jit
Deep Blooper
Posts: 8
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Post by jit on Oct 22, 2021 21:43:19 GMT
Hello, I recently bought a Duo-R model. If I put a Hucard game, it works very well : good picture, good sound, etc. But if I don't put a hucard, I get a white screen instead of the bios. I tried to load systemcard 2 and 3 from my Turbo Everdrive but this produced a black screen with a strange and short "bip". The motherboard is very clean with no mod (seems brand new). So I don't know what check I could do. s I first thought that it could be some capacitors, but they all look normal and if I understood correctly, the Duo-R and RX don't really have capacitors problems. I searched several times on the internet, but it seems difficult to find duo-r problems and answers. My kind of "last hope" is here  any clue or advice ? |
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keithcourage
Punkic Cyborg
https://www.facebook.com/turbografxfan/
Posts: 220
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Post by keithcourage on Oct 25, 2021 3:33:15 GMT
This problem can be caused by a few different things.
1st thing to check is if both 7805 Voltage regulators are producing 5V. Sometimes the 2nd one can go bad in which case the Bios won't load. I hope this is your problem because the other possibilities are harder to fix.
2nd option, bad trace or connection on the board. This could be in a number of places but more often than not, it's a bad trace above or below the hucard slot.
3rd option. Faulty chip on the board.
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jit
Deep Blooper
Posts: 8
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Post by jit on Oct 25, 2021 6:51:44 GMT
Thank you for your help.
I tested the two voltage regulators, and they are working.
I guess I will have to remove the hucard shield and check the traces over there.
I also found that 2 transistors in the CD-ROM region was not giving any voltage (in nor out), but I don't know whether it is normal while the cd part is not running
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keithcourage
Punkic Cyborg
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Posts: 220
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Post by keithcourage on Oct 26, 2021 1:01:18 GMT
Check for Bad traces just above the Hu card slot on the bottom of the board. The traces going to these chips postimg.cc/QKbHwwKf |
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jit
Deep Blooper
Posts: 8
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Post by jit on Oct 26, 2021 8:03:50 GMT
Thank you for the tips, I will check that in a few days (I'm not at home for now)
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jit
Deep Blooper
Posts: 8
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Post by jit on Nov 1, 2021 14:05:12 GMT
I found that the pin 26 of the hucard slot is not wired to IC517. The trace seems to go under the ic517c but I can't see where it is supposed to go.
Do you know if the pin 26 should be wired to any pin of the IC517?
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jit
Deep Blooper
Posts: 8
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Post by jit on Nov 2, 2021 21:02:12 GMT
Hmmm, I may have a new clue. I tried a game that handle save in another machine (a DUO).
The working console show a "backup" menu, but the same game in the DUO-R do not display this backup menu. Maybe somehting is wrong around the chip that handle saves ?
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jit
Deep Blooper
Posts: 8
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Post by jit on Nov 5, 2021 13:46:27 GMT
I don't have the console anymore, so I won't update this thread anymore.
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keithcourage
Punkic Cyborg
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Posts: 220
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Post by keithcourage on Nov 8, 2021 1:11:17 GMT
Sorry I didn't see your post sooner. It could be bad traces to the NEC D91317GD chip or a bad chip altogether.
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any clue or advice ?
