Film-Tech Forum ARCHIVE: strong switcher power supply question

This is topic strong switcher power supply question in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=011602

Posted by John Geary (Member # 668) on 02-04-2014, 05:04 PM:

I have a question about a strong switcher supply I just acquired with a Highlight 2a console. The console was running a 4500 watt lamp & since I bought this for a screening room with a 20' throw, I would like to spare the retinas of the audience & use a 2000 watt bulb instead. The power supply is marked 3-5000 watts, is there a way to use this supply by changing something internally? The manual doesn't really make it clear, just that the bulb current is adjustable.
thanks for any help you can provide.

Posted by Mark Gulbrandsen (Member # 72) on 02-07-2014, 05:06 PM:

No can do. You'll have to run a 3kw and defocus the lamp.

Posted by Dave Macaulay (Member # 813) on 02-07-2014, 06:52 PM:

Not too sure it's hopeless. As I recall, if the power control pot plug falls out it goes to a very low current - sometimes the lamp will stay on but I think it's really low like 30A maybe? There were a couple of types of Strong electronic supply as well (not counting the useless first generation bricks) and I believe they had internal adjustments for a few things... so lowering the minimum power might be possible.

Posted by Steve Guttag (Member # 268) on 02-07-2014, 08:46 PM:

I'm pretty sure one can set the range on that supply to go down to 1KW if need be. There are internal trimmers on the main PCB that allow one to alter its range.

Strong used to call it a 1-5K rectifier and then changed it to a 3-5K. One never had the full range of 1-5K with just the external pot. Going from 40A to 150A would be way too large of a range and would make the pot very sensitive. At least with a 3-5K, one is only going from 85A to 150A...still a pretty wide range.

Posted by John Geary (Member # 668) on 02-07-2014, 09:19 PM:

Thanks for your input guys. I was thinking about it & maybe with the coarse adjustment internally I can lower the current enough to run my 2000. I admit it doesn't sound too hopeful, & as Steve has said, maybe the trimmers on the pcb will allow me to lower the current to what I need. I'm running a 2000 watt in my xetron lamphouse right now that is set at the lowest current possible that will still allow the bulb to strike & I have it severely defocused. That gives me an acceptable level. I'd like to avoid buying a new bulb since I have a couple 2000's & a 4500 that are in good shape. To be frank, I'm on a budget. I think I will see first if it's possible to lower the current internally, if not I might just go with the 4500 & see if I can defocus & lower the current to it. It would be great if I could get the service manual on this, would anyone know where I could find a copy? the user manual is pretty basic.

Thanks again guys, I appreciate all your help. If anyone's interested, I'll post what I come up with.

Posted by Mark Gulbrandsen (Member # 72) on 02-17-2014, 07:58 PM:

It had too much inrush current for the smaller lamps. Thats why they switched it to 3 to 5K.