advise SX-1250 repair

inkman69

inkman69

Active Member
I took my SX-1250 to a local repair shop. The unit was shutting down at a little over 1/4 volume and was needing a good cleaning inside. (I bought this unit from a co-worker who had it stored in basement for several years)
I got the call yesterday telling me that all 4 large capasitors (around the transformer) are bad. 2 are not very low valued and one is cracked and one is cracked and leaking all over board. He says this is whats causeing my voloume problem and that It will gradually get even worse. Said this is caused from the unit sitting for a long time and then powering up again. That these were made to be played reguarly.
He says its fixable....He says he can get Pioneer origanal capasitors at 90.00 each (he says they are hooked up and mounted with screws an easy fix for him. The other way would be to use aftermarket compasitors at 20.00 each,but he would have to rig these up but can make them work. But the values are diffrent , i dont remimber the values what he was saying and im not a repair man.
I was surprised that he says he can get origanal pioneer parts.
was woundering if anyone in here has any experianse in this type of repair?
my other choice is ....I have another SX-1250 in much nicer condition...very clean. It has a problem with the ballance controle...it quits on the right side....i sprayed it before with radio shack spray when i had the faceplate off and it worked fine for a couple of months. But is in need of a spray again. And the Loudness switch cuts off also.
So I have two units with issues and thought about taking parts from one to make a good one. and keep the parted onr incase of another break down.
what would you all do?

Thanks Inkman69 :scratch2:
 
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Keep them both. Don't use the radio shack spray, use Dexoit, and clean your controls again. Make sure you are cleaning them correctly. You have to drop the controls down, out of the bottom, to do it right.

Email this dude on Ebay, he might make you a better deal for 4. I use them myself in my 1250. I got mine for 80.00 delivered for 4 of them. The only modification needed was a slight enlargement of the wire terminals using a small file, very simple. I did mine myself, took my time, probably about an hour. Any "original" Pioneer caps would be old, you don't want those.


http://cgi.ebay.com/2pcs-ADCOM-100v...ryZ36336QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


You can use these as well. the Pioneer has a soft start circuit, so you can go up in uF values. Original caps are 22000uF each. But these 35000uF work fine too. Your main concern is physical size, spacing of terminals, voltage (you can go up in voltage rating, actually better to go up to a 100 volt cap than the original 80 volt cap), and quality of caps

http://cgi.ebay.com/4pcs-80V-35000u...ryZ36336QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 
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VintageNut said:
Keep them both. Don't use the radio shack spray, use Dexoit, and clean your controls again. Make sure you are cleaning them correctly. You have to drop the controls down, out of the bottom, to do it right.

Email this dude on Ebay, he might make you a better deal for 4. I use them myself in my 1250. I got mine for 80.00 delivered for 4 of them. The only modification needed was a slight enlargement of the wire terminals using a small file, very simple. I did mine myself, took my time, probably about an hour. Any "original" Pioneer caps would be old, you don't want those.


http://cgi.ebay.com/2pcs-ADCOM-100v...ryZ36336QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


You can use these as well. the Pioneer has a soft start circuit, so you can go up in uF values. Original caps are 22000uF each. But these 35000uF work fine too. Your main concern is physical size, spacing of terminals, voltage (you can go up in voltage rating, actually better to go up to a 100 volt cap than the original 80 volt cap), and quality of caps

http://cgi.ebay.com/4pcs-80V-35000u...ryZ36336QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Click to expand...


How did they work out VN? Any change in output characteristics of the unit? Would the larger caps give stronger bottom end? Just curious to what I have heard about the 35,000 uF caps.

Rebel
 
They are just power supply filtering caps, not in the audio path. I don't hear any difference myself, but if your old ones are defective, it might improve your bass. The 44000uF the SX-1250 has in stock form per channel is overkill , so 35000uF is really overkill, but it won't hurt anything since the Pioneer has the soft start circuit in it.
 
One more thing. For myself, I replace them in units I plan to keep, even before they go bad. They don't always leak when they go bad, but many of them will. When these big caps leak, like any electrolytic cap, it's corrosive, like battery acid. It will make a rusty mess of your bottom plate. Sometimes, they explode, venting out of the cap's bottom vent, spraying acidic electrolyic goo all over the chassis underneath. How would like to have a peachy SX-1250, that you open up one day to find a big rusty mess indside? The horror of it.
At any rate, l SX-1250s are pushing 30 years old, recapping them is not a bad idea.
 
I lean in the direction of non-Pioneer capacitors. Why? Because the "OEM" capacitors may have been sitting around in the Pioneer warehouse for years -- and may have suffered deterioration from this alone.

For example, the current Mouser catalog (p. 546) lists 22,000uF electrolytics at 100vdc, priced at $30.36 each. These are new-production devices.

HB Electronics lists (p. 21 in latest catalog) 22,000uF/100v caps for $32.45.

You should also check Digi-Key.

Physical size and mounting are important considerations. If substitute devices are used, make sure that the technician doing the work is a good craftsman. Too often, I see huge non-stock parts mounted LOOSELY.

Also, make sure that the service company CLEANS UP the leakage from the capacitor super well. This stuff is highly corrosive, and if it lands on a pc board it eats circuit foil and component leads like a ten-year-old with a bag of Oreos.

Good luck on this.

Fred Longworth
StereoTech Classic Audio Repair
a new AudioKarma advertiser!
http://www.repairaudio.com
 
The 22000uF caps on Ebay are made for Adcom, the amp maker, so they are designed for power supplies of amplifiers. I got mine last year from this same Ebay seller. I was curious, and called Adcom to see their price on them. Over 60.00 EACH, plus shipping. I immediately emailed and got my caps later that week. They work just fine, and a bargain for what I got them for. His price has gone up, probably in part due to the advertising on this board. Many AK members are now using these very same caps in the 1050 and the 1250. The 35000uF are even priced better than the 22000uF. No modifications needed for the chassis or the clamps, just needed the simple enlargement of the screw terminals. I now have done 2 SX-1050s and 2 SX-1250 receivers, all with no problems, and excellent sound. Installed them myself, and I'm not a tech. If you can change a car's oil, you can probably handle this job. JUST DON'T GET YOUR POLARITY REVERSED, OR BOOM!
Do a search here on AK, you will find several theads dealing with this subject. And no, I'm not affiliated with the Ebay seller at all, but he owes a commission, I think.
 
Newark sells a Nippon Chemi-Con cap, 22,000uf 100V for about $25 each (plus their S&H). PN 95F4479.

Same physical size as stock, but the screw terminal mounts are #10 screws, and the #10 is too large for the stock ring connector, which will have to be hogged out or replaced to accept the proper size screw.
 
Those work too, I hear. I remember Echo's main complaint of the Adcom caps were installing the Adcom name into a Pioneer receiver :nono:
Of course, one could easily rub off the Adcom name, if you lose sleep over it.
 
Nothing wrong with the Adcom caps...just throwing another option out there.

I think inkman is about the least interested one in this thread anyway.
 
Thanks for the help guys. This forum board Rocks! Im copying this info as I type. I will run this info buy the tec on monday. And hopefully I dont step on his toes with this info. The old new stock sounds right ....It being old and my have problums as before.And With the supplyer info that you guys gave me can stear him in the right direction. Im hoping he has already found some of this out though.Would make me feel better at payup time. If this goes well I will be taking my other SX-1250 for the same.
 
He might be an OK tech, but I have to wonder why he wants to use original Pioneer caps that would likely be old. Caps sitting on a shelf for years and years can age faster than ones in use. Unless they have a new production line going for them, and I doubt it. 90.00 each is just not acceptable anyway. I wonder if he wants to put used caps in, and say they are new? Really no need to rig anything, in fact, in my opinion, chassis modification in order to make the caps fit lower the value of the receiver. Why modify anything on a collectable receiver when new caps are available that exceed original specs, that require no mods, except for the ring connectors the screws go into.
 
EchoWars said:
Newark sells a Nippon Chemi-Con cap, 22,000uf 100V for about $25 each (plus their S&H). PN 95F4479.

Same physical size as stock, but the screw terminal mounts are #10 screws, and the #10 is too large for the stock ring connector, which will have to be hogged out or replaced to accept the proper size screw.
Click to expand...

Now that's news to me. This thread's got me almost ready to recap my 1250. I love the fact that the caps EW mentioned are the same size. Good info :yes: They show 149 in stock.
 
OK, I got a couple of private messages asking more about the Adcom 22000uF caps and the 35000uF Cornell Dublier caps , so let me clarify. These fit just fine, right into the stock clamps. No chassis modifications needed, just the enlargement of the terminal holes. So, the fit will be the same if you buy the Nippon Chemi-Con or the Adcom or the Cornell caps. All will require the very simple enlarging of the terminal holes. The Cornell caps are shorter, if that bothers you.
By the way, the last few Cornell auctions have ended at a final cost of about 42.00 delivered for 4 of them. The Cornell caps are a nice quality cap, 80 volt, like the originals, the Adcom caps are 100 volts. 100 volt caps may last longer, but I look at it that the original 80 volt caps lasted a very long time, and any of these new caps will be of higher quality anyway.
 
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Inkman69, next time drop me a line. I've got plenty of work here, but I'll always go out of my way for a local guy, even if I'm swamped.
 
If it was me, and I was near Echo, I would pick it up and take it to him. Let EW go through it, maybe even rebuild the power supply while he's at it. You'll get top quality service that way
 
Well Thanks guys for all the advise. Alot more than I wanted to tackle alone. So I took
vintagenuts advise. I droped off one of my SX-1250s to Echowars last night. I was impressed. I seen lots of nice equipment right up close! It was a real treat to step back in time like that. Im lucky to have a guy like echo right in my own back yard! I left his place feeling safe that my SX-1250 was in the best posable hands. Echo even sent me home with a loaner Tuner to hook up to my SA-9100 to keep my wife happy while our baby is away! I will keep you guys tuned in , And thanks again.

inkman69
 
Help needed...blowing fuses after cap upgrade

I opted to replace my 4 power-stage capacitors after I found them leaking out onto the bottom plate (and the bass boost was starting to sound like a fart at high volumes). I just got the new caps in from Digi-Key, I reamed out the wire posts for the larger capacitor bolt holes, powered up the unit and after 15-30 seconds the mainline 12A-250V fuse blows (the panel lights dim and brighten a few times, then it is lights out).

I have inspected the unit for any hardware that might have fallen, but no such luck. I have a service manual on order and a full box of pricey 12A fuses.

Help! I am limping by on my backup SX-636, but it is nowhere near the umph of the 1250.
 
Probably needs a rebuild on your power supply. Look for threads here at AK, you should find several by Roger (Rstsgsas) where he describes the process, and diagnosis or of course, posts by by Echowars.
 
kaiser_will said:
I opted to replace my 4 power-stage capacitors after I found them leaking out onto the bottom plate (and the bass boost was starting to sound like a fart at high volumes). I just got the new caps in from Digi-Key, I reamed out the wire posts for the larger capacitor bolt holes, powered up the unit and after 15-30 seconds the mainline 12A-250V fuse blows (the panel lights dim and brighten a few times, then it is lights out).

I have inspected the unit for any hardware that might have fallen, but no such luck. I have a service manual on order and a full box of pricey 12A fuses.

Help! I am limping by on my backup SX-636, but it is nowhere near the umph of the 1250.
Click to expand...
Check for any shorts built in due to your exchange of the caps! Maybe the the cup of the negative supply capacitor is touching chassis? Or you reversed one of the caps?
 
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