The cost really depends on where you get it. When I shopped around, the cost ranged from $99.95 at Jameco to over $200 at another supplier (don’t remember) with several others in between. The only caveat with Jameco – at least, at the time, it was not in stock and I had to wait for about 3 weeks to get it. For my application, the output voltages and current capabilities are just right. As I mentioned in an earlier post, I modify all my S-100 boards to run on 5V instead of 8V by shorting the regulator, input to output, or I remove the regulator entirely. (When building a new board, I don’t even install the regulator.) The 5V current is 15A, which is plenty for my systems. Very few boards need +16 or -16, and those that do seem to be just fine with +15 and -15. And of course, the +24 is only needed by my 8” disk drives, and though it is rated at 3A, there’s never a time when any more than one disk drive is active, so that’s plenty too. I never thought about using this supply to run unmodified boards, but it has an adjustment on the 5V output. So, just now, I disconnected everything from the supply and tried adjusting the 5V to see what the range was. Turns out the control lets me adjust it from 4.25 to 5.48V. Unfortunately, that’s not enough for standard, unmodified S-100 boards. Perhaps there is a way to mod the PS to increase the output voltage above this high, but I’m not going to go there. So for now, the QP-200F works just perfect for me with my modified boards, and I consider it to be a great value for its four output voltages with adequate current, it’s relatively small form factor, and a known name. The only other thing I see that might be an issue for some, is there is some noticeable switching noise on the 5V output. It is actually visually noticeable in my video if one looks close at the monitor. (I use a bus-based video controller, Fulcrum VIO-X, driving a standard composite monitor.) It’s also easy to see on a ‘scope, but so far, it does not seem to be causing any other problems. If it does become an issue, I’ll build a filter to make it better. Hope this helps! Bob Bell From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of J. Alexander Jacocks I have noticed several folks are using the Meanwell QP-200F PSU, recently. I looked it up, and it is a bit expensive, but it appears to be much smaller than my current 8/16vdc pair of units. I assume that the unit can be adjusted for the proper voltages? Do folks who have them think they're worth the money? Thanks! - Alex -- |