diff --git a/src/calng/Gotthard2Correction.py b/src/calng/Gotthard2Correction.py
index 24429baeba5aba06701019d85af15ae626073ffe..64578f92dea1a90b2a5663efa94eb2a18d7f54a8 100644
--- a/src/calng/Gotthard2Correction.py
+++ b/src/calng/Gotthard2Correction.py
@@ -19,7 +19,11 @@ from karabo.bound import (
 
 from . import base_calcat, utils
 from ._version import version as deviceVersion
-from .base_correction import BaseCorrection, add_correction_step_schema
+from .base_correction import (
+    BaseCorrection,
+    add_correction_step_schema,
+    preview_schema,
+)
 
 
 _pretend_pulse_table = np.arange(2720, dtype=np.uint8)
@@ -235,11 +239,16 @@ class Gotthard2Correction(BaseCorrection):
             .dataSchema(streak_preview_schema)
             .commit(),
 
+            OUTPUT_CHANNEL(expected)
+            .key("preview.outputFrameSums")
+            .dataSchema(preview_schema)
+            .commit(),
+
             FLOAT_ELEMENT(expected)
             .key("preview.replaceNanWith")
-            .displayedName("Replace streak NaNs by by")
+            .displayedName("Replace streak/sum NaNs by")
             .assignmentOptional()
-            .defaultValue(-1000)
+            .defaultValue(0)
             .reconfigurable()
             .commit(),
         )
@@ -340,31 +349,27 @@ class Gotthard2Correction(BaseCorrection):
         self._write_output(data_hash, metadata)
 
         if do_generate_preview:
-            self._write_preview_outputs(
-                (
-                    ("preview.outputRaw", preview_raw),
-                    ("preview.outputCorrected", preview_corrected),
-                ),
-                metadata,
-            )
-            # custom additional preview for this 1D detector
             streak_preview = buffer_array.copy()
             replacement = self.unsafe_get("preview.replaceNanWith")
             streak_preview[np.isnan(streak_preview)] = replacement
             streak_preview[np.isinf(streak_preview)] = replacement
-            self.writeChannel(
-                "preview.outputStreak",
-                Hash(
-                    "image.data",
-                    ImageData(
-                        streak_preview,
-                        Dims(*buffer_array.shape),
-                        Encoding.GRAY,
-                        bitsPerPixel=32,
+            frame_sums = np.sum(streak_preview, axis=0)
+            self._write_preview_outputs(
+                (
+                    ("preview.outputRaw", preview_raw),
+                    ("preview.outputCorrected", preview_corrected),
+                    (
+                        "preview.outputStreak",
+                        ImageData(
+                            streak_preview,
+                            Dims(*streak_preview.shape),
+                            Encoding.GRAY,
+                            bitsPerPixel=32,
+                        ),
                     ),
-                    "trainId",
-                    train_id,
+                    ("preview.outputFrameSums", frame_sums),
                 ),
+                metadata,
             )
 
     def _load_constant_to_runner(self, constant, constant_data):