SX-1250 died

[Matt817394]

Hello, total Noob here. I inherited an SX-1250, decent condition, a few months ago. It worked ok. A few weeks ago, I took it apart and cleaned all the switches and contacts and it worked beautifully after that. Yesterday, the receiver was idle for several minutes after listening to some music and my APC power conditioner went into overload and shut down.

After a few minutes, I tried to turn things on again and the Pioneer kept overloading the APC and tripping it off. During this time I noticed that the heat sinks of the Pioneer were super hot. I let everything chill and cool down and now I have no power to the Pioneer at all. Flip the power switch, nothing. I tried other power outlets independent of the APC and no luck either. Tried again the next morning, same status.

All the rest of my equipment on the APC is functioning normally. Any suggestions for getting the Pioneer back to life? I'm so bummed. It was sounding amazing so I'm not sure what happened. I'm fine taking it apart again, but am just not sure where to start looking. Thanks for any help.

 

[mikiekimi]

Sounds like something shorted and that's why it tripped the APC. When you plugged it into unprotected power it most likely damaged several additional components beyond whatever caused the initial short.

It's a beast for a first receiver to work on. There is going to be significant time that will be required to sort it out, as well as some $$ if you don't have the proper test equipment.

First thing I would do is NOT PLUG IT IN AGAIN. If you're up to it, you can crack it open and check for anything that looks cooked on the inside and note any fuses that may have popped. From this point forward it can only be connected to a DBT for power.

To tackle this repair, you'll need (at a minimum) a DVM (multi-meter), DBT (dim bulb tester), a soldering iron, a schematic, the ability to follow directions and post pictures, and lots of patience.

OR

Opt to take it to a local tech to sort out.

 

[Matt817394]

Thanks so much, Mikie. I found a local guy who seems really reasonable so that may be the most prudent course of action...

 

[elvi]

Never
Never
Never
Choke a high current device through a unit designed for a small current item

This reciever can and will trigger large inrush and runtime currents.

Best of luck with your repair.

Best lessons learned the hard way

 

[zebulon1]

It’s going to need a good look see.
Check the main fuse. Report back.
Check the thermal fuse located against the large wire wound resistor on the lower chassis rectifier board. If open:
Check all the outputs for condition. (Shorts)
There’s a short cut using a DBT but a DMM check is best.
There’s a chance it’s a thermal fuse but vital’s have to be checked before plugging it back in.

 

[Matt817394]

Never
Never
Never
Choke a high current device through a unit designed for a small current item

This reciever can and will trigger large inrush and runtime currents.

Best of luck with your repair.

Best lessons learned the hard way

So, I thought I was protecting it by running it through a power conditioner. Is that what you think caused the problem? Why did it get so hot? Thanks for all the help. Dropping it off at a repair place today.

 

[ivandezande]

Never
Never
Never
Choke a high current device through a unit designed for a small current item

This reciever can and will trigger large inrush and runtime currents.

Best of luck with your repair.

Best lessons learned the hard way

This just isn't true.
How do you know the APC isn't rated for 15A of current? He didn't give a model number.

The 1250 has a inrush preventor and APC is a good reliable brand.

 

[ivandezande]

So, I thought I was protecting it by running it through a power conditioner. Is that what you think caused the problem? Why did it get so hot? Thanks for all the help. Dropping it off at a repair place today.

Better pray the guy knows what he's doing. For every competent tech I've met, there's at least 10 other bozos that wreck everything they touch.

 

[elvi]

For UPSs, very rarely are they scaled to manage quick transition current draws.
Like a laser printer/copier with a fuser.

Trust me, a UPS scaled to support that reciever would be scaled for a Server.

I use an isolation transformer, with filtering and MOVs. It's rated for 1500 watts.

It's expensive to implement, but I feel my kit is worthy as some is quite dear and scarce.

 

[Matt817394]

Thanks, everyone. I'm using an APC H10 Power Conditioner.

 

[elvi]

That appears to be a conditioner, not a UPS.

That's " better ".
A UPS is sometimes offered as " power prtection"
Typically just one MOVs on the line and if your lucky, one on the neutral.

I'm on the fence about some conditioners... most literally are just surge absorbing, not line regulating and a simple button breaker.

Don't sweat it for now, just take time and keep your eyes open as you start your repair.

 

[koolkat62]

Matt817394, you can tackle this yourself! My first "big" receiver I re-capped was my 1250 I'm listening to at this very moment...it's playing some smooth tunes from my Akai 635D R2R and sounds just great! Anyway, it can be done and you can do it yourself. You have access to the absolute best advice and all the information you will ever need on that monster right here! These guys can guide you all the way from start to finish and believe me, if you do this, it'll give you such an awesome sense of accomplishment! You will need some equipment of course, but everything needed can be bought and you don't need the most expensive stuff out there. For what you would pay a tech, you can buy just about everything needed and get the satisfaction of doing yourself. If you don't know about vintage electronics, there's plenty of info online. I read and studied for quite awhile before starting, so that when I was inside of mine, things made more "sense" if you know what I mean. For example, on Youtube, there's a guy, Xray Tony, that does a video of working on the 1250..very informative. It won't show or tell of everything you'll need to know, but it's a good start. If you do decide to do this and when you are ready to order your caps, resistors, etc., you'll find a list of everything to order from Mouser or wherever right here on audio karma. That plus all the information you will ever need from these guys is all you need man!

 

[QSilver]

Follow Zeb's instructions. They're exactly what you need to do now. If your heatsinks were getting hot, the power amps are not happy. If both heatsinks were hot - it's really not happy. The Power conditioner most likely isn't the culprit. Just another victim. I wouldn't both with one as the SX-1250 is built like a tank. But that's my opinion.

 

[PabloX]

Where are you located? AK can probably recommend a tech in your area. I really doubt the APC is the problem.

Regardless, the 1250 is very much worth getting fixed, and very fixable.

 

[MIJ_Pioneer]

If it's a UPS I doubt it had anything to do with any failures. In my experience they generally continue to work but disable any battery backup function (and sound an alarm) when overloaded. Never seen it where they cause damage to themselves or a device connected to them. They are meant for a device with switching power supplies. They are not fit for your sump pump or refrigerator. One for a server just has a higher VA rating capable for higher power requirements along with other bells and whistles like replicating a proper AC sine wave (so the server does bark as it watches for that stuff) and the ability to shut down your server when the UPS reaches a capacity threshold.

On topic, definitely get a tech to take a look at it first, it's worth it. I wouldn't recommend working on it for your first rodeo, there is a lot to it and it's just too valuable of a unit.