Ibanez AD-150 help needed !!

[MartyMart]

Trying to get this 1/2 rack type unit working properly, it's 80% there but there are some issues :
First, I can only find a schem of the AD-100, which is similar but not quite close enough !
Symptoms :
Delayed signal is VERY dull and overloaded with lots of pops in the sound  and very easily runs off into
distorted "bangs" with the regen anything above a couple of repeats. ( not a pleasant sound )
Input bypassed volume about unity with the delay "mix" at max - this seems fine.
Delay's/delay time adj is working, so the MN3005 isn't broken, the unit doesn't have a 3101 clock chip, which
seems wierd as there is one in the AD-100 !!
Next to the 3005 are three trimpots, the nearest chip being either a TC4069UBP and a TC4013BP a "clock width" trimpot
sits directly at the 4069UBP  ??
Regen trimpot and min/max delay trimpots all seem to work and adj properly
It's mains powered and has 0v and +15v on the board, voltages seem fine on the IC's - such as three Malaysian 4558's
- pin voltage's suggest power circuit is OK.
No obvious repairs or damaged components/burn evidence etc at this stage and all caps "look" clean and good.
Any idea's are welcome, reducing input/output volumes still causes the horrible breakup to happen, it's just quieter overall.

Many thanks for any pointers,
Marty.

[StephenGiles]

Marty, what about the bias voltage to the opamps which presumably should be around 7.5v - although it isn't always.

[MartyMart]

Bang on 7.56 - where required, some pins are between 4.5 and 6v pin 8's are 15.2v
All that stuff seems fine, perhaps one of my trimpots is way off, though I have nothing as a guide
voltage to go by !!
Where's that 3101  chip !! ??

[MartyMart]

Bump ! - need some hints on this one .....