I made a search on website about Equivalence Prom's that can replace MMI 6301-1. None of them tested from me, but i know some that tested from other members. If any of you have did some test's from the prom's that listed below, please report it here.
MMI 6301-1 Equivalence Prom's.
AMD: 27S11, 27S21
HARRIS: 7611-5
INTERSIL: 5623, 5623A
FAIRCHILD: 93427, 93467
INTEL: 3611
NATIONAL: 74S287
T.I.: 74S287, 24S10
FUJITSU: 7114, 7052
RAYTH: 29661
SIGNETICS: 82S129
RUSSIAN: KR556RT11
IMG_20190709_094134.jpg
I wish i had the authorized to access edit my first post to mark "green" the tested ones.
Is that posible?
Macintosh_Nik, what devices did you use for the +5V regulator and the diodes? They look kinda cool.
This is not my replica, I don’t know. Everything is classic for me.
TESLA: MH74S287
PHILIPS: N82S129
... I have personally tested AMD 27S21, NSC 74S287, TI 74S287, Signetics 82S129 and they all work with no trouble.
You can also use AMD 27S13 if you program the WOZMON or ACI software into the lower 256 nibbles (the 27S13 is 512x4).
No changes to the Apple-1 or ACI are necessary. It's just that the higher 256 nibbles can't be accessed by the Apple-1.
The price situation for bipolar PROMs is always moving. Last year I had found an IC broker who had the 27S21APC for below $2 each. I did not buy any as I tought I had enough in stock. Now having misplaced some tubes of 27S21 (at least I can't find them) I looked again and the same greedy bastard now rings up a price of more than $10 for the 256x4 27S21. At this usurious price point you are better off buying 27S13 which are 512x4, because they don't cost much more.
I started to sell the 27S13 with my complete IC kits since the lack of 27S21 came to my attention. In the unused upper 256 bytes there is a little easter egg. Just not to waste half of the space available.
I was interested in Soviet orange diodes, here are a couple of photos with markings.
IMG_20210302_122306_283.jpg
IMG_20210302_122313_214.jpg
Thank you Macintosh_Nik... That was exactly what I was looking for.
Thanks for sharing!
I’m glad to help (but I don’t really share interest in this). If you still need to ask something, I and the author of the "ghost of communism" live in the same city, we know each other personally.