Upgrade an Optimod Power Supply
switching power supply used in Gary Morgan’s Optimod 8200 (Fig. 1) died, the
OEM replacement would have cost around $600. He sought to find another
Fig. 1: The dead Optimod
If you’re still using the original power supply
module, the small switching power supply may go bad. This little supply
can be replaced easily and re-soldered for about $75 (Artesyn NFS40-7608), but
with a lack of adequate cooling, it will be gone again in a couple of years.
Gary got the idea of replacing this supply
cheaply by using an ATX computer power supply. It comes with its own cooling
fan. Naturally a 300-watt ATX computer supply won’t fit into the 8200
processor box, but it does sit on the top nicely and doesn’t take up much space
in your rack.
As long as the original 8200 15 V linear supply
is in good shape, this ATX switching supply will last for many years. Any
decent 300-watt ATX computer power supply will work just fine. You’ll be
using the +12 V, –12 V, +5 V feeds, as well as the circuit grounds.
Pull the fuse on the original Optimod switching supply,
and leave it in place. You can then route your computer supply wires through a small
hole drilled in the back of the original supply. The voltage feeds are then
soldered to the TP (marked test points) on the original power supply
Gary soldered his wires first to the TPs in the
box, as seen in Fig. 4, and then attached the wires to a Molex plug (Fig. 3). This
way, the ATX supply can be disconnected from the Optimod if needed. You “turn
on” the ATX supply by shorting its green wire to any black (ground) wire. You
can use an external switch, short or solder your wires to the internal Optimod
supply connections are as follows:
Fig. 2: The new supply
sitting on top of the Optimod.
VDC (Yellow) — TP-11
–12 VDC (Blue) —TP-8
+5 VDC (Red) — TP-10
Grounds (Black) —TP-9
has two 8200s that have been running on ATX supplies 24/7 for more than five
editor of The CGC Communicator newsletter, writes in a recent issue that the
FCC’s Enforcement Bureau has done a wonderful job of reorganizing its field actions
list into year-by-year pages.
This means you no longer need a supercomputer to
download years of data just to see the most recent enforcement actions. Kudos
to the commission staff for getting this done. Visit http://transition.fcc.gov/eb/FieldNotices/.
And thanks to
Robert Gonsett for getting the word out.
* * *
Craig Pringle started his electronics career as a hobbyist,
“playing radio” with a rented Wollensak reel-to-reel and a low powered Allied/Knight Kit
three-tube AM transmitter (Model 83Y706). After graduation, Craig worked at a
variety of stations.
Being around all that broadcast equipment he caught
the engineering bug, which led to a First Class License and, eventually, the
formation of Telfax Communications, maker of the first truly compact telephone
remote audio mixer.
venture is VistaBright.com, where he specializes in energy-efficient lighting
products for commercial and industrial applications.
He has used the lettering process we outlined in the
March 1 column, “Your Panel Lettering Made Easy,” but instead of printing on
paper, he uses aself-adhesive printing
media known as BestPrint, made by Chartpak.
The product is a thin opaque white appliqué film (8.5-by-11-inch
sheets with peel-off paper backing), which works nicely in laser printers and
copiers. An inkjet version is available.
The finished product is durable and trims up nicely
using an X-Acto knife, resulting in a professional appearance for any project.
* * *
Paul Sagi sends his regards from Kuala Lumpur,
and offers a really slick resource for Workbench
readers using Google Chrome.
Fig. 3: A Molex plug is
inserted in-line for quick disconnect.
radio engineers who use the Chrome browser should have a look at CircuitLab, an
extension for Chrome. You’ll find the link at radioworld.com/links.
CircuitLab is a
schematic editor and circuit simulator. It lets you build and test circuits
right in your browser. Use CircuitLab to design circuits with their easy-to-use
schematic editor. Then perform accurate analysis in seconds.
The software provides
beautiful schematic printouts in PDF form. Watch the video for an idea of what
the tool can do. If you do any kind of circuit design, this tool is a must.
Fig. 4: Solder the wires
to the Optimod test points to complete the modification.
Paul also sends a link for multiple virus
scanners. Not all virus scanners will detect every virus every time. Thus, it’s
best to use multiple virus scanners. However that’s usually inconvenient — until
now. The URL is also on our links page.
Contribute to Workbench. You’ll help your
fellow engineers and qualify for SBE recertification credit. Send Workbench
tips to email@example.com. Fax to
Author John Bisset has spent 44 years in the
broadcasting industry and is still learning. He handles West Coast sales for
the Telos Alliance. He is SBE certified and is a past recipient of the SBE’s
Educator of the Year Award.