Boss DD-3 repair help

[RickL]

I've been asked to repair a version 2 DD-3 (surface mount delay chip, through hole components). Symptoms: ticking (which is pitched on the longest delay setting like a little ping) that exactly matches the delay repeat time, turning the feedback up enough will send the ticking into uncontrolled feedback, turning the balance control down turns the ticking down, volume of ticking is about the volume of the guitar repeats, pedal works correctly otherwise.

If it's just clock noise shouldn't it be noticeably faster than the repeat time and also audible even with the balance turned down? Both trim pots on the board appear to be in their original position (the paint used to hold them in position is unbroken).

Any advice appreciated.

Rick

[Processaurus]

Hello, haven't heard your problem before, but from the little I  know from poking around in those, and other people's repair successes, might be worth replacing the obsolete DRAM to see if that cures it.  You can find it at online arcade game repair places.

Does it delay the normal time (nothing wrong with the clock generation)?

[RickL]

Except for the ticking it works normally. Play a short note and it repeats with exactly the same frequency as the tick, except it decays as you would expect. The tick doesn't decay.  Is it possible that a short blip of sound is somehow not being erased from the memory?

[Processaurus]

Yes, that sounds like bad dram.