This is a very nicely made small footprint low power amplifier using quasi-complimentary capacitor coupled output. It's had all the problem transistors replaced and most capacitors (not the main filter cap as it is fine). Switches cleaned, face plate removed and cleaned, everything else works well and it sounds great. This also has wooden "cheeks" on the sides of the case. Fault condition: This is quite an interesting amplifier it has an unusual (unique?) shut off system if there is are certain faults it. It apparently shuts of the input and stops the outputs to speakers all without using a relay. This example when powered up still outputted to the speakers, there was an unusual buzzing that varied in pitch over time, sounded like there was a feedback problem, oscillation of some sort; I expected electrolytic capacitor issues and isolated the problem to the mid stages of the power amp, (voltage amplifier and possibly bias area) I replaced a few suspect electrolytic capacitors and the sound changed, the capacitors were so far out of spec I replaced all electrolytics on the board, it was still oscillating albeit to a different tune. I decided to replace the known problem transistors next, I also pulled and tested the 2sc715 transistors and found them OK except for the gain value, (Hfe), it was very, very low one was 3 and the other channel 4! they should be 80 or more so even into the hundreds. I put new modern replacements in and tried the amplifier Bingo! we had sound, lovely music- the mute system had allowed the amp inputs to start. I then carried on and replaced all the other smaller electrolytic capacitors and a few more transistors that are know to cause issues. The "metal can" transistors in the phono section stayed, they are not reported to go bad and indeed work fine the phono section sounds great. Overall typical Kenwood, warm (mellow, not harsh at all) with detail in mid and upper range, very easy to listen to and nothing seems to be missing. Cosmetically it has cleaned up well and looks lovely. Sound: warm, clear, plenty of clean bass (I left the new coupling capacitors at the same value, some people change them for larger to give more and lower bass? but it can then get a bit "flabby"). I do like this amplifier, Kenwood designs are deceptively simple but they seem to get it right most of the time, especially in the 1960's (mostly valve) & 1970,s models. Just a note, the model here has two Phono inputs (apparently there was a single phono input model), for turntables; the phono amplifier stage (now restored) is excellent, you may have to spend quite a bit to better it with an external phono stage; but it is moving magnet only neither input is moving coil.
N.B. I'm not really a fan of wholesale replacement of capacitors but when they are this old and test far from spec, like these, they really do need replacing. Despite the spec saying tolerance of -10% to +20% for most new capacitors you will very rarely find them more than a few percent off the stated value for good quality brands), for the old capacitors any largish deviation means they are bad or soon to go bad.