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The Problem My Macintosh Classic II suffers from an issue where the display CRT goes dim after a few minutes on a cold boot. Every time it happens, I need to crank up the cut-off and brightness  pot behind the machine to show the image. The Analyze At first, I thought it must be the brightness issue, so I searched for the Macintosh Classic analog board schematic to check the brightness line. I found the schematic from Bomarc, and the schematic is suitable with my board, since there are two analog board versions.  I started to suspect the resistors and potentiometer on the brightness line. This Macintosh version has software-controlled brightness, so the analog board will get a 22.25 kHz square wave PBM signal from the logic board to control the brightness. I checked and replaced some resistors and cleaned the potentiometer, but nothing seems to work. The signal is there, and no sign of degradation that makes the screen dim after a few minutes.  Brightness Line So I suspec...

I got this beautiful old keyboard from my friend, it is an Apple mechanical keyboard from 1986. Why do I love this keyboard? because it’s mechanical, and I believe that a mechanical keyboard has a longer age than a membrane keyboard. The keycaps mostly use PBT plastic, but the plastic cover case and the space button are made with ABS plastic so they are yellowing over time. So I decided to restore the plastic using an H2O2 solution. Before Restoration This is the picture before the restoration PCB Inside The Cover Apply 12% H2O2 Solution Result I got no photos of the keyboard being under the sun, so here is the result after a couple of hours under the sun. Maybe it can be more white, but the current weather is cloudy and not very good for retrobrighting, maybe I need a UV light to do indoor retrobrighting.

28 April 2023 I found a nice and complete collection of Macintosh Classic II. It included the Mac itself, keyboard, mouse, and an external 800k drive. Someone sold this thing on Instagram, and then I contacted the seller to ask about its condition. He said that it was first hand from his uncle and last January 2023 it was tested okay and running. But currently, he didn’t have the power cord to test it. So I decided to gamble to buy this old machine, I hope that the internal battery is not leaked or better it has already been removed. It was manufactured in October 1991, which was before I was born 🤣 After dealing with the price and shipping charges, it then shipped with cargo to Yogyakarta from Bandung. My concerns were the internal battery and the CRT. I hope the CRT is not broken by the shipping. He said that he added more plastic wrap to protect the CRT. 1 May 2023 At noon around 1 PM, I was contacted by the cargo courier that they will send a package to my home, and they need me t...

Saya mendapatkan kalkulator HP 32S ini dari toko @lokal_shot yang ada di instagram. Kondisinya lumayan mulus, ada cat yang terkelupas namun bodynya tidak ada tanda pernah dibuka sebelumnya. Namun pada layar LCD nya sudah burn-ed pada lapisan reflektor belakangnya. Biasanya polarisator belakangnya juga terkena jadi lcd nya gelap sekali. Semua tombolnya masih berfungsi bagus dan tidak ada korosi pada bagian baterai. Akhirnya saya bongkar dengan susah payah, karena kalkulator ini tidak menggunakan sekrup, namun menggunakan cokotan yang berada pada atas kalkulator dan dibawah. Harus dengan power extra untuk mencongkel namun juga harus extra hati - hati sehingga tidak merusak komponen lain.  Berikut adalah penampakan isinya kalkulator HP 32s, PCBnya tanpa dicat sama sekali. sangat sedikit komponen, hanya processor dan tantalum saja yang terlihat. Semuanya proses perhitungan dihandle oleh prosesor. Pada bagian belakang PCB juga tidak terdapat komponen lain. Berikut penampakan LCD ketika ...