ARC repair needed

What does, "is going out" mean?

They’re only worth around $700 or so and can be unreliable. Maybe the Mk2 is more reliable although your experience suggests not.

The right channel starts to fade after about 10-15 minutes.  It grows faint by about 30 minutes.  

Try Pyramid Audio (Texas) or United Radio (Rochester NY)

Problem is the transistors in that amp are obsolete and it's very difficult to find an equivalent that will work. Transistor amps are very intolerant to transistor substitutions no matter how close the specs are.

In Southern California, you might ask George Meyer AV. They do repairs but I don't know if they'd have the parts and information needed for your specific model.

Sounds like a thermal issue on one side which is invoking a protection circuit. Can you swap the speaker leads to see if the fault moves to the other side? If it does, it's a speaker or cabling issue. 

I tried swapping both input leads and outputs to speakers.  I tried reverse on the preamp and inverting in the amp.  It’s always the same output.  I suspect it’s either a solder or a capacitor.  

You can use freezer spray to check for cold joints.

High End Audio Repair in Phoenix is great.  James is the owner.

shipping power amps always an issue, for risk of damage as well as cost

george meyer av in downtown la is your best bet

I live in Los Osos CA next to Morro Bay. I got a great tech that'll fix pretty much anything. He doe tubes to solid state gear. There's my other tech who works in LA about every other week ( southwest airlines at LAX) who drives down and works 2 days at a time. He usually takes stuff for me down or back up. 

Search Pioneer sx-1250 in the Torrance Craigslist and you'll see his contact on there.  there.

Tell him Jr said to ask about Charlie. He fixed my B&K pro-10mc without schematics and found 3 bad transistors and now working like a champ. He serviced my Conrad pv12 preamp and changed the tubes and fixed a switch. Took 2 Bryston 3b amps and bypassed the remote gain control that was used for a studio amp and now i can use it at home. Saved me $$$ for   packing  and shipping 2 amps   to Bryston. 

I want to thank everyone for your great responses!  I’ll check out these recommendations.  

Again, thank-you all for your great responses.  I got it fixed!  I found a local shop here in the Palm Springs area.  The problem was two bad capacitors and a loose ground.  It cost $55.  I highly recommend “Mr. Charley’s Fix It Electronic Repair” if you’re in the area.  

Good to hear. Very fair price. 

Any onlookers that maybe a little closer to thee border ... these two gentleman I highly recommend "Classic Audio Repair, Inc" located in La Mesa, San Diego.

No ARC service according to their website however. Very similar to the original post, "no support from said vendor." That doesn’t necessarily mean in all cases, call to confirm.

@groverton

Palm Springs Aerial Tramway? Great destination to get lost in ... highly recommend.

@dabel yes, and I found myself in PS!  Great place to live.  

:-)

Love Palm Springs @groverton. A yearly destination.

I am in New Jersey close to NYC.  Been repairing, rebuilding, modifying components for 20+ years.  We are also manufacturers of tube audio components.  If you want us to take a look PM me.

Happy Listening.