[rescue] Sun2 P2 termination

[Dave McGuire]

   I don't remember there being two different ones, but it has been 35 
years since I've been on the inside of a Sun2.

   But I'm following this with great interest, as I expect that we'll 
start working on one of the Sun2s at LSSM probably this coming weekend, 
so please share what you find.

           -Dave

On 9/28/26 16:24, Dan Moisa via rescue wrote:
> Is there a different framebuffer card for the older backplanes, or does 
> it just get double-terminated?
> 
> On Mon, Sep 28, 2026, 06:12 Romain Dolbeau via rescue 
> <rescue at sunhelp.org <mailto:rescue at sunhelp.org>> wrote:
> 
>     Le lun. 28 sept. 2026 à 15:04, Dave McGuire via rescue
>     <rescue at sunhelp.org <mailto:rescue at sunhelp.org>> a écrit :
>      >    From dusty memory I'm pretty sure the P2 termination is
>     provided by
>      > the framebuffer in older Sun2 backplanes, and on the backplane itself
>      > for later ones.
> 
>     That's also what the Sun Hardware FAQ part 4 implies
>     (<https://www.sunhelp.org/faq/sunref4.html <https://www.sunhelp.org/
>     faq/sunref4.html>>):
> 
>      >501-1003        monochrome video/keyboard/mouse TTL only Multibus
>      >(...)
>      >        This board must be placed in a slot in the Multibus P2
>      >        section shared by the CPU. For backplane P/N 501-1090, it must
>      >        be placed in slot 6 to terminate the P2 bus; for newer
>      >        backplanes, it is usually placed in slot 6 anyway.
> 
>     Cordially,
> 
>     -- 
>     Romain Dolbeau
> 
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> 
> 
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-- 
Dave McGuire, AK4HZ
New Kensington, PA