InfiniteSquareWell

http://retroconsoles.wikia.com Hello everyone, I'm the administrator of Retro Consoles Wiki (there I go by ITEM-3), a brand new website whose goal is to collect all the scattered information for repairs and mods for all video game consoles, especially older consoles. This includes high-quality pictures of every revision of each console's motherboard, identification of the chips, and links to their documentation. Related information like controllers, accessories, flashcarts, console clones, and general tips for working with electronics will eventually be a part of it. The site is just over a week old and has mostly been an effort on 4chan's /vr/ board (thread: http://boards.4chan.org/vr/res/694016), and so there isn't much content yet, but it is an ongoing project, and more content is being added everyday. It's hosted on Wikia for now, but I will move the site to paid hosting if more people start using it. Here are a couple examples of the types of pages and guides that are currently on the site: Sega Genesis motherboard info: http://retroconsoles.wikia.com/wiki/Sega_Genesis_Hardware 3DO FZ-10 Repair: http://retroconsoles.wikia.com/wiki/3DO_FZ-10_Repair_-_Lubricate_the_Laser_Sled I'm here to spread the word about the wiki and see if anyone would like to contribute or make a request for specific content. If you have a complicated issue with a console that you have not been able to repair, I encourage you to create a page detailing the problem. I'd like to hear any suggestions you might have for the site as well. I hope to see you all there!

UPDATE: I may be on the verge of solving this problem and getting the 3DO to work again. I've been making careful adjustments to the potentiometer, and I've found a region in which the disc will be seen by the laser and begin spinning, albeit briefly. I can breathe easy now that I know the problem isn't with the spindle, it's for sure with the laser. What I need to figure out now if there is a magic position, a sweet-spot that will revive my 3DO, and I'm proceeding very cautiously. Even if no one can offer any help, I will still update this thread with my success or failure with as much detail as possible. Hopefully in the future this will benefit some 3DO owner with a similar problem.

Hi everyone, I need your help. I'm sure I've broken my model FZ-10 3DO, but I'm not sure if the problem is with the spindle motor or the laser. Some background: I just picked the 3DO up from a guy on Craigslist 2 weeks ago for $20. He thought it was broken, but after lubricating the tracks the laser moves along, I got it working again. However, it was having some problems reading some discs, and at certain points in certain games (always the same places), the game would freeze, the laser would go crazy, and the disc would spin very fast and eventually stop. I have good reason to believe that the problem was not with the discs, so I decided to try adjusting the potentiometer on the laser. I had never tried to adjust a laser's potentiometer before, but when reading about laser issues for the Dreamcast, I always read to adjust the potentiometer only a quarter of a turn, usually counter-clockwise. So I adjusted the potentiometer, tried a few games, and found that freezing occurred more frequently, and so I figured I went the wrong direction. First I returned the potentiometer to its original position and confirmed that the consoles behavior returned to normal. Then I adjusted the potentiometer a quarter-turn in the other direction. The game started to boot at first, but then the laser made violent sounds, and the spindle motor started spazzing out and even started spinning the disc backwards. I turned the 3DO off and returned the potentiometer to the original position. Now the disc will not spin, although the laser appears to be functioning, or at least it goes through the motions: the laser is active (I can see the red beam), it attempts to focus on the disc (lens moving up and down), and it will move along the track. According to this thread http://atariage.com/forums/topic/166045-3do-fz-10-laserlens-repair/ , if the laser cannot see a disc, the spindle will not spin. I'm hoping that instead of the spindle motor being dead, which I have no idea how to fix or replace, that the issue is a damaged laser which I could potentially find a replacement for. Do any of you have any ideas what's broken or how I can test the individual components? I've heard that I should just run a DC voltage along the spindle motor to see if it spins, but it is connected to the motherboard with a 6-pin ribbon cable, and so I'm not sure how to do this. Any help will be greatly appreciated!

I finally managed to borrow an oscilloscope for a brief time, but I still have not diagnosed the problem. Most of the oscilloscope waveforms provided by the technical manual were unhelpful since most were given for the blue game select screen, which of course I could not reach. I did confirm that the clock is working properly, and I did get signals for MREQ and IORQ on the Z80, and so I suspect that the processor works. I am now more suspicious of the BIOS chip, but I have no idea how to test it since the technical manual offered no advice on diagnosing a faulty BIOS chip. The schematics were extremely helpful, although I am confused by the depiction of the BIOS chip in the schematic. The BIOS chip only has 24 pins, but the schematic has pins numbered above 24. I assume the four unoccupied holes between the chip and the "U2" label have been included, but where does the numbering start? I'm guessing that pins 1, 2, 27, and 28 are the unoccupied holes, and that the first pin on the chip itself is pin 3. At this point, I'm about to give up. I cleaned the power switch just in case that was the problem, but it did not make a difference. Does anyone have any suggestions for testing the BIOS chip? I'm sure a logic tester would be helpful, but can I use a multimeter as a substitute?

Yes I have, although I expect the problem lies elsewhere since I should still see the intro screen without a cartridge inserted. Well, I'm not going to give up that easily. I will, however, put off the project until I acquire an oscilloscope. By your statement, I assume a replacement VDP chip would be hard to come by, and so the unit would essentially be lost if the VDP were damaged. What would cause shorts underneath the ICs?

When it was given to me, it had abandoned bug nests inside of it, the shielding was rusty, and the contacts were noticeably dirty. I did clean it then, and now it's not as bad as you would think. The peeled label is my fault because I thought at the time that you needed to remove the front panel to lift the top, and the three screws were underneath the label. The games all work, but their labels are brittle and falling off. I haven't cleaned the power switch yet, but I plan on doing so as soon as I find some dielectric grease for it. I've skimmed through the technical manual, and it's clear that I'm going to need an oscilloscope to test all of the chips. The manual provides troubleshooting flow charts for various problems, one of which is no picture. The chart asks me to check that pin 36 of the VDP is "good," but it does not say how to do this. Other indicated pins have oscilloscope graphs in a later section. That pin, however, is the monochrome Y output, and so I attempted to test it by touching the tip of an RCA cable to the pin with the other end connected to the composite input of an old CRT TV, and I appeared to just get a clearer black screen. I think it's outputting properly since the signal engages the screen, but I don't know how to check it properly.

Never mind my fifth question. I found the technical manual. (I would have edited my original post, but it seems I can only do so once.)

I have two Colecovisions, one of which works. I bought it after I received the first one, which I was told had spent about 20 years in a roofless shed in a hurricane-prone area. Needless to say, it does not function properly. Lately I have been getting into modding older game consoles (I just finished overclocking a model 1 Sega Genesis with a VA7 board), and so now I have turned my attention to repairing the broken Colecovision. The primary issue is that, upon turning it on, there is only a black screen with a constant tone. No BIOS screen is displayed. From what I have read on this site and others, this is a somewhat common problem without a clear culprit. That being said, I have played around with the Colecovision and have drawn the following conclusions: 1. The problem must not be the power supply, since it properly powers the working Colecovision. Also, the Atari 2600 module still works with the broken Colecovision, so it must be getting enough power. I have also tested this with a second power supply. 2. The problem may be the power switch, but I doubt it. Even when I would get the Atari 2600 module to work, it occasionally took a couple of turn-on attempts and some pressure on the power swtich. However, I have never seen the Colecovision BIOS screen appear, and I would assume that if the issue was just poor switch contacts that I would eventually get the BIOS screen to appear. 3. The sound chip works. This I assume because I still get a constant tone when I turn it on, and the tone isn't always the same. I'm guessing it's just outputting whatever random value it starts with. I've wondered if this implicates the CPU or the BIOS since I would assume one of the first things it would do is set the sound chip to output no sound. 4. The video chip probably works. I found that with a cartridge inserted, I could occasionally get random color bars to appear on screen after jiggling the power switch some or rapidly turning the console on and off. However, it's very rare that I manage to achieve this, and I only remember it happening from when I first attempted to repair the console a few years ago. At this point, I am unsure about how I should proceed, and so I humbly ask for your advice on this issue. Specifically, I want to know the following: 1. Which component is most likely to fail and cause this to happen? 2. If a chip has failed, I know that most of them are (or were) common and could be replaced, but what about the BIOS chip? I'm sure these can only come from other Colecovisions, and I would prefer to repair mine with destroying another. If I do need to replace the BIOS chip, would it be possible to create a custom chip? 3. Could it be a capacitor? I've never encountered a faulty dielectric capicitor, but I've read that their tops puff out when they leak. How visible is that effect? 4. What can I do to diagnose the problem? If need be, I might be able to borrow an oscilloscope. 5. I've seen mention of a Colecovision service manual which gives detailed information on how to test each of the components. Does a .pdf of it exist anywhere? Any input on this problem would be much appreciated.