diff --git a/src/hwapi.cpp b/src/hwapi.cpp
index b41c27d..95f55c8 100644
--- a/src/hwapi.cpp
+++ b/src/hwapi.cpp
@@ -89,10 +89,20 @@ void hwapi::hwapi_slotPrintFinished_Err(void) {
 
 void hwapi::hwapi_slotGotCoin(void) {
     // new coin was inserted while transaction and new amount reported:
-    emit hwapi_gotNewCoin();
-
     uint32_t newSum=epi_CurrentPaymentGetAmount();
 
+    // this slot is called sometimes irregularely and providing
+    // invalid sums!
+    // TODO: preveent irregular call. Meanwhile, we need this
+    // limit check: 75000Ft ~200€
+    if (newSum > 75000) {
+        qCritical() << "Fixme: irregular gotNewCoin() signal";
+        return;
+    }
+
+
+    emit hwapi_gotNewCoin();
+
     if (newSum>=hwapi_lastStartAmount)
         emit hwapi_payStopByMax();