[Yaesu] Rehabilitating An FT-901DM

[Greg Queen]

I have an FT-901DM which has been sitting idle for 20+ years.  I have just
re-licensed (awaiting my call sign) and I am in the process of firing up the
rig.  After dusting and a general check, I powered up the rig and it
basically came to life.  It looks like none of the electrolytic capacitors
dried out.  In testing the receiver I have encountered a problem and an odd
situation (which probably indicates a second problem) and was hoping people
on the list might have some suggestions.

The confirmed problem is with the ATT (attenuator) switch.  The switch has a
"good" mechanical feel but it is intermittent.  If I hold it just right
(especially if I apply lateral pressure, that is pressure perpendicular to
the pushbutton shaft) or if I work the switch a number of times, I appear to
get good reception.  When it is not working I either have an "open" circuit
in the antenna feed to the receiver or I have the 20db attenuator.  I can
not tell which (no real test equipment) but from the schematic, I am
guessing that I have an open circuit.  Has anyone experience problems with
the FT-901DM's push button switches?  If so, is there any magic I need to
know about?  If I have to replace the switch, does anyone know of a source
for the switches (Yaesu no longer stocks parts for the rig)?

The second issue I have is with the "width" control.  As I understand it,
this control moves one of the IF frequencies around causing the IF bandwidth
to narrow.  The manual indicates that with the width control in the center
(detent) position you would have normal bandwidth.  Rotating the control
either left or right would narrow the bandwidth on either the high or low
frequency side.  At present, I have to run with the control fully clockwise
to effect reasonable reception.  Is this normal?  If not, does anyone have
any ideas of what may be causing the abnormal behavior?

Thanks in advance for your efforts.

Greg Queen
GregQueen@cal.berkeley.edu