On Tue, Jan 3, 2023, 5:30 PM segaloco via TUHS wrote: > I'd love to get my hands on a 3B2 someday, this'll be cool if I can get it > going but that'd be a much more robust machine. > > I'm starting to suspect if there isn't any sort of boot ROM that spits out > commentary on the UART and that doesn't get flexed until UNIX is up, I may > not be able to get very far. I referred to > http://bitsavers.trailing-edge.com/pdf/att/3b1/999-809-010IS_UNIX_PC_Remote_Access_1986.pdf > for the serial settings and it appears: > > 9600 baud, 1 stop bit, no parity, 8 data bits > > And the relevant pins > > Pin 1 - GND > Pin 2 - RX > Pin 3 - TX > Pin 4 - RTS > Pin 5 - CTS > Pin 6 - DSR > Pin 7 - GND > Pin 8 - DCD > Pin 20 - DTR > > So I've plugged my USB-TTY GND/RX/TX into the relevant pins and setup the > necessary tty settings. The manual then suggests if running null modem mode > to short pin 4 to 5 and then pins 6, 8, and 20 together, presumably > omitting any need for modem signalling from the remote machine, doing basic > serial RX/TX. Unfortunately even with all of this bypassing I get nothing > out of the RS-232 port. What I don't know is if I could even expect > something or if this is unlikely to bear fruit whether the hardware works > or not. In any case, if I do get this thing running I'll have a writeup for > folks afterwards. If not, then hopefully I can figure out something useful > to do with this thing rather than junking it. > Silly question... did you level shift to RS 232 levels? You likely did... but if not... Warner - Matt G. > ------- Original Message ------- > On Tuesday, January 3rd, 2023 at 3:53 PM, rob@atvetsystems.com < > rob@atvetsystems.com> wrote: > > Hello Matt, > > I’ve got one of these in my garage. I bought it about twenty years ago as > a working system but when I got it home I noticed that the hard disk wasn’t > connected but at some point I’d like to get it and my 3b2/300 working. > > Regards, Rob. > > On 3 Jan 2023, at 23:27, segaloco via TUHS wrote: > > And here are some pictures of the guts. > > https://imgur.com/a/E1ioxZl > > Various bits inside date this to late 1985. The good news is it at least > turns on, but that's about as far as I've gotten with it. The display never > turns on, nor do I hear any sounds indicating it tries to start the CRT. > The fans kick on and there it stays until I turn it off. I plugged in a > USB-TTY to pins 2, 3, and 7 (RX/TX/GND) and listened at 9600 baud 8 bit 1 > stop no parity and got nothing. Swapped the RX/TX, still nothing. Of > course, that's all predicated on the assumption there's something there to > even interact with. I have little faith that whatever UNIX install was on > this is extant. Additionally, it didn't come with a keyboard, so if there > was some futzing with key combos that would trigger some sort of UART over > those lines, I can't do that. I wonder if there are some contacts inside I > can just poll for activity with this serial connector, not sure how safe > that is... > > Anywho, the CPU has a bit of corrosion on the surface, not sure how that > bodes for the innards, but this is in kinda rough shape either way. I hope > I can salvage it but if not, I'm going to at least do some study on the CRT > particulars and see if I can extract and keep the monitor from it, been > wanting a smaller CRT to have around for a while. > > - Matt G. > ------- Original Message ------- > On Tuesday, January 3rd, 2023 at 12:20 PM, segaloco via TUHS < > tuhs@tuhs.org> wrote: > > Good day everyone, just starting a thread for yet another project I'll be > tinkering on over time. Picked up a (presumably broken/untested) 7300 off > eBay to at the very least tear down and get some good pictures of and, with > some luck, perhaps get working again. > > https://imgur.com/a/CExzebl > > Here are some pictures of the exterior for starters. I'll update this > thread when I've got pictures of the guts and also with any info I can > glean regarding whether this might be salvageable. The rust on the back is > pretty nasty but I've seen older/worse start up just fine. > > - Matt G. > > > > >