I’ve got an issue with my EHX Russian Small stone which seems common.

When the Effect is engaged, the pedal will not instantly “Phaser”. It sounds as though the phased notch signal is present, however the sweep is not working. You can wait for a while and the sweep will start working, or adjusting the rate know triggers the sweep to begin.

Here are several threads I’ve found where people describe a similar issue:

https://www.thegearpage.net/board/index.php?threads/anybody-work-on-russian-ehx-smallstone.933190/

Russian Small Stone problem

Russian Small Stone R.I.P?

Because of the nature of the fault, I’m assuming that the issue is in the LFO section of the circuit. I’ve checked the 33uF cap neat the 1M pot and it tested fine. Before I go messing with too much, does anyone have advice or suspicions on what the problem could be?

Schematic I’m referencing:
http://www.montagar.com/~patj/smlstone.gif

EHC Smallstone Pic
https://guitars.azureedge.net/aza/user/gear/ehxsmallstonerussian-2.jpg