Weird phasing problem w/ a Sovtek Small Stone...

[scott_v]

Just about to crack open my old Sovtek Small Stone (Army Green tall font version) and try to trouble shoot a problem
but wanted to see if anyone has come across this same-type of issue before...

This is what's going on, the Rate knob seems to work for any the upper half of its rotation, that is i hear a faster phase which is continuous.  However, when I try to run a slower rate it starts to run through a phase cycle and sorta stalls out like a fixed wah and doesn't continue its phase cycle, but for faster rates it will continue to phase.  If i nudge the rate knob from a slow setting where it sounds like its stuck to a more slower setting it kinda sounds like its gonna start to phase again, but then gets stuck again. Doesn't matter if the color switch is up or down... 

Basically the upper half of the rotation sounds like a phaser (fast) and the lower half abit like a wah. 

Could it be a bad Rate pot? or one of the chips gone bad, I hope its not the chip     ... or

my guess is a chip, not sure how hard it is to find one of those for these units.

[scott_v]

Okay I'm not sure whats up with this thing but i have left it powered up now for awhile and now its phasing at full rotation but if i move the rate knob fast from slow to fast or vice-versa it will stop phasing at slow settings and do that stall out, but if a slowly creep the phase from fast to slow and back fast it will phase at all fixed points of the pot rotation... weird!  (I once had a reissue NYC small stone and it didn't do this as well as my current primary phaser the mxr phase 90).  btw i've only used a 9V battery with this unit, its a band new one measuring more than 9V on my DM.

I'm not to keen on taking this thing apart as i hear that these old heavy duty green things are abit of a pain to disassemble and reassemble.