[1000mp] FT1000MP Mk V repaired...

[Guido Tedeschi]

Sunday, I opened the FT1000MP MkV to repair the power and swr meter problem.
First, I was surprised that a radio of this class is so badly engineered in
wiring and mechanical layout, I think that anyone that needs to have access
to PA board or LPF board (in the PA module), will say many bad words to
Yaesu engineers...
It is a nightmare with disorderly wires, hidden screws that you can handle
very very very carefully only with magnetic screwdriver, too short cables,
etc.
After disassembling the LPF board, I found that D6001 and D6002 were short
(15 OHM).
The swr bridge is the classic one with toroidal transformer and the
rectifiers seems to be in a doubler configuration with one capacitor in
series, one diode going to ground and one diode in series but then there is
no capacitor to ground but a 1mH choke in series.
It is clear that, in this configuration, the diodes in series (D6003 and
D6004) are not used for doubling but only to add a voltage drop to the
signals, why?
I don't understand why the designer's did this...
D6001 and D6002 are the diodes going to ground and this explain why I had no
power indication and no swr indication, the diodes in series seems to be ok,
so, I replaced D6001 and D6002 with D6003 and D6004 and wired a little
jumper instead of these series diodes.
Now, all is working again fine, even only with two diodes instead of four, I
will order to Yaesu some spares HRF32 diodes but I will not open again the
rig until some other failure will happen and I hope never!!! :-)
Ciao and 73
See you in CQWW with IU2R callsign.
Guido, ik2bcp / iu2r / ab9dg