Analog synthesizer Modifications, Poly-800 MK-1 memory backup battery

The Poly-800 didn't have any dedicated battery for keeping the patch memory.
(The MK-2 and the EX-800 have backup battery as standard.) If you remove the power and C-cells at the same time the patches are lost.
This modification shows how to add a dedicated backup battery. After the mod the patches will be kept at all times.
However, beware that the firmware of the MK-1 has a bug which cause a total crash with memory loss when hooked up to certain sequencers.
If you have this problem, try to connect the Poly-800 after the sequencer is started.

  • Open the Poly-800 by removing ALL screws at the bottom. Note that those in the front are shorter than the rest.
    Locate the processor board. This is the large circuit board next to the battery compartment.
  • At the middle of the board you find two square solder lands, you mount the lithium battery (CR2032 or larger), or battery holder, here. The upper land is positive.
  • Remove C87, C88, D23.
  • Cut the trace to the left of the plus lane as shown. Short between trace and trace and D15 as shown. (D15 can be removed)