diff --git a/UI/UI_Mixer.c b/UI/UI_Mixer.c
index a672d78..6690fd1 100644
--- a/UI/UI_Mixer.c
+++ b/UI/UI_Mixer.c
@@ -53,8 +53,33 @@ void DrawAllFaders(void)
     drv_nvm_save_to_flash();
 }
 
-/* 0902-06：实心蓝色圆钮（勿用同心空心圆，会透出色条） */
-#define MIXER_KNOB_R   14
+/* 0902-06：圆钮定位半径 = 色条半宽；填充略大以盖住柱端抗锯齿白边（夹紧不画出柱外） */
+#define MIXER_KNOB_R        15
+#define MIXER_KNOB_FILL_R   16
+#define MIXER_TRACK_HALF_W  15
+
+/* 与柱端半圆同形的实心圆钮：顶/底档位与色条圆角完美贴合，无虚线白边 */
+static void DrawMixerKnob(uint16_t cx, uint16_t cy)
+{
+    int16_t dy;
+    int32_t r2 = (int32_t)MIXER_KNOB_FILL_R * (int32_t)MIXER_KNOB_FILL_R;
+    for (dy = -(int16_t)MIXER_KNOB_R; dy <= (int16_t)MIXER_KNOB_R; dy++)
+    {
+        int32_t xx = r2 - (int32_t)dy * (int32_t)dy;
+        int16_t dx = 0;
+        int16_t half;
+        if (xx < 0)
+            continue;
+        while ((int32_t)(dx + 1) * (dx + 1) <= xx)
+            dx++;
+        half = dx;
+        if (half > (int16_t)MIXER_TRACK_HALF_W)
+            half = (int16_t)MIXER_TRACK_HALF_W;
+        LCD_FillByColor((uint16_t)(cx - half), (uint16_t)(cy + dy),
+                        (uint16_t)(cx + half + 1), (uint16_t)(cy + dy + 1),
+                        COLOR_GRAD_MID);
+    }
+}
 
 static void DrawFaderSlider(Fader_t *f, uint16_t slider_y)
 {
@@ -62,9 +87,9 @@ static void DrawFaderSlider(Fader_t *f, uint16_t slider_y)
     uint16_t ly = f->y + f->h + 8;
     uint16_t cy = (uint16_t)(slider_y + MIXER_KNOB_R);
     char buf[8];
-    LCD_FillCircle(cx, cy, MIXER_KNOB_R, COLOR_GRAD_MID);
+    DrawMixerKnob(cx, cy);
     sprintf(buf, "%d", f->val);
-    LCD_ShowString_AutoAlign((uint16_t)(cx - 8), (uint16_t)(cx + 8),
+    LCD_ShowString_AutoAlign((uint16_t)(cx - 10), (uint16_t)(cx + 10),
                              (uint16_t)(cy - 5),
                              (uint8_t*)buf, LCD_ALIGN_CENTER, WHITE, COLOR_GRAD_MID, 0, 11);
     LCD_FillByColor(cx - 15, ly + 17, cx + 15, ly + 19, UI0902_BG_COLOR);
@@ -149,17 +174,14 @@ void UpdateFaderByTouch(int idx, uint16_t y)
 }
 
 // ============================================================
-// ??????Y????????val? 0~10??
+// 滑块顶边 Y：val0/10 时圆心落在色条底/顶半圆中心，两端对称贴合
 // ============================================================
 static uint16_t CalcSliderY(Fader_t *f)
 {
-    uint16_t slider_h = (uint16_t)(MIXER_KNOB_R * 2);
-    uint16_t fill_h = (f->val * f->h) / 10;
-    if (fill_h > f->h) fill_h = f->h;
-    uint16_t slider_y = f->y + f->h - fill_h - (slider_h / 2);
-    if (slider_y < f->y) slider_y = f->y;
-    if (slider_y > f->y + f->h - slider_h) slider_y = f->y + f->h - slider_h;
-    return slider_y;
+    uint16_t top_cy = (uint16_t)(f->y + MIXER_KNOB_R);
+    uint16_t bot_cy = (uint16_t)(f->y + f->h - 1 - MIXER_KNOB_R);
+    uint16_t cy = (uint16_t)(bot_cy - ((uint32_t)(bot_cy - top_cy) * f->val) / 10);
+    return (uint16_t)(cy - MIXER_KNOB_R);
 }
 
 int CheckTouchFader(uint16_t x, uint16_t y)