[1000mp] RE: FRB-5A Relay and the FP-29

[Joe Subich, K4IK]

> Does anyone know what the FRB-5A controls in the FP-29? 

The FRB-5A does not control anything in the FP-29.  It 
senses when the 30 volt line from the FTV-1000 is turned 
OFF (the 30 Volts is passed through when the FTV-1000 is 
OFF and cut off when the FTV-1000 is switched on). 

If the FTV-1000 is supplying 30 volts to the FRB-5A, the 
Field (or original MP) will operate normally,  If there 
is no 30 volts, the final amplifier of the Field/MP will 
be disabled.  In the 200 Watt Mark V, the 30 volt supply 
is used for the final amplifiers, if it is missing, the 
final and drive are disabled - the FRB-5A replaces that 
function for the original MP and Field. 

> I don't have an FP-29 and was going to use separate 12 V 
> and 30  V power supplies that I have on hand. I see that 
> the connection for the FRB-5A  passes through the 
> FTV-1000 and goes directly to the FP-29. I pulled up the  
> schematic for the FP-29 but they don't show the pin out 
> for the power output so  I couldn't see what the FRB-5A 
> is switching (or vice versa). 

The FP-29 pinouts are: 

   1  Ground (30 V) 
   2  Ground (13.8 V) 
   3  n/a 
   4  +30 V 
   5  +13.8 V
   6  n/a 

> Does anyone  know how this works? 

Do you have enough information to figure it out now? 

73, 

   ... Joe, K4IK