I’ve seen this piece of crap lying around at the thriftstore for months. Even the employees started to notice it and decided to slap a sticker on it: 50 eurocents. Well, yellowed buddy, you can come with me.
I could not really find any information about this particular alarm clock radio, and I even feel like I am the first on the internet to give any form of unneeded attention to it. Judging from the design, the ICs I bet it is late 80s, early 90s.
Upon plugging it in the whole darn thing didn’t turn on or respond to any button or switch configurations, I would find out later why this is so…
Features
I’m not even going to go in depth on this one. It’s a simple alarm clock radio with all the functionality you would expect from one. Leave a comment if you need details.
Teardown
Opening up is a piece of cake, four or so philips screws and we’re in.
All the interesting stuff in the upper part and the speaker and button interface PCB on the lower part. Tranformer is center tapped with about 9.5V per tap. Lets zoom in further.
As visible, a simple rubber dome interface of which the former didn’t survive long. Dried out and broken off. Junk.
Pretty much all functionality is put into an LM8560 from some funky company. This chip is well documented and is for some still a hobbyist favourite. The display is an LED 7 segment variety.
Absolutely terrific decades old manual children labour.
The amplifier chip is a KA2201. Pretty much comparable to an LM386: low voltage, low power mono amplifier in DIP8. Also visible some coils, transistors and passives of the RF tuning circuitry. This thing does both FM and AM.
It even has 2 germanium diodes! I can now sell it for a big profit to some guitar pedal enthusiasts.
Not much to see on the backside. The tuning mechanism and the marking NL-329 AM/F. There is also a marking of some company with “KF” as logo.
Repair
As previously mentioned, the thing doesn’t start up when plugged into mains and the 9v backup battery leads were cut off for some reason. I incidentally found out it actually does turn on when holding the mains cable at a certain angle. I almost feel bad for resurrecting it.
The radio and audio portion of the device works fine. The alarm clock portion however does not as the button pads on the PCB barely react to any for of manual shorting. I’m not motivated enough to debug and repair this.
Trevor's Repair Café 