It ain't easy.... being GZ!
- Thread starter blu_fuz
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caution
Member (SA)
LOL thanks SLO 
Mmmm updates, sweet sweet updates....
Both decks are humming along, the lower one was missing that super-thin machine screw for the back so I bored out the plate and used a slightly larger self-tapping one. It was the only one I could find that was even close, but the head was stripped, so I dremeled a groove in it. Flathead screw now
The bottom of the plate has to be secure against the rest of the deck or else the catch for the groove in the solenoid falls out. You don't want that, that's bad.
Now the buzzing. It's strange, you can see the tape run lights get brighter when it buzzes, like the whole radio is surging off the mains. If you use either deck the buzzing goes crazy. If you just listen to the radio though, the buzzing is less often, and when it's not there it sound crisp and clear.
I tried a spare transformer board from a Conion and it worked fine, but the buzzing remained. Okay, not that board. The buzzing is there on batteries too, and it's not the stereo mode switch as I thought, so I'm thinking it might be cracked solder joints on the bass/treble/balance knobs, your bass knob is doing freaky stuff like mine did, but it cleared up with a resolder, so I'm going to try that. I'll have the whole board out at that point and I can take a good look at all the parts. The way it buzzes when things pull hard, i.e. a tape motor, on the main power, makes me think there's improper grounding in either an intermittent solder joint or a bad part like a cap or amplifier chip. We. Shall. See.
Props to Joe for the nice harnessing
Mmmm updates, sweet sweet updates....
Both decks are humming along, the lower one was missing that super-thin machine screw for the back so I bored out the plate and used a slightly larger self-tapping one. It was the only one I could find that was even close, but the head was stripped, so I dremeled a groove in it. Flathead screw now
The bottom of the plate has to be secure against the rest of the deck or else the catch for the groove in the solenoid falls out. You don't want that, that's bad.Now the buzzing. It's strange, you can see the tape run lights get brighter when it buzzes, like the whole radio is surging off the mains. If you use either deck the buzzing goes crazy. If you just listen to the radio though, the buzzing is less often, and when it's not there it sound crisp and clear.
I tried a spare transformer board from a Conion and it worked fine, but the buzzing remained. Okay, not that board. The buzzing is there on batteries too, and it's not the stereo mode switch as I thought, so I'm thinking it might be cracked solder joints on the bass/treble/balance knobs, your bass knob is doing freaky stuff like mine did, but it cleared up with a resolder, so I'm going to try that. I'll have the whole board out at that point and I can take a good look at all the parts. The way it buzzes when things pull hard, i.e. a tape motor, on the main power, makes me think there's improper grounding in either an intermittent solder joint or a bad part like a cap or amplifier chip. We. Shall. See.
Props to Joe for the nice harnessing
caution
Member (SA)
One thing I forgot to mention is that the switch in the AC outlet that cuts off the batteries is shot. There are three plates, and they were all scratched up from somebody else previously in there trying to fix it, presumably to make a better connection. But one of the rails in the plastic molding to keep the plates parallel chipped away, so it's loose, and so the button doesn't have pressure on it and doesn't switch to batteries when the cord is out. I can't think of a safe way to fix this part. We could repurpose the 110/220 switch to be battery/AC if all else fails.
caution
Member (SA)
Scavenged an outlet from an old Panasonic after some drilling and slicing. Not as beefy but will work. I ground off the DC plug and kept that. Used a detachable power plug from a PC for the radio power.
What's the history on the two main boards, are they both new?
I was able to reattach things with it spread open for testing, crossing fingers for power-on tonight...
Also, a well-spent $50 at Harbor Freight and a $7 DT-600 from the Goodwill
What's the history on the two main boards, are they both new?
I was able to reattach things with it spread open for testing, crossing fingers for power-on tonight...
Also, a well-spent $50 at Harbor Freight and a $7 DT-600 from the Goodwill
The 2 main boards are from another clairtone box. The history of them was "the boombox works but makes some weird noises".
I did a trade for the boards atleast knowing that they did something. I was hoping after swapping that the contacts/pots might have just needed a good cleaning but it didn't help the distortion BUT I was VERY happy to have some sound and getting this boombox to function at all.
The original boards I removed only allowed the radio to turn on and the siren to work. There was no noise, no music, no output, no tapes, no radio, no line in, nothing would make the meters swing or the LEDs light up.
I do still have the original boards here just in case.
I did a trade for the boards atleast knowing that they did something. I was hoping after swapping that the contacts/pots might have just needed a good cleaning but it didn't help the distortion BUT I was VERY happy to have some sound and getting this boombox to function at all.
The original boards I removed only allowed the radio to turn on and the siren to work. There was no noise, no music, no output, no tapes, no radio, no line in, nothing would make the meters swing or the LEDs light up.
I do still have the original boards here just in case.
-GZ-
Member (SA)
What joe said. ^^^ Only one other person has worked on that box besides joe while its been in my possession. I have no idea what else has been done to it.
You are a maniac, Eric!!!! Much respect to the Panny for the organ donation....may she rest in pieces.
Just put it all on my tab, and send me your paypal so i can float some cash your way so youre not doing this all out of pocket.
You are a maniac, Eric!!!! Much respect to the Panny for the organ donation....may she rest in pieces.
Just put it all on my tab, and send me your paypal so i can float some cash your way so youre not doing this all out of pocket.
caution
Member (SA)
Haha well you know any reason to tear apart something with electronics inside, I go crazy
Some updates!
Since it made no sound with the previous amp/control boards installed, it's impossible to say if the noise issue originated from the replaced boards or something else inside. I've now narrowed it down to the two boards Joe replaced. Nothing from the tuner, lower deck or record level board are attached, just two cables from the power switch to the amp board, and three connections from the amp board to the control board (and some audio on line-in).
An initial series of buzzings occur but dies down within a few moments and the audio sounds just fine, with the exception of higher volumes and/or heavy bass, you will hear very noticeable clipping.
I got a new set of caps for the amp board and new amp chips, but I'm trying to make sure they actually need replacement. I'm going to try reflowing some connections tonight, and will probably try recapping the largest set and see if it makes a difference.
The weirdest thing I've noticed is that the cable from the power switch that goes to the lower deck board must stay plugged in or else I get the loudest buzzing, it fades between each channel about every second. Nothing else is plugged into the lower deck board, so I'm thinking the cap soldered on the back side by this connector is providing some sort of much needed stabilization in the system's current state. This connector does not have any impact on audio if I unplug it from a reference C100-F frame I have that I plugged into your chassis.
Gettin' there!
Some updates!
Since it made no sound with the previous amp/control boards installed, it's impossible to say if the noise issue originated from the replaced boards or something else inside. I've now narrowed it down to the two boards Joe replaced. Nothing from the tuner, lower deck or record level board are attached, just two cables from the power switch to the amp board, and three connections from the amp board to the control board (and some audio on line-in).
An initial series of buzzings occur but dies down within a few moments and the audio sounds just fine, with the exception of higher volumes and/or heavy bass, you will hear very noticeable clipping.
I got a new set of caps for the amp board and new amp chips, but I'm trying to make sure they actually need replacement. I'm going to try reflowing some connections tonight, and will probably try recapping the largest set and see if it makes a difference.
The weirdest thing I've noticed is that the cable from the power switch that goes to the lower deck board must stay plugged in or else I get the loudest buzzing, it fades between each channel about every second. Nothing else is plugged into the lower deck board, so I'm thinking the cap soldered on the back side by this connector is providing some sort of much needed stabilization in the system's current state. This connector does not have any impact on audio if I unplug it from a reference C100-F frame I have that I plugged into your chassis.
Gettin' there!
baddboybill
Boomus Fidelis
OK I'm not trying to cause any waves here but since I was one of the members to try and restore this I had to post. First upon receiving unit there was no power on initial power up. After opening unit I found someone had replaced the clip going into transformer board with a generic attachment that was taped. So there were more individuals in unit than mentioned here..... And I did clean inside unit and work on decks some, found that the female outlet had issues and did try and remedy this very little luck. I think I also fixed the spare cassette door. Because of the clip issues I was trying to figure out the correct wire location since it had already been rigged. When I finally figured it out and went to test the unit it only powered up but made no sound. I explained all this to Greg but he claimed unit had worked once before. When I explained that most likely somehow the generic repair must of somehow shorted because tape that was suppose to separate each wire was not covering good and that it don't take much to short. All I know is I have repaired/restored over 100 boomboxes in the last 8 years or so with very good turnout. Honestly I tried my best and as we all know anything can happen even when a unit sits for some time without use. Greg once again I'm sorry about not being able to help with this unit!!! Thanks I've said my peace
Bad Boy Bill
Bad Boy Bill
caution
Member (SA)
Hey you did your best but sometimes these beasts get the best of ya. Let's be honest these C100F's are some of the more difficult ones to work on because of all the extra wires to deal with and the lack of any sort of service manual/schematic to follow, so if you're unlucky enough to have a board-level issue, it can be a real challenge. I've spent a lot of time documenting the insides so they are easy to navigate, and I've had a lot of experience repairing boards over the years on and off the job so this is a good training opportunity.
caution
Member (SA)
All bees have left the building. The buzzing is history! 
I was sitting there hearing it at full volume all the time and wavering left and right, so I thought perhaps it's a part on the amp board common to both channels. I resoldered the amp chips and the five largest caps, and to my surprise the problem got worse!
Then I realized the crud around the largest cap wasn't from dirty glue. I think the heat from resoldering the leads made the connection it was clinging onto inside the cap even worse. After I got the leads loose and wiggled it free from the glue, only the ground side came out, the other one corroded away from the inside. There's a little stain around the hole and crud where the lead came out of the cap. Another one farther away had crud around it too, but it looked fine underneath when I removed it. I might replace the other larger ones too as a precaution.
With the buzzing gone I could better hear the scratching in the volume and balance pots. I removed both and wiped their tracks clean with a Q-Tip and alcohol and bent the contacts back up a bit, but the left side on the balance pot is still making scratchy noises just sitting in one spot, but I'm not sure if it's because I didn't try to bend the leads up or the track needs lubrication. I want to try taking it off again to try tweaking the contacts, but they aren't like the volume pot where they have a tip, they're sort of like a dent in a half-ring, and can't easily be bent up or down.
Getting close!
I was sitting there hearing it at full volume all the time and wavering left and right, so I thought perhaps it's a part on the amp board common to both channels. I resoldered the amp chips and the five largest caps, and to my surprise the problem got worse!
Then I realized the crud around the largest cap wasn't from dirty glue. I think the heat from resoldering the leads made the connection it was clinging onto inside the cap even worse. After I got the leads loose and wiggled it free from the glue, only the ground side came out, the other one corroded away from the inside. There's a little stain around the hole and crud where the lead came out of the cap. Another one farther away had crud around it too, but it looked fine underneath when I removed it. I might replace the other larger ones too as a precaution.
With the buzzing gone I could better hear the scratching in the volume and balance pots. I removed both and wiped their tracks clean with a Q-Tip and alcohol and bent the contacts back up a bit, but the left side on the balance pot is still making scratchy noises just sitting in one spot, but I'm not sure if it's because I didn't try to bend the leads up or the track needs lubrication. I want to try taking it off again to try tweaking the contacts, but they aren't like the volume pot where they have a tip, they're sort of like a dent in a half-ring, and can't easily be bent up or down.
Getting close!
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