Refurbing an old school classic Orion 250 HCCA x2!!!

[Wicks]

Pulled all the old power supply FETs.................all 18 of them.

New ones installed.

The originals were SMP60N06. Rated at Vds=60V, Id=60Amax, Rds=18mOhms.

I went with my usual STP75NF75 FETs which I've used in all my prior refurbs.

STP75NF75's rated at Vds=75V, Id=80Amax, Rds=<11mOhms.

Higher voltage rating, higher current rating and lower On resistance so they should run cooler.

i doubt we'll be able to tell physically without some comparison testing but it should help.

New 12V Input Caps and 50V Bulk Caps installed.

I kept the large 3300uF 50V caps the same vendor and series. Nichicon VX.

The smaller 12V input caps were Samhwa 1000uF 35V. We'll be upgrading those...

I searched online and found some Nichicon KA Series "Audio Grade" 1000uF 35V caps for just a little more $, so I went with those.

[bcbrassard]

Super clean replacement. Amp will be better than new.

[Wicks]

Super clean replacement. Amp will be better than new.

Thx!

Yeah I dig these pads on the board where the part lays flat, rather then through-holes.

Old boards like this can get damaged pretty easily if you apply too much heat to those solder barrels.

But these pads are fairly tough.

Man, I wish the amp was in better condition so I could have ran some before and after tests.

Would be pretty interesting.

I'm stoked to see what this beast will do when its complete.

Now to see if I have a bench power supply big enough to feed this thing...........

[2loud4uboyz]

Man will say this to I'm BLUE in the face wish you where my friend. You sir do great clean right on the money work.

[Wicks]

Measured the Capacitance, Dissipation Factor and ESR (Equivalent Series Resistance) on the old and new caps to see where they where at.

The old 12V input and rail caps don't look too bad.

Couldn't find a decent specification for these caps, but minimum capacitance for a 1000uF cap would be 640uF.

DF is at 5% which is good. Limit is about 15%.

New Nichicon "Audio Grade" KA caps measure right on the money!

The big old Nichicon 3300uF 50V bulk caps which look bulged somewhat from the wrapping (or at least maybe overheated).

Lower limit would be 2,112uF and this is showing 2,900uF.

DF is good as well as ESR.

They look ugly but don't measure that bad surprisingly.

New Nichicon's again right on the money!

Rated 3300uF and showing 3423uF.

[Wicks]

Pulling out the old opamps.

Installing new Texas Instruments LM4562 opamps. Same ones I used on my PPI refurbs.

They have great reviews and good specs:

The LM4562 is part of the ultra-low distortion, low-noise, high-slew-rate operational amplifier series optimized and fully specified for high-performance, high-fidelity applications. The LM4562 audio operational amplifiers deliver superior audio signal amplification for outstanding audio performance. The LM4562 combines extremely low voltage noise density (2.7nV/√Hz) with vanishingly low THD+N (0.00003%) to easily satisfy the most demanding audio applications.

Pulling more of the old opamps.

Four new LM4562 opamps installed.

Had to source some new bolts, star washers and flat washers but I finally got the power cables reattached which was no small feat.

Some thermal paste on the backs of the silicon.

Cleaned and prepped the insulation tape on the heatsink.

Then..............realized I needed some new foam tape for the aluminum brace bar that holds down the transistors and FETs.

Remember this:

I didn't want to just use some ordinary foam tape and have this happen again.

So I hunted around and found some "Viton" rubber mat which should cushion the parts nicely and can handle 400 degrees F

[bcbrassard]

Your Skills sir are on Par. Even when you go all "Rainman" and i dont know what the hell your doing i still admire your rebuilds. Thank you for sharing and teaching.

[la_01ninja]

This work is just amazing!!!! I'd never have the bawlz to do this but man o man..... ???

[x infektid x]

whats the reasoning for the op amps. i dabbled in repair for a bit but i knew but didnt know the reason for them .. is it for the input section? like the rca input area?

[Wicks]

whats the reasoning for the op amps. i dabbled in repair for a bit but i knew but didnt know the reason for them .. is it for the input section? like the rca input area?

The opamps are right at the signal input of the amp.

The new parts are relatively inexpensive and have much better parameters then the stock parts.

So I like to change them out when possible since every little bit helps.

I don't have a THD meter to know exactly how much they may help, but since I'm "under the hood" I might as well since they're fairly easy to swap.