Factory radio tune up and adjustments

Discussion in 'Sparky's corner' started by CJay, Feb 12, 2011.

  1. CJay

    CJay Supercar owner Staff Member

    Let me preface this thread by saying that Im not a radio guy. I have no formal training in it. I know enough to be dangerous!

    With that being said, I'll try and show you a few tip and tricks Ive learned and pass along some information Ive gleaned in fiddling with these.

    I want to touch on bench testing. Its not that difficult to set up a bench testing station. I have a Samlex adjustable DC power supply I use. Its adjustable from 0-30 volts. For bench testing radios, I set it to battery voltage- 12.75. You can use any transformer that puts out 12 volts DC. Test it first though, dont assume! You'll need a radio harness pigtail cut from a parts car or a set of test leads. A cheapo 9.99 aftermarket radio antenna. And lastly, an 8-10 ohm speaker. I have an old home stereo speaker that just happens to be 8 ohm. make sure you verify the ohm rating as many modern speakers are 4 ohm which cant be used.

    [​IMG]

    If the radio crackles when you turn it on, the tuner is dirty. You'll need to get a can of tuner cleaner. Radio Shack still sells it. You want to spray the cleaner in between the sleeve and the shaft. Make sure you put a rag or a paper towel over the straw as it comes out with a bit of force and may spray back in your eyes. So be carefull! :Smarty: Work the volume control back and forth a little. You make need to give it a few applications before it clears up.

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    Next you'll want to adjust the antenna trim. Tune the radio to a station near 1400 khz that can barely be heard with the volume on full. Adjust the trimmer screw back and forth till you find the spot that gives you the maximum volume. The antenna trim gets adjusted on AM only.

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    Another adjustment you can make is a bias adjustment. The bias should be adjusted to 1.5 volts. Get a digital volt ohm meter, place the positive lead on the FM output transistor and the black to case ground. You can also check this voltage at the speaker wires. The FM output germanium transistor is on the black heatsink and is usually marked "Delco DS-501"

    If its out of adjustment, adjust at the control pot on the bottom of the radio. You dont even have to take the bottom panel off the radio. There is a hole for a small screwdriver. Adjust to as close to 1.5 as you can. This one's a little out of focus because I needed three hands.

    [​IMG]

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    There are more in depth adjustments to a factory radio. The Delco service manual outlines the alignment procedure to adjust all the trimmers. But for that you need a signal generator like a Sencore SG-165. In a nutshell you inject a specific radio signal through the antenna socket, attach an analog multimeter like a Simpson 260 to a specific area of the curcuit board and adjust the specific trimmer for peak. I'll be teaching myself how to do that in the near future. This pic is what the radio looks like from underneath. The tall square things are the trimmers.

    [​IMG]

    If anyone has any other knowledge that they can share, please add to this. I'd like this thread to become a reference for factory radios
     
    BUQUICK likes this.
  2. 71stagegs

    71stagegs bpg member #1417

    Hey Jason After all those adjustments can you hear the radio in your black car with the 308:moonu:
     
  3. dl7265

    dl7265 No car then Mopar

    great job Jason, let's make this a sticky.
     
  4. CJay

    CJay Supercar owner Staff Member

    Replacing the electrolytic capacitors-

    First, its my posture that, like anything else, if your radio is operating normally, leave it alone! There's no reason to fix it if its not broken.

    From my research, electrolytic capacitors smooth out fluctuations in voltage. The reason radio places want to change them is because have an electrolyte liquid in them that over time dries up causing problems like low volume, poor radio performance, noise, squealing, etc. Older tube radios have paper capacitors that MUST be replaced as they arent sealed and are always dried out after so many years. Solid state radios like ours use metal sleeved, sealed caps that dont go bad that easily like the older style. There are only a few electrolytics in our radios.

    From what Ive learned, there are two values stamped on them, the capacitance which is measured in microfarads (uF) and voltage. A typical one you'll see is a 12v, 100 UF cap. The types are radial and axial. Axials have a leg coming out of each end. Radials have the legs coming out of the same end. For our purposes, they also have a polarity. There is a pos and a neg leg. On an old Delco axial, it will be stamped +, the newer capacitors have a stripe. On an axial, the stripe will have an arrow pointing to the negative end. If you put them in backwards, they explode! So, in order to get the right cap, you'll need the style, uF and voltage rating.

    There are only a few of the electrolytic variety in a typical Delco radio. They seem to be readily available and are inexpensive. I have a couple of derelict AM radios Im going to try experimenting with. I havent replaced any on my radio yet, but it doesnt look that bad. looks like a simple soldering procedure. Like anything else, once you learn about something, it doesnt seem that difficult to do.

    As I said, Im no radio expert, but these are a few of the things Ive learned so far. More to come.
     
  5. Brad Conley

    Brad Conley RIP Staff Member

    Stuck.

    Only one thing...the antenna trim should be only adjusted in the car using the antenna there. Using a different antenna, which may or may not be a different length than the one in the car, can affect the adjustment. It will probably be real close though.

    Just speaking as an old radio amateur...
     
  6. CJay

    CJay Supercar owner Staff Member

    Good point Brad. The final tweak should be with the car's installed radio.
     
  7. errickrb

    errickrb Active Member

    ----- Re-posted elsewhere
     
    Last edited: Apr 19, 2011
  8. CJay

    CJay Supercar owner Staff Member

    I thought I would add to this thread with some cosmetic restoration tips that will make your factory radio look factory fresh with just a little bit of elbow grease .

    First, remove the two 5/8" nuts on the tuner and volume controls. Remove the 4 1/4" screws on the chrome housing and carefully remove it.

    [​IMG]

    Now flip the chrome housing over and you'll find a small clip that on a plastic stud and two screws that attach the metal insert and lens to the plastic chrome housing. Take a small right angle pick or other small instrument and carefully remove the clip without breaking the stud! Pry up under the clip a little at a time alternating sides and it should work its way up the stud till its off. Once you remove the two screws and the clip, you can remove the metal insert and lens.

    [​IMG]

    You should have these items in your hand now-

    [​IMG]

    Use a soft toothbrush and some mild dishwasing soap and clean all three items. Use some Mothers metal polish on the chrome and lens. Yes, the lens too. Mothers will remove the scratches in the lens and make it crystal clear again.

    Now, remove the 5 screws holding the top cover of the radio in place. The light and bracket are clipped into the underside. The clip just slides off. Now would be a good time to replace the light bulb. Most of the time the light has silvered or is just dim. The factory number is 216. Your local auto parts store should be able to match it up for you.

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    Next lets remove the little red pointer. If you look down into the radio, you'll see a little copper colored clip- remove it. Once its removed, gently lift up the pointer to remove it from the stud the clip was on and slide it forward. You'll notice that the back of the pointer has a small white plastic roller that will slide right out of a slot.

    [​IMG]

    You should have this in your hand. Take the pointer and give it a bath. Sand down the old red paint and repaint it on the backside as the factory did. Use Testors flouresent red or Guards red. Once its dry, give it a coat of white over the red to make it really bright.

    [​IMG]

    Next, we're going to remove the black metal housing that the band indicator is in. First, remove the cord from the AM/FM selector arm. Take a small screwdriver or pick and remove the loop from the botton its on

    [​IMG]


    Now slide the cord out from the eyelet in the front of the radio. You'll see by looking down into the radio that the dial indicator housing is held in by two 1/4" screws. One of them has a small clip. Remove both screws (and clip). Notice that this piece has two locating pins that it fits into. You can see them just inboard of the screws. Keep that in mind come reassembly time. Now carefully slide the dial housing out through the front.

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    You should have this

    [​IMG]

    Next, remove the band indicator. This is a little tricky as the right side has a small spring. Push the clear plastic indicator as far to the right as possible. That should allow the pin on the left side to remove itself from the hole its in. Carefully remove the band indicator from the black metal housing

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    Take note of how the spring is oriented.

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    You can now give the black metal housing a fresh coat of Sem trim black if required. If your band indicator is sun faded or damaged from age, I have replacements. You can see the difference in the original vs the new replacement

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    Take the time to polish up the black pushbuttons while everything is apart.

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    Now, in order to re assemble, just reverse the steps. With the nicely polished chrome and lens, the repainted pointer, fresh light bulb, replacement dial, polished push buttons and new black paint, your Buick radio should look as good as new!
     
  9. BRUCE ROE

    BRUCE ROE Well-Known Member

    When I spray the control cleaner, I look for openings in the back.
    If there are no natural spots, some might go in where the lugs
    come out, do each section. Doesn't take much here.

    Caps do fail with age, the polarized ones are the worst. They
    have + and - marks, unsymmetric cases. You can trace them
    down one by one each time one gets marginal, many of us just
    replace them all when they are old or there is a problem. The
    radio could still work marginally, with marginal caps.

    Mica or ceramic caps are usually good. Paper, very suspect. I
    have replaced them all many times, as the expedient way. For
    a tube radio, I wouldn't even think about it. good luck, Bruce Roe
     
  10. robs71redriv

    robs71redriv robs71redriv

    Jason this would be great thing for the Boattail Library - as would be your reference book - could you send me copie or your Ok to copy it from here.
     
  11. CJay

    CJay Supercar owner Staff Member

    If you think its worthy for your website, sure. I don mind. Like i said, Im no radio expert, but its a nice weekend project anyone can manage for not alot of money. And not too terribly involved. But just bear in mind, the appearance portion would not apply to a big car radio. The AM/FM selector slide on a big car radio is crimped onto the selector arm on the radio. So if you try and remove the chrome housing, you'll damage the radio (or at least the slide) . I havent gotten into the big car radios yet. so I havent worked out how to go about taking those apart. So this portion would only apply to the A body radios.

    Here is the finshed product. As you can see the radio really pops now. The freshly repainted pointer really makes a difference.

    [​IMG]

    Couple things to keep in mind-

    Make sure you dont put any finger marks onthe inside of the lens on reassembly. Make sure you only touch the edges of the lens.

    When you reinstall the chrome housing, make sure the AM/FM selector slide engages the selector arm on the radio.

    The chrome housings, lenses and metal inserts all interchange between AM/FM and AM radios. So if your AM/FM chrome is no good for example, you can steal it off that spare AM radio you have.
     
  12. robs71redriv

    robs71redriv robs71redriv

    Thanks Jason
    it will be bit before I get to - still working on the Christmas download
    Its really done up well - good knowledge - The library isn't just boattail - it covers all models. same principles for big car radios just things are moved round a little . and they may me the odd big car with one of these radios.
     
  13. dl7265

    dl7265 No car then Mopar

    In my spare time I've been doing a "chassis off" restoration. :laugh:
    The case was clear zinc plated, and phosphate on the screws.

    [​IMG]

    DL
     
  14. Olds F-85

    Olds F-85 Dr. Olds

    I Don't see the "Hit with BFH step":moonu:
     
  15. DelcoMan

    DelcoMan New Member

    GREAT JOB JASON! One of the very best reference pages i have found!
    Being some what of a Delco Car Radio expert my self. Certified by Delco in 1967 at the age of 14 i would like to add this:
    Electrolytic Capacitors are kin to two other items most car enthusiasts are very aware of the battery and points consider.
    With a lifespan of five to ten years at the very best. They do not age gracefully, soak up moisture like a sponge with a good quality one feeling to light to believe and bad on having noticeable weight. Most of the time.
    When they do fail they tend to take out other components many of which can only be found in parts donor units in 2014.
    They are the first item most of the time to go bad and no reliable trouble shooting can be done until all in a unit have been replaced.
    They should be replaced as routine as a oil change for preventive maintenance every 10 years. A bit less time in harsher climates.
    As well as the speaker as they are the tires of the radio.
    The pointer should not be sanded on the back side to remove paint as it will give a defused appearance to pointer. I use 91% ISP or Acetone on a Q~Tip just enough to wet the paint a few time then for removing old paint. Cleaning up with withe vinegar. This will yield a factory finish. And not as much danger of breaking tip off pointer.
    Great craftsmanship in the cosmology! Looks brand new!
    Something one might consider though? "It's only factory once" Collectors looking at a survivor with only necessary maintenance done to the car had much rather see the Sun baked faded patina and will use this as a tool to devalue Your Classic's worth.
    With some of the 70s GM cars now hitting $40~80K at Barrett Jackson Auction this could be a few $K.
    KEEP UP THE GREAT WORK
    Tony Mac Crutchfield aka TonyMac
     
    Last edited: Dec 23, 2014
  16. gs66

    gs66 Silver Level contributor

    Is there someone on the board here who reconditions factory radios? Bill Merrick used to do mine before his recent passing. I have a 66 Skylark AM/FM that I need looked over and working properly.
     
  17. wovenweb

    wovenweb Platinum Level Contributor

    I haven't tried this guy yet, but am considering, southtexasantiqueelectronics.com
     
  18. gs66

    gs66 Silver Level contributor

    Thanks, I will check them out!
     
  19. j69shep

    j69shep Active Member

    I restore all BOP radios and 8 track players from 64-72. I also sell them and I have a substantial amount of Buick radios in storage right now. I have over 15 years experience restoring old radios. Recently I successfully added bluetooth to this Pontiac AM radio but it will work on any AM radio including Buick. You basically stream AMFM stations or music services from your smartphone to your bluetooth enabled stock radio, Adjust the volume and tone from your radio while changing stations is done on your phone. I have developed a bluetooth receiver that mates perfectly with the old radios. A cost effective way to play FM stations on your AM radio while retaining all of the original circuitry inside your radio. The sound quality is very good and it works seamlessly while driving down the road.


    I successfully added bluetooth to this 1971 Firebird AM radio.
    It's a cost effective alternative to the expensive radio swaps out there. Your radio retains all of its original circuitry and your radio works normally when the bluetooth is turned off. It basically turns any AM radio into an AM FM allowing the user to play music services like spotify,sirius, or pandora. I use mine to play IHEART radio. IHEART is a free app that streams music from over 150 fm stations nationwide. Spotify and Pandora are subscription based but they do stream for free but you have to put up with commercials. Check it out.

    https://www.youtube.com/watch?v=K-Q0...m-upload_owner

    For info on radio repair or this modification email me at j65pony@aol.com or call/ text me 480-235-1964

    Thanks for adding me to this forum. Love the Buicks!
     
  20. 72newbiebuick

    72newbiebuick Gold Level Contributor

    He has done my radio and am quite happy with the work as well as the interaction when I had questions. Can't go wrong with this guy!

    Mark



     

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