WM-150 (applies to other units) gear skipping one second in reverse play

This thread covers a very common problem found in the following walkmans:
WM-A602/WM-B602/WM-B603/WM-AF604/WM-150/WM-170/WM-F181/WM-190/WM-506/WM-2091/WM-F2095/WM-EX48/WM-EX49/WM-EX49C/WM-EX50/WM-FX50

The problem manifests the following:
When unit is left with a cassette in and REVERSE PLAY mode (which is the deafult one on this mechanism) you will hear a gear rattling sound for a few seconds before the intermediate gear fully engages.

The main cause of this problem is the spring that connects the PLAY button to the main mechanism lever.
Unfortunately, the only thing that can be done is to bend the ears of the spring a little bit closer to the spring itself thus making the spring a bit harder.
However, it it to be mentioned the correct solution would be to replace the spring with one that has a thicker wire diamter so it can pull the mechanism with higher force.

There are a couple of other things which can be done to reduce the symptoms, but none of these are a fix:
1. Excess play in the play fork lever which will need to be bent back in order to eliminate the play.

2. The mechanism will also need a general cleaning and re-lubrication with watch oil on the points indicated with red arrows (do not use grease !).
While it is not possible to remove the parts which need lubrication, as the retainers are stamped onto the chassis, cleaning on the edges with plenty of IPA and cotton swab is enough.

3. The tab which engages reverse play (marked blue in second picture) may need to be bent left in order to make sure it fully engages the white gear.
This problem only manifests itself in reverse play because the white gear rotational torque acts against the lever which pushes it into position, so if the levers are not fully engaged gear will skip teeth.

NOTE: The mechanism does not need to be fully disassembled, what you see in the pictures is for illustration purposes only.
Only two things that need to be removed are the black pulley and the clutch assy.