i was doing a cross reference search on fairchilds website and when i entered 2n6491 it came up with bd537 as a cross.It seems to me by looking at the data sheets that the bd537 is a lesser part.The main thing i noticed was a power dissipation of 50 watts on the bd537 and 75 watts on the 2n6491.I'm not sure if I'm missing something or what but it seems like the BD537 part wouldn't work in place of the 6491.Does anyone know if it indeed will work?It would be great if it did as the bd537 is quite a bit cheaper than the 6491.I might actually finally get my orion up and running.
The BD537 is the Fairchild cross for the 2N6488 but it's not a good substitute.
The 537 is only rated for 8 amps. The 6488 is rated for 15 amps.
If you want a cheaper part, the BD911 and BD912 have been used successfully by several people here. I've never used them. I always use On-Semi 6488s and 6491s.
The 537 is only rated for 8 amps. The 6488 is rated for 15 amps.
If you want a cheaper part, the BD911 and BD912 have been used successfully by several people here. I've never used them. I always use On-Semi 6488s and 6491s.
you may want to check the mpsu57/07 pre drivers and drivers also.
those go bad more often than the output transistors from the old orions ive come across... when they go bad they can make the outputs appear to throw out dc, do to lack of either a negative or positive drive signal.
check the 5534 opamps too, especially the teardrop mylar thats connected to the power supply legs.
check out my post on : orion 2150sx
lots of good stuff in there...
good luck!
those go bad more often than the output transistors from the old orions ive come across... when they go bad they can make the outputs appear to throw out dc, do to lack of either a negative or positive drive signal.
check the 5534 opamps too, especially the teardrop mylar thats connected to the power supply legs.
check out my post on : orion 2150sx
lots of good stuff in there...
good luck!
I've already got some new mpsu07's and 57's ready to go.I've actually got this thing playing cleanly But i've only got one set of output transistors in either channel and a partial set of power supply transistors.Every sink mounted transistor is being replaced as well as all the electrolytic caps.I've heard someone say that all the tantalum caps should be replaced as well although i'm not sure what the value of them are.It looks like the caps say 2u2 25 volt.I'm not sure if 2u2 means 2.2 microfarad or what.
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