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Taijigamer

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Posts posted by Taijigamer

  1. Posted

    The flashing access light and and sled behaviour is classic for a laser struggling to read the disc. I haven't seen that flickering behaviour before. I would try to adjust the pot to try and get the laser to read the disc. What was the base resistance before u adjusted the pot?

     

    I would look into replacing the laser. Replacements are hard to find as there is no direct drop in replacement. The SF-92.5 is the nearest replacement but requires modding to work in the Panasonic 3DO. There were some direct drop in replacements available on AliExpress a few years back but I've had no response from the seller regarding restock. I'm looking into easy reliable solutions with the SF-92.5 but it could take time as I'm also in the middle of designing RGB mods for the 3DO.

  3. Posted · Edited by Taijigamer

    I've been meaning to open up my 3DO and get some values from the FZ-1 CD drive but life has been slowing me down recently. I'm not sure of the voltage supplied to the laser but its the current that's important. This post from 3doplanet explains measuring the current supplied to the FZ-10 CD drive http://forum.3doplanet.ru/viewtopic.php?f=17&t=701.

     

    post-61381-0-55854100-1503350087_thumb.jpg

     

    By measuring the voltage across R720 (FZ-10) we can workout the current supplied. According to the thread, 50-100mA is the norm for a healthy laser. I'm not sure what the equivalent resistor is on the FZ-1 but I will try to look when I next get a chance.

     

    The other option is to adjust the laser pot on the laser head. This isn't the best method but it may be a quick way to see if the problem is a failing laser. There is no set resistance that lasers come with as they are all calibrated slightly differently. Just take a baseline resistance reading of the pot with a multimeter and then reduce the resistance by 50 Ohm at a time, testing in between. Hopefully the laser should manage to read the disc. Just make sure u are testing with a retail disc with minimal scratches. I was going to recommend this video

     

     

    but I see u have already asked GadgetUK about the laser problem. He brings up good points, did u change the CD drive caps when u recapped?

     

    As for the service manual, I'm currently following a few leads and hopefully may be able to get hold of a copy. I'll post a link if/when successful.

  4. Posted

    I'm working on a RGB board using the BU3616K encoder. It's been done before by modders here and in Japan with success. Once I've finished designing and testing, I'll put out a post to gauge interest. I don't think Otakus store are producing any at the moment which has pushed me to develop and updated version. There is another member looking at the ADV7125 encoder as another solution http://atariage.com/forums/topic/260654-new-3do-rgb-mod-possibility/?do=findComment&comment=3808787

  5. Posted

    Are u still getting the 3DO logo at the start before black screen? I have a theory with this 3DO problem. The CD drive must be included somehow with the 3DO start up. When I remove my cd drive and try to boot the console, it behaves the same as yours.

     

    Either a malfunctioning cd drive logic board or a bad laser head could be the culprit. The way to test would be to get another known working panasonic 3do cd drive and attach it to see if the console boots. If you don't have access to another Panasonic 3do then attempting to replace the laser head could be your next option.

     

    If u have an oscilloscope, u could also make sure your psu is delivering stable voltages. A cap replacement won't always solve this as your voltage regulators etc could be faulty. I would look at the laser first though.

  6. Posted

    What currency are referring too? $130 - $150 seems like the common price at the moment. Depends on what they come with, games, controllers etc. Even faulty ones sell for $60. Then u need to be aware of importing models from other regions which may need a step down/up converter which will add to the price. It's a shame they cost so much but retro consoles have grown in price. I managed to get my FZ-1 for $60 as faulty but was easy to repair.

     

    I would shop around, hopefully a cheaper Panasonic 3DO will become available. I've heard that Golstar and Sanyo 3DO aren't as good as Panasonic.

  7. Posted

    Thanks for the link. His instructions refer to the Goldstar 3DO but the principals are the same. Here is the wiki link for the Panasonic FZ-1 caps and ICs.

     

    https://console5.com/wiki/Panasonic_3DO_FZ-1

     

    I haven't read about problems with the CD drive caps but it's worth a look. The more likely issue with the CD drives is Laser heads. These are SF-92.5 laser heads. They can be found easily enough but some may require modification to work in the CR-563 type drive.

  9. Posted · Edited by Taijigamer

    Hi, how's it going. I have seen this behaviour in some Panasonic 3DO where it will not boot to Bios screen. My Fz-1 does it when I remove the cd drive ribbon cables. This leads me to believe it might be a dead laser issue. Something is probably happening in the communication between the cd drive and the CPU which is sketching it out. Your psu and video encoder are working fine because u get the 3DO logo at the start of boot. The other reason could be the bios chip isn't getting the correct power which leans towards re- cap. The system is almost 25 years old sons laser replacement and re-cap is inevitable. The price we pay for maintaining antique hardware.

     

    Lasers are hard to come by. U will need an SF92.5 but they sometimes need modification.

  10. Posted

    Hope u get it sorted, man. Check this thread out for info on diagnosing and fixing FZ-10 psu

     

    http://forum.3doplanet.ru/viewtopic.php?f=17&t=209&start=60

     

    It's in Russian but easy to translat with Google. Those guys know their stuff. Going back to your original problem, I've been reading around and a lot of people have come forward with this issue although some get the 3DO logo for a brief second before a black screen. The same symptoms are replicated when I power on my FZ-1 without the cd drive connected. The console must do a POST before booting the Bios. Maybe a failing laser also causes an issue with booting.

     

    These consoles are now almost 25 years old so a laser replacement and a recap are inevitable. Good luck.

  12. Posted

    Unfortunately there is very little official documentation on the 3DO. I have tried to find the service manual but no luck so we have to troubleshoot as best we can. The first reading on your list should be 5~V AC, not DC. Your multimeter may have been looking for DC and got a 0v. Sounds like your Vp536 is fine. Next would be to check the voltage out on pins 32 (Luma), 34 (CVBS) and 36 (Chroma) of your VP536. This will tell if the graphics chip and encoder are pumping out video signals.

     

    Also check the voltage regulators on the mobo. We know the psu is good. If they are all good then it can point back to your CD drive. Has it ever been able to boot games or to the bios? Have u tried different retail games, are they for the same region? Have u tried getting a new laser? It's strange that it won't boot to bios.

     

    The other culprit could be bad capacitors which could be stopping the CPU/ bios chip from working properly.

  15. Posted

    My mistake. The pixel clk equation threw me off course. U are absolutely right, the pixel clk is that of the system, in this case the system is using a square pixel clk (14.75mhz PAL, 12.52mhz NTSE). So clk12i/o should be good to go and shouldn't require buffering. Square pixel refer to the pixel aspect ratio though, not the shape of the waveform.

     

    Sometimes the blanking level is also referred to as the back porch (probably erroneously). It's voltage level should be the same and therefore may provide your blank level reference.

     

    I've looked at your board designs, very nice. The data sheet recommends double terminating the Analogue outputs with a 75ohm resistor which I see u have done. It is also recommend with RGB to add a 75ohm resistor in serial along with a 220uF capacitor to maintain the 75ohm impedence and filter unwanted DC signals.

  16. Posted

    Very interesting idea. A couple of points to add, if I may. U mention buffering for TTL, the data sheet says it is TTL compatible, it isn't a requirement though. The levels of the digital RGB, sync and blank should be fine without the need for extra circuitry.

     

    The ADV7125 doesn't use a square pixel clk as far as I can see so using clk12i maybe out. U might needs a dedicated pixel clk, which would need buffering potentially.

     

    Sync can be stripped from luma and either sent straight to to/ monitor or fed back into ADV7125. If sent back to chip, it will be put into Green signal as Sync on Green which may be undesirable for some TVs/ monitors. If sent direct to TV, it will be 2 clk cycles out from RGB due to a pipeline delay in the DAC. Not sure what effect this will have but is something to consider. If sync is used directly, Sync pin on ADV7125 needs to be tied to GND. Also the VP536 produces HS and VS separately do maybe it's possible to get RGBHV working on a VGA monitor?

     

    Regarding blanking, again doesn't need to be TTL buffered. The LM1881 also strips Backporch from the video signal, this might be useable to provide blank level but I'm not sure. At this point some experimenting may be in order.

     

    Finally, regarding the Analogue out lines, u have tied them to ground using 75ohm resistors I assume. U may also need 75ohm resistor and 220uF capacitors in serial with those lines, this could be incorporated at the pcb end or in the SCART connector if using SCART.

     

    Hope this helps, I'm working on a 3DO at the moment with the BT910x chips so I may look at using one of your designs to experiment with. I'll let U know my findings.

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