Am/Fm Blue-Light Radio

[mark x22]

My car was built 12 B 1968 and has the same numbers 7307331 , 91BFM2. It is an original blue light radio

[IZRSSS]

Thank you Mark!
Obviously more research has to be done on this radio. There are too many discrepancies between FM1 & FM2 designations.

[mark x22]

My serial number starts with 31FSB

[IZRSSS]

Thanks again Mark...Paceme PM'd me and it looks like more research is needed. As they say; to be cont'd...

[KurtS]

Looks like you can't assume there's a correlation between the light color and the FM1/FM2 codes.

[Steve Shauger]

Well so far we know the blue light was available in FM1 & FM2.  One way to possibly define the transition date from blue to amber light is dating the units themselves. I believe the output transistors are date coded. One example I have is a FM2 blue light I purchased fall Carlisle 1981 it has an output transistor dated 6916 = 1969 , 16th week. I also verified one of my survivor cars built 9B of 68 which has an AM radio PB1 with an output transistor dated 6837 or 1968 37th week.  Obviously this is not a perfect way of dating a radio but....


Here is a start of data table:

Rev        Light        Transistor date     Date
FM2          Blue          6916              1969   16th week



Anyone else?

[IZRSSS]

If this is the only way to distinguish between FM1 and FM2 then perhaps a lesson in radio vasectomy is in order.

Steve, will you please explain the dos and don'ts of prying into one of these radios? This is a much smaller scale but when I was young and stupid I opened the back of a TV thinking that simply unplugging the unit would cut the power. I touched something inside with a screw driver and it knocked me out.  My hand was the ground and the carpet underneath started on fire. Electronics to this day scare the boigie's out of me, think that's a word.

Will you also post pics of the transistor you are referring to.

Thanks

[Steve Shauger]

The transistor I was refering to is locate on the external heat sink on the back of the unit. I used and inspection mirror and its relatively easy to identify.

I reviewed my radio service manual 1969 edition bulletin 6D-1969-1 and it has the schematic and parts list for the later FM2 revision. It notes that for FM1 schematic and parts list use the service bulletin 6D-1968-1.

[IZRSSS]

Is this service bulletin (6D-1968-1) on-line or do you have a pic of the page that references this transistor?  In addition, can you access it without removing the radio?

http://www.camaros.org/crgrefs.shtml#1968Refs  (1968 Specific References #14)

[KurtS]

Thanks for mentioning the transistor date. I was going to, but forgot.

In this pic, the blue and brown wires appear to come out of the transistor. It's silver and round. See them in Chris' pic.

[IZRSSS]

Thanks KurtS & Steve!

Build Date     Rev     Light      Transistor Date        
12A               FM2     Blue       6843          

[1968...43wk (3rd wk Nov)]

[Steve Shauger]

  Car Build             Rev        Light        Transistor date     Date
      NA                FM2          Blue          6916              1969   16th week
      NA                FM2          Blue          6917              1969   17th week
     12A               FM2           Blue          6843             1968    43rd week


      9B                 PB1         AM             6837              1968   37th week

If anyone has an amber light stereo your assistance is needed so that the transition from date from blue to amber can be determined.

[IZRSSS]

Just curious...Why are you including Am's (#4)?

[Steve Shauger]

Just curious...Why are you including Am's (#4)?

Just providing data that the transistor date correlates to the bulid date of the radio, and to the car. At this time we only have your car build date . I seperated it from the FM list so as not to confuse the issue.

[mark x22]

Mine is 12B 1968 car FM2  blue liight  6842   1968 42 week