The radio…it’s alive – 37 years later

A former owner, Jim, told me that the original AM radio never worked during the time he had the Z/28.  He said that’s why he put the 8-track player between the seats.  That means the radio didn’t work for at least 37 years. 

At Labrecque’s, Kevin and I took the radio out of the console. 

I brought the radio into work, plugged in the restored/reconed speakers, connected a power supply and nothing happened.  Nothing except the power supply immediately went from +12V to +3V.  It looked like something was shorting out big time.

Almost all radio restoration places start by replacing electrolytic capacitors.  I read somewhere, that 90% of the time the problems come from dried out electrolytics and they can cause shorts. 

The AM radio model is:

91APB1
9 = 1969 model year
1 = GM vehicle division: 1 = Chevrolet division. (2=Pontiac, 3=Oldsmobile)
A  = the vehicle is either a Camaro or a Chevelle
PB = AM pushbutton radio
1 = first design run.

Through Sams Photofacts, I was able to buy a schematic for model 91APB1 which identifies the electrolytics.  After loads of searches, I found a vendor that had original GM electrolytics.  This is nice because it keeps the radio with original type components.  Especially for the huge can type that has 3 different electrolytics in one can.  It was a pain to get the circuit board off but after a while it finally gave up fighting me and I was able to replace the capacitors.

 

 After replacing the caps, I soldered everything back together, hooked up the speaker, put power to it and then……..thundering classical music BLARED from the radio.  I didn’t realize the volume was at full blast.  It almost knocked me off my seat.  Engineers came down from the engineering offices asking me what was going on.  Once the volume was set low, it was so nice to listen to the AM radio with the 43 year old electronics working as they’re supposed to.