On Tue, Jan 3, 2023, 5:30 PM segaloco via TUHS <tuhs(a)tuhs.org> wrote: 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(a)atvetsystems.com <rob(a)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 <tuhs(a)tuhs.org> 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(a)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.

https://www.amazon.com/NOYITO-Module-Conversion-Arduino-communicates/dp/B07… is my go-to for when I need a simple one, though something like https://www.amazon.com/NOYITO-Module-Conversion-Arduino-communicates/dp/B07… might work better for your setup if you just have more of the TTL gear than RS-232 gear (I have way too many old RS-232 cables because I never know when I'll need them again...) Warner On Tue, Jan 3, 2023 at 5:46 PM segaloco &lt;segaloco(a)protonmail.com&gt; wrote: > Nope, unfortunately I only know as much as is needed to plug into the > GPIO RX/TX/GND working on single boards. I wouldn't be surprised if my > assumption I just run these pins into the D-25 in the right holes is > bunk...but that's how we learn sometimes. Once I move I should be able to > setup a proper work bench where I can tinker on this sort of thing more > intentionally rather than haphazardly. So perhaps a silly question for an > expert but a valid one for me. I'll chase that angle and see if it bears > fruit. > > - Matt G. > ------- Original Message ------- > On Tuesday, January 3rd, 2023 at 4:40 PM, Warner Losh &lt;imp(a)bsdimp.com&gt; > wrote: > > > > On Tue, Jan 3, 2023, 5:30 PM segaloco via TUHS &lt;tuhs(a)tuhs.org&gt; 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… >> 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(a)atvetsystems.com < >> rob(a)atvetsystems.com&gt; 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 &lt;tuhs(a)tuhs.org&gt; 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(a)tuhs.org&gt; 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. >> >> >> >> >> >

Matt - send me an email offline if you need more help. Warner speaks the truth - although he left out some wizardry that has sadly been lost for ages. The first board he offers will create the interface that an IBM PC/AT created which was originally not a standard either (eventually EIA back fit it, in RS 232-E IIRC, but RS-232 C which is what the UNIX PC's interface was defined does not use it]. From your email, it looks like AT&T out a standard Data Terminal Equipment (DTE) pinning on the back of that system (which would make sense). That means it should be a >>male<< 25 PIN (i.e. male) D style 'B-sized' connector with pins 2 (TX), 4 (RTS), 20 (DTR) being driven; and pins 3 (RX), 5 (CTS), 6 (DSR), 8( DCD), 22 (RI) as inputs. With Pin 7 being the signal reference ground and Pin 1 being the frame ground (often N/C - but do not short to 7 on your board) The signals should swing from +3 volts to up to +30 when assert as a spacing time, and -3 to -30 volts marking time. However, anything over +/- 15 volts is unusual, but the interface is required to accept it. Frankly, +/- 9 volts is most likely what you will see with the 1488/1489 driver pairs which were the preferred chips used in those days. Amazon does not seem to sell an equiv that spits out real RS-232C using the D connector, but rather this PC/AT variant, so you will need to make a cable -- the good news is they do sell: https://www.amazon.com/Kentek-Female-Serial-RS-232-Adapter/dp/B07KVFM4MS My suggestion would be to use this on you Mac/WIndows or Linux box: https://www.amazon.com/Sabrent-Converter-Prolific-Chipset-CB-DB9P/dp/B00IDS… connect it to the cable I just mentioned -- at that point your Mac/Windows/Linux Box will look like a Proper 'terminal' as the being expected then if needed a 25 pin null modem between it that the 3B1 such as: https://www.amazon.com/Monoprice-DB25-Null-Modem-Adaptor/dp/B001VL8RK2 or whatever one you need M/M, M/F -- etc... On Tue, Jan 3, 2023 at 7:58 PM Warner Losh &lt;imp(a)bsdimp.com&gt; wrote: > > https://www.amazon.com/NOYITO-Module-Conversion-Arduino-communicates/dp/B07… > > is my go-to for when I need a simple one, though something like > > > https://www.amazon.com/NOYITO-Module-Conversion-Arduino-communicates/dp/B07… > > might work better for your setup if you just have more of the TTL gear > than RS-232 gear (I have way too many old RS-232 cables because I never > know when I'll need them again...) > > Warner > > On Tue, Jan 3, 2023 at 5:46 PM segaloco &lt;segaloco(a)protonmail.com&gt; wrote: > >> Nope, unfortunately I only know as much as is needed to plug into the >> GPIO RX/TX/GND working on single boards. I wouldn't be surprised if my >> assumption I just run these pins into the D-25 in the right holes is >> bunk...but that's how we learn sometimes. Once I move I should be able to >> setup a proper work bench where I can tinker on this sort of thing more >> intentionally rather than haphazardly. So perhaps a silly question for an >> expert but a valid one for me. I'll chase that angle and see if it bears >> fruit. >> >> - Matt G. >> ------- Original Message ------- >> On Tuesday, January 3rd, 2023 at 4:40 PM, Warner Losh &lt;imp(a)bsdimp.com&gt; >> wrote: >> >> >> >> On Tue, Jan 3, 2023, 5:30 PM segaloco via TUHS &lt;tuhs(a)tuhs.org&gt; 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… >>> 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(a)atvetsystems.com < >>> rob(a)atvetsystems.com&gt; 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 &lt;tuhs(a)tuhs.org&gt; 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(a)tuhs.org&gt; 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. >>> >>> >>> >>> >>> >>