diff --git a/frontend/src/utils/ChartManager.ts b/frontend/src/utils/ChartManager.ts
index 820f570..63d3845 100644
--- a/frontend/src/utils/ChartManager.ts
+++ b/frontend/src/utils/ChartManager.ts
@@ -928,6 +928,24 @@ export class ChartManager {
         );
       }
 
+      // ── OBV 진단 로그 (개발용) ────────────────────────────────────────────
+      if (config.type === 'OBV') {
+        const plotKeys = Object.keys(result.plots);
+        const seriesIds = seriesMeta.map(m => m.plotId);
+        const volSum = this.rawBars.reduce((s, b) => s + (Number(b.volume) || 0), 0);
+        // eslint-disable-next-line no-console
+        console.error(
+          '[OBV Debug] series:', seriesList.length,
+          '| plotIds:', seriesIds,
+          '| resultKeys:', plotKeys,
+          '| plotVisibility:', JSON.stringify(config.plotVisibility),
+          '| plot0Color:', config.plots?.find(p => p.id === 'plot0')?.color,
+          '| bars:', this.rawBars.length,
+          '| volSum>0:', volSum > 0,
+          '| pane:', pane,
+        );
+      }
+
       // hlines(과열선/중앙선/침체선)는 첫 번째 시리즈에만 한 번 생성 (중복 방지)
       const hlineRefs: IPriceLine[] = [];
       let fillPrimitive: IndicatorFillPrimitive | undefined;
@@ -2903,6 +2921,11 @@ export class ChartManager {
       } else {
         opts['color'] = plot.color ?? '#aaa';
       }
+      // ── OBV plot0 스타일 진단 로그 ──────────────────────────────────────────
+      if (entry.type === 'OBV' && pid === 'plot0') {
+        // eslint-disable-next-line no-console
+        console.error('[OBV Style] plot0 opts:', JSON.stringify({ visible: opts['visible'], color: opts['color'], lineWidth: opts['lineWidth'] }));
+      }
       // eslint-disable-next-line @typescript-eslint/no-explicit-any
       series.applyOptions(opts as any);
     });