RE: HENG LONG OWNERS ONLY THREAD!
Yep, a fan is a great idea. It is hard to find a small fan though- some people just do not have an old laptop to salvage for parts. I have ordered three Dell Inspiron 3500 laptop cooling fans for my tanks (one for my Dad's Tiger and one as a spare) as I have installed one from a scrapped laptop in my posession. The fan is about 1" square and 1/4" thick. Also, it runs on 5 volts DC, unlike a lot of desktop cooling fans which need 12 volts. The three fans (brand new) are costing me $15 with the shipping. I think $5 per tank is a good deal....especially if it keeps you from blowing boards!
Please disregard the location of the fan in my pic- the turret hits it when it's there. I've relocated it on my Pershing, but now it is not easy to see. You just need to put the fan (in whatever model of tank you have) so it blows on that aluminum angle on the board. Even if you just have it blowing on one end, that's ok. Aluminum is a wonderful heat transferer, and the heat will equalize across the heat sink.
If you need any advice please feel free to PM me- I'll help however I can. It is terrible to hear the frustrations you are having, especially since there are so many of us who love these tanks so much.