Pioneer sx 1050 - no sound

[Newbie2022]

Hi there, newbie here but have lurked at AK for a while now and even read articles to help repair my g6000 sansui a few weeks back. I really appreciate everyone taking their time to help others out.

So I recently purchased a sx 1050 that was for sale as repair needed. I tested with my speakers and managed to get sound from both channels after working the balance and volume pre purchase. I brought it home, used deoxit on all the knobs, then tried and was able to get sound but suddenly just no sound at all. I removed the jumper and connected the preout to a powered speaker and aux/FM/phono all work. I'm a bit lost on what to try next given it worked briefly. Maybe something small?

It's very clean (pics attached) even though it was in storage for a long time (previous owner). I do have multimeter and can solder.

Appreciate some pointers

 

[ivandezande]

If it's in protection (no click on turn on) it could be a billion things. Get it to a tech, it's not going to be something small.

Every 850-1250 I've had always has multiple issues with one just waiting to be a problem even if you fix the main one.

 

[Newbie2022]

If it's in protection (no click on turn on) it could be a billion things. Get it to a tech, it's not going to be something small.

Every 850-1250 I've had always has multiple issues with one just waiting to be a problem even if you fix the main one.

I get a click, light comes on etc but I don't hear a second relay click. Is that what you mean?

 

[ivandezande]

I get a click, light comes on etc but I don't hear a second relay click. Is that what you mean?

Yup. First click is soft start relay.

 

[Newbie2022]

Oh okay, Iet me do some research and see if there are any leads as to what the problem might be. Will take it to a tech as last resort. Thanks!

 

[ivandezande]

Oh okay, Iet me do some research and see if there are any leads as to what the problem might be. Will take it to a tech as last resort. Thanks!

Why a last resort?
It’s in protection either because the amp section is putting out rail voltage or the circuit itself is acting up. Those are the two options that’s it.

1050’s are great. Please don’t use it as a learning experience, start smaller. This is coming from someone who has ruined a nice unit or two early on.

 

[Newbie2022]

I did call a reputable shop but they have a back log and said it would take 6-8 weeks before they can diagnose.

I guess having fixed the sansui, my confidence level is a bit high haha..(phono wasnt working so went through each part, measured and found the problem to be 4 resistors which I changed to get it working )

But honestly, if you think this is a big task, I'll reconsider.

 

[Newbie2022]

https://audiokarma.org/forums/index.php?threads/sx-1050-in-protection.542310/

I missed this, maybe similar issue?

 

[mikiekimi]

https://audiokarma.org/forums/index.php?threads/sx-1050-in-protection.542310/

I missed this, maybe similar issue?

Could be, but as mentioned before this isn’t a beginner’s receiver and the problem might prove tricky to track down. If you choose to continue, it’s going to take some time. Likely more than the 6-8 week wait, with the chance you do more harm than good as you troubleshoot.

I had one that I worked on that presented several issues that needed to be addressed. I had to set it aside a few times while I gained more experience.

Do you have a dim bulb tester? If not, and you want to pursue the hobby, I’d get/build one ASAP to verify nothing has shorted. Once it comes up on the DBT normally, I typically start by checking voltages per the schematic, starting with the power supply board, then the protection board, then the amp section to see what surfaces.

I’m still not totally comfortable deciphering results, but a bad voltage reading and the right questions could help lead the way.

 

[Newbie2022]

Thanks for the explanation. Do you have an idea as to how much it might cost to repair/service/recap etc for something like this?

 

[mikiekimi]

Thanks for the explanation. Do you have an idea as to how much it might cost to repair/service/recap etc for something like this?

Unfortunately there are too many variables involved...source of the issue being the main driver.

Bench fee + hourly rate + parts. Area of the country and/or scarcity of skilled labor are also factors.

I'd expect a couple hundred dollars, but it could be more or less. A quick half-hour transistor replacement on the protection board will be much cheaper than diagnosing the cause of, and replacement of, blown outputs, drivers, resistors, diodes, etc...

A recap on a 1050 would be an expensive endeavor. Lots of parts to replace and several hours to replace them depending on the tech's experience level. Some techs will do recaps/restorations, others won't. They are just too time consuming.

I do work for a few small shops (basic testing/service/troubleshooting, cleaning equipment up, replacing bulbs). I also do a little on the side, strictly as a hobby, as I work full time. I try to stick to smaller, less complex units but I do occasionally work on larger stuff.

For example, I don't charge a bench fee. I do charge $50 for a basic service/eval and $65 an hour + parts to troubleshoot problems. Most of my work involves around an hour labor, but some have taken considerably more time. I'm in a position to refer more complex repairs to other techs since I understand my 'sweet spot' given my limited experience.

I don't do recaps because they take too much time so I price them pretty high - folks need to pay me for the time and bench space involved

 

[Newbie2022]

Totally understand. I wished you lived closer (NJ). I would love to give it to someone who is good and does it as a hobby on the side so I could learn a few things aswell. Given it is vintage, I don't want to run to a shop everytime something goes wrong. Figuring out repairing the sansui was therapeutic to be honest haha.. just to focus on something other than my regular job.

Maybe I should stick with the lower end equipment since to be honest, this thing probably has more power than I need. I did find a couple of long videos on YouTube of someone repairing this exact model. That's going to be my movie night

 

[mikiekimi]

Well I hope I didn't overstate my skillset...if you read my SX 3900 thread, you'll see I'm still very much in learning mode and am unfortunately prone to making mistakes

Fortunately now only about 1 of every 10 pieces of equipment that passes through my hands results in a call for assistance here on audiokarma.

xraytonyb has a few in depth YouTube videos where he (painstakingly) dives into the 1050 and also talks about some common modifications. Definitely worth the watch...

I tell customers (my own, and the shops I work with) that buying vintage audio gear is like buying a vintage car. You wouldn't expect a '78 Firebird to run like a '22 Camry. Older gear requires more care and feeding than modern stuff. Bone-stock older units (especially that have sat unused) will develop issues as the old parts are exercised and regularly used. Vintage requires a realistic expectation of what ownership entails.