I am attempting to repair an older piece of equipment and have found what looks like a damaged component. There are two identical sections on this circuit board and each have this component. The component designators on the board start with R and all other normal looking resistors on the board also start with R.
The one I think is good measures 25K and the one I think is damaged measures around 5K. They are light yellow discs and measure approximately one inch across and are very thin, around .065" They each have two legs. The good one appears to have the marking 40/3 and appears to be newer and to have been changed before. Both were wrapped in a heavy piece of heatshrink and dated 91/01/07 with a marker.
If I heat the good one up the resistance drops but not dramatically 25K to around 16K when too hot to touch. These components are part of an output power transistor circuit and they each have a diode in a TO16 package bent over and siliconed down to the top of these discs. The discs were mounted flat against the PCB. I assume the diodes are some type of thermal protection and are also found siliconed down to some power resistors on the same board.
Any help identifying or finding a suitable replacement would be appreciated.
thanks for your time,
Could these be some older style NTC inrush limiters or what???
The good one measures 25K
The damaged one measures 5K