repairs


Inter-space (re)build: Asteroids

Long ago in a space far, far away, the Quelab crew had a means of amusement: Asteroids.

A donation from Adric, the Asteroids cabinet has seen its fair share of hands across its buttons: life at, presumably, an arcade and then later at Southwest Cyberport, it was brought to Quelab after it just didn’t have any more go in it. Never one to give up, we replaced the required parts, added a high score save kit, and pounded out more hours on it, racking up high scores in the 15,000 range. Some time later, we moved, and the cabinet stayed dormant: Nobody really wanted to play it much anymore. The buttons had been abused and left in a sorried state, dust had crept in, and the final straw came when a known issue with contact corrosion had made the board unable to boot again.

That is, until someone decided to fix it. Morgan G. (myself) and Ben L (of Black Lodge Research in Redmond, WA) decided to dig in and, over a weekend, get the thing up and going properly. Some preliminary work had gone into getting it working again.

So, what needed to happen? Just some cleanup, love, and a bit of attention. New fuses, cleaned contacts, and lots of reading schematics later made it clear what the problem was, and some new features we could add in for fun, and a beautiful, well-loved cabinet was given new life.

We left a note to anyone who opens the cabinet up in the future, as well as a copy of the manual, reproduced in true Atari form, plus some spare parts.

The root cause of the cabinet not working is a well-documented flaw in power supplies that use a sense line: the sense line needs to be really good in order for the whole thing to work, and if it isn’t, there’s a good chance the PSU will just cause problems. In an ideal world, they’re self-regulating; From an EDN article on the topic:

The remote sense function automatically increases the output voltage at the output terminals of the supply to compensate for any unwanted voltage drop in the output cables with heavy load currents. Likewise, the remote sense function decreases the output voltage of the supply when the required load current is reduced. In some applications, the power supply’s output needs to be adjusted by the user to voltage higher than its nominal (e.g. 5V nominal, adjusted to 5.5V). Always adjust the power supply’s output while measuring the voltage at the load.

The EDN article concludes saying these are only really useful in extremely high load environments (read: not the environment that Atari had been building for) and should be avoided in newer designs. Perfectly reasonable in Atari’s days, but we’ve learned new things about how the world works. It’s bad enough that bypass hardware exists for these since a bad sense line can cause insane voltages (40-80V!) when they go bad.


Floor Resurfacing (CLOSED 2-4 APRIL)

Greetings everyone; the Tsar of Maintenance here…

Quelab is not closing for good, but we do have to close the space temporarily for a few days in the first week of April. As part of the work that our landlord originally scheduled for November (before we were supposed to be moved in) we were going to have the tile floors in the lab cleaned and sealed…they’ve finally gotten around to doing it.

This means we have to remove everything from the floor in these rooms so the contractor can come in and work on the floors. Then we can’t walk on them for a day or two while the sealant cures. The rooms affected will be 1, 49, the Core, the Kitchen, the hallways, and the bathrooms. Since this covers our exterior doors and most of the lab space itself, we have no choice but to close while this is done.

To this end, Quelab will be closed from 2 April until 4 April (the week before the general meeting). Additionally, we will need help at the hacknights on 1 April and 30 March to move all of the contents of these rooms out to make space for the workers, and then help again before the general meeting on 6 April to put everything back.

Sign up to help with the moving in the linked gDoc, and in the words of Douglas Adams “we apologize for the inconvenience”.