Circuit board damage due to leaky components

I was recently browsing eBay and a Walkman style cassette player popped up in the list. I was immediately interested as the player was a National Way RQ-WJ1 Cassette Player. These were made in the early 80’s by National that later went on to become Panasonic. The asking price was AU$400.00 (about US$270.00). It was being sold as faulty. Apparently the power light comes on but the tape doesn’t move. I found others for sale that were cheaper. All said they either didn’t work or were untested. One that sold as non functional went for AU$194.00 (US$130.00).

The reason I was interested is that I have two of these. My wife and I bought one each in the summer of ’83 for around AU$100.00 each. According to the RBA inflation calculator that is about $337.00 in today’s money, so not exactly cheap. We didn’t use them much, but I have good memories of them. They were working when last used and since then they have been sitting in a cupboard.

The National Way is quite a small Walkman style cassette player, not much bigger than a cassette. It measures 75 x 108 x 30mm. Probably not the smallest player but definitely small. One interesting feature is that it has two headphone jacks so two people can listen at once.

I got them out and inserted batteries, a cassette and pressed play. The power light came on, but the spools didn’t rotate. I suspected a perished belt. Strangely after a while the spools began rotating but there was no sound. I decided to open up the case. It is quite easy to get the back off. It has lots of small screws and the back comes off easily when they are removed.

I was not expecting what I found, both in terms of damage and technology. It mainly uses surface mount components and there are lots of them. Most that I could see didn’t have values marked on them. According to Wikipedia, surface mount technology was developed in the 1960’s and “By 1986 surface mounted components accounted for 10% of the market at most, but was rapidly gaining popularity.” So not very common in 1983. The parts are mounted on a thin flexible PCB. The other big surprise was the damage. I’m fairly sure batteries were not left in them and I can’t see any evidence of damage around the batteries. It appears there have been a lot of damage due to leaking capacitors.

This is where I gave up, at least for now. Even if they were working, I have no plans to use them. I’m posting this as an example of what work may be required if you buy some old untested or not working technology. If you already have one, I found this tutorial that covers change the belt which required removal of the PCB National/Panasonic RQ-WJ1, RQ-KJ1, RQ-SJ1 belt change (tutorial).