Vintage Synth Repair

Hi! 

I have a Moog Source with problems to the Arpeggiator and Sequencer:

If you select the Sequencer, the display shows the 88 digits for a very 
short time, then goes black again. You can not record anything into the 
Sequencer and play it back. Both sequences are empty at the moment.

Also for the Arpeggiator. Here you can play in a sequence, the digits 
count down in the display, until you hit the first note played again. 
But then you can not play it back, there is no sound. 

Everything else with the level 2 functions (S&H etc.) is working.
The battery is good (3,4 V) and the membrane switches are working 
pretty well! The unit is in a good overall condition. No other problems.

Any ideas?