move jumpers.
>
Yup, did come across some documentation on the 800 which describes
moving some jumpers on the primary transformer for 220/240v operation.
>> I'm new to DG hardware and machines of this vintage so is there anything else that I need to be aware of?
> The common traps are failing to understand how the interrupt and data channel priority and acknowledge lines (intp, inta, dchp, dacha) need to be jumpered around empty slots and the need in larger chassis to keep a board in the topmost slot if there's not an external terminator on the I/O bus ) -- otherwise the bus rings like a bell and the machine will exhibit seriously unwanted behavior.
>
> The 1210 is a baby chassis. CPU goes in slot one, slot two would*typically* get the basic I/O board (unless you have the 8107 hardware multiply/divide option which needs to be in slot two) with slots three and four available for memory or I/O. On the 1210 (when viewed from the back) there's a large edge connector on the backplane that is the external I/O bus; you may or may not find a terminator sitting on it. Next out from that (if present) would be a card with three edge connectors; the top most would be the connector for the factory paper tape reader option, the middle the EIA option and the bottom the paper tape punch option. The teletype would be a push-on connector on the backplane, although from the sounds of it you won't have this present on your machine and you'll need to wire wrap one into place.
>
Thanks for the info. Clears up a few things about how it all fits together
> If you're looking for a discrete paper tape reader (as opposed to
> using the reader on an ASR TTY) you'll need the paper tape reader
> option on the basic I/O board, option 4011 (or you'll have to add it
> yourself -- it's not hard). You should look for a copy of "How To Use
> The Nova Computers". I have a preference for the 1972 (brown-covered
> with a photo of a stack of 1200s) version over the 1970 version (white
> cover with a photo of a stack consisting of a nova 800, a supernova
> and a unicorn, aka supernova SC). It's a good one-stop shop for a lot
> of stuff (although you'll still need the prints)
Downloaded a copy and will be reading it over the next couple of weeks
whie I wait for the machine to arrive.
>
> Welcome to the brotherhood of Edson de Castro
Thanks! :)
> On 2/13/14 10:09 PM, Bruce Ray wrote:
>> G'day Dave -
>>
>> I will contact you off-group with information...
>>
>> Bruce
>>
>>
>> Bruce Ray
>> Wild Hare Computer Systems, Inc.
>>
>>
>> On 2/13/2014 2:35 PM, David Williams wrote:
>>> Hi Folks!
>>>
>>> Just managed to score a DG Nova 1210 and need a little advise & help.
> Just so other know, Bruce is THE guy to talk to WRT DG.
Thanks for the replies. I've emailed Bruce with regard to documentation.
Cheers,
Dave
I have just pulled my HP 7907A out of storage and tried to power it up. No joy, it emitted a couple of squeaks from the power supply and that was it.
I have taken a look on bitsavers and HP museum but can only find general service information for this unit. Does anyone out there have more detailed service information for this box?
The PSU itself is a switcher, manufactured by SSI (Switching Systems International) - model SQV250 - 1421 manufactured 6/89. Perhaps someone has the schematic for a similar PSU?
Does anyone have a copy of the user manual for the 7907A? The unit has been powered down with a cartridge installed - will the heads have been fully retracted? Is there a way that I can power the unit up that ensures the heads will remain retracted so that I can remove and check the media?
Peter Brown
So, anyone here able to offer some Beige G3 tech guidance or advice?
I've just given my Beige G3 minitower away to a friend. That meant my
other Beige came out of the garage to be fixed up & sold. It's a
desktop with about 192MB of RAM (I think). No hard disk. Came off the
local Freecycle group.
It boots, bongs happily, and then will start to load MacOS 9 from CD
or MacOS 8.6 from a SCSI HD I have to hand. I get a Happy Mac, then it
just stops. Never gets past that point.
So it's not the disk -- both HD & CD worked fine in the minitower.
It's not the EIDE bus or cabling, as it affects a SCSI drive too. I've
zapped PRAM - no difference.
What could be wrong? I am mystified. :?(
--
Liam Proven * Profile: http://lproven.livejournal.com/profile
Email: lproven at cix.co.uk * GMail/G+/Twitter/Flickr/Facebook: lproven
MSN: lproven at hotmail.com * Skype/AIM/Yahoo/LinkedIn: liamproven
Tel: +44 20-8685-0498 * Cell: +44 7939-087884
