A few years ago, when Xiaomi was making its Dafang WiFi camera, I bought two of them for a relatively low price. Since then, before every family vacation, I’ve set up one of them to
spy on monitor our cat during the day before the cat sitter comes to take care of her in the evening.
The Xiaomi Dagang wifi camera.
The main argument for this camera is, of course, the availability of a hacked firmware that disables any “cloud” access. This year I felt lucky and decided to upgrade to the open source u-boot bootloader first. I am still not sure what I did wrong, but I ended up with a bricked camera that no longer connected to my network. To fix this problem, “You will need to desolder your bootrom, reflash it and solder it back,” as the update instructions happily announce.
The refurbishment and repair of the C16 and Plus/4 motherboards is largely complete. Next up is a small stack of C128 boards. Recently I received a C128 diagnostic cartridge with harness as a donation, which was also only slightly tattered.
The C-128 Diagnostic Test cartridge that was donated
It was a “C-128 Diagnostic Rev 1.4” with harness “ASSY NO. 325093-01”, which I had never heard of before. Information on this cartridge seems sparse, but I found it mentioned on Jani’s page on diagnostic carts and in an older forum thread (German).
In my previous post I described in detail how I created a ROM replacement for the Commodore Plus/4 computer and how I made sure that it would fit into the very tight space of the closed case.
Five in a row: The four ROM chips of the Plus/4 to the left and the PLA to the right.
The four ROM chips of the Plus/4 are sitting all in one row, and then there is a fifth IC right next to them: the 251641-02 PLA. This PLA chip is the same for all TED based Commodore computers, the C16, the C116, and the Plus/4. In the past, I used the excellent PLA16V8 from D. Mantione as a replacement. The PLA16V8 is quick to build from cheap parts that are easily available. And for a C16 with it’s roomy case, it’s a perfectly adequate solution.
The original PLA16V18 is much too tall to fit under the keyboard of the Plus/4.
With the Plus/4, however, it’s all about space again: There are only a few millimeters between the original PLA and the keyboard above it. So while the PLA16V8 works fine on a Plus/4 motherboard, it is far too tall to fit inside the Plus/4’s case.
Recently, I’ve been repairing a few broken and slightly weathered motherboards for Commodore C16 and Plus/4 computers.
Despite its stylish design, the Plus/4 was no success for Commodore.
When I ran out of spare parts, I replaced the defective Kernal ROM on one of the Plus/4 boards with a W27C512 EEPROM. You can still source a used W27C512 easily and somewhat cheaply (on eBay, for example), making it my all-purpose tool for replacing ancient parallel ROMs.
I’ve been meaning to build myself a mouse adapter for the Commodore 64 for quite some time. The recent release of the unofficial port of “Eye of the Beholder” for the C64 was a welcome excuse to finally get to work on this project.
The Mouse 1351 made by Commodore can be plugged directly into the control port of the C64 or C128 and it has two different operating modes. In joystick mode, the input from the mouse is compatible with that of a regular, digital joystick. In proportional mode, which is the default, it behaves and feels like any mouse used on modern computers.
Commodore Mouse 1351. (Image source: Wikipedia, License: CC BY-SA 3.0)
Around this year’s Black Friday I noticed the “Hama 176584 WiFi LED-Bulb” on sale for as low as €2.49 with free shipping here in Germany. Although Hama doesn’t mention it, chances were high that such a dirt-cheap device would be using the Tuya platform.
Recently, I got hold of quite a few broken Commodore 64 motherboards. It has been a while since I last had the chance to repair one of those boards and it was fun! I dubbed this repair project the “Blank Screen Marathon” and documented the whole process in German on Forum64. I might still give a summary in English here at a later point. But today, I’d like to introduce a small side project that resulted from this repair marathon.
The 3 ROM chips on a C64 motherboard
It’s been over four years now that I created the SyncFix64 module in order to connect a cheapo car TFT display to my C64. This setup has served me well and it helped me repair quite a few motherboards since then. A few years later, when I got my first VIC-20 the display again failed to show anything despite the integrated SyncFix64 module. That was kind of disappointing, but I was lacking time and motivation back then to investigate further.
Composite video signal from a C64 as opposed to…
The ZX81+38 is a clone of the Sinclair ZX81 home computer that replaces the ULA found in the original with standard logic ICs. That means, it can be built with all parts still readily available today. It was created by Mahjongg, introduced on a forum dedicated to Sinclair computers, and document on the web with construction files available on Github.
The empty PCB as I received it.
Pagefox is a DTP (desktop publishing) software that comes as a cartridge for the expansion port of the Commodore 64. It was developed by Hans Haberl — who also created the graphics editor Hi-Eddi and the word processor Printfox — and it was published and sold by the small German company Scanntronik which is actually still in business today.
Pagefox cartridge pried open