Kai Robinson Posted Sunday at 08:49 PM Author Report Share Posted Sunday at 08:49 PM Only $254... Quote Link to post Share on other sites
Trash80toHP_Mini Posted Monday at 12:11 AM Report Share Posted Monday at 12:11 AM LOL! Gotta love the listed prices for new books And that only gets you the paperback version! Click on the 7 used from $25 link to get over the sticker shock. I'm wondering if the selling of "new" books on Amazon angle is a faster, safer path to laundered money than the usual eBay schtick? Quote Link to post Share on other sites
ronan Posted Monday at 01:09 AM Report Share Posted Monday at 01:09 AM Did you have a look here : https://www.abebooks.com/servlet/SearchResults?cm_sp=SearchF-_-topnav-_-Results&ds=20&kn=Macintosh Family Hardware Reference&sts=t ? Quote Link to post Share on other sites
Crutch Posted Monday at 02:34 AM Report Share Posted Monday at 02:34 AM +1. AbeBooks (which is owned by Amazon!) is the place to get such things. Never Amazon proper. Quote Link to post Share on other sites
Trash80toHP_Mini Posted Monday at 03:51 AM Report Share Posted Monday at 03:51 AM Definitely +1 for AbeBooks, looked there first yesterday and search reported the title was sold out. Didn't know Amazon owned them or I'd have been more hesitant to use them in the past. Finally got past my hatred of Amazon, now it's just skin-crawly when I buy from there. This time a couple of Amazon prices are lower: https://www.amazon.com/gp/offer-listing/0201192551/ref=tmm_pap_used_olp_0?ie=UTF8&condition=used Quote Link to post Share on other sites
Kai Robinson Posted Tuesday at 03:17 PM Author Report Share Posted Tuesday at 03:17 PM (edited) Okay, it's done... See pics for details! No boot, but a checkerboard again at least... Edited Tuesday at 03:18 PM by Kai Robinson Quote Link to post Share on other sites
ronan Posted Tuesday at 03:31 PM Report Share Posted Tuesday at 03:31 PM Congrats on all the work done ! I'm really impressed ! Good luck for the future of this project Quote Link to post Share on other sites
cheesestraws Posted Tuesday at 03:49 PM Report Share Posted Tuesday at 03:49 PM Well done! I'm lagging significantly behind you, I fear... but most of mine is done too, so I will hopefully join you in checkerboard land shortly Quote Link to post Share on other sites
techknight Posted Tuesday at 04:12 PM Report Share Posted Tuesday at 04:12 PM Nice! that looks like uninitialized RAM, so the CPU isnt starting up for some reason. Wonder if theres another address/data line that was missed or unconnected. Quote Link to post Share on other sites
Kai Robinson Posted Tuesday at 04:32 PM Author Report Share Posted Tuesday at 04:32 PM I just checked the test points for voltages - instead of reading +5v, it's reading +7.5v!!! I think my analog board has potentially killed some chips... Quote Link to post Share on other sites
quorten Posted Tuesday at 04:36 PM Report Share Posted Tuesday at 04:36 PM Oops, well... actually I'd vouch the essential chips are still working: GLU and BBU for one. You can double check that the ROM and CPU are okay, and if so, that should actually be good enough for initial oscilloscope debugging. Quote Link to post Share on other sites
quorten Posted Tuesday at 04:39 PM Report Share Posted Tuesday at 04:39 PM Easy way to check the CPU is still working in some vein: If you can trigger *HALT + *RESET and it will respond by de-asserting/asserting *AS after a few clock cycles, it should be okay. Quote Link to post Share on other sites
Kai Robinson Posted Tuesday at 04:40 PM Author Report Share Posted Tuesday at 04:40 PM I'm thinking my analogue board is potentially in need of repair as well - seeing as the video is very off centre as well as being wonky...voltages are something i'll have to measure....if only i had an extension cable to be able to test this flat on a bench! Anyone make one at all? Quote Link to post Share on other sites
max1zzz Posted Tuesday at 05:20 PM Report Share Posted Tuesday at 05:20 PM Very nice! As for extension cables, iirc you can get a normal 20pin ATX extension cable and just use one side of it (I haven't tried this personally though) Quote Link to post Share on other sites
techknight Posted Tuesday at 08:16 PM Report Share Posted Tuesday at 08:16 PM 3 hours ago, Kai Robinson said: I just checked the test points for voltages - instead of reading +5v, it's reading +7.5v!!! I think my analog board has potentially killed some chips... Yikes! yea that spells death to semiconductors Quote Link to post Share on other sites
Kai Robinson Posted Tuesday at 08:32 PM Author Report Share Posted Tuesday at 08:32 PM (edited) Well, most ttl has a bit of leeway, I'm hoping it hasn't taken out the BBU - everything else is expendable... Here's the result of a 20 second power on with a set of 256k simms : Edited Tuesday at 08:36 PM by Kai Robinson Quote Link to post Share on other sites
360alaska Posted Tuesday at 08:48 PM Report Share Posted Tuesday at 08:48 PM In case the problem actually is the board how you ever used one of these: Maybe comparing your board to a stock board with a huntron will yield some clues? Quote Link to post Share on other sites
Kai Robinson Posted Tuesday at 11:19 PM Author Report Share Posted Tuesday at 11:19 PM An Oscilloscope is on the way - i do have a logic analyser - but i'll be damned if i can find a DIP64 IC test clip! Quote Link to post Share on other sites
Kai Robinson Posted Tuesday at 11:24 PM Author Report Share Posted Tuesday at 11:24 PM Knocked up an adaptor for the SE ROM's - i have a funny feeling mine aren't making proper contact in the sockets, the legs, even cleaned, are tarnished...the ones from the spare board i have...well i tried removing them and the legs stayed in the sockets, so i now have a load of icosaoctaplegic Mask ROM's I have 10 prototype boards in a panel with ENIG and V-Scored edges on the way from PCBWay (Making use of the $100 or so commission i earned from the Amiga stuff i've done in the past) so if anyone wants to test these, i have 9 available. Quote Link to post Share on other sites
quorten Posted 23 hours ago Report Share Posted 23 hours ago (edited) Losing legs from a ROM, ouch. The price of those DIP64 IC test clips just keeps going up and up, but they're at least out there... https://www.digikey.com/en/products/detail/3m/923739-64/12091 Another note, I also looked deeper into the Unitron's logic equations and tried coding them up in Verilog mainly to run a simulation that I could compare the BBU's waveforms with. Indeed this was helpful in answering a few last questions, though it did feel a bit like a "distraction" from the BBU. One interesting note, though, I found the Unitron's C3.7M clock is generated by inserting two C16M cycle waits every eight C4M cycles, rather than one C16M cycle wait every four C4M cycles. It could be that the original Macintosh actually used this behavior, but of course there's no need to copy the inferior approach for the BBU. Edited 23 hours ago by quorten Fix minor error Quote Link to post Share on other sites
cheesestraws Posted 11 hours ago Report Share Posted 11 hours ago On 11/24/2020 at 11:24 PM, Kai Robinson said: Knocked up an adaptor for the SE ROM's - i have a funny feeling mine aren't making proper contact in the sockets, the legs, even cleaned, are tarnished...the ones from the spare board i have...well i tried removing them and the legs stayed in the sockets, so i now have a load of icosaoctaplegic Mask ROM's If you want a spare "stock" set I can drop some in the post to you. Quote Link to post Share on other sites
Kai Robinson Posted 11 hours ago Author Report Share Posted 11 hours ago @cheesestraws Oooh, i may have to take you up on that - i basically need a whole other SE board, so i have some duplicate customs for testing... Quote Link to post Share on other sites
cheesestraws Posted 11 hours ago Report Share Posted 11 hours ago 9 minutes ago, Kai Robinson said: i basically need a whole other SE board, so i have some duplicate customs for testing... We can sort this. I'll send you one of my spares. Quote Link to post Share on other sites
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