diff --git a/modules/pcjs/lib/chipset.js b/modules/pcjs/lib/chipset.js
index 5f74489d8..eed74e76b 100644
--- a/modules/pcjs/lib/chipset.js
+++ b/modules/pcjs/lib/chipset.js
@@ -1024,13 +1024,14 @@ ChipSet.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {ChipSet}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-ChipSet.prototype.powerDown = function(fSave)
+ChipSet.prototype.powerDown = function(fSave, fShutdown)
 {
     return fSave && this.save? this.save() : true;
 };
diff --git a/modules/pcjs/lib/cpu.js b/modules/pcjs/lib/cpu.js
index e68f58f5f..bfa765a92 100644
--- a/modules/pcjs/lib/cpu.js
+++ b/modules/pcjs/lib/cpu.js
@@ -277,13 +277,14 @@ CPU.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {CPU}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-CPU.prototype.powerDown = function(fSave)
+CPU.prototype.powerDown = function(fSave, fShutdown)
 {
     /*
      * The Computer component (which is responsible for all powerDown and powerUp notifications)
diff --git a/modules/pcjs/lib/debugger.js b/modules/pcjs/lib/debugger.js
index 637b01e60..37afb2d29 100644
--- a/modules/pcjs/lib/debugger.js
+++ b/modules/pcjs/lib/debugger.js
@@ -41,6 +41,7 @@ if (DEBUGGER) {
         var Interrupts  = require("./interrupts");
         var Messages    = require("./messages");
         var Bus         = require("./bus");
+        var Keyboard    = require("./keyboard");
         var State       = require("./state");
         var CPU         = require("./cpu");
         var X86         = require("./x86");
diff --git a/modules/pcjs/lib/fdc.js b/modules/pcjs/lib/fdc.js
index f0da299a1..150fc378a 100644
--- a/modules/pcjs/lib/fdc.js
+++ b/modules/pcjs/lib/fdc.js
@@ -606,13 +606,14 @@ FDC.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {FDC}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-FDC.prototype.powerDown = function(fSave)
+FDC.prototype.powerDown = function(fSave, fShutdown)
 {
     return fSave && this.save? this.save() : true;
 };
diff --git a/modules/pcjs/lib/keyboard.js b/modules/pcjs/lib/keyboard.js
index f83c43fce..4965c051e 100644
--- a/modules/pcjs/lib/keyboard.js
+++ b/modules/pcjs/lib/keyboard.js
@@ -1357,13 +1357,14 @@ Keyboard.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {Keyboard}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-Keyboard.prototype.powerDown = function(fSave)
+Keyboard.prototype.powerDown = function(fSave, fShutdown)
 {
     return fSave && this.save? this.save() : true;
 };
diff --git a/modules/pcjs/lib/mouse.js b/modules/pcjs/lib/mouse.js
index c27b8647d..3cbebbf63 100644
--- a/modules/pcjs/lib/mouse.js
+++ b/modules/pcjs/lib/mouse.js
@@ -263,7 +263,7 @@ Mouse.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {Mouse}
  * @param {boolean} fSave
diff --git a/modules/pcjs/lib/panel.js b/modules/pcjs/lib/panel.js
index b3ca2d2bf..f87d47dde 100644
--- a/modules/pcjs/lib/panel.js
+++ b/modules/pcjs/lib/panel.js
@@ -38,6 +38,7 @@ if (typeof module !== 'undefined') {
     var Component   = require("../../shared/lib/component");
     var Bus         = require("./bus");
     var Memory      = require("./memory");
+    var X86         = require("./x86");
 }
 
 /**
@@ -364,13 +365,14 @@ Panel.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {Panel}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-Panel.prototype.powerDown = function(fSave)
+Panel.prototype.powerDown = function(fSave, fShutdown)
 {
     return true;
 };
diff --git a/modules/pcjs/lib/ram.js b/modules/pcjs/lib/ram.js
index 5e99da428..76d2e8b4b 100644
--- a/modules/pcjs/lib/ram.js
+++ b/modules/pcjs/lib/ram.js
@@ -113,13 +113,14 @@ RAM.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {RAM}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-RAM.prototype.powerDown = function(fSave)
+RAM.prototype.powerDown = function(fSave, fShutdown)
 {
     /*
      * The Computer powers down the CPU first, at which point the X86 state is saved,
diff --git a/modules/pcjs/lib/rom.js b/modules/pcjs/lib/rom.js
index 11470df58..c75a802fa 100644
--- a/modules/pcjs/lib/rom.js
+++ b/modules/pcjs/lib/rom.js
@@ -174,7 +174,7 @@ ROM.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * Since we have nothing to do on powerDown(), and no state to return, we could simply omit
  * this function.  But it doesn't hurt anything, and maybe we'll use our state to save something
@@ -183,9 +183,10 @@ ROM.prototype.powerUp = function(data, fRepower)
  *
  * @this {ROM}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-ROM.prototype.powerDown = function(fSave)
+ROM.prototype.powerDown = function(fSave, fShutdown)
 {
     return true;
 };
diff --git a/modules/pcjs/lib/serialport.js b/modules/pcjs/lib/serialport.js
index 78ca438b1..d3eeb682b 100644
--- a/modules/pcjs/lib/serialport.js
+++ b/modules/pcjs/lib/serialport.js
@@ -401,13 +401,14 @@ SerialPort.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * @this {SerialPort}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-SerialPort.prototype.powerDown = function(fSave)
+SerialPort.prototype.powerDown = function(fSave, fShutdown)
 {
     return fSave && this.save ? this.save() : true;
 };
diff --git a/modules/pcjs/lib/video.js b/modules/pcjs/lib/video.js
index c141c0768..020a0a067 100644
--- a/modules/pcjs/lib/video.js
+++ b/modules/pcjs/lib/video.js
@@ -2451,16 +2451,17 @@ Video.prototype.powerUp = function(data, fRepower)
 };
 
 /**
- * powerDown(fSave)
+ * powerDown(fSave, fShutdown)
  *
  * This is where we might add some method of blanking the display, without the disturbing the video
  * buffer contents, and blocking all further updates to the display.
  *
  * @this {Video}
  * @param {boolean} fSave
- * @return {Object|boolean}
+ * @param {boolean} [fShutdown]
+ * @return {Object|boolean} component state if fSave; otherwise, true if successful, false if failure
  */
-Video.prototype.powerDown = function(fSave)
+Video.prototype.powerDown = function(fSave, fShutdown)
 {
     return fSave && this.save? this.save() : true;
 };
diff --git a/modules/pcjs/lib/x86cpu.js b/modules/pcjs/lib/x86cpu.js
index bd92fc0c7..0147fab88 100644
--- a/modules/pcjs/lib/x86cpu.js
+++ b/modules/pcjs/lib/x86cpu.js
@@ -1344,7 +1344,7 @@ X86CPU.prototype.restoreProtMode = function(a)
  * UPDATES: The current speed multiplier from getSpeed() is now saved in group #3, so that your speed is preserved.
  *
  * @this {X86CPU}
- * @return {Object}
+ * @return {Object|null}
  */
 X86CPU.prototype.save = function()
 {