Mallory Ignition Issue

[ACMamba]

My Mallory ignition system in a 351 balanced Windsor has been giving
problems.

It will run-then will leave me stranded nearby with a dead Mallory distributor module-either the 6100 E-spark or the 605 version. (3 iced modules so far)
The system was originally equipped with a Hy-Fire Mallory box, but that has been disconnected earler in this car's history. It has a Promaster coil with vaccum advance Mallory distributor.

These are the symptoms-now looking for the cause. The alternator also had
a diode that went bad recently-but that has been fixed. Againower surge or spike through the system?

The ballast resistor is set at.3 OHMs to correspond to the setting needed for the mallory module. So far no other issues. Accel module in the distributor now.

Disconnected the older Promaster Mallory coil-I fitted an extra Pertronix coil and it produces almost 13.7 V while at idle-as
the car is running-but not leaving the garage/.driveway until I have this issue found and fixed.
Resistor wiring is in some cases used in the circuit between ignition switch and coil. See no evidence of this-EXCEPT-a 12 V battery strength wire coming fom the solenoid to a Hella relay/v regulator very close to the coil.
This is protected by a 35W fuse in line. Since its Hella and-a relay type
box-it very well may be a light switch. Between the unknowns and possible short to ground-in the system-
I am now going thru looking for wires rubbing against frame or loose wiring/straps anywhere in the igntion or car anywhere.

Would appreciate any ideas on this frustrating problem.

Thanks in advance...::

[Buzz]

Some sort of short or power surge is causing the modules to fail. I had a failure once when the wires at the alternator accidentally crossed.

Until (and even after) you find the source of the problem, I would highly recommend you install one of these active power filters to protect the module from spikes.

[ACMamba]

Thanks Buzz.

I had a Mallory Power Filter in place at the last dead module incident.
Which means the surge went thru the coil wire to the distributor cap.
UPDATE:
Installed a Petronics Performance FlameThrower with an additional.5 OHM ballast resistor in the wiring between coil and ignition. The Flamethrower had 1.5 OHM of resistance. Ironically-the ProMaster 29440 coil requires a separate
ballat resistor-which I have not found. So -originally someone left out the ballst resistor in the circuit.

Had a talk with the Summit Tech folks-they said that I had the right idea with a lower OHM ballast resistor COMBINED with a coil that has 1.5 OHM
resistance. Not every coil has a ballast resistor built in-but you need one
for the proper resistance-and my suspicion is that was the cause-
NOW its power filter AND ballast resistor with the right coil.

Its always something......

[Buzz]

Lets hope that's the last of your ignition problems. I've had no issues at all with my setup (Hyfire VI AL, Promaster coil, 2 ballast resistors) other than my own screwups . The power filter has saved my module at least once. Enjoy your Unique - I could not be happier with mine.