6 Aug
1997
6 Aug
'97
6:51 a.m.
On Mon, 4 Aug 1997, PDP11 Hacker ..... wrote:
Scott Ware wrote:
>There is what appears to be an RC clock composed
of a 4.7 nF capacitor and
>a multi-turn trimmer potentiometer in the upper left corner of the M7260
>data path board in my 11/10. It looks like this clock feeds a 74197
>counter, which has a 5-position rotary switch connected (presumably for
>selecting what the incoming clock is divided by). I'll put a scope on pin
(snip)
If that's the board I think it is, it's an 11/10S. The preset was adjusted at
the factory, and you could set most standard baud rates using the switch. It
can't hurt to measure the frequency, of course.
I can check the printset next weekend for you if you can't figure it out.
I'll measure the UART clock frequency for each position of the rotary
switch after I fire up the 11/10 (hopefully this weekend). That should
give me all of the information that I need (for now...)
Other than the different CPU boards and the ability to function
as a "slave" processor to another PDP-11, how does the 11/10S differ from
a standard 11/10? My 11/10(S?) (10.5 inch box, single 16kW core plane,
most date codes in early '74) was configured as a standalone system when I
got it. Were the later 11/10 machines identical to the 11/10S, or did
DEC just produce an "improved" CPU board set for the 11/10S and use it in
the later 11/10 machines? Of course, I realize that it's possible that
some board swapping has taken place and neither is the case.
Thanks to everyone for the DEC key information. There isn't quite enough
of a key left in the 11/10 for a screwdriver to work. I'll probably pull
out the keyswitch and take it (and the key code for the 11/24 key) to a
locksmith sometime in the near future.
--
Scott Ware s-ware(a)nwu.edu