Differences

This shows you the differences between two versions of the page.

--- x68000:soft_power_switch_troubleshooting_and_repair [2012/11/20 23:36] – 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**. 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 symptom: System 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.
-The problem is almost surely located on the IO board.
+If this is your case then the problem is almost surely located on the IO board.
 Here is the power on/off logic behind the /PSON signal (named CH2 in the schematics). Click on them to enlarge.
@@ 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 you're talking about, signal **/MPWOFF).
+  *Via the front power switch (/PSON)
+  *Via the soft-sequence signal from the system controller (/MPWOFF)
-On 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  |
+|/EXPWON  |GPIP1  |
+|/PSON  |GPIP2  |
-  */RTC_ALARM ==> GPIP0
+**A program for testing these signals can be found here :**
-  */EXPWON    ==> GPIP1
-  */PSON      ==> GPIP2
-**Links uz softu**
+[[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)
-If EXPWON = 0 :
+**If EXPWON = 0 :**
   *Check the expansion riser, or remove it.
   *Check the "Remote" plug on the back, if I remember right, it's also connected to this line.
-if PSON = 1 :
+**If PSON = 1 :**
   *Damaged resistor R54 (should act as pullup)
   *Bad power switch
-And if all is ok, it could be :
+**And if all is ok, it could be :**
   *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.