[les_garten]

   
I'm assuming $60 to ship it (confirmed on USPS.gov), plus $30 to get it back (based on rates for similar amps on their site), but yes that's still a "deal".  Pretty huge hassle though!
 
I just sent an e-mail.  Will see what happens.
 
Oh, something I found interesting.  Two years ago I wrote:
 
 
The shipping costs two years ago were around $160.  I don't know why it is half the price now, but if it was still $120 + $30 I am still not really sure if it would be worth the trouble of sending it back versus just listing it for parts in the FS/FT forum.

 
 
He should pick up the tab for return shipping IMO.

 

[Chu]

   
 
He should pick up the tab for return shipping IMO.

 
Yeah, I still have it in my head that Audio-GD is a small struggling company, when five years later they have a pretty nice market now.  Mine was one of the initial units that got destroyed by customs.  Between Kingwa setting such a low declared value on these amps to help with VAT and ruining the insurance value, the huge number of Head-FIers who got destroyed units, and the margin on each unit I was worried it would be enough to bring the company under.
 
Really, they handled that incident better than many US audio manufacturers would have which is why I'm still willing to do business with them despite sitting on a bad amp.  Did Kingwa ever mention what sort of impact that incident had on the company as a whole?

 

[les_garten]

   
Yeah, I still have it in my head that Audio-GD is a small struggling company, when five years later they have a pretty nice market now.  Mine was one of the initial units that got destroyed by customs.  Between Kingwa setting such a low declared value on these amps to help with VAT and ruining the insurance value, the huge number of Head-FIers who got destroyed units, and the margin on each unit I was worried it would be enough to bring the company under.
 
Really, they handled that incident better than many US audio manufacturers would have which is why I'm still willing to do business with them despite sitting on a bad amp.  Did Kingwa ever mention what sort of impact that incident had on the company as a whole?

 
I seem to remember they put them in padded envelops or something.
 
He made it right though.

 

[zeroibis]

I did a bypass and it has been working great. I just turn down the volume to 0 when I shut the unit off so that I will not get any "pop" when I turn it back on later.
 
FYI the issue with mine was apparently the UPC1237. I could just order up another and replace it if I ever wanted to but given the bypass works well and even if I do forget to turn my volume to 0 the pop is very quiet so I am not too worried.

 

[Chu]

  I did a bypass and it has been working great. I just turn down the volume to 0 when I shut the unit off so that I will not get any "pop" when I turn it back on later.
 
FYI the issue with mine was apparently the UPC1237. I could just order up another and replace it if I ever wanted to but given the bypass works well and even if I do forget to turn my volume to 0 the pop is very quiet so I am not too worried.

 
Just finished a bunch of back & forth with Kingwa, and it is the same issue -- the μPC1237 chip needs to be replaced.  I am guessing this is a common failure.
 
On eBay it looks like it's $12 for a new chip from a US seller, $7 for a pulled chip from a US vendor, tons for $2ish from Chinese vendors with different markings than the NEC chips, and $4 for a chip with the same markings from a Hong Kong vendor that claim it's genuine and in new condition.  I'm going with the $4 chip and just wait the 2 weeks it takes to get here.  Also, that daughterboard the chip is on doesn't seem to want to come out after unscrewing it -- is this just old wires that lost their plasticity or is there something (the headphone jack?) attached to the case soldered to the board?
 
For future reference, this is how you diagnose:
 
1.  Short the following two points *with the power off*.  If you do this with power on, you run a good risk of damaging whatever is connected to the output.
 

 
2.  Turn the unit on, and see if the amp is "working" again.  If it is . . .
 
3.  Take the following measurements.  I used one of the four screws in the picture that attach the card to the case as my voltage reference.  Also, given the quality of my multimeter, I would not be surprised if these values are as high as 10% off. 
 
I am not sure exactly what the correct measurements are, but given the following measurements Kingwa was 90% sure the chip was at fault:
 

 

[les_garten]

Glad to see Kingwa still supporting a great product.

 

[zeroibis]

The 2 that I shorted were different I shorted to the resisters on either end. (ie the one to the left of the one that you did in your image)
 
In my case prior to the short I found that under the correct conditions I could amp the hell out of the signal with other amps and confirm that sound was actually passing though the compass just very very quietly. (so in other words something in the unit such as that bad chip was applying too much resistance on the line)
 
I got to say after being forced to only use a MK1 and my motherboard DSP for a few weeks I was reminded how great the sound from the compass really is all over again.

 

[Mad Max]

   
Just finished a bunch of back & forth with Kingwa, and it is the same issue -- the μPC1237 chip needs to be replaced.  I am guessing this is a common failure.
 
On eBay it looks like it's $12 for a new chip from a US seller, $7 for a pulled chip from a US vendor, tons for $2ish from Chinese vendors with different markings than the NEC chips, and $4 for a chip with the same markings from a Hong Kong vendor that claim it's genuine and in new condition.  I'm going with the $4 chip and just wait the 2 weeks it takes to get here.  Also, that daughterboard the chip is on doesn't seem to want to come out after unscrewing it -- is this just old wires that lost their plasticity or is there something (the headphone jack?) attached to the case soldered to the board?
 
For future reference, this is how you diagnose:
 
1.  Short the following two points *with the power off*.  If you do this with power on, you run a good risk of damaging whatever is connected to the output.
 

 
2.  Turn the unit on, and see if the amp is "working" again.  If it is . . .
 
3.  Take the following measurements.  I used one of the four screws in the picture that attach the card to the case as my voltage reference.  Also, given the quality of my multimeter, I would not be surprised if these values are as high as 10% off. 
 
I am not sure exactly what the correct measurements are, but given the following measurements Kingwa was 90% sure the chip was at fault:
 

 
Where you are getting 14.28V I am getting 0.68V.  The rest are about the same for me.

 

[Chu]

   
Where you are getting 14.28V I am getting 0.68V.  The rest are about the same for me.

 
The measurements I posted were for a broken amp where the chip is defective.  One of those measurements is going to be suspicious -- assuming your amp works I assume that's the test point that is driving Kingwa's conclusion.
 
I asked Kingwa for the correct measurements, and how to remove that daughterboard since I was having so much trouble figuring it out.  He didn't respond with the correct measurement -- but did say that board is not removable and to cut off the legs of the old IC and solder the new IC onto the legs of the old one.
 
Anyone have some good advice for the best way to do that?  I have an idea in my head but want some input for people who've done more soldering than is necessary to build a Cmoy.  My biggest fear here is having too much heat on the leg when trying to solder the new IC (or wire or socket) to the old legs, and ruining the solder joint on the other side of the PCB that the old leg is attached to.

 

[Mad Max]

I was telling you so you know what the measurements should be as Kingwa no longer knows, I'm assuming.
 
The PCB can be lifted to reach the underside after removing the four screws and disconnecting it from the headamp board.  You should just barely be able to reach the chip's legs.  Or unscrewing the transformer will allow you to reach the underside easily, I think.
 
If you go with cutting the old chip off then make sure you use excess solder flux to protect the new chip from your iron's heat (most important!).

 

[les_garten]

   
The measurements I posted were for a broken amp where the chip is defective.  One of those measurements is going to be suspicious -- assuming your amp works I assume that's the test point that is driving Kingwa's conclusion.
 
I asked Kingwa for the correct measurements, and how to remove that daughterboard since I was having so much trouble figuring it out.  He didn't respond with the correct measurement -- but did say that board is not removable and to cut off the legs of the old IC and solder the new IC onto the legs of the old one.
 
Anyone have some good advice for the best way to do that?  I have an idea in my head but want some input for people who've done more soldering than is necessary to build a Cmoy.  My biggest fear here is having too much heat on the leg when trying to solder the new IC (or wire or socket) to the old legs, and ruining the solder joint on the other side of the PCB that the old leg is attached to.

 
 
I don't see an IC in that PIC?  Can you describe where it's at in the PIC?

 

[Mad Max]

The one surrounded by five resistors and a diode.

 

[les_garten]

  The one surrounded by five resistors and a diode.

 
Can somebody get a low angle shot from the side of the diode to show how much working room there is?

 

[Chu]

   
Can somebody get a low angle shot from the side of the diode to show how much working room there is?

 

 
For reference, 8 legs 0.1" (2.54mm) apart, with the entire IC being 0.8" (20.32mm) wide.
 
I asked on another forum how they would go about with this repair, and I like their suggestion a lot.  Cut off the IC, and then remove the legs one at a time using a soldering iron while holding the leg with needle nose pliers.  Cleanup with braid, then just solder the new IC on the "wrong" side of the PCB.  I didn't even consider that it was fine just soldering to the back instead of the front.  Are all "holes" on a single layer PCB vias?

 

[les_garten]

   

 
For reference, 8 legs 0.1" (2.54mm) apart, with the entire IC being 0.8" (20.32mm) wide.
 
I asked on another forum how they would go about with this repair, and I like their suggestion a lot.  Cut off the IC, and then remove the legs one at a time using a soldering iron while holding the leg with needle nose pliers.  Cleanup with braid, then just solder the new IC on the "wrong" side of the PCB.  I didn't even consider that it was fine just soldering to the back instead of the front.  Are all "holes" on a single layer PCB vias?

 
You could do it that way, but desoldering has it's own issues/dangers.  If there is a board underneath you could drop solder on it shorting something out.  Why can't you get the board out? Can't yo just desolder all the wires?  Do you have the IC?  How long are the leads?