It ain't easy.... being GZ!
Posted 06 January 2016 - 12:47 AM
Great work BTW - the C100F is certainly not an easy boomer to work on - quite the challenge I recall!
Posted 07 January 2016 - 01:45 AM
I just remembered the C100F I worked on had a channel that would pop and carry on. Take a look at the amp chips. I found that when it popped, the volume of the pop was much louder than the music volume level and would cause the VU meters to go crazy. After I reflowed and resoldered the amp chip legs, full output was restored.
I assumed at the time that the brief interruption of the power supply to the amps would cause the pop when power was restored, thus bypassing any pop suppression circuitry (if indeed that circuit exists in the C100F). The problem worsened as you turned up the volume - this I assume could be because of the increased power needed by the amp being interupted by the increases resistance caused by cold solder joints or the extra vibrations caused by the speakers rattling the chips!?
From memory, the legs from the Conion factory had very little solder. When the C100F is lifted, a slight amount of flex of the chassis causes a slight twist to the main board that stresses the amp leg solder joints.
Worth a try. I was able to reflow them without completely removing the main board.
Or you could at the least, take the back off and try gently flexing the main board to replicate the fault.
Edit: After watching the video again, it appears to be motor boating so a recap may be in order.
Posted 08 January 2016 - 12:31 AM
I'm pretty sure this vacation she's going on is her best shot at rejuvenation.
I know she'll be in good hands.
Thanks for everything Joe....you're a saint.
Posted 11 February 2016 - 01:12 AM
Rest assured it's not dead, or maybe it was dead, because I'm really hoping this belt has rigor mortis and not something else less proper.
Posted 11 February 2016 - 08:19 AM
You're even working on the decks!?!? I did not see that coming.
Posted 11 February 2016 - 09:17 AM
Maybe he has to investigate the record bar for the deck. Either way, this is great to see!
Posted 11 February 2016 - 10:08 AM
Maybe he has to investigate the record bar for the deck. Either way, this is great to see!
It sure the f is!
Posted 11 February 2016 - 10:52 AM
Posted 11 February 2016 - 12:24 PM
I got to see Eric's work during a visit. He showed me GZ's Clairtone, and mentioned it was going to receive some TLC to fix it. I have all the confidence in Eric's ability to fix the rest of the issues.
Can't even describe how happy i will be if he gets that thing runnin. His efforts are greatly appreciated.
Posted 13 February 2016 - 12:35 AM
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
Posted 13 February 2016 - 11:54 AM
Eric, I wish I could be there while You work on it, so I can learn more "Electrickery" skills.
Posted 13 February 2016 - 05:14 PM
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.
Posted 13 February 2016 - 05:36 PM
Posted 13 February 2016 - 08:24 PM
Posted 16 February 2016 - 11:48 AM
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
Posted 16 February 2016 - 01:14 PM
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.
Posted 16 February 2016 - 02:18 PM
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.
Posted 25 February 2016 - 06:31 PM
Haha well you know any reason to tear apart something with electronics inside, I go crazy
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.
Posted 26 February 2016 - 03:43 PM
Bad Boy Bill
Posted 26 February 2016 - 04:04 PM
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.
Posted 28 February 2016 - 01:00 PM
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.
Posted 28 February 2016 - 04:26 PM
Not as excited as me! Eric the boombox whisperer!
Posted 28 February 2016 - 11:53 PM
GZ your gonna have one hell of a fresh box! Go Eric GO!