Ramsey Electronics FZ-146 Specifications download pdf (Page 47)

FX-146 • 47

despite the detail of our explanations, be sure you set one channel up for

146.52 MHz Simplex before you pursue troubleshooting. It is very important

to have a clear understanding of how to program the frequency synthesizer

and offset matrixes of your transceiver.

It's fairly easy to double-check "obvious" details such as IC orientation, diode

polarity, electrolytic capacitor polarity, and those other construction

essentials that we stress repeatedly. SOME of the more subtle assembly

errors which take very careful checking to find include the following:

 Any use of 2N3904 where VHF 2SC2498 is required

 Use of NPN where PNP is required: Q12,Q13,Q14

 Mistaken use of .01 or .001 disc capacitors where a small picofarad

value is specified.

 Major error in selecting resistors with similar color codes, like 100 ohm

(brown-black-brown) used for 100K (brown-black-yellow), or vice-versa.

 Reversal of the 8V and 5V voltage regulators

 L16, L14 or L13 touching the top groundplane.

 A single IC pin or IC socket pin bent under the plastic body of the device.

Simple operational tests are discussed at the end of most of the assembly

stages. Use these as a guide for tracing the circuit. If you make the effort to

understand each of the small sections of the big picture, you should have no

trouble in identifying the source of your problem.

If tracing and repairing complex circuits is new to you, we urge you to retrace

your assembly steps thoroughly. Take the extra time to really understand

circuit functions that might have been hazy during the excitement of

construction. Use basic LOGIC to narrow down the problem to a specific

stage.

If you ask a more experienced ham friend to look at your unit, it is up to you

to be able to recognize whether this person has the know-how and proper

equipment and tools to be of real help to you. Most hams really WANT to be

helpful, but good intentions are no substitute for competence. (If your friend

drags out the trusty soldering gun and big, rusty alligator clips, suggest a

fishing trip or antenna-fixing party instead!)

The best favor any friend can do for your kit project is to review the

correctness of part choices.

Factory Service is, of course, available at prevailing shop rates. The hams at

Ramsey enjoy providing kits to hams and hobbyists in addition to our Test

and Measurement Division work, and we're sure that you understand that

our company is not a ham club, and that our professional technicians aren't

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Ramsey Electronics FZ-146 Specifications Page 47