Realistic STA-2080 Semiconductor Replacements

[Brivan]

Hi, folks

I have another Realistic STA-2080 undergoing open-heart surgery. This one had what appears to be a small fire on the left main amp board. The output transistors appear to have shorted and took out some other components at the same time. The PC board is salvageable, and I've replaced most of the damaged components. The output transistors have been replaced on both sides, as well. I've read through many of the threads regarding replacement components for this receiver and am looking for a general yay or nay consensus on the replacement component info I've gathered below:

A915 (2SA915) transistor replacement = KSA1381 @ Digikey or Mouser
Alternate replacement is KSA916 (schematics show original as 2SA916)
NTE replacement is NTE288 (least favorable)

C2275 (2SC2275) transistor replacement = KSC2073TU @ Digikey or Mouser
Preferred replacement is 2SC5171, but it’s obsolete
NTE replacement is NTE375 (least favorable)

Final output transistors 2SB705 & 2SD745 available on Ebay
Final output transistor 2SB705 possible replacement = 2SA1494
Final output transistor 2SD745 possible replacement = 2SC3858

I have some NEC 2SA915 transistors coming from an Ebay seller to replace the original, but also ordered some KSA1381s from DigiKey. I also have some KSC2073TUs coming from DigiKey to replace the original NEC 2SC2275. I already installed OEM NEC 2SB705s and 2SD745s to replace the originals.

Also, VR501A was toasted and I replaced it with another similar 220-ohm (but slightly smaller) variable resistor I had in stock. I had to bend the pins a little to get them to stretch out and reach the existing mounting holes and they barely protruded through the PC board. Does anyone have a supplier for the correct physical-size variable resistor?

Thanks!

 

[redk9258]

Final output transistors 2SB705 & 2SD745 available on Ebay

Most likely counterfeit Chinese knockoffs. These have not been produced in years... or maybe decades. Be careful where you buy semiconductors from. Many inferior parts out there. Buy only from authorised distributors like Digikey, Mouser, Arrow, etc.

 

[OMGCat!]

The 1494 and 3898 should be available from bdent. They are a safe supplier of obsolete devices.
I'd much rather go that way than chancing anything from eBay.

 

[Brivan]

Most likely counterfeit Chinese knockoffs. These have not been produced in years... or maybe decades. Be careful where you buy semiconductors from. Many inferior parts out there. Buy only from authorised distributors like Digikey, Mouser, Arrow, etc.

I got those numbers from a thread on another forum. The OP stated they worked fine, but he was under attack from another poster for using those components on a customer's receiver and the thread turned into a slugfest, with many of the posts being deleted by the moderator. I would only try them as a last resort, or maybe out of curiosity to see how they held up over time.

 

[Brivan]

The 1494 and 3898 should be available from bdent. They are a safe supplier of obsolete devices.
I'd much rather go that way than chancing anything from eBay.

I checked bdent, and those transistors are available under the Sanken brand name. If I get time, ambition and a receiver that I plan on keeping, I might give these a try. Until these are proven as a solid replacement for the originals, I won't install them in a receiver for resale. Thanks for the info!