A cd player error's dance (aka, how to monitor read errors in a CD player with TDA1541 chipset)

NOTE: THIS POST IS A COMMENT TO WHAT YOU CAN WATCH IN THE ATTACHED VIDEO.

Today I wanted to investigate the behavior of the error signal in one of my Philips CD-670 players.

The error signal is coming out from the decoder chip (SAA7210)  to advise the following interpolation &digital filter chip (SAA7220) that errors have occurred while reading samples out from the playing cd.

Again on Philips CD670 and the CDM/2 cd transport

During the last year BOTH my Philips CD670 cd players have began to express annoying symptoms:

• randomly unable to read the TOC even with CDs that yesterday successfully played many times;
• randomly stopping playing with "error" message on the display (mainly when playing your preferred piece of music of your preferred cd...), even with CDs that yesterday played ok many hours;
• being very very very sensitive to mechanical shocks (I was attempted to use them as earthquake warning tools ...). Even a strong "bass" tune could lead to  the "error" condition as well as my son just walking by in front of it - the cat didn't have the same effect, however...).

Philips CD-670 CD player: a CDM2 pickup surgery

This old CD player came to me from a flee market for 15 EU. Not so much for a CDM2/10 transport and a TDA1541 (non-A) DAC.
It is in good shape but it randomly failed to read CDs.

After a lot of testing on the transport controller and power suppliers electronics, laser power adjustment, etc. ..my attention was driven toward the CDM2 transport itself. You know, it is a beautiful galvanometric transport (the arm swings like needles in galvanometers..) ..but it is prone to failures.

I cleaned the lens and double checked the foiled PCB. Nothing.

Playing with the transport (remove-check-reinstall-test cycles) I got random results. I was not able to reproduce a predictable sequence of behaviours... BUT....