Tips on alternative power supply, road rack wiring, and rubber belts

July 1, 2008


A bad power supply module -- note the bulging capacitors and heat marks.

Alternative power supply

The 24/7 nature of broadcasting is hard on equipment — particularly power supplies. It used to be most broadcast equipment had a built-in, linear-type power supply, designed by the equipment manufacturer. Modern trends have led to smaller, switching-type supply modules that are off-the-shelf items. Several pieces of equipment approaching 5-plus years of continuous use in our facility are experiencing power module failures. And finding replacements quickly is often expensive. (One well-known T1 multiplexer manufacturer quoted $700 and a lead time of four weeks.)

The new power supply module on the T1 shelf card.

Out of necessity I stumbled on an affordable, immediate alternative: The International Power Sources model UP0653S-03. This supply provides 5 (at 8 amps!), +15V and -15V, and will fit in tight spaces most others will not. It is used in one specific ISDN audio codec, but I found it will replace similar supply modules (including the one that cost $700) and even wall-wart type supplies. It cost $71 and is available from XP-Foresite in New Jersey. And the bad supplies? I have been able to repair most of them by replacing all the capacitors. For about $20 each in parts and one hour of time I have reliable spare supply modules on the shelf at a fraction of the cost and with no hassle of searching for an exact replacement.

Resource: XP-Foresite
1-800-278-6650


Wiring a road rack

Rack wiring with a piece of RG-6 used as a skeleton

It seems that wiring a large rack in a rack room is always easier than wiring small racks for remotes. The number of wires needed is less, and usually the hardware to make the wiring neat takes up too much room. A simple solution is shown at right. Take a scrap of stiff cable (such as RG-6 or plenum CAT-5) and use it as a lacing bar. It will hold the smaller wires together in a bundle, making a nice neat wiring job for the road rack that looks just as good as those in the big racks.


Belts are a cinch

Recently a client asked me to repair a cassette deck. It turns out all it needed was rubber belts. No sooner than I had it working, an IT person asked me for help with a DVD drive that wasn't working (and he needed to fix it yesterday and there was no time to run to Comp USA). Quick inspection revealed that it too needed a rubber belt. Since I have a stash of small belts, soon the DVDs were rolling again. Luckily the PRB line of belts is still available, and thanks to the Internet I found a good place to get belts, tires and rollers. Ken's Electronics has a large stock of new belts and a great index online, complete with instructions for measuring or guesstimating the size of a belt. Ken's also has a large inventory of electronics parts and info on his website.

Resource: Ken's Electronics
www.kenselectronics.com/lists/belts.htm


Landry is an audio maintenance engineer at CBS Radio/Westwood One, New York.


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