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   Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:52 JST Miguel Arroz

   Starting to look at the ImageWriter to get it ready for #MARCHintosh. Managed to pop out the board through the bottom panel after disconnecting the printer head cable and a lot of other connectors. Aside from the dust it looks OK! I had never seen a 15000uF cap…

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     Paul Cantrell (inthehands@hachyderm.io)'s status on Sunday, 28-Dec-2025 12:08:47 JST Paul Cantrell

     in reply to

     • Chris Espinosa

     @arroz @Cdespinosa

     Oh!! I think that may be the exact model we had when I was a kid. That dot matrix sound takes me back instantly!

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:48 JST Miguel Arroz

     in reply to

     It has been a while since I plugged in one of these cables. And PowerBook still works!

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:48 JST Miguel Arroz

     in reply to

     WOW! It prints! And I don’t mean “the printing head works”. I mean it ACTUALLY prints! The ink is not dry after decades, literally, decades of being stored in a closet! I’m speechless and giggling! Folks, how do I share this thing on #globaltalk?

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:49 JST Miguel Arroz

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     Ok folks are saying the low resistance is normal because it’s a transformer so the electromagnetic fields will do their magic and not draw 11 amps. So you know what, let’s dooooooo it! Preparing for powering this thing on for the first time in who knows how many decades.

     May I note that none of these caps have pressure relief vents so there’s potential for fun here.

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:49 JST Miguel Arroz

     in reply to

     • Daniel Tufvesson

     OMG it works! 😁 At least the basics. Let’s wire this thing to that thing and see what happens.

     Also as @danieltufvesson suggested, the transformer has two inputs, one for 220V and one for 240V, and because Portugal used to be 220V, that’s what this printer is wired for. We are now at 230V so I should rewrite this which will be a problem since I need to figure out how to get to the transformer.

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:49 JST Miguel Arroz

     in reply to

     As curiosity, here's the voltage and frequency here in the past 24h (on a different phase, though, because I still didn't get rid of the dumb three-phase system at home):

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:50 JST Miguel Arroz

     in reply to

     Heh look at this old diodes!

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:50 JST Miguel Arroz

     in reply to

     Ok so I measured the resistance between the two AC poles and it reads 19 ohm. That is waaaay too low. Not gonna plug it in yet.

     There are a few things I assume are filtering caps inside a sleeve next to the transformer which may be bad, but I can't get to it from the PCB panel.

     I think I found a way to pop out the top plastic case, but I can't get to the screws without removing a lot of the printing mechanism, and I'm not sure I want to do that… at least not today.

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:50 JST Miguel Arroz

     in reply to

     I measured the huge caps (in circuit) and they seem fine, so there's that.

     I'll continue another day, after a bit more research on how to open this thing properly. But we'll get there, hopefully!

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:50 JST Miguel Arroz

     in reply to

     Meanwhile if anyone has an ImageWriter (even a II or LQ), can you discharge the capacitors (by pressing the power button to turn it on *after* unplugging the mains cable) and then measure the resistance between the two AC power cable poles, and let me know how much it measures? Thank you!

     Doesn't need saying, but MAKE SURE NOTHING IS CONNECTED TO THE MAINS. I want you to measure the poles of the AC cable connected to the printer, not the mains! Don't do it unless you know what you're doing.

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:51 JST Miguel Arroz

     in reply to

     This uses an Intel 8085 as its main CPU plus some Toshiba fancy RAMs.

     There are two spots on the board with some weird stuff. Rust? Just dirty? Not sure what they are, there are no caps or batteries nearby that may have leaked.

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:51 JST Miguel Arroz

     in reply to

     Just dirt. IPA took it out. I wonder is I should recap first or just turn this thing on… maybe I recap the smaller caps with the stuff I have around and leave the huge ones in place? Huummm…

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:52 JST Miguel Arroz

     in reply to

     Well, this screw is not cooperating. Kinda hard to dust this and do more work inside without disconnecting this ground cable. 😖

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     Miguel Arroz (arroz@mastodon.social)'s status on Sunday, 28-Dec-2025 12:08:52 JST Miguel Arroz

     in reply to

     • Luis Correia

     It’s out! Thanks to @luisfcorreia since I didn’t realize this was a terminal.🤦♂️