Ed Murlatt & Associates, Inc.
RF Services for the Broadcast Industry
We are discovering that IOTs can last a very long time when maintained properly.  One of the leading causes for IOT failure is arcing in the gun region, and the main reason for these arcs is dirt accumulation on the gun rubber and input cavity.  If you see dirt buildup in the junction box region similar to that shown in the picture at the bottom left of this page, or if you are experiencing random crowbars, it may be time to remove the input cavity and do some maintenance.  If you aren't experienced with IOT circuit assembly, we recommend you call for assistance. 

Before removing the input cavity, you'll need to have some additional materials on hand.  The list below is pertinent to MA2665K or MA2665M ONLY.  If you have any other e2v cavity, you should consider updating to one that is designed for DTV use.  At a minimum, contact e2v for repair parts.

Parts List for E2V Input Cavity Models MA2665K (Used on all Channels Except (38 - 40) and MA2665M (Used on Channels 38 - 40)
Quantity
Part Number
Description
2
MA3534A
Finger Stock for Anode and Cathode Drum
1
MA2315A
Grid Ring Finger Stock Assembly
1
MA2352A
Cathode Finger Stock
1
J-BOX-CON-H
Junction Box Connector - Heater
1
J-BOX-CON-HK
Junction Box Connector - Heater/Cathode
1
CAP-KIT
Capacitor Kit for Input Cavity and Junction Box
This is a Dirty Junction Box           Input Cavity Before Repairs      Same Input Cavity After Repairs   Cathode Drum with New Parts
Picture 1 Dirty J-Box Input Cavity Before Repairs Input Cavity after Repairs Cathode Drum with New Parts
MA2665(K or M) Input Cavity & Gun Rubber Maintenance