Repair amp circuit board

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Most likely a transistor has blown in the amp. If you would like me to repair it for you, contact me at [email protected]

I have the same problem with my Boston acoustics subwoofer. have you find resolution for this problem?

Let us use a bit of logic to resolve this... I have an Axiom but it would be a lot of screws to take out to get to the part... so let us think about this. The resistor value starts with a "1" and we know it is 5% tolerance (gold). we know the resistor burnt up with likely 5 volts on it... Value could be 1000 ohms, however the voltages present (12 volts max) would NOT have burned up a resistor of 1000 ohms. The USB area is mostly 5 volts and across 100 ohms is only a quarter watt... not enough to really burn up a resistor... First thing is to MEASURE that the resistor s open... in spite of being burned, it MAY still be OK... these resistors now usually either open or remain close to their value. The resistor ALSO may be a fusible resistor intended to act as a fuse... Is the resistor open or not? is it near a resistance with a "1" as the first digit? If it is not open I suspect it is not all of the problem. In that case, look for a burned circuit trace on the board. If it is open, then MEASURE the voltage across the resistor with the power applied. If you find 5 volts, then it MIGHT be a 10 ohm used to limit the USB current to 500ma. Get back to me with your findings... I have unraveled many of these things...

The resistors are color coded.There should be 3 bands which are slightly separate from the 4th band.The 4th band is usually gold,silver,or i forget the third color which is actaually a %.The top 3 bands can tell me the value of the resistor.If you tell me all 4 colors I should be able to tell you the value,with the gold/silver/whatever as the fourth.The first one should be right near the end or top.The only 1 problem will be trying to determine the wattage rating but is usually very small within a circuit.Greg

R466 is chip resistor 220 Ohms 1/8 watt connecting between Emitter pins of Q408 and Q409.
Its part number is ...
R466 "1-216-182-00" RES-CHIP 220 5% 1/8W
Available in Part Store.
Let me know if you need further info.

When I put an ohm-meter across it, I get 505-ohms. The color code looks like maybe green, dark brown, brown? Mine is discolored too. Green, brown, brown would be 510ohms. . .so that must be it. The tolerance band is gold, so that's +/-5% so that would explain the 5 ohm variance.

I was trying to be as clear as possible, sorry. There are several resistors, both in the youke return circuit and feed circuit for the amps that should be checked with a digital or analog meter to see if they have changed in value or have opened as a result of the amp failure. If you've never tested a resistor before then I would strongly suggest having this repair done by a shop. There are several types of resistors, the ones you'll encounter here are a flameproof resistor 1 or 2 watt design respectively.
If you're attempting this you'll need a good analog or preferrably a digital meter with an ohms readout setting. Meter across the resistor and the value of the resistor should not be more than 10% of the rated value. If you read infinity you can assume the resistor is open and clearly should be replaced.
If any of this isn't clear enough then I STRONGLY suggest having a qualified technician do the repair... These are common repairs and if you lack any of the necessary testing or soldering skills you could make matter even worse...
Bill

Only use the same part number when replacing convergence amps, or you will need to replace all of the power resistors with recommended values for the convergence amps subsituted.

I was just working on replacing my stk's and was wondering if you could tell me what value the resistors are? Here is my previous post if you would like to see it. http://www.fixya.com/support/t191186-blue_out