Thursday, March 9, 2017

Inside 1980s Sanyo Radio Alarm Clock

When my Dad was in college in Boston, there was a nearby RadioShack where he got all his parts.
I believe this is one of those purchase from said RadioShack. 
This alarm clock has been in my room (used by my brother) for as long as I can remember. I brought it to college with me as a desk clock. I thought it was a beautiful design, and I liked looking at it when I was working.

Cosmo Model CR 2001A

This past December I believe there was a power surge while we were on break. I came back to a broken hard drive and a busted alarm clock. I attempted to fix it. Here are some pictures of the insides for anyone interested!

There's a 9v battery in case of power outages to keep time.

A warning that I will not heed.

Taking off the front cover

I was stunned when I opened this up. It didn't hit me that in the 1980s, electronics were still very new.

The entire interior was very dusty and fragile.

A better look inside. The speaker is on the top, the clock circuit is on the left, and the AM/FM radio is on the right.

The circuit board for the switches and buttons is screwed to the top cover.

The circuit boards made back usually have phenolic as a substrate

Look at this crazy tuner! A string is wrapped around the potentiometer to move the pointer.

This is such a clever way of making a display.

The wires are kind of messy. Old circuit boards have a lot of smooth traces.

Top view of the radio board.

The clock doesn't display correctly.

I decided that perhaps the problem was in this IC chip.
This is the LM8560, which is used specifically for alarm clocks.

Thanks to eBay, I could buy one of these outdated chips!

I soldered in the new chip. It was painful, I broke several pads.

Notice anything broken? Me neither.

Broken pads are pretty hard to find, especially if you didn't make them. I had to jump some connections.

You also sometimes discover broken components! This capacitor was bulging like crazy and had a broken lead.

It's amazing how components deteriorate over time. There were plenty of resistors that didn't have paint on them anymore.

The college dorm life...

I couldn't fix the alarm clock. Unfortunately, the IC chip was not the issue. I tried tested out the other components.
However, every time I desoldered, tested, or even touched a component, I risked breaking a very delicate and irreplaceable part.

Primum non nocere - "First, do no harm" - from the Hippocratic Oath (??)

I decided that I was probably going to do more damage than help, so I put the clock back together.

At least the radio works!