diff --git a/src/debugger/gui/DebuggerDialog.cxx b/src/debugger/gui/DebuggerDialog.cxx
index 4c75e2be5..23c04f9b9 100644
--- a/src/debugger/gui/DebuggerDialog.cxx
+++ b/src/debugger/gui/DebuggerDialog.cxx
@@ -658,8 +658,8 @@ void DebuggerDialog::addRomArea()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Common::Rect DebuggerDialog::getTiaBounds() const
 {
-  // The area showing the TIA image (NTSC and PAL supported, up to 260 lines)
-  return Common::Rect(0, 0, 320, std::max(260, int(_h * 0.35)));
+  // The area showing the TIA image (NTSC and PAL supported, up to 274 lines without scaling)
+  return Common::Rect(0, 0, 320, std::max(274, int(_h * 0.35)));
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/debugger/gui/TiaZoomWidget.cxx b/src/debugger/gui/TiaZoomWidget.cxx
index e45853534..8bf1debcf 100644
--- a/src/debugger/gui/TiaZoomWidget.cxx
+++ b/src/debugger/gui/TiaZoomWidget.cxx
@@ -41,7 +41,7 @@ TiaZoomWidget::TiaZoomWidget(GuiObject* boss, const GUI::Font& font,
 
   // Use all available space, up to the maximum bounds of the TIA image
   _w = std::min(w, 320);
-  _h = std::min(h, 260);
+  _h = std::min(h, 274);
 
   addFocusWidget(this);
 
diff --git a/src/emucore/tia/frame-manager/FrameManager.cxx b/src/emucore/tia/frame-manager/FrameManager.cxx
index 456796ddf..ebe03e8cf 100644
--- a/src/emucore/tia/frame-manager/FrameManager.cxx
+++ b/src/emucore/tia/frame-manager/FrameManager.cxx
@@ -28,12 +28,12 @@ enum Metrics: uInt32 {
   vsync                         = 3,
   frameSizeNTSC                 = 262,
   frameSizePAL                  = 312,
-  baseHeightNTSC                = 228,
-  baseHeightPAL                 = 274,
+  baseHeightNTSC                = 228, // 217..239
+  baseHeightPAL                 = 274, // 260..288
   maxLinesVsync                 = 50,
   initialGarbageFrames          = TIAConstants::initialGarbageFrames,
-  ystartNTSC                    = 16,
-  ystartPAL                     = 19
+  ystartNTSC                    = 23,
+  ystartPAL                     = 32
 };
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -