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Apple Techstep I have almost all of the ROMs here and some info!
Posted by: SuperSVGA on 2022-02-13 18:36:39 Almost done with the first one, just need to add some cuts and drills to the board itself.
Posted by: jajan547 on 2022-02-13 18:37:38 nice work this is the revision 2 right for the later ROMs?
Posted by: SuperSVGA on 2022-02-13 18:52:33 nice work this is the revision 2 right for the later ROMs? Yes, although it's just a quick change to the schematic to produce one for the AM27C512 as well.
Posted by: jajan547 on 2022-02-13 19:02:49 Sweet you rock for doing this, when your done I'll order some components and test on mine too if that works?
Posted by: SuperSVGA on 2022-02-13 19:47:29 I think this should work for the MX27C1000, as well as similar chips like the AT27C010. Assuming I didn't make any stupid mistakes. I think it was originally a 4 layer board, but I made it 2 layers to save on cost. It's probably fine...
Posted by: jajan547 on 2022-02-13 19:49:24 I'll order the stuff right now to test you are awesome! Do you have the 1st too?
Posted by: jajan547 on 2022-02-13 20:43:59 Ok I went ahead and have everything ordered hope to provide some good news in a few days!
Posted by: jajan547 on 2022-02-13 20:53:02 Also I think doing a .stl or new 3D printable case for these would come in handy so I can try and work on that but I'm not too good with that stuff either. Also that small chip is a X25C02P which is hard to find but a 25LC640A (PDIP) is a newer chip with the same pinout so it should be compatible.
Posted by: SuperSVGA on 2022-02-13 21:45:19 Here's the one for the AM27C512 pinout, as well as variations for the M95020-WMN6TP EEPROM chip, which I think is a compatible replacement for the X25C02P.
Posted by: jajan547 on 2022-02-13 21:46:53 Awesome! You just brought TechSteps back to life!!!
Posted by: jajan547 on 2022-02-13 22:05:11 Okay I've ordered 5 of each board as well as five of each component needed so we shall see what does and doesn't work. Fingers crossed!
Posted by: SuperSVGA on 2022-02-14 00:18:43 I guess I'll order some boards and parts as well, not like it will make much of a difference adding to my already $750 LCSC order.... Edit: I now realize I am very stupid and have ordered the 100 of the EEPROM twice, first from Mouser and now from LCSC. Maybe someday I'll switch to BOM software that supports tracking orders so this won't happen.
Posted by: jajan547 on 2022-02-14 02:29:59 Awe sorry that happened, did you get it all fixed?
Posted by: SuperSVGA on 2022-02-14 02:45:42 Awe sorry that happened, did you get it all fixed? It's no big deal, I'll just have to find something else to use the extras on someday.
Posted by: jajan547 on 2022-02-14 07:15:18 Ordered quite a bit huh?
Posted by: SuperSVGA on 2022-02-14 11:27:08 Ordered quite a bit huh? I usually order a good bit because the volume discounts are sometimes as much as 50% off. Either that or buying full reels for that pick and place machine I hope will arrive someday. Most of the expense in that order was the 160 STM microprocessors, and parts to build a new logic board for a Macintosh SE.
Posted by: Skate323k137 on 2022-02-14 11:32:35 I usually order a good bit because the volume discounts are sometimes as much as 50% off. Either that or buying full reels for that pick and place machine I hope will arrive someday. Always good to eye the volume prices / standard packaging on Digikey for sure.
Posted by: olePigeon on 2022-02-15 13:22:49 This is really neat. I had pondered about this quite a while ago. I wonder if new ROMs could be made for other machines, or additional tests could be done. A Network Test would be useful, for example, to test that an ethernet card is functioning. Help rule out it it's MacTCP or the card itself.
Posted by: SuperSVGA on 2022-02-15 15:37:29 This is really neat. I had pondered about this quite a while ago. I wonder if new ROMs could be made for other machines, or additional tests could be done. A Network Test would be useful, for example, to test that an ethernet card is functioning. Help rule out it it's MacTCP or the card itself. I have to wonder if the designers of the TechStep intended for different connections to be released in the future, considering that the entire IO section on the TechStep is detachable.
Posted by: jajan547 on 2022-02-15 18:06:33 I hope so I haven't looked much into but ROM 4 I believe is of the color classic and LC520. I'll take a ponder at it.
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