My IC-703 came with one working output transistor. Good enough to sell the rig as "working" but not much more. I tried replacing the RD07MVS1 but they are a bitch to replace.
Granted, by now the PCB had been reworked at least twice (the finals I got were not the original finals) so things were a bit iffy.
|C165||0.1||C2012 JB 1C 104K-T||2012 (0805)|
|R160||2k2||ERJ3GEYJ 222 V (2.2k)||0603|
|R206||33||MCR10EZHJ 33R (330)||2012 (0805)|
|C201||0.1||C2012 JB 1C 104K-T||2012 (0805)|
|C155||0.1||C2012 JB 1C 104K-T||2012 (0805)|
|R211||220||ERJ1TYJ 221U (220R)||(2512)|
|R210||220||ERJ1TYJ 221U (220R)||(2512)|
|C150||0.1||C2012 JB 1C 104K-T||2012 (0805)|
|C200||0.1||C2012 JB 1C 104K-T||2012 (0805)|
|R205||33||MCR10EZHJ 33R (330)||2012 (0805)|
|R163||2k2||ERJ3GEYJ 222 V (2.2k)||0603|
|C161||0.1||C2012 JB 1C 104K-T||2012 (0805)|
Then in a fit of not double-checking I assumed (never assume) that the current to the finals goes through the fuse right there next to them on the board, so that's where I inserted the multimeter to set the idle current. Don't do that. RD07MVS1s can and do catch fire.
So much for that then. Something had to be done.
I should have been a bit more conservative, I think. But I wouldn't have been able to save those two traces, so I'll just have to add wires. One trace runs from R300/R305 to R306, the other is the T8 line between R100 and R250/R301.
It's ugly, but I'm back on the air again. With cheaper, more robust finals. I'll call it a win.
hits since 2017-04-26.
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