x68000:soft_power_switch_troubleshooting_and_repair
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| Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision | ||
| x68000:soft_power_switch_troubleshooting_and_repair [2012/11/21 00:17] – eidis | x68000:soft_power_switch_troubleshooting_and_repair [2012/11/21 00:31] – eidis | ||
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| The problem might be due to a signal that is always stuck Low. | The problem might be due to a signal that is always stuck Low. | ||
| - | If you look at the Buffered IO part in the schematics, 3 of these signals are connected to the MFP GPIP port. They can be queried via software and are connected like this : | + | If you look at the Buffered IO part in the schematics, 3 of these signals are connected to the MFP GPIP port. |
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| + | **They can be queried via software and are connected like this :** | ||
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| *Bad IC28 (74LS08) (stuck output). | *Bad IC28 (74LS08) (stuck output). | ||
| *Bad Q9 transistor (shorted). | *Bad Q9 transistor (shorted). | ||
| - | *Bad C64 (generating noise). | + | *Bad C64 capacitor |
| *IC29 (74LS244) might have bad output on pin 5. | *IC29 (74LS244) might have bad output on pin 5. | ||
| *The power signal from the main board, which I miss infos actually. A fix to this could be soldering a 10K ohm resistor between IC28 pin 10 and 14. | *The power signal from the main board, which I miss infos actually. A fix to this could be soldering a 10K ohm resistor between IC28 pin 10 and 14. | ||
x68000/soft_power_switch_troubleshooting_and_repair.txt · Last modified: 2019/08/27 20:45 by 127.0.0.1