Author Topic: Am/Fm Blue-Light Radio  (Read 43232 times)

Mark

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Re: Am/Fm Blue-Light Radio
« Reply #45 on: November 03, 2010, 09:34:05 PM »
Nope. The 91BFP1 is the mono radio, the 91BFM1 is the early version of the AM/FM Mulitplex blue light radio, and the FM2 is the revised version (Zener Diodes - DS149 unit) AM/FM Multiplex radio.  Need to dig into my 69 delco Radio service manuals to see if i can find the yellow light version in there, but i don't think its actually a 69 radio, I think its a 70 model year radio and it was used in the camaro becuase production ran so long.  The 70 and up radios with the square heat sink fins do fit in a Camaro, The fins will touch the defroster vent but not really badly.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

Steve Shauger

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Re: Am/Fm Blue-Light Radio
« Reply #46 on: November 03, 2010, 11:07:08 PM »
Nope. The 91BFP1 is the mono radio, the 91BFM1 is the early version of the AM/FM Mulitplex blue light radio, and the FM2 is the revised version (Zener Diodes - DS149 unit) AM/FM Multiplex radio.  Need to dig into my 69 delco Radio service manuals to see if i can find the yellow light version in there, but i don't think its actually a 69 radio, I think its a 70 model year radio and it was used in the camaro becuase production ran so long.  The 70 and up radios with the square heat sink fins do fit in a Camaro, The fins will touch the defroster vent but not really badly.

I am leaning that way as well Mark. I was hoping Chris's car had the factory wiring with the 70 connector. I knew a 70 stereo radio would fit but rather snug. I would like to confirm by examining an unmolested Oct/Nov built car with a stereo.  I remember years ago talking to the radio repair guy located in Fairless Hills, Pa,  and he stated he has never seen a amber light stereo in the 69 configuration (ext multiplexer and large side pount plug) FWIW.   
Steve Shauger
Vintage Certification™ Program, Providing Recognition And Status To Unrestored Vehicles.  The Supercar Registry-www.yenko.net-

Dave69x33

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Re: Am/Fm Blue-Light Radio
« Reply #47 on: November 04, 2010, 01:53:39 AM »
Is the bracket shown in the picture attached for a '68 with the U79 radio amp? 

Were the U79 Amps different between '68 and '69?

The '69 AIM, page 445 covering the U79 option, shows the amp bracket was part of the #7307361 amp, and mounted behind the glove box.  Attached are pictures of my U79 "Blue Light" receiver #7307311 with DS-501 transistor date code 6838 or the 38th week of 1968, and the amp #7308261 which is not the #7307361 amp noted in the AIM. 

Also, the U79 option used the U63 AM FM Receiver but then added the stereo amp and included the four speakers, correct?

Steve Shauger

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Re: Am/Fm Blue-Light Radio
« Reply #48 on: November 04, 2010, 02:03:51 AM »
Marty (IZRSSS) asked me if his radio FM2 was in fact a stereo radio and what the zener diode change was in a PM to me. He also asked me to post my response to him as a clarification for others.

"Real simple. You have a am/fm stereo (FM2) second design which incorporated a change in the zener diode(per Mark). A zener diode can be used for many purposes with the radio's  circuitry, such as setting a reference voltage or stabilizing/regulating voltage in the amplifier stage. This is a very minor change..."
                                                                                 RPO
1969 AM radio                 91APB1                                  U63    
1969 AM/FM MONO  radio  91BFP1                                  U69
1969 AM/FM-STEREO radio 91BFM1   First Rev Ext MPX       U79
1969 AM/FM-STEREO radio 91BFM2 Second Rev Ext MPX     U79

Hope this clears it up."

Steve Shauger
Vintage Certification™ Program, Providing Recognition And Status To Unrestored Vehicles.  The Supercar Registry-www.yenko.net-

IZRSSS

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Re: Am/Fm Blue-Light Radio
« Reply #49 on: November 04, 2010, 02:22:02 AM »
Nope. The 91BFP1 is the mono radio, the 91BFM1 is the early version of the AM/FM Mulitplex blue light radio, and the FM2 is the revised version (Zener Diodes - DS149 unit) AM/FM Multiplex radio.  Need to dig into my 69 delco Radio service manuals to see if i can find the yellow light version in there, but i don't think its actually a 69 radio, I think its a 70 model year radio and it was used in the camaro becuase production ran so long.  The 70 and up radios with the square heat sink fins do fit in a Camaro, The fins will touch the defroster vent but not really badly.

Thank You Mark and Steve! All of a sudden these radios became very complicated and its nice to know there are knowledgeable individuals such as yourselves to help out. I don't think I'll ever forget this lesson in radiology  ;D!

Hopefully the second phase is close in hand...transition from blue to yellow.

Thanks again.

Mark

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Re: Am/Fm Blue-Light Radio
« Reply #50 on: November 04, 2010, 02:31:57 AM »
68 U79 was a unique radio setup, every part was different than any other radio used in 68, no parts are the same as any 69 part either.  The bracket looks correct for a U79.  Attached is a picture of a complete unit for a 68 Convertible.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

Mark

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Re: Am/Fm Blue-Light Radio
« Reply #51 on: November 04, 2010, 02:43:24 AM »
This is the 69 Multiplex bracket, its upside down from how it is installed in the car.  The two bolts are under the cowl panel down in the windsheild wiper well. They are installed from outside the car, must have been fun to line up with the bracket inside the car.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

Dave69x33

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Re: Am/Fm Blue-Light Radio
« Reply #52 on: November 05, 2010, 12:19:29 AM »
Mark,

Is the bracket you show permanently attached to the '69 U79 amp?  Is there a date code and/or unit serial number on this amp or amp transistor?

After looking at my “L” shape bracket, did you mean that the bracket looks correct for a '68 amp?

I wonder if there was a change early in the '69 model year from the "L" shape bracket to the cradle style bracket, and if it can be determined from the date code of the amp, or  date code of the transistor to date the amp, when the bracket change took place?.

I was also wondering if the radio and amp serial numbers relate to the unit’s date code in any loose sort of way.

I now live in Indianapolis, but I was born and raised in Kokomo, IN, about a 45 minute drive north of Indy.  As you can see on the labels attached to the radio and amp units we are discussing, Kokomo is where the Delco Electronics plants are located that once designed and manufactured nearly all GM radios and speakers until the early to mid 1980s. 

Since the “arranged marriage” between Delco and Delphi, GM spun-off of Delphi, and then more recently bought back what was left of Delco Electronics.  Today, Delco E is primarily a R&D and design center for automotive electronics, and still operates a clean room physicality manufacturing IC chips.  I have family who retired from Delco and have friends still employed there.  It might be a fat chance, but I’ll try and track down some people who can “shed some light” on the blue light vs. amber light, and other radio related details. 

The old Delco Remy plants are located about 35 minutes northeast of Indy in Anderson, IN, that manufactured starters, alternators, voltage regulators, horn relays, etc.,  I am also trying to track down some information on the CZ vs. CZ1 vs. CZ4 stamped 1100837 alternators used on the ’69 Z28 and several other HP GM vehicles.  If I am successful, I’ll keep our Camaro friends on CRG posted!

Thanks,

Dave

Mark

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Re: Am/Fm Blue-Light Radio
« Reply #53 on: November 05, 2010, 01:22:07 AM »
No the bracket comes off, its bolted to the bottom of the multiplex amp it uses those two diagonally spaced holes to attach the bracket to the amp.

Yes, the L shaped bracket looks correct for a 68 multiplex amp.  It goes on the opper left corner of the amp as it sits in my picture, the bottom of the L would be on the side at the top in the picture, and it would run down the left side of the amp, and the angled part would turn out away from the amp.  This amp is not the same as the 69 one, its part number is 7305221 and it is actually mounted vertically up above and to the right of the steering column on a 68.
Mark C.
1969 Indy Pace Car
350/300HP RPO Z11

Dave69x33

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Re: Am/Fm Blue-Light Radio
« Reply #54 on: November 05, 2010, 11:58:41 PM »
Thanks Mark.

rpol78

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Re: Am/Fm Blue-Light Radio
« Reply #55 on: March 18, 2014, 12:25:00 AM »
I have a yellow light AM/FM Stereo radio.  It's an FM2 model with a 6919 transistor date. 

rpol78

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Re: Am/Fm Blue-Light Radio
« Reply #56 on: March 31, 2014, 01:58:06 AM »
Here are a couple of pictures of the yellow light radio.

rpol78

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Re: Am/Fm Blue-Light Radio
« Reply #57 on: March 31, 2014, 01:59:55 AM »
Here's a couple more pictures of it.

Dave69x33

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Re: Am/Fm Blue-Light Radio
« Reply #58 on: January 19, 2023, 01:45:43 AM »
Hello Mark,

I would like to revisit the topic concerning the cradle bracket used with the ‘69 U-79 “Blue Light” radio.

Do you still own it?

If so, can you check to see if the bracket is stamped with a part number?

Can you post several more pictures of the bracket from different views and perhaps laying next to a tape measure. I may try to reverse engineer it and make one.

Thanks,
Dave