Showing posts with label vintage. Show all posts
Showing posts with label vintage. Show all posts

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Thanks to eBay, I could buy one of these outdated chips!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