Heathkit H-11

[Allison]

The standard H-11 was heath varients of dec cards and a official
DEC LSI-11/03 quad height card.  Memory was heath design and
usually static.  Some heath cards were better than dec some no so.
one item in the h11 that was really no so was the power supply
as it tended to fail easily and frequently.

What is often seen is a H11 upgraded with 11/2 or 11/23 cards
and a plethora of DEC boards as often they were available
in later years cheap and could (for the 11/23) give a substantial
 performance boost over the older 11/03.

Allison

Ethan Dicks wrote:
> On Thu, Jul 03, 2008 at 07:21:25AM -0400, Marden P. Marshall wrote:
>   
>> On Jul 3, 2008, at 7:06 AM, David Griffith wrote:
>>
>>     
>>> Just in case anyone's interested, someone's selling a Heathkit H-11 on
>>> Ebay (#380042473453).  Looking at the card cage of the thing, it seems
>>> that Heathkit simply cloned some DEC boards.  What's actually going  
>>> on?
>>>       
>> They didn't clone the boards.  They're real DEC boards.  It's  
>> basically a dumbed down LSI-11, very similar to something like a  
>> PDP-11/03. 
>>     
>
> I can't check that particular auction right now, but I do know a bit
> about DEC equipment and I do own a working H-11.  In my experience,
> I'd say it's a bit of both - Heath made their own boards _and_ they
> sold DEC boards.  I don't know what "officiall" came with an H-11
> back in the day, but in my experience, folks bought an H-11 rather
> than a real DEC box to save money, so they used whatever came along
> that was the cheapest (to buy).
>
> I have a Heath parallel printer board (LPV11 equiv, AFAIK), a couple
> of Heath serial boards (DLV11-E? equiv) including one unassembled,
> plus the backplane in my H-11 does *not* use DEC edge connectors.
> In addition, I have a Heath H-27 interface card that is register-
> compatible with, I think, the RXV11, but that talks its own protocol
> out the connector to a Heath-specific intellegent drive (Z-80-based
> with "standard" 8" drives inside).  In addition to that, my H-11 has
> a genuine DEC CPU board and genuine DEC memory.
>
> Heath tended to use generic white plastic module handles for
> their dual-height cards; I don't know if they ever made any quad-
> height cards.  If you see an H-11 picture and you see maroon
> handles, those are probably DEC boards, especially if the M-numbers
> make sense (DEC CPU, memory, disk, etc).  You might also see other
> vendors' boards in there, too, depending on how extensively the
> previous owner(s) stuffed in upgrades.  I've seen green (not DEC
> G-series green), blue (same), and yellow for sure, plus white,
> of course.  I don't know that DEC made too many dual-height boards
> for Qbus outside of the M-series (perhaps an A-series or two?)  There's
> much more variety in the Unibus line, and of course, for non-bussed
> machines like pre-OMNIBUS PDP-8s.
>
> I'll have to check the auction out when the 'net comes up.  I don't
> want to sell my H-11 (it was a gift from a former employer when the
> company went bust and he moved), but it would be nice to know what
> one can get these days.
>
> -ethan
>
>