Ibanez UE305 (AD9?) delay won't self oscillate...trim pot advice?

[CaveDweller]

I unearthed a "mint-ish" UE-305 recently (Ibanez 9-series compressor, analog delay and stereo chorus...all housed in a large footpedal unit). It sounds lovely but the delay won't self oscillate. I also own a UE-405 (rack version)...which (I think) has the same delay and it will self oscillate to beautiful oblivion. I've never touched the trimpots on the UE405. I just assumed the UE305's delay would operate identically. It does in every respect except "number of repeats" (fading slowly silent instead of self oscillating when set to maximum repeats). I ONLY want to adjust the repeat level to achieve this (oscillation). Assuming this is set up like an old AD9 (which I think it is)...any idea what to look for if I decide to open it up? Is there any numerical designation or marking for the trimpot that adjusts the repeat amounts level? Any advice appreciated. Cheers.

p.s. The photo attached is just a generic one I found on the web.