Old School Orion 2150 gx.I must repair this amp

[Perry Babin]

Yes.

Silicone insulators are supposed to work without compound but I still use thermal compound or dielectric grease on them. All others that are used in car amps need thermal compound.

[spooney]

Does anybody know the wattage rating on the .1 ohm emitter resistors in this amp?The are definitely bigger than 1 watt.Could wirewound resistors be used in place as long as they are the correct value and wattage?

[Perry Babin]

Doesn't the 2150 use 0.24 ohm resistors?

These should fit but measure the alloted space to make sure.
594-AC03W0R240J (mouser)

The originals are wirewound.

[spooney]

this one has .1 ohm resistors (brown,black,silver,gold) . did they use the .24 ohm resistors in later amps?Would changing them help reliability at all?

[Perry Babin]

I misread the header. I was looking at the 2150SX. It appears that the GX did use 0.1 ohm resistors.

Mouser has these:
71-RS02BR1000FE12

They are 3 watt resistors.
http://www.vishay.com/docs/30204/rsns.pdf

Check the dimensions before ordering.

I like to use tight tolerance resistors. These are 1% components. I've never found 1% components that matched the originals. These are black. If you're concerned about the color, you'll need to use a different resistor.

[spooney]

sorry to bring up an old thread but I have an update. As of about a week ago I got everything soldered back into this amp and I'm happy to say that she appears to be working flawlessly. Due to my own stupidity/lack of knowledge when I first started working on this amp about 3 years ago I ended up toasting most of the power supply and output transistors.I've replaced every output and power supply transistor,the mpsu 07/57'S, all electrolytics,and all tantalum caps. All in all it was a real pain getting this thing going but I learned a lot of valuable lessons about amplifier repair. I learned the hard way on some of it but sometimes that is better I think. It makes it easier to remember because I know I never wanna make some of those mistakes again. Anyways I just wanted to chime in and thank everybody for their help on this amp. I have a few pics of the amp as it sits now with the endcaps and bottom plates I fabbed up for it as I never had the originals.

rough start of the end caps :




finished up minus some white lettering and original colored wiring that I have yet to source:








shot of the internals:

[1moreamp]

Nice work, you did a very clean job.....

[spooney]

Thank you Cecil. I never did make it bridgeable by the way. I decided I would make the din plug bridging module if I ever needed it and keep the amp as original as possible.

[grjr]

spooney, where did you get the MPSU07/57 transistors from? I'm in need of a pair. I've got the same amplifier, they are really hungry for current Nice work on fixing yours up.

[spooney]

I got lucky and got exactly four of the MPSU07's from somebody on here. They offered them in this thread so if you look back through it you might be able to find who I got them from and see if they had some more. As for the MPSU57's I actually sourced those from some website which I can't seem to remember the name of. They weren't originals however they were the Central Semi version (CEN-U57 is the number I believe). I still have six of those if you want them. These are not easy parts to find unless you wanna go on ebay and pay 7 bucks a piece for them. Just let me know if you want the CEN-U57's. I don't see myself working on another one of these anytime soon.