Sharp sf 7900 copier, after paper jammed and removed the trouble shooting code light H-4 keeps flashing

It seems your copier has a low battery?
check this page: Sharp Copier error code codes AR sharp errors copy

That error aprears from having the same paper jam over and over. It is possible that you did not get all of the paper out of the machine. Otherwise most likely you have an issue with a sensor in the paper path you could try blowing all the sensors with canned air. Turn off both power butmtons or use sim 14-1 to clear the trouble and have it try starting up again.

I’m happy to help further over the phone at https://www.6ya.com/expert/ethan_e84416e0b13809d2

H4 Heat roller low temperature detection

There is probably still paper stuck in the paper path, this is very common. What happens if you load it with paper and press the test button?

clean the paper feed rollers with soap and water damp cloth take paper tray out use flashlight to locate rollers also clean registration roller under the drum check and see if u have any broken gear teeth on your fusing assemby also if after cleaning it works i recommend u replace feed rollers

There is no code to run.
Did the paper come out as an entire sheet? Or was it torn? There is either a small piece of paper that remains in the machine, or you dislodged a paper switch in removing the jam.

I'm sure you may find a manual, but your copier is rather old.... When you make a copy do you get a error code? How about when you make a copy, do you see the scanning lamp turn ON? Here is you thing you can try, make sure the Primary Corona unit is pushed in all the way in. It has a grey handel on it and it should be found right above the Drum... Good Luck

A piece of paper torn from copy paper is caught around registration switch, exit switch or feedshift switch.
so check theme.

1-check and make sure the paper sizes coreresponds : If using Letter it must indicate 8 1/2x 11 or (Letter) not Legal or 8 1/2 x 14.

2- the tires are slipping and trowing the timing off. change tires (cheap)

Open right side door and check for a jam in the fusing unit (the one that is normally hot). Remove jam carefully. Hit P * C * and enter 14. Push the start button like you are making a copy. Machine should reboot and code should not return. if it does, you may have a dirty themistor, or blown lamp.