Need Reliable Source For Darlington STK-0050 PowerPaks

racfan9

Super Member
Hello Everyone, I'm repairing a SX-780 with a blown channel, so I'm trying to find at least one, preferably two 0050's if possible. I no NOS are probably history, so are there any others out there that you can rely on?

Thanks,
racfan9
 
I flip good used ones on eBay.

I list them as used but working.

Meaning, used working originals are the only reliable source I know of.

Currently sold out.
 
I've been told that you can use the STK1050 or 1060 in the SX-780 as replacements, is this a possibility?
 
To be honest, building the stk-00050 replacement pcb's is a good place to learn, you are having to solder anyways, so whats a few more solder joints. It is the best option imo, that is why I designed it for the community.
I do not know for sure, about STK1050 or 1060, looks like they probably will work based on the schematics, have to verify pin outs, mechanical fits etc. The bias current is now shared between two parallel sets of bjts, so by rights the bias should be increased so that the current through each pair is the same as if using only one, meaning that the V dropped across the single 0.22 ohm emitter R's is now to be doubled from the spec. I do not know if the 780 will allow bias those pairs correctly.
Ask the person who told you it was okay to see what they experienced.
 
The only way you will be able to tell is to do one, then get THD readings of that channel. See if it meets spec.

But I'd bet that THOSE aren't original EITHER.

My suggestion: find someone to do the build and installation for you.

OR take your chances with the eBay cheap knock offs re-engineering attempts and don't expect to use it as a party system.
 
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