Dead $20.00 KB3

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Pappy B
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Dead $20.00 KB3

Post by Pappy B » Fri Aug 26, 2016 12:14 pm

Bought a KB3 for twenty dollars yesterday. Figured I'd get at least $20.00 worth of parts out of it if it was a melt down. Quick check showed a good transformer and I didn't have to go very far to find the dead spot. 2 resistors just before the rectifier diodes. Made me wonder why so I started looking closer at the board and discovered a 22uF cap that was mounted backwards on the board according to the silk screen. I lifted the board, removed it and put a new one in with the polarity according to the silk screen. It appears to be good now. My lap steel sounds great through it.

The chassis and boards didn't show any signs of having been messed with. Appears that this came from the factory (China) this way. Although it is made in China, everything looks very good on the chassis. I prefer American made, but I got over the stigma of being made in China. I will play with it for awhile then probably sell/trade it.

Classic30inCincy
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Re: Dead $20.00 KB3

Post by Classic30inCincy » Fri Aug 26, 2016 1:47 pm

Maybe, In China, They Read Schematics DIFFERENT From How We Read In The USA...... :!: :roll: :!: :oops: :!: :lol: :!:

PAF Classic Series Tube Kit.......Created By Classic30inCincy
Majic Mojo Tradename..........Created By Classic30inCincy
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Pappy B
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Re: Dead $20.00 KB3

Post by Pappy B » Fri Aug 26, 2016 3:41 pm

At least it was soldered in. Over the years I've had 1 TV and 2 computer monitors with caps that were not soldered, just stuck in the board with the leads spread just enough to keep them from falling out. Made in Mexico, Korea and Japan. Is there a pattern here?

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Enzo
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Re: Dead $20.00 KB3

Post by Enzo » Fri Aug 26, 2016 5:38 pm

No there is no pattern. All the boards are made by machine, regardless of where they come from. There is no room full of guys stuffing individual parts into boards and then soldering them. The caps all come off tapes and are installed by pick and place machines. Why one might be backwards I have no idea. How it might have passed a function test, I have no idea. Perhaps the unit had a problem and some technician tried to repair it and installed a cap in reverse.

The parts placer machine installs the part, and trims and crimps its leads. Then the board goes over the wave solder machine. The whole board is soldered at once. A bubble in the solder bath or other anomaly might cause some joints not to get soldered.

Most of the problems you see will be in Chinese made amps for one reason: most amps are Chinese made. When we made all our amps in the USA, than all the amps with problems came from the USA.

In 1956 Japan meant cheap junk. in 2016 Japan mean highest quality.

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Pappy B
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Re: Dead $20.00 KB3

Post by Pappy B » Sat Aug 27, 2016 12:13 am

I actually agree with you Enzo. It doesn't matter where something is made, a malfunction is just a malfunction. And it is possible that it occurred after it left the factory. If it did get repaired somewhere, they did a very good job, other than the cap polarity was backwards. I looked for signs of it having been worked on and couldn't see any. I collect old radios and have had some that some Goober had so screwed up pretty bad.

I have Korean and Chinese made guitars that are very good players, sound good, look good and affordable.

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