Troubleshooting - Ramsey Electronics FM25A Assembly And Instruction Manual

Ham radio books and magazines are filled with antenna principles and ideas
which can be adapted to your application. Also, you may wish to look at Radio
Shack book No. 62-1083 on antennas. Our new TM-100 Tru-match FM an-
tenna is an ideal mate to your transmitter. It features proper impedance match-
ing for optimum power transfer and range. See our catalog for details.
ANTENNA ALTERNATIVES
If your situation involves a single large building or multi-level home where re-
ception from the FM25A antenna may tend to be uneven because of walls and
other VHF path obstacles, you might set up the FM25A's output in a "carrier-
current" configuration. If you know how, then do so - safely. If not, you can
show your FM25A and this book to a licensed radio engineer and negotiate with
that person for a safe installation which will feed your signal through interior wir-
ing of your home or building. Do not attempt such an installation unless you
know exactly what to do and not to do. Also, because such an installation is be-
yond the original purpose of this kit and the safety standards intended for all
Ramsey kits, and because we have not tested the FM- 25 in such an installa-
tion, we cannot provide further details for such an installation.
TROUBLESHOOTING GUIDE
If your FM25A does not work at all, re-check the following:
•
correct orientation of U1, U2, and U3 (see PC board layout diagram)
•
correct polarity of all electrolytic capacitors.
•
correct orientation of diodes D9 - D20
•
correct orientation of Q1, Q2, and Q3 transistors,
•
all solder connections.
Hints
•
Erratic or unstable operation is caused by faulty solder joints or cable con-
nections.
•
Replacement stereo transmitter IC chips may be ordered from Ramsey
Electronics, Inc.
•
The 2SC2498 transistor is a bipolar silicon NPN low-noise UHF/VHF ampli-
fier in a TO-92 BEC case, suitable for service up to 5 GHz. Standard
2SC2498 replacements: ECG10 or SK9139, which may be found at most
local electronics parts dealers.
FM25A • 21