The original MFOS Sound Lab Mini-Synth sync circuitry is a bit weak.
This is a small PCB you can add to your SLMS (SMD from V1.0 to V1.3, or THT version) to dramatically improve the Sync.

The installation is pretty easy. Simply remove the following components:

Solder the following components on the Mod Board:

• DK_1 and DK_2 are 2 x 1N4148 (SOD323)
• R72 is 20k ohms (1206)
• RK_06 is 470k ohms (1206)

Then, with thin wire, connect the 4 pins from the Mod Board to the SLMS board at the following empty pads:

You can read Ray’s documentation here.