Help! I need a fresh pair of eyes to look at a VERY
mysterious problem I am having with a repair.

I am repairing a 582 that has lost the ability
to record/erase tapes.

I have replaced the faulty caps in the bias oscillator
and checked the frequency. The bias oscillator
function has been restored and is right on spec.

I was just about to start checking/calibrating the
deck's EX/SX/ZX record bias, when the deck lost
its ability to go into PLAY mode.

It simply cannot enter PLAY mode. When you
hit PLAY, the deck goes into PAUSE
mode instead.

PAUSE = PAUSE
PLAY = PAUSE

I have checked the reference voltage at the
sliding contact of the cam control
10k volume pot, and the voltage is definitely
LOW for both PLAY and PAUSE
functions.

PLAY voltage reads 1.04VDC.
PAUSE voltage is identical.

It's as if PLAY and PAUSE functions have
merged and are now the EXACT same PAUSE
function, with a complete loss of PLAY function.

Adjusting VR401 (the Play mode voltage adjuster)
does nothing. A preliminary check of all related
transistors and diodes on the logic board has
produced no clues. Everything checks out OK.

I am starting to suspect op amp 4558C
(IC405), but am not sure how to proceed.

SOME INFO: The Play and Pause modes both
involve negative DC voltages. The 10k "volume"
pot previously mentioned is an internal motor-
driven pot that gets voltages directly from the
deck's logic board. This pot SHOULD be getting
slightly less than 3VDC in PLAY mode, but instead
gets just over 1VDC.

Here is the service manual:
http://www.analogstereo.com/nakamich...ice_manual.pdf

What should I be checking that I haven't checked
already?

Any help with this "tough dog" will be most appreciated.