Ed Murlatt & Associates, Inc.
RF Services for the Broadcast Industry
When Bad Things Happen to Transmitters
Arced IOT in Trolley Arced IOT Closeup Arced Input Cavity Arced Input Cavity
The thumbs below show a dirty cavity before and after cleaning (left two thumbs), and what happens to an IOT with excessive harmonic emissions (rignt two thumbs).  When installing a new IOT, we will clean the cavities to improve arc detector performance, as well as improve finger stock contact and door operation.  We also record harmonic emissions, and if required, we take corrective action to reduce them to meet the manufacturer's specification.  Click the tumbs to open in a new window.
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Here are a couple of before (left 2 thumbs) and after (right 2 thumbs) shots of an IOT that overheated due to an air flow restriction.  The IOT was arcing upon arrival.  We cleaned the ceramic, removed the restriction in the air supply, and we were able to return this tube to service.
Here are some pictures of an IOT (left two thumbnails), and an input cavity (right two photos) that failed due to arcing.  It has been determined recently that the majority of these failures can be attributed to excessive dirt accumulating in the input cavity.  Moving forward, we may suggest removal and inspection of your input cavity and IOT if we suspect a dirty environment, or if you've had construction in the building.  We don't try to make work, but we sure like to avoid the opportunity to take pictures like these!  There is some good news; E2V repaired the cavity and there is hope the IOT can be repaired as well.  They have repaired worse in the past.  The bad news - repairs are done in England, so there can be a long wait.  Click the tumbs to open in a new window.
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