I am working on a Realistic (Radio Shack) HTX-100.  I purchased two of these for $45 last May, and was told "one works, one does not".  I joined the HTX-HF_Tech Yahoo group and started looking into things.

The initial problem (but not the ONLY problem) was that there was a lot of static noise from the speaker.  This noise was internal to the radio (thanks to a troubleshooting tip I got on Google+ that told me to short the antenna center to shield at the back of the radio).

I started poking around at things, and found that a trimmer resistor was dirty and was causing the static.  Combined with the fact that the speaker was desoldered from the board (an oh-so-difficult fix!), I thought maybe I fixed it.

Then I hooked it up to an antenna and checked its ability to receive.  Nothing.  I could tune stations in on one HTX (and on my Ten-Tec), but not on this one.  In fact, I couldn't tune anything.

One of the things available (not only on the group but also from a few additional websites) is a repair manual, which is really very helpful.  I started into the alignment procedure and noticed that in step 3, I was nowhere near the target value of 10.695 Mhz, and was not able to adjust to get anywhere close.  So I started looking at the troubleshooting section for the PLL board (where the coil in step 3 was located).  A few steps in the process, I checked voltages on one of the ICs and found a handful of them off.  I started checking further, and questioned a crystal.  I replaced the crystal and found no change.  So, I started looking at other things.  I checked the voltages on other ICs and found a handful of others that are off.  I looked at capacitors, and noticed a few that have tears that seem to indicate that they've failed.  I replaced one that I happen to have, and it fixed one of the voltages on one of the ICs.  Progress!  I have a few more to do, but I need to order the parts.

Blown Capacitors

Blown Capacitors on the HTX-100 PLL Board

HTX-100 Main board

Main Board of HTX-100

PLL Board

PLL Board of HTX-100

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Category: Equipment

About the Author

Andrew is the owner of this blog and enjoys computer programming, building things, and photography. He's a pretty busy guy, which explains why updates to this blog are so infrequent.

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