[Kenwood] TS930/940

[John E.Cleeve]

In recent exchanges, reference has been made to several sites
where service and modification information is available on the 
TS930/940. In copying, an error in transistor type number has been 
spread across these sources. The error states that 40 volt, 150 watt  
2N3771, is a replacement for the original 60 volt, 200 watt 2N5885 
transistors, the two TO3 series regulators in the TS930/940 PSU. 
Clearly this information is wrong. The original author says that this 
was a "typo error" and it should have read 2N3773(UK cost £3.75) which 
is a 140 volt, 150 watt transistor, although the voltage rating is 
adequate, the power rating is not, therefore, I would caution the use 
of this transistor. It is far better to use a higher rated component, 
and then under run it, and thereby reduce the risk of further 
expensive component failure, in the PA for example.  Alternative, 
higher power TO3 NPN transistors are easily obtainable as suitable  
replacement. I use ST Microelectronic type MJ15003( cheaper!!UK cost 
£2.26)which is rated at 140 volt 250 watt. Others are 2N6276, 2N6341, 
2N6277, all TO3 mounting, 140 volt, or more, working, and at least 
200/250 watt power rating.  I hope that this warning will be of use to 
the group, best regards, John G3JVC.