"Bell and Howell" cooling

[Graham Ritchie]

I have been meaning to post these photos from last year, when after many years owning this projector from 1996. I thought it was time to improve the interior cooling.

What got me getting involved, was the lamp cooling fan tripped a fuse. I found the cooling motor itself was faulty. This prompted me to fit the spare motor, while I was doing this, I thought I would check out the air intake to the motor. After looking at the back of the projector, I only found some small vents. I did not think it was enough. As the lamp cooling motor draws in the air from the back, this in itself could be a bit warm side before it got to the lamp.

So I decided to cut a hole in the back, and mount a fairly high speed silent hydrodynamic bearing case 12 volt fan, blowing air from the outside, to the inside the back of the projector. This same air gets picked up by the lamp cooling fan as well. I installed a small 12VDC Switchmode power supply, it has a input range from 85-264VAC. There is a small adjustment on it as well and wired directly from the mains fuse, I needed 12VDC voltage for the extra fan. Thinking also I could use that same power supply to run the projector cooling 9VDC lamp as well. I added this neat little device from the 12VDC out, that has a range of step down voltages one being the 9VDC I needed. When you switch the projector ON at the mains both fans will run.

So that's my wee 16mm project over, everything is running fine, but this time with the addition of "I think" improved cooling all around.


fixed the transformer on the side cover

The 12VDC to 9VDC device

[Terry Sills]

Commendable project but I’m not convinced that extra cooling is needed on Bell&Howell projectors. I think replacement of the old worm gear would be a higher priority, but not something that most owners could take on and do a good job.

[Graham Ritchie]

Certainly if the worm gear was cracked then its worth replacing, but at present and after 26 years of use with me as my main 16mm, the worm gear so far with this projector on inspection still looks good. I wonder if those later models like the B/H 1680 GS above, were less prone to worm gear failure, certainly all the Green model B/H that I have come across in the past had worm gears that had failed, but so far on inspection there does not seem to be any cracking evident on rotation, I certainly hope it says that way.