You should put a resistor in parallel with the LEDs. I suggest 10 kΩ or so.
At really low currents, the voltage across an LED will be nearly its forward voltage (Vf). So an LED rated at 2 V might be 1.6 V at less than 1 μA. Just for fun, at no current an LED with a Vf or 2 V will have a voltage across it of around 1.6 V in bright light.
If you are running at 5 V, and loosing 1.6 V across your LEDs, you do not have the 4 V needed to turn on the IRF630B.
The 10 kΩ resistor will only have 10 mV across it at 1 μA, and it will absorb any current generated by the LED in bright light. That means you will get the full 5 V to turn on the IRF630B. When the LED is powered up, there will only be about 0.2 mA though the 10 kΩ resistor, so you won't loose much power.
Hmm. I've tried this and it does seem to have a positive effect! I also replaced the fried resistor.
I have been trying out a few things to watch the response.
I have emptied the capacitors by shorting their leads. After this I connected the circuit to my bench power supply I'm running it at roughly 5V. It is designed for use with 4 AA batteries, at 4.5V effectively.
After I connected the circuit to my power supply, nothing happened for a while. After a second or two, the third, blue, LED array lit up rather quickly. It stayed lighting up the blue array alone for minutes.
Deciding minutes was long enough to conclude the circuit wasn't working properly, I connected an extra lead to my 5V in and connected it to the second array's transistor's gate.
This made the middle LED array light up. After roughly a second, the third array grew dim very quickly. Then, the first LED array lit up. After a few seconds, the middle array started to grow dim.
Another few seconds later, the first array started to fade rather quickly and the third array started to grow in light intensity reasonably slowly. It stayed stable in this position for minutes yet again. It seems that the fault must be here. (Cheapskate capacitors?)
I decided to now connect my extra 5V lead to the gate of the first array's transistor's gate. This caused the first LED array to grow in light intensity quickly, and after reaching its peak it started growing dimmer, until it was off again. This happened VERY rapidly. A seconds at most.
The state of the third array did not change at all.
To clarify, with first, second and third array, I mean the order of the LED arrays from left to right.
The first chain consists of 6 blue LEDs wired in parallel, rated for 3.2V at 20mA which gives us a total current draw of 160mA.
The second array consists of 12 red LEDs, also wired in parallel, rated at 1.8V at 20mA, giving us a total current draw of 240mA.
The third array consists of 8 blue LEDs, same ratings as the first array, and draws 200mA in total.
Does anyone have a clue what is going on? I will run over the wiring again.
EDIT: I connected the second array's transistor's gate directly to 5V again. The situation that occured wasn't any different from my previous experience. But this time I noticed that the first array did not grow dim until the second array was turned off completely.
On an added note, the second array seems to never stay at its maximum light intensity, but rather starts to grow dim very slowly.