[rescue] sun 3/60 update

[Romain Dolbeau]

Le jeu. 22 mai 2025 à 08:28, Dan Moisa via rescue <rescue at sunhelp.org> a écrit :
> Putting the BOM together is a PITA because about 40% of the components are not on Digikey/Mouser

Just checked the 74xx chips for stock or alternative at Mouser, and
there's hope:
* The ALS are in stock in SOIC, all but the ALS652 in DIP (and for
that one, the FCT652 is a cheaper option that might work as a
substitute)
* The F00, F04, F175 are all there, the F374 in SOIC only, the F534 is
MIA but there's an ABT that might work as a substitute; also it's just
a register for BERR, and the 3/160 uses a different part (slower,
non-inverting), so there's options to substiture/reengineer
* The AS are mostly not in stock/no made or expensive; however it's
possible they can be substituted by F, which are cheaper and usually
available. The exception is the AS286, but the FCT11286 has similar
functionality though different pinouts. Also, it's for the parity
generation/checking, required for real workstation/server usage but
could be disabled in a replica if some components are no longer
available.

On the SRAM side, updating the vintage stuff will be wasteful but
doable; pair of 7188 (u200/u201) could be replaced by IS62C1024AL-35
(8x the needed size...) while 2168 could be replaced by IS62C256AL-25
(idem), though while u205/6 and u207/8 can be merged pair-wise,
u202/u203 have different /WE so need different chips (8-bits SRAM dont
have 4-bits granularity).

The ICM7170, Am7990 (lance), AM7992, Z8530 I don't see a way to
replace (unless by re-implementing in programmable logic, or having a
go at recreating them with open-source EDA & PDK perhaps as FOSH, but
that's not happening anytime soon).

The Am25LS2518 is just a dual-output register, it might be possible to
replace it by two registers in parallel with the same input and
control, one for the always-on output and one for the three-state
output.

I'm not sure what "TRANSF" is ?

(the PALs are a problem of their own, discussed in the GitHub already).

Cordially,

-- 
Romain Dolbeau