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   Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:29:01 JST Davide Bucci

   I could save an #IBM model M #keyboard that was about to be sent to the e-waste. It is the dirtiest keyboard I have ever seen 😅 But it works and will be cleaned. It is in a good shape, too! #mechanicalkeyboard

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     botvolution (botvolution@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:28:55 JST botvolution

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     @davbucci
     Is that a DIY capacitance tester?

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:28:56 JST Davide Bucci

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     The screen is also horribly dirty. I opened it (after buying a set of long security Torx bits). Its electronic circuit is quite simple, as it’s a monochrome monitor, yet it is not very nice to work on: you have to disassemble almost everything to check components. I was suspicious of the capacitors and the TDA1170 that controls the vertical deflection. #repair #IBM #monitor

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:28:56 JST Davide Bucci

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     Ah, here’s the culprit! A 470uF capacitor in series with the deflection joke vertical coil reads about 1/10 of the rated capacitance. The TDA1170 is perfectly fine! That was an easy repair. #IBM #repair #retrocomputing #capacitor

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:28:58 JST Davide Bucci

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     I can now start trying to repair the #IBM PS/2 model 30 computer. After a deep clean and a global check, the computer starts, but both the disk drive and the hard drive do not work. The screen, a nice #IBM8503 002, does not work properly, neither: the vertical deflection is very distorted. #retrocomputing #IBMPS2 #repair

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:28:59 JST Davide Bucci

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     Well, I could put together again the #IBM model M keyboard. Now it is very clean! I also got an USB to PS/2 converter and it works very well. I love the feeling when I am typing. Just one ALT keycap cover is missing. Love it! #mechanicalkeyboard #retrocomputing #IBMtypeM

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:28:59 JST Davide Bucci

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     I mean, look at that beauty 😍 #IBMmodelM

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:29:01 JST Davide Bucci

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     I could also save the computer that went with the keyboard, an #IBM PS/2 model 30 with a screen that seems to be monochrome. I could not resist saving also a #SUN #SPARCstation 5, that I found there. I don’t know if they work, and they stayed one night under heavy rain. I will check them also to remove #batteries. #retrocomputing

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     Davide Bucci (davbucci@mastodon.sdf.org)'s status on Friday, 16-May-2025 06:31:04 JST Davide Bucci

     in reply to

     • botvolution

     @botvolution yes, it can do in-circuit measurements, too. I use it quite frequently for repairing things. Capacitance measurements can not be precise when done in circuit, but it helps spotting strange things. https://github.com/DarwinNE/EsrMeter