airbone Posted January 27, 2017 Share Posted January 27, 2017 Hi Folks, I am new here. Decided to revive one old forgotten game gear. When found after lying for years in attic (exactly for 16 years). The system was sort of running - but had corrupted display and off course hardly visible due to leaky caps. So what I did was I ordered new better screen from McWill here at the forum and installed everything... Had some issue that system was shutting down quickly after powered on. That revealed to be a problem with weak power supply which was not original and only 300mA. Of course I have "recapped" that GG completely. And what happened..? Now GG runs, McWill display runs, sound sounds... but... all runs slow! I mean, the game runs very slow like GG was underclocked to half CPU speed or even less.... Also music plays half-speed, I hear ding-nothing-dong-nothing etc.... Initially I thought that it could be faulty cartridge, but today I have tested it in another GG with original screen and it runs ok... Just that damned GG runs it half-speed.... I can't really say if that problem was present before I did screen and recap, since I only powered it up for a test and screen was corrupted... Anybody has an idea what the hell that could be??? or head of such an issue??? also that GG shows some SEGA disclaimer on start-up for a few seconds followed by SEGA logo, while the other GG doesn't show it and shows SEGA logo only... but I guess that has to do with different version or whatever... So any suggestions ? Quote Link to comment Share on other sites More sharing options...
briwayjones Posted January 27, 2017 Share Posted January 27, 2017 (edited) You said you haven't recapped the whole thing? Maybe it's somehow a bad cap that you haven't replaced yet? But I'm not knowledgeable with the electronics really so I don't even know if that's a possible cause. Edited January 27, 2017 by briwayjones Quote Link to comment Share on other sites More sharing options...
Flojomojo Posted January 27, 2017 Share Posted January 27, 2017 Needs a new Blast Processor. (Sorry, I got nothing ...but I admire your interest in restoring old game hardware that most people would just chuck) Quote Link to comment Share on other sites More sharing options...
airbone Posted January 29, 2017 Author Share Posted January 29, 2017 Yes, this piece of hardware was priceless few years ago, but now I have strong interest to get this thing working, even though I do not know why McWill, the guy who sells improved display kit for GG, suggested to measure few capacitors and resistors responsible for CPU clocking. DOne that, all was ok and also replaced Quartz Oscillator, but problem persists... Will try to think of what else I can do before I use different mainboard. I will keep you posted here. Quote Link to comment Share on other sites More sharing options...
Saroulepourvous Posted December 30, 2019 Share Posted December 30, 2019 Hi Airborne, Nearly 3 years after your last post, I have the same problem you encountered. My GG seams to be very slow after installing MCWill new magnificent screen. Can you please tell me how you solved your problem? Many thanks for your help Jerome Quote Link to comment Share on other sites More sharing options...
anthotho Posted February 24, 2020 Share Posted February 24, 2020 On 12/30/2019 at 12:21 PM, Saroulepourvous said: Hi Airborne, Nearly 3 years after your last post, I have the same problem you encountered. My GG seams to be very slow after installing MCWill new magnificent screen. Can you please tell me how you solved your problem? Many thanks for your help Jerome Hello, I also have the same problem, did you find a solution? thanks Regards Anthony Quote Link to comment Share on other sites More sharing options...
Jumbo Posted April 3, 2021 Share Posted April 3, 2021 Hello, the key question here is what is the board you are installing onto. For example 837-7996 and also where the board was manufactured e.g Japan or Taiwan. The Taiwan version has a lower crystal oscillator speed of 10.7386. Also posting pictures of your wiring will help identify any problems. Quote Link to comment Share on other sites More sharing options...
Paul Maidment Posted February 17 Share Posted February 17 I found this page because I ran into the same issue. You need to make sure that the R24, R25, C39 and C40 components (VA1 Taiwan) are correctly attached and are of the correct value. These components are used as part of the clock circuit. Some of the older McWill guides mentioned changing things in this area. I don't think you need to do this for more modern screens. I made the mistake of removing the components, replacing them again when I realised my mistake (thankfully I had a donor board) But I made a mistake when soldering and discovered that I had a slow CPU. A quick "reflow" of these components later and everything is back to the correct speed. Just thought I would share. Quote Link to comment Share on other sites More sharing options...
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