Ramps V1.4 without D2 1N4004 diode

Hi, This is my first post

I have a reprap printer with mega board and of course a ramps, and last night i have miss connected the green power connector 1 pin off, so the power polarity are reversed.
i know this is stupid, but then i just realized the power connector doesnt have a hardware lock or somekind of a side wall that prevent you doing that. im using a 500W rated PC Power supply BTW

and after that the little polyfuse become overheat when pluggin, but after replacing it with 5A old style automotive fuse the D2 1N4004 get exploded when i power up.
But.. the printer LCD turn on even without the D2
my question are
1. is it my polyfuse or the D2 diode that are broken? i can sense the heat coming from that area, is it probably the heat coming from D2 not from poly?
2. can i run it with no D2 diode? what will happen without them?
3. in my area its hard to find the 4004 type, i only got 4002 which are rated half from 4004? CMIIW. can i used the 4002 to replace 4004?
or
4. can i install them in tandem? i mean parallel so that i can get the same capacity as a 4004

thanks for your kindness to reply

best regards

D2 diode on RAMPS has a protection function against revers polarity. As it seem, it worked
Without the diode, the protection is gone, so better check twice next time.
Replacing it with a 4002 is a problem IHMO, it will burst earlier. Maybe too early for your car fuse to melt?

thanks for your reply.

what are you mean is that things will be allright without D2?
As long as i dont miss plug the polarity again?

right now im using two identical 4002 running with parallel, but it seems did not power up the extruder well, it only good around 210 degree celcius, above that my led light are blinking, im using abs so i need 230, and it doesnt serve me

is it okay if i took the D2 away?

and.. is it my previous polyfuse still working well? but my car fuse works well it didnt heat up, what are you mean it will melt shortly? im using 5A car fuse btw

Edited 1 time(s). Last edit at 04/05/2018 11:55AM by enrik0.

I would remove the polyfuse and replace it with a solid copper wire. That will help you to heat up to 230°C again.
You can leave the two 4002 diodes in place.