| audio, gear, JVC, vintage | 12 comments

This receiver is over 45 lbs and almost two feet wide. Rated at 120 watts/channel, it's a monster. I had to replace the power switch because it was almost completely corroded inside, causing visible arcing and smoke.

This was another one of my recent summer acquisitions. Weighing in at just over 45 lbs and almost two feet wide, the JR-S501 was the top of the line receiver that JVC had to offer in the late 1970s and early 1980s. It is the big brother to the JR-S401 and JR-S301 models released at the same time. Rated at an incredible 120 watts per channel RMS, this thing is a monster. With an extremely low THD rating of 0.008% and a 95dB SN ratio, it is also one of the cleanest sounding receivers you'll hear from that era.

Another standout feature is the five band SEA (Sound Effect Amplifier) graphic equalizer, which not only provides more control of the sound, but also introduces far less distortion than standard tone knobs found on most other receivers. JVC actually licensed this technology out to various other high end manufacturers, one of which being McIntosh who apparently still uses it today for their modern equipment.

Unlike some of my other recent restoration projects, this unit needed a bit more work. The main issue was that the power switch only worked half of the time, and when it did, the lights cut in and out repeatedly. After removing the top cover, I immediately saw the problem. With the power turned on, I could see electricity arcing within the power switch assembly—a healthy wisp of smoke followed as well.

My first attempt to fix it involved desoldering the switch from the circuit board (got some good practice doing this) and taking the switch apart. Inside I found that the metal contacts had been almost fully corroded from constant arcing. I tried to clean them up with some contact cleaner, but it was futile. The switch needed to be replaced.

Finding a replacement switch for a vintage receiver that perfectly matches the circuit board is just about impossible. I tracked down the part number from the service manual, and a few online parts stores claimed to sell it, but they all listed it as "out of stock". I contacted a few of them to get specific information regarding it's availability, but nobody responded.

Out of options, I contacted my cousin who helped me with the Sansui AU-5900 a few months back to see if he had any suggestions. He suggested we buy a modern switch that closely matched the dimensions of the original and build our own damn circuit board for it. It sounded crazy, but he was confident. The power switch had its own little circuit board that was separate from the rest of the receiver, so I knew it wouldn't be too difficult. We took measurements, ordered the parts, and waited.

A few days later, I took the receiver to my cousin's place where he showed me his work. He actually integrated a TRIAC into the circuit which greatly reduced the voltage on the switch, essentially guaranteeing that the arcing problem will never happen again in the future. This was a suggestion I had previously read about on Audiokarma.org, but I dismissed it as an option because I had literally no idea how to do it myself.

With the switch replaced and the new circuit board wired and mounted into the receiver, it was time to reassemble everything. Accessing the power switch was pretty tricky, and I had to remove the tuning string for the radio to get to it. Even with the re-stringing diagram in the service manual, it was a huge pain in the ass to get right. I think it took us more time to re-string the tuner dial than it did to replace the power switch. Finally though, we got it, and the receiver was back in one piece.

I've been using this receiver as my primary unit for the past few weeks, and the new power switch works gloriously. It's just a shame I can't utilize all 240 watts while living in a condo.


good looking unit, iam a little confused as to whether or not this is for sale? if so do you still have it or has it been sold . I have a 401 with the same problem I think, unit used to blink on and off before , now it wont even turn on . looking for options

It was for sale, but it's been sold months ago. Sorry!

i have a jvc jr-s301 with the same problem, arcing power switch that will not turn on, only the lamps will come on. how did you do this & what parts did you use to do this. live in birmingham, alabama

I'd be grateful if you would let me know what switch you used to replace the original.

I have this model and I do use every bit of its 240 watts, sorry Jeff but you should've cranked it up when you had it, neighbors come and go it's better to send them off with loud music.. Always rock out. No problem with my power switch but I do have a problem blowing speakers out.

I purchased this unit in 1979 with all the money I earned form working all summer. Can't remember the strobe light turntable brand/price but I remember the stylus was $78. I bought (2) 3-way speakers-- w/very large cabinets. The mid range was 5," Woofer probably 7," and a 3" tweeter if memory serves me correctly. 'The Rover' by Led Zeppelin never sounded better. This stereo system was the reason I failed most of my classes in high school and 37 years later ended up in a dead end, low wage job in a warehouse.

I purchased one in 1978, what a monster it was....

I had one of these 1979 awesome being young 8never appreciated how lucky I was to own such a beast of an amplifier.
I recently bought the Jr-s401 as I could not find the one you have but I forgot that the 401 does not have the auxiliary function which is a shame, anyway you have done a great job and your unit looks fantastic, well done 🖒

I have one for sale

I bought one of these in the BX at Zaragoza AB, Spain in 1978. I had it hooked into two JBL L-110 in the front, and two Bose 301s in the rear. I also had two cassette decks and a nice Technics turntable. I sold it a couple years later in Korea. Big mistake. I wish I'd kept it.

Please relay to Tom cannon APRIL 2, 2017 | 6:28 PM
"I have one for sale"

I have the same problem in an hitachi amplifier with the same power switch. What is the power switch reference you used to repair your amplifier ?
Thank you for your help