#garfield Logs

Apr 03 2025

08:30 AM rue_mohr: heh, wow look at that stock market slip
08:45 AM rue_mohr: aandrew, I was stucked scrolled up about 3 days thinking nothing was going on
08:45 AM rue_mohr: I wonder how far it'll go this time
08:45 AM rue_mohr: oh interesting, the usd and cad are separating
08:45 AM rue_mohr: almost 4% slip
08:47 AM rue_mohr: settling somewhere near the consumption amount sourced within the usa
10:03 AM aandrew: rue_mohr> aandrew, I was stucked scrolled up about 3 days thinking nothing was going on
10:03 AM aandrew: hahaha
10:03 AM aandrew: irssi is nice in that the status bar has a "--more--" on the right side if you're scrolled up
10:04 AM aandrew: did you see my answering machine disassembly? the actual tape mechanism is very nicely separated from everything else, so some poking around should be able to figure out the pins to drive it without too much trouble
10:05 AM aandrew: gotta record some frequency sweeps at various amplitudes to characterize what the tape can actualy do (compared to what the main board would be doing to filter/limit the frequency response)
11:50 AM aandrew: rue_mohr: https://images.gatesnotes.com/12514eb8-7b51-008e-41a9-512542cf683b/34d561c8-cf5c-4e69-af47-3782ea11482e/Original-Microsoft-Source-Code.pdf
11:51 AM aandrew: altair basic source code
11:51 AM aandrew: might want to wait for it to show up on github though, that's literally photos of printouts
01:45 PM polprog: 15:35 < rue_mohr> polprog, do you have that multidata chart again?
01:45 PM polprog: which one?
01:45 PM polprog: rue_mohr:
07:03 PM rue_mohr: aandrew, the tape handler usually is, no, I didn't see it yet
07:03 PM rue_mohr: I suggest repurposing the orig head amp, the circuit not neccisarily the pcb
07:04 PM rue_mohr: aandrew, yea, I got that, I been comparing it with the nascom basic
07:04 PM rue_mohr: polprog, the stock one, usd:cad:eur
08:01 PM rue_mohr: aandrew, I cant find the images
08:07 PM aandrew: yeah I'll take a look at it
08:07 PM aandrew: um, they should all be up above
08:08 PM aandrew: https://ibb.co/rK2TH48G
08:08 PM aandrew: https://ibb.co/BHLkNTyX
08:08 PM aandrew: https://ibb.co/RpJj2JYT
08:08 PM aandrew: https://ibb.co/4nQ6Qk0X
08:08 PM aandrew: https://ibb.co/WvtW2YV2
08:08 PM aandrew: https://ibb.co/XfRcQRbR
08:08 PM aandrew: https://ibb.co/TDsDwVPn
08:08 PM aandrew: https://ibb.co/yxDKQpq
08:08 PM aandrew: https://ibb.co/pv1DDwdS
08:08 PM aandrew: https://ibb.co/mYcmVGm
08:08 PM aandrew: https://ibb.co/3Y8s7xLt
08:08 PM aandrew: https://ibb.co/Jjss9fLP
08:08 PM aandrew: nice little unit, mechanical bit is completely self contained (ALPS 5169?)
08:08 PM aandrew: https://datasheet4u.com/pdf-down/D/7/5/D75112CW_NEC.pdf looks like the microcontroller, I also see an 8-pin SPI flash in there (93C46), a 4089 DTMF generator, MT8870 DTMF receiver, and the TA31065 is a PSTN hybrid
08:09 PM rue_mohr: they usually are
08:09 PM rue_mohr: is that the motor speed or tape amp on it?
08:09 PM rue_mohr: must be motor speed
08:09 PM aandrew: motor h-bridge
08:10 PM aandrew: the heads are on a completely separate connector
08:10 PM rue_mohr: what did they use for an amp?
08:10 PM rue_mohr: must be smt...
08:10 PM rue_mohr: wow nice
08:11 PM aandrew: must be on the bottom, I haven't lifted the main PCB out yet
08:11 PM aandrew: didn't think to given how everything was PTH
08:11 PM rue_mohr: rememebr to work out the votltages they used for everything before you throw parts out
08:12 PM rue_mohr: yea, they will have an erase oscillator and read/write amp
08:12 PM rue_mohr: the write might be modulated
08:12 PM rue_mohr: so
08:12 PM rue_mohr: there is no solinoid?
08:12 PM aandrew: got some more stuff off ali today, just a bunch of linear servos for my son and also some apple authenticator ICs
08:13 PM rue_mohr: its rewind or play/record (fast/slow)
08:13 PM aandrew: I didn't see one but didn't take the tape mechanism apart beyond those photos
08:13 PM rue_mohr: oh I wanted to try to make some of those actuators
08:13 PM aandrew: it's possible there's a very small one for engaging that cam
08:13 PM rue_mohr: yea, mine has a huge one
08:14 PM rue_mohr: mine also has an eat-tape mode
08:14 PM aandrew: hahaha
08:14 PM rue_mohr: so, your going to make a stand alone, usb external tape drive with it, right?
08:15 PM aandrew: don't know if I'll screw with USB but yeah I was just gonna basically wire it up to an stm32 and have the stm32 do the signal processing
08:15 PM rue_mohr: :]
08:15 PM rue_mohr: so
08:16 PM rue_mohr: my method is a set/reset latch thats tripped by high/low spikes on the tape
08:16 PM rue_mohr: I can prettymuch save and record a serial data stream
08:16 PM aandrew: makes sense
08:16 PM rue_mohr: which is where I'm going with it for now
08:17 PM rue_mohr: tho its positivly not using all the bandwidth
08:17 PM rue_mohr: price of gas went down today
08:17 PM rue_mohr: but I hear the price of crude did too
08:18 PM aandrew: gas never follows crude that closely
08:18 PM rue_mohr: apparently cad follows crude
08:20 PM aandrew: hm
09:33 PM rue_mohr: I have to stay awake for 2 hours more
09:33 PM rue_mohr: I'm ponering learning how to sleep in a lazyboy