Last year I took on a new hobby – vintage audio equipment. Since then I’ve amassed a LOT of vintage equipment, including 1970s gear from Sansui, Pioneer, Harman Kardon, Sherwood, Kenwood, and Yamaha. I’ve got about 10 of these now, as I love the sound of 1970s transistor-based receivers and amps. But in buying these devices, I also took on two new hobbies – finding ways to interface modern equipment to the ancient devices, and then repairing them when they inevitably break due to their age. Capacitors, transistors and solder joints don’t last forever.
The first new task – finding ways to integrate old tech into new tech (Bluetooth, DACs, modern connectors) was fun. Chi-Fi (the Chinese industry of making millions of parts/devices for audio, at bargain prices) means that almost anything you can imagine, you can find online. I’ve gotten pretty good at coming up with ways to modify modern speaker cables to work with the panoply of crazy power-out interfaces on old the old gear – every receiver types uses a different speaker connector. And the cream of the Chi-Fi crop is my Fiio K13 R2R DAC – that thing really makes the sound come alive, and gives a way to bridge new tech (Bluetooth and a superb DAC) to vintage AUX interfaces. I like it so much I have one in CA and one in KY.
In my previous life I didn’t have the time or patience to do all this. My stereo ventures from 2000-2024 were new gear, stuff I knew would sound good and not need immediate repair. But now I’m all in on the geriatric stereo gear. So I finally decided to dive into the final stage – learning to repair vintage audio gear. There are VERY few people who actually do this today – it’s complicated, frustrating, daunting in terms of how much one has to learn, requires patience (uh oh), and is a bit expensive to get started in, as you need a lot of repair tools/devices. Sounds perfect.
It helps that I’m a degreed EE – I can understand everything I need to do, but going hands-on with circuitry, debugging it and then fixing it, is something I haven’t done since my very first job at Goodyear Aerospace in the 1980s. At that job I wore a three piece suit every day, replaced the suit coat with a white lab coat once at work, and spent the day tracing and repairing wiring on what was then one of the world’s fastest computers. Wild times.
I really have come full circle. That first job was the time when I was truly happy with work – I learned constantly, and the hands-on aspect felt right to me. I only got into management for the money. And yeah, the money part worked out, but I was miserable for a very long time. Lesson learned, though a bit late.
Sooooo, in the last couple of days I dove in. Ordered a boatload of techie shit from Amazon, and took on my first two repair jobs. One, my old PSB Stratus Mini speakers – I broke a speaker terminal years ago and just let them sit unused since then. And two, my Sherwood 7450 receiver, in which the left channel drops out often and drives ugly noise through the speakers.
I just finished the speaker repair, and it was a bitch. Had to remove the entire crossover from the speaker, and then try to remove one terminal where the lock nut was buried deep in the assembly. Took me hours just to get the broken terminal removed. Here’a shot where you can see the broken terminal, but what you can’t see if how deeply the lock nut is inside the crossover assembly. Very inaccessible. The wrench hanging off the side is a clue.

The replacement terminal I bought on Amazon (from China, natch), wasn’t ideal. Its center spindle was way too long, so I had to come up with a hack to reduce the spindle length poking through into the crossover. The result is ugly (next picture), but it works. It’s ugly enough that I’ll probably re-do the repair with a different terminal, but that’ll have to wait a while. I just wanted to be finished with something before I took on the Sherwood.

The jumpers you see in the picture (the original gold jumpers and a new red one) are because the Mini’s can be bi-amped – you can drive the woofer section with a different amp than the tweeter. When you don’t want to do that, you just bridge them. And I couldn’t use the original gold jumper on the new terminal hack. I won’t be able to sell these speakers until I do a better job with the repair. But on to the Sherwood.
It’s taken me most of a day just to strip the receiver down to where I can get at most of the inside. The physical disassembly of the Sherwood isn’t easy – looks to me like the thing was not designed for easy repair. Getting the faceplate off was tough. The title picture above shows the mess I made just getting set up and disassembling. And here’s a shot of the receiver ready for troubleshooting.

The last/latest update on all this is that I think I’ve found the problem through visual inspection – there’s a solder joint obviously missing on the underside of the main control board. I have to wait to get the service manual/schematic before I can be sure, but if that’s it, then I got off easy. No test tones, no oscilloscope work, no laborious multimeter work – just a solder repair. Here’s an up-close shot of the offending solder point – at center/top, you can see the device leg sticking through with no solder connecting it to the circuit trace. Even if that’s not THE problem with the Sherwood, it sure doesn’t seem right. More later.





















