diff --git a/app/src/main/java/su/comp/bk/arch/io/VideoController.java b/app/src/main/java/su/comp/bk/arch/io/VideoController.java
index f53d1a8..a9ace10 100644
--- a/app/src/main/java/su/comp/bk/arch/io/VideoController.java
+++ b/app/src/main/java/su/comp/bk/arch/io/VideoController.java
@@ -187,9 +187,8 @@ public DisplayMode getNext() {
     private final static int FRAME_LINES_VISIBLE = 256;
     // Frame horizontal sync period (64 uS, in nanoseconds)
     private final static long FRAME_SYNC_PERIOD_HORIZONTAL = 64 * 1000L;
-    // Frame vertical sync period
-    private final static long FRAME_SYNC_PERIOD_VERTICAL =
-            FRAME_SYNC_PERIOD_HORIZONTAL * FRAME_LINES_TOTAL;
+    // Frame vertical sync line number
+    private final static long FRAME_SYNC_LINE_VERTICAL = FRAME_LINES_VISIBLE + 1;
     // Current displayed line number
     private long currentLine;
     // Current displayed frame number
@@ -402,7 +401,8 @@ public void uptimeUpdated(long uptime) {
                 // Check for VSync
                 // Get displayed frame number (numbered from 0)
                 long currentLineFrame = currentLine / FRAME_LINES_TOTAL;
-                if (currentLineFrame >= currentFrame) {
+                if (currentLineFrameLine >= FRAME_SYNC_LINE_VERTICAL
+                        && currentLineFrame >= currentFrame) {
                     // VSync
                     storeLastFrameVideoData();
                     notifyFrameSyncListenersVerticalSync();
diff --git a/app/src/main/res/raw-ru/changelog_data.xml b/app/src/main/res/raw-ru/changelog_data.xml
index 69d03f3..e2d3fe0 100644
--- a/app/src/main/res/raw-ru/changelog_data.xml
+++ b/app/src/main/res/raw-ru/changelog_data.xml
@@ -4,6 +4,7 @@
         <changes>
             <change>Реализован режим "чтение/запись" для образов флоппи-дисков.</change>
             <change>Добавлен полноэкранный режим.</change>
+            <change>Поправлены тайминги генерации прерывания от таймера 50Гц.</change>
         </changes>
     </release>
     <release version="0.7.0" date="05.06.2020">
diff --git a/app/src/main/res/raw/changelog_data.xml b/app/src/main/res/raw/changelog_data.xml
index 2f94450..1795dc9 100644
--- a/app/src/main/res/raw/changelog_data.xml
+++ b/app/src/main/res/raw/changelog_data.xml
@@ -4,6 +4,7 @@
         <changes>
             <change>Implemented read/write mode for floppy disk images.</change>
             <change>Added full-screen mode.</change>
+            <change>Fixed 50 Hz timer interrupt timings.</change>
         </changes>
     </release>
     <release version="0.7.0" date="2020-06-05">