[TenTec] Omni VII Internal Tuner failure - advice please.

Stuart Rohre rohre at arlut.utexas.edu
Mon Jan 3 15:45:19 PST 2011


Don't fear returning your radio to Ten Tec if you have the orginal box 
and padding, or can repack appropriately.  Insure the shipment as well.

However, before going to that trouble, get the internal tuner exposed by 
taking off the cabinet, and if you have a DVM with diode check, check 
the diodes on the tuner board with the meter, (Radio off of course).  If 
you don't get 0.6 volt across one direction of each diode, you have 
found a bad one.  The other direction should not show a voltage barrier 
of 0.6, unless for some reason two diodes are in shunt.

The main use of diodes in the tuner will be for SWR bridge, and for 
relay back EMF suppression.  You can use the ohms scales to check the 
relays for correct contact action.  This might require an "Elmer" if you 
are not accoustomed to working on your own electronics circuits.

The diodes are the most prone to fail component in any SWR measuring 
circuit.

Of all your options, checking the diodes is the easiest to do yourself 
and least costly.  IF diodes test bad, you can get the parts from 
distributors or Ten Tec, and carefully solder them in to replace the 
originals.  Just pay attention to polarity, Make a sketch of which 
direction any bands are oriented on the diodes, before removing old ones.

-Stuart Rohre
K5KVH



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