1978
Philips High Fidelity Laboratories 784
AM/FM Stereo Receiver

Serviced and Fully Working!

Full transparency. When I received the unit, AM and FM were not working. I diagnosed a broken FM mixer transistor lead. In my attempt to be clever, I melted the top of an FM coil (see the second photo). However! My cleverness worked, the transistor was repaired, and now AM and FM work fabulously in this receiver. There are stations it pulls without an external antenna that other receivers in my collection can't pull with an antenna.

The power supply has been fully recapped. Of the 8 capacitors, 6 tested out of spec, so I replaced them all. I also replaced one out of spec capacitor in the AM tuner. Everything else tested okay. In addition to recapping the power supply, I replaced a dangerously tattered power supply cord with a new, 16 gauge cord.

As seen in the video (minus the turntable - I didn't have one close by, but phono does work) AM, FM, AUX, and Tape all work great. FM stereo locks in with full separation. It even pulls my local AM station at full strength. On the scope, this 18 wpc receiver tested at 22 wpc after the power supply recap.

All of the tone controls were cleaned with the appropriate Deoxit and work great. Loudness, mono, and tape monitor work with no issues. Speaker A, B, and headphone inputs work, too. The lamps are the original incandescent lamps. I saw no need to replace them. They work great.

I enjoyed this stereo for about a week, powering some NHT 1.5 speakers and it impressed me with full sound for a low watt receiver. I don't currently have space for this in my collection so it's here to find a new home.The spec sheet from HiFi Engine:

Specifications

• Tuning range: FM, MW
• Power output: 18 watts per channel into 8Ω (stereo)
• Frequency response: 20Hz to 20kHz
• Total harmonic distortion: 0.1%
• Damping factor: 25
• Input sensitivity: 2.5mV (MM), 150mV (line)
• Signal to noise ratio: 70dB (MM), 90dB (line)
• Year: 1978

1977-1980 Kenwood KR-4070 AM/FM Stereo Receiver. 

Selling this receiver As-is.

FM works great. Aux, tape, and phono inputs work great. 

AM tuner does not work. I replaced several components in the AM tuner section including transistors, resistors, capacitors, and the AM IC chip. I could not resurrect the AM tuner and do not have the proper equipment to test further. I believe the AM oscillator is not firing.

In addition to the AM tuner work, I replaced bad filter capacitors.

The tuning dial lamps have been upgraded to warm white LEDs. The meter and stereo lamps are working originals.

All of the pots and switches were cleaned with a combination of CDC Contact Cleaner and the proper type of Deoxit. The faceplate is in great shape and all of the knobs are original. There is no issue with the power/speaker selector switch.

This is a nice late 70's, silver faced receiver.

Specifications

• Tuning range: FM, MW
• Power output: 40 watts per channel into 8Ω (stereo)
• Frequency response: 15Hz to 70kHz
• Total harmonic distortion: 0.1%
• Damping factor: 40
• Input sensitivity: 2.5mV (MM), 150mV (DIN), 150mV (line)
• Signal to noise ratio: 73dB (MM), 95dB (DIN), 95dB (line)
• Output: 150mV (line), 30mV (DIN)
• Speaker load impedance: 4Ω to 16Ω
• Dimensions: 468 x 149 x 360mm
• Weight: 9.4kg