![]() With the jumper in place on the bottom of the IF board, the receiver picked up stations immediately, and indeed the dial tracking was very close to correct. Unfortunately these IF transformers aren’t exactly easy to obtain, however, it was easy to bypass entirely with a small capacitor out of the way and no real significant change in operation. Additional tracing revealed that the problem was the 2nd IF transformer, between the 2nd and 3rd IF Amplifier ICs – so, this receiver had both a dead transformer and a dead chip in the IF chain. I obtained some new Fairchild UA703HC chips in a more reliable metal case (date code 7603!) and replaced the defective amplifier.īetter! The new IC passed a signal, but the IF chain was still broken. A bad IC!Īccording to Internet research, these UA703 IC amplifiers are a common failure item. However, when bypassed with a cap, the tone came in loud and clear. Good injecting into the discriminator, but injecting into the input of the 4th IF Amplifier IC gave no output. Starting at the detector and working my way back, I injected a modulated 10.7 MHz signal into the circuit and listened for the tone. This radio checks out much like any other. The Germanium output transistors gave this one a very warm, tube-like sound. Time for a power-up! It did great, given the low power, on the AUX input and Phono settings, but the FM tuner was dead. There were several styles of electrolytic capacitors, but no real challenges. Inside, it’s built on a pretty simple chassis, with separate boards and jumpers connecting everything.Ĭomponent replacement was entirely uneventful. ![]() Sensitivity measured at 150 mV LINE and 4 mV PHONO for maximum output. I’d more accurately describe it as a self-propelled FM radio, more or less, because the -20 in the model number “HHS-20” represents the total power output: a maximum of 10W per channel, as measured after the repair was complete. It’s a cute little receiver with an FM MPX tuner, a tape loop, a single aux and phono input. Inside, it used construction that would have been at home in a late-’60s early solid state receiver with a couple of odd exceptions, there’s a single PDIP-14 op-amp chip, and an assortment of TO-39-style op-amp chips in the FM IF strip. The HHS-20 was a very entry-level receiver, and not much information turned during research other than some speculation about it sharing an FM section with a bigger sibling. It worked a few years ago when he put it away, although not without a few issues of its own, and when he dug it out it was right to the shop for an overhaul. A local repeat customer recently brought in his old HH Scott HHS-20 receiver for an overhaul.
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