Original vintage Memory Man echo/chorus: Problems

[randomair]

I was given a Memory Man at a garage sale: no switches or jacks or chassis, just the circuit board with the pots. I was able to find a photo of the inside of one of these units and figure out the wiring so I could test it. Here is the problem, everything is wired correctly but the poor thing does nothing but oscillate. There is a clean guitar signal coming through but the circuit itself just makes this crazy oscillating tone that changes when the controls are adjusted. I also tried adjusting the smaller on board pots next to the chips but it only changed the oscillating even more. There are four 4558's , one MN3005, one MN5554n and one other 14-pin chip. I have heard that the MN3005 is no longer made and that you can buy NOS for approx $25. Any insight on this? Also, I realize me telling what is wrong with the unit its hard to diagnose without hearing it, but I was just wondering if anyone has ever run into similar problems with the chips or the unit. Thanks!