Schematic was bounced by server as too large.
Available here


http://public.fotki.com/RussellMc/misc-1/piclistdesktops/zpump01.html

Larger version via link ata bottom of photo.

The catch diodes appear to be on the PCB if I understand the PCB OK
(down right hand side by BC337's).
These are all commoned with links and returned to the 7805 positive output.

- Having the diodes ON the actual coil connections or, next best,  on
the socket pins of the relays (assuming sockets) may be needed. As
implemented the collapsing field has both a nice serial loop into the
rest of the system and a common path for current and ... . (You may
have diodes on the relays as well already. If not, adding them along
with the PCB ones dos no harm).
- If the bottom vertical link  in the series of links from diode clamps to
7812 were o/c one the clamps may be isolated.

- 7805 is supplied from the 7812 output, along with the relay
supplies. Try temporarily moving its input to the 7812 INPUT. This
gets its input away from the spike from the switching relay
- Connection 7812_out to 7805_in not obvious but presumably switch or
link on contacts on PCB edge. .


               Russell McMahon
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