Showing posts with label Mac SE/30. Show all posts
Showing posts with label Mac SE/30. Show all posts

Tuesday, December 8, 2020

Recapping a Macintosh SE/30 and a IIsi logic boards and the IIsi power supply

Many vintage (15+ years) electronic boards (PCBs) are at a higher risk of having its non-solid electrolytic capacitors leaking by now. Such leaking occurs regardless of whether the component is actually being used/energized (although storage conditions may further contribute to the component degradation). The leakage happens due to natural aging of the component sealing and/or internal corrosion within the capacitor. The consequence of such leakages can be catastrophic not only for the capacitor itself, but for the electronic board as a whole. Here is why...

The most commonly used capacitor (aka caps) in computer logic boards and power supplies are the non-solid electrolytic capacitors, which use a liquid or gel as electrolyte. The problem is that the electrolyte liquid/gel used in these caps are conductive and corrosive and both these characteristics do not go well if spilled over your PCB. Therefore, when these capacitors leak, they can cause:

1) The PCB to malfunction by creating electric contact (short circuits) between components that were intended to be connected. Depending on the short circuits created by the conductive liquid, it could completely burn components and even create holes in the PCB, potentially damaging the board beyond repair. 

2) In addition to shortening components, the corrosive nature of the electrolyte will (with time) corrode the copper traces on the PCB as well as the components terminals to a certain extent. The electrolyte will also cover the solder joints creating a crusty layer that shields the solder joint from heat, requiring you to add more heat to be able to remove components (by desoldering).


Macintosh IIsi Power Supply with leaky capacitors

Sunday, October 18, 2020

Exploration into the Retr0bright world...

Hello everyone! I would like to share my experience restoring old computers to its original (or close to) beige/grey colour. 

If you are reading this post, chances are that you know what retrobright (or retr0bright) is. In any case, here is a short explanation: ABS plastics were largely  used in computers and game consoles in the 80s, 90s and early 2000s. Plastic manufacturers mixed bromine within the ABS formula to give these plastics fire retardant properties. With time, these ABS plastics turn yellow due to a chemical reaction between the bromine and UV light (radiated plenty by the Sun and also fluorescent lights among other sources).

The state of my vintage Apple keyboard prior to the process


Sunday, August 30, 2020

My first Macintosh SE/30!

The Macintosh SE/30 is considered by many the holy grail of the Classic Macs. It is the fastest and most expandable of the classics 9" B&W form factor Macintoshes. It can accept up to a whopping 128Mb of RAM (!!!), what is impressive for a machine that was released back in Jan/1989.