[cctalk] Re: Identifying This Component from VT100 Monitor Board

I have a VT100 externally dated May 1983. Q414 on this unit is a BU407 (T0220 package) mounted on a small vertical heatsink, there does not appear to be a CR406. Q310 appears to be a Motorola MJ3029 There are some TO3 packaged devices mounted on heatsinks - none of these have the captive star washer style nuts shown in your images. None have mica washers I agree with others that the unit may have been 'repaired' by someone without a service manual. It may be an entirely different circuit topology - the image that you included does show Sanyo 2SB411 power devices Are you able to trace the circuit through and give an idea of the topology? Peter