[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: 1.1k 10-pin Resister Pack supplier (or alternative values)?

The 1.1k are used as pull-up on TTL/cmos logic, almost any value from 470 ohm to 4.7k would be just fine... I used 1.0k, easy to find...


On Tuesday, June 19, 2012 10:31:37 PM UTC-7, pbirkel wrote:
The S-100 MSDOS Board, Z80A Master CPU Board, and Serial I/O Board all
specify the use of a 1.1k 10-pin Resister Pack.

This seems to be an uncommon part.  Is there a recommended supplier?

Alternatively, is the value critical in these three board-uses?

The S-100 MS-DOS Board uses a pair of packs (RR7/8) as input pull-up
resistors on the two 74LS165 address decoders. The Z80A Master CPU
Board similarly uses three packs (RR3/4/7) as input pull-up resistors
on its three 74LS165 address decoders.  It seems to me that in this
use the values are fairly non-critical.  What is the recommended,
commonly-available, alternative resistor value?

The Serial I/O Board is a bit more complicated.  It uses a single pack
(RR1) which connects to PU1K-A thru PU1K-I.

    1. PU1K-A/B/C are used on the Z8530 UART_INT*, UART_IEI, and
UART_INTA, apparently as input pull-ups.
    2. PU1K-E/F are used as pull-ups on two outputs of a
open-collector 74LS06N (the other 4 outputs are spares).
    3. The remaining 4 pack-resistors are spared.

Given this mixed-use, what would be the recommended,
commonly-available, alternative resistor value?  Or should I consider
hand-wiring single resistors in each case -- and then what would be
the recommended values in each case (UART input pullups; o.c.