Just bought Super A with 6 volt system. have 100 with 12 volts I may keep for parts. would it be good idea to use 12 volt from 100 on A?

you have a starter generator... you can go to most specialty 12 volt shops ( starter re-builder ) or online and find a good quality universal V.R. can't remember if thats a 6 or 12 volt system... google 12 volt external voltage regulator and you will get an idea what I am talking about. I've done this repair a number of times

likely DC 5 to 9 volts but perhaps as high as 12 for most devices. 9 is a good middle ground to start. You can get adapters with a switch for 3.5 to 12 volts, just be certain of the polarity and always start at lower volts like 5 or 6.

It is not a good idea to connect 12v to a 6v system. It can short out the ignition system, generator, and any electronics that are energized. It is best to use a 6v charger.

It sounds like your preheat system is not working properly on the cold startup. Haynes has a Diesel Engine Repair Manual, part #10330 that will help you correctly diagnose and repair.
Battery volts at 13 is good but a fully charged battery should be close to 14.2. It would be a good idea to get the alternator output checked and a load test done on the batteries.
Hope this helps.

105 or 130 is amperage not volts. The voltage should 14 to 14.5 volts to the battery when the engine is running.

I have a list of problems common to this series here:

Cause #1
1. (Lamp may light and go out) suspect bad lamp part # 915P020010 2. Check for
12-volts DC at J-9 connector pin 4 on the Engine Driver PCB, if missing check
for an open F9A09 on the Power PCB, if it is open replace F9A09 part #
283P127060 and the Light Engine part # 939P977010 3. (Lamp may light and go out)
Check for 5-volts DC at J-9 connector pin 1 and 2 on the Engine Driver PCB if
low or missing check C9A37 and C9A38 both 3300 UFD 10 V part # 181P732040 on the
Power PCB (part # 930B921002) 4. At power on the lamp turns on and off three
times and then the unit shuts down with a red lamp LED (lamp error). Replace the
Light Engine part # 939P977010 5. Lamp enable line at J14 pin 6 does not switch
to 5 volts after turn on, 12 and 5 volt supplies are good. Suspect the Light
Engine part # 939P977010 6. Lamp enable line at connector J14 pin 6 on the
Engine Driver PCB switches to 5 volts after turn on and does go to 0-volts (low)
after 5 seconds, 12 and 5 volt supplies are good. Suspect the Lamp Power PCB
(ballast) part # 939P978010 7. Lamp enable line at connector J14 pin 6 on the
Engine Driver PCB switches to 5 volts after turn on but does not go back to 0-
volts (low) after 5 seconds, 12 and 5 volt supplies are good. Suspect the Light
Engine part # 939P977010

I would start with #3, checking the 5 volt line and replacing the listed capacitors if needed.
Please be sure to rate this solution. Thanks!

There is a list of things you need to check, but offhand I'd say that the 5 volt line is low and probably right on the"edge", which is why it works sometimes and not others take a look at this list:
Cause #1
1. (Lamp may light and go out) suspect bad lamp part # 915P020010 2. Check for
12-volts DC at J-9 connector pin 4 on the Engine Driver PCB, if missing check
for an open F9A09 on the Power PCB, if it is open replace F9A09 part #
283P127060 and the Light Engine part # 939P977010 3. (Lamp may light and go out)
Check for 5-volts DC at J-9 connector pin 1 and 2 on the Engine Driver PCB if
low or missing check C9A37 and C9A38 both 3300 UFD 10 V part # 181P732040 on the
Power PCB (part # 930B921002) 4. At power on the lamp turns on and off three
times and then the unit shuts down with a red lamp LED (lamp error). Replace the
Light Engine part # 939P977010 5. Lamp enable line at J14 pin 6 does not switch
to 5 volts after turn on, 12 and 5 volt supplies are good. Suspect the Light
Engine part # 939P977010 6. Lamp enable line at connector J14 pin 6 on the
Engine Driver PCB switches to 5 volts after turn on and does go to 0-volts (low)
after 5 seconds, 12 and 5 volt supplies are good. Suspect the Lamp Power PCB
(ballast) part # 939P978010 7. Lamp enable line at connector J14 pin 6 on the
Engine Driver PCB switches to 5 volts after turn on but does not go back to 0-
volts (low) after 5 seconds, 12 and 5 volt supplies are good. Suspect the Light
Engine part # 939P977010

I would say try #3 first, the two caps on the pwer supply board. A couple of warnings: as always, unplug the unit before servicing. The power supply is located on the left side, if you behind the unit. It is in a shielded box and the shield has VERY SHARP EDGES so use care when you try to open it or you will slice your fingers.
Please be sure to rate this solution. Thanks!

Good Day; I would suspect the ballast, but try these first:

Causes: Cause #1 1. (Lamp may light and go out) suspect bad lamp part # 915P020010 2. Check for 12-volts DC at J-9 connector pin 4 on the Engine Driver PCB, if missing check for an open F9A09 on the Power PCB, if it is open replace F9A09 part # 283P127060 and the Light Engine part # 939P977010 3. (Lamp may light and go out) Check for 5-volts DC at J-9 connector pin 1 and 2 on the Engine Driver PCB if low or missing check C9A37 and C9A38 both 3300 UFD 10 V part # 181P732040 on the Power PCB (part # 930B921002) 4. At power on the lamp turns on and off three times and then the unit shuts down with a red lamp LED (lamp error). Replace the Light Engine part # 939P977010 5. Lamp enable line at J14 pin 6 does not switch to 5 volts after turn on, 12 and 5 volt supplies are good. Suspect the Light Engine part # 939P977010 6. Lamp enable line at connector J14 pin 6 on the Engine Driver PCB switches to 5 volts after turn on and does go to 0-volts (low) after 5 seconds, 12 and 5 volt supplies are good. Suspect the Lamp Power PCB (ballast) part # 939P978010 7. Lamp enable line at connector J14 pin 6 on the Engine Driver PCB switches to 5 volts after turn on but does not go back to 0-volts (low) after 5 seconds, 12 and 5 volt supplies are good. Suspect the Light Engine part # 939P977010. Good Luck, big IRISH.

Good Day, monkbuist;

TRY THIS:

1. (Lamp may light and go out) suspect bad lamp part # 915P020010 2. Check for 12-volts DC at J-9 connector pin 4 on the Engine Driver PCB, if missing check for an open F9A09 on the Power PCB, if it is open replace F9A09 part # 283P127060 and the Light Engine part # 939P977010 3. (Lamp may light and go out) Check for 5-volts DC at J-9 connector pin 1 and 2 on the Engine Driver PCB if low or missing check C9A37 and C9A38 both 3300 UFD 10 V part # 181P732040 on the Power PCB (part # 930B921002) 4. At power on the lamp turns on and off three times and then the unit shuts down with a red lamp LED (lamp error). Replace the Light Engine part # 939P977010 5. Lamp enable line at J14 pin 6 does not switch to 5 volts after turn on, 12 and 5 volt supplies are good. Suspect the Light Engine part # 939P977010 6. Lamp enable line at connector J14 pin 6 on the Engine Driver PCB switches to 5 volts after turn on and does go to 0-volts (low) after 5 seconds, 12 and 5 volt supplies are good. Suspect the Lamp Power PCB (ballast) part # 939P978010 7. Lamp enable line at connector J14 pin 6 on the Engine Driver PCB switches to 5 volts after turn on but does not go back to 0-volts (low) after 5 seconds, 12 and 5 volt supplies are good. Suspect the Light Engine part # 939P977010. Good Luck, big IRISH.