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--- x68000:soft_power_switch_troubleshooting_and_repair [2012/11/20 23:53] – eidis
+++ x68000:soft_power_switch_troubleshooting_and_repair [2019/08/27 20:45] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-===== Soft power switch troubleshooting and repair =====
+===== Soft-power troubleshooting and repair =====
-The following information is kind contribution by our forum members **Lydux** and **Caius** and this fix was applied to X68000 ExpertHD and SUPER.
+The following information is kind contribution by our forum members **Lydux** and **Caius** and this fix was applied to X68000 SUPER and Expert HD.
-The symptoms: X68000 powers on fine, but does not shut down when the soft-power button is pressed. The screen fades, Power LED does not change from Green to Red and the system fan keeps spinning. The same happens with a regular ATX PSU.
+**The symptoms:** X68000 powers on fine, but does not shut down when the soft-power button is pressed. The screen fades, Power LED does not change from Green to Red and the PSU fan keeps spinning. The same happens with a regular ATX PSU.
 If this is your case then the problem is almost surely located on the IO board.
@@ Line 11: / Line 11: @@
 {{:x68000:soft-power_schematic.png?400|}}
-A condition using 4 signals is used to get the X68K turn on/off correctly :
+**A condition using 4 signals is used to get the X68K turn on/off correctly :**
-  *Via the front power switch (/PSON)
   *Via the RTC (Real Time Clock) alarm signal (/RTC_ALARM)
-  *From the expansion bus (signal /EXPWON)
+  *From the expansion bus (/EXPWON)
-  *A signal from the system controller (the soft sequence signal /MPWOFF).
+  *Via the front power switch (/PSON)
+  *Via the soft-sequence signal from the system controller (/MPWOFF)
-In normal operation, all these 4 signals must go logic High (+5v) to get a system shutdown.
+In normal operation, all these 4 signals must go to logic High (+5v) to get a system shutdown.
 The problem might be due to a signal that is always stuck Low.
-If you look to 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.
+**They can be queried via software and are connected like this :**
-  */RTC_ALARM ==> GPIP0
+|/RTC_ALARM  |GPIP0  |
-  */EXPWON    ==> GPIP1
+|/EXPWON  |GPIP1  |
-  */PSON      ==> GPIP2
+|/PSON  |GPIP2  |
-A program for testing these signals can be found here:
+**A program for testing these signals can be found here :**
-[[http://nfggames.com/X68000/Misc/SoftPower%20Test%20Program/x68k_pwrtest.zip|X68k Power Test]]
+[[http://nfggames.com/X68000/Misc/Diagnostics/SoftPower%20Test%20Program/x68k_pwrtest.zip|X68k Power Test]]
-Execute it more than one time. You should get :
+**Execute it more than one time. You should get :**
   *RTC_ALARM = 1 or 0, depending on the current RTC configuration.
   *EXPWON = 1
   *PSON = 0
-**If RTC_ALARM always stay to 0 :**
+**If RTC_ALARM always stays 0 :**
   *Bad RTC chip (RP5C15)
@@ Line 49: / Line 51: @@
   *Bad IC28 (74LS08) (stuck output).
   *Bad Q9 transistor (shorted).
-  *Bad C64 (generating noise).
+  *Bad C64 capacitor (generating noise).
   *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.