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software error,master system game
Posted: Sun Apr 02, 2023 9:23 pm
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Attempting to fix a master system game that shows ''software error''
measured the values in diode mode from the ground to every pin on the chip and in one pin shows the value of ''1'' the rest are 8 to 9 Did the trick with the 1k resistor and although the value now is on 9 still nothing have reflowed the chip and checked continuity to every pin on the board Have fixed a couple of mega drive games that way but with master system dont work any ideas if its fixable or the chip is fried? its a cheap games anyways i just do experiments Thank you |
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Posted: Mon Apr 03, 2023 6:12 pm |
What's the "trick with the 1k resistor"?
From your photo looks like that could be the A5 pin, although I'm not sure from your description about measurement what might be wrong with it. Diode modes can vary a bit on multimeters in terms of what they display. Can you measure the resistance in ohms between that pin and both pin 14 (gnd) and pin 26 (vcc)? If either are zero or very close to zero then there's a dead short and I'm afraid little you can do to resolve. It looks like you have some solder filaments or other crap between a few pins, possibly as a result of your reflowing. Worth cleaning up as much as possible to exclude some new problem from the reflowing. |
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Posted: Mon Apr 03, 2023 7:26 pm |
Some Megadrive cartridges can be fixed in this way by adding a 1k resistor at pin 8.
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Posted: Mon Apr 10, 2023 12:51 pm |
Hi @nick_rx8 - I'm replying to your DM here as I don't think I can attach files in DMs (at least not from my mobile device I guess)
Firstly, there are two ways to reply to threads that I know of - you can hit the reply button right at the bottom left of the screen; or you can hit the quote button to the top right of any previous post. I have attached screenshot of both below. Secondly regarding the readings you took, I must apologise but I made a mistake about the pinout of this device so I'm afraid those readings won't be useful. Taking a step back can you first confirm a few things: 1) That we are dealing with a chip marked 315-5208? I'm almost certain this is the case but best be completely sure. 2) That your previous testing (on your first post) identified pin 1 as potentially faulty - i.e. the one with the square pad, top left of chip as you look at it from the front? 3) That you have definitely cleaned the strange looking gunk / potential solder shorts between pins 5, 6 and 7 and any other pins that look contaminated; removed your resistor mod and checked the cartridge again? P.S. this might be a useful reference when communicating about pin numbers: https://www.smspower.org/uploads/Development/315-5208.gif |
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Posted: Mon Apr 10, 2023 3:56 pm |
It's not for MS but this saved 2 of my Megadrive games ! Thanks !!! |
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Posted: Wed Apr 12, 2023 2:03 pm |
That wouldn't be a fix for Grind Stormer, would it?
(a rather in demand Genesis game known for randomly failing) All people had last I heard of it years ago was "swap the ROM chip to a donor PCB and it works again". |
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