Installed the fets clamped them down and we have power. Great sound and no smoke. Until then......
BTW the NDP7060 Fairchild fets came from UTSOURCE.NET receipt included US contact number. These were authentic exactly the same as what came out of the amp. They seem to be performing flawlessly. I've been playing DeJ Loaf cd for the last 20 min the amp is operationally warm at best.
Thanks again for the assistance offered here on DIY Audio.
HH
BTW the NDP7060 Fairchild fets came from UTSOURCE.NET receipt included US contact number. These were authentic exactly the same as what came out of the amp. They seem to be performing flawlessly. I've been playing DeJ Loaf cd for the last 20 min the amp is operationally warm at best.
Thanks again for the assistance offered here on DIY Audio.
HH
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Ill have to check but pins 9 and 10 have that same characteristic at the chip before I installed the fets. I suspected maybe the chip was on the edge but it fired up sounds great and no excessive heat.
Thoughts?
Sometimes there are slight differences in the output drive signal from the IC but this IC relies on pulldown resistors to drive to ground. Check the resistance from the base of the drivers to ground and from the emitters of the drivers to ground. Compare readings for the two groups of drivers. They should be very nearly identical.
You don't have to do this if you believe that the amp is working perfectly.
You don't have to do this if you believe that the amp is working perfectly.
I think maybe the tolerance of the 1K resistor I pulled. It was 1% but replaced with 5% I measured it it was .998k. It's what I had here on hand so I installed it.
I dont know about perfection or that this amp stamped US but made in korea was ever that but it seems to be operating as it should.
1% or 5% won't be an issue. It would, however, be a problem if a resistor in one drive circuit was far out of tolerance or open.
I previously checked all tolerances and they are withing acceptable limits and worked around the damage by using the unused pads and new gate resistors which are indeed 1%. Ill check the resistance of the transistors to be sure but all looks well from here. It may be noted that the replaced MPSA06 and MPSA056 are from motorola not fairchild as the originals.
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Hi Perry,
The signals still carry the same shape but all resistances from bases to ground and emitters to ground of the respected pairs all measure out the same.
Ill let you know how it goes after a good drive still looking good thus far......
The signals still carry the same shape but all resistances from bases to ground and emitters to ground of the respected pairs all measure out the same.
Ill let you know how it goes after a good drive still looking good thus far......
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Hello,help me! I'm Paolo from the Italy and i have buy an Orion Xtreme 500.4 broken.
I haven't the schematic and some resistors is impossible to write the colors....
The 2 resistors are the number R35 and the other resistor near Q21.
Can you help me? In Italy is impossible to find the schematic...
Thank you.
I haven't the schematic and some resistors is impossible to write the colors....
The 2 resistors are the number R35 and the other resistor near Q21.
Can you help me? In Italy is impossible to find the schematic...
Thank you.
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