Hello!
I'm Ryan, I'm new to the forum and was wondering if anyone could help me please with an XR600E that has a blown output stage. The story is my brother's band bought this from a building site, used it a handful of times and then it blew a fuse. I've opened it up and the first thing I see is it has blown up before, in style. A lot of scorch and burn marks on the board.
I started checking the transistors and found that Q200 (Currently a TIP41C) conducts between the collector and emitter. I unsoldered the collector pin and still got a reading, so pretty sure that's blown. I started checking the nearby resistors and found that R230 looked burnt and appears to be open, as I believe it should be 100Ohms but measures 77K one way and 56K another. And then we get onto the odd part, which is what I need some help sanity checking please.
R104 and R204 go between the emitters of two transistors and according to the schematic, should be 180Ohms. Whoever fixed this last has replaced both with 180K and 190K. I normally deal with valve gear and so I'm still a begineer with solid state, but is there any good reason why someone would do this? Or have they simply just put in the wrong value? Perhaps read the schematic wrong?
Thanks in advance
XR600E Blown Output
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XR600E Blown Output
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Re: XR600E Blown Output
If Q200 is shorted then it is a good bet Q201 0r 202 is also bad. check them.
Don't know that I ever saw a 190k resistor. In any case, if it wants to be 180 OHMS, then replace it.
Don't know that I ever saw a 190k resistor. In any case, if it wants to be 180 OHMS, then replace it.
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- New Member
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Re: XR600E Blown Output
Thanks for replying Enzo.
Q202 and Q207 were both shorted. Weirdly, both of these have been replaced already (MJ15024 and MJ15025), whereas Q201 and Q206 are original parts with the original Peavey part numbers and are both fine.
The only thing that concerns me is that these parts have been replaced already. Not knowing the history of the amp before my brother bought it we don't know how long it actually worked for after being repaired previously, or if it ever really worked properly afterwards. Will just have to suck it and see I guess.
Q202 and Q207 were both shorted. Weirdly, both of these have been replaced already (MJ15024 and MJ15025), whereas Q201 and Q206 are original parts with the original Peavey part numbers and are both fine.
The only thing that concerns me is that these parts have been replaced already. Not knowing the history of the amp before my brother bought it we don't know how long it actually worked for after being repaired previously, or if it ever really worked properly afterwards. Will just have to suck it and see I guess.
Re: XR600E Blown Output
It kinda doesn't matter. When a repair crosses my bench, I have to fix it as it sits. Whatever history it has doesn't so much enter into it. The MJ15024 are good subs for the PV types.