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SX-1010 tuner

Maddart

Maddart

Active Member
I am new to this forum and didn't realize that there was such a following of the old pioneer gear. I owned a sx-434, sx-737, sx-1010 , and an sx 1050 way back when, and purchased another sx-1010 5 years ago for $100.00. The unit when plugged in and turned on worked fine for a couple of hours then the tuner ceases to work both with speakers and headphones. I stored the unit away in the crawl space. I recently found this forum and decided to try to resurrect the old beast. When the unit is turned on it plays fine for 2-3 minutes then the tuner signal meter stops working along with the tuner itself. I have also noticed that one of the Elna 18000uf cap has a major leak. I haven't checked out any other functions since i just started this last night. I am not a technician but am capable of using a fluke(179) and desoldering and soldering at component level.
 
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welcome to AK, a service manual would be a good investment. The search function is a valuable asset as well, lots of good info on the 1010 here.

good luck!
 
Welcome to AK.
The above poster has you on the right track. Get a manual definitely.

Do you have experience with repairing electronics? This is something we really need to know. If your not familiar with how to properly work on and repair these units, you can easily do more harm than good. Instead, we can direct you to one of the excellent technicians here that can help bring your 1010 back to life. Just let us know your location.

I would first turn my attention to the power supply board. Pioneer made the mistake of placing this underneath the chassis where all the heat will build up. They will almost ALWAYS need resoldering of the regulator transistors and new capacitors. use caps rated for 105 degrees rather than the stock 85. If it was working then went dead, the tuner probably lost power. Start there.
 
Hi Jordan

I do have experience working with PC boards, soldering, and using a Dmm, but not repairing recievers.
I am located in illinois. The unit does power up and work, then 2 minutes later the tuner cuts out. Shut the unit down for 10 minutes and turn it back on and the tuner is working for another 2 minutes.
The first thing i was going to do is replace the leaky 18000uf 63v caps.
Thanks Mark
 
Sounds like a thermal failure. To track down the defective component(s) you'll need a can of Component Cooler.

Ron
 
HI!! Welcome to AK and the Pioneer (repair :D) Forum...

The tuner section runs on 12 - 13 volts and is usually the only section inside that does (car stereo heritage for the chips in the tuner).

The solder joints on the power supply card between the power transistors and the pc pattern tend to flex when heating and cooling. This causes them to crack and loose contact.

The power supply card is about in the center of the underside of the chassis.

The 3 power transistors are mounted on the heatsink, and one of the two D313 transistors is the one to look at the leads on the underside of the board. It won't hurt to resolder ALL 3 power transistors (B507 included).

If this doesn't help, then we can get much more involved.

Good Luck!!
 
I got home today and plugged the 1010 in and powered her up. I am getting 13.3v at pin 8 but now the protection relay keeps cutting out and in. there is no set rhythm to this. All other pins seem to be close to proper voltages per the shop manual example Pin 14 before tuner cuts out 56.5v after 52.7v. I ordered new nichicon gold 22000uf caps to replace that leaker.
Thanks Mark
 
You need to look at the no-signal DC output voltage of each power amp before the protection relay interrupts it's path to the speaker terminals.

Pins 1 & 3 on the protection board are a good point. (referenced to a metal chassis ground)

Then we will know if the protection circuit is justified in disconnecting the speakers.
 
Markthefixer

Protection board AWM062 pin 1 is 0v and pin 3 is erratic reading .230v and OL on the fluke. this is as the relay is clicking on and off. I flipped the PS board to look at the solder joints and the joints on the D313 look to be slightly corroded due to flux. I will try to reflow these joints this weekend.Will also try to post a photo. Also if anyone has a parts list for re-capping the PS board it would be most appreciated
Thanks Mark
 
Maddart said:
Markthefixer

Protection board AWM062 pin 1 is 0v and pin 3 is erratic reading .230v and OL on the fluke. this is as the relay is clicking on and off. I flipped the PS board to look at the solder joints and the joints on the D313 look to be slightly corroded due to flux. I will try to reflow these joints this weekend.Will also try to post a photo. Also if anyone has a parts list for re-capping the PS board it would be most appreciated
Thanks Mark
Click to expand...

pin 3 is erratic reading .230v and OL
This is the problem, the amp is sending out DC. The protection circuit is operating properly in disconnecting the speakers.

The rub is that the entire amp is balanced front to back like a teeter-totter. Something somewhere out of whack. IF it STAYED at OL then we have a fighting chance. As it is I have to think a bit...
 
This relay clicking on and off just started after i opened the unit. Although i find that the AWM062 board is accessed from the top unlike the service manual shows.
 
The board likely needs to be recapped, and the differential pair replaced.

FWIW, tackling the amp board on a 1010 is not advisable for the novice. Start busting those solid-core wires and tearing up multijunction diodes and you'll have a serious mess on your hands.
 
I assume the board you are refering to is the power supply board AWR-054A, which actually looks in very good condition, and the differential pair you are refering to are the D313 transistors?Please see photos
 
I went ahead and resoldered the D313 transistors and used a flux cleaner to clean the board(See photo in previous post). I ran the unit for about a half an hour and the tuner didn't kick out. The protection relay clicked off at intervals of approximately 10 minutes. Protection board pin 1 .001v to.015v and pin 3 .001v to.022v. I am only using headphones and don't have any speakers connected.
 
Well, now the amplifiers appear stable and the protection circuit seems unjustified in operating. This is actually a more familiar fault.

The awm-062 protection board's C5 (4.7uF/25v) C6 (100uF/16v) may need to be replaced, as well as Q7 the 2sc1384 transistor which drives the relay.

Q7 could be getting weak over the years, and more suceptible to heat (including it's own internally generated heat)

I will also talk you through adding an additional protection diode for Q7 to be connected between terminals 9 and 10 (banded side of diode) which was done in later and more expensive Pioneer models.

You see, the relay coil generates a negative voltage spike every time the magnetic field collapses, and the spike gets into the transistor, not usually killing it overtly, but rather nibbling away at the junction over the years. This extra diode limits the spike to -0.6v, and it can withstand the current involved in clamping to -0.6v.

You may be able to modify the protection on/off cycle by cooling Q7 with either freeze spray or "canned air" keyboard duster...

If you are game (and in the U.S.), I can work up a parts list to be ordered from a net supplier that should be under 5 bucks shipped.
 
These parts need to be replaced:
c3, c4 330 uF 6 volt capacitors (two) part # 140-XRL16V330-RC @ $0.11 ea
c5 4.7 uF 25 volt capacitor part # 140-XRL25V4.7-RC @ $0.06 ea
c6 100 uF 16 volt capacitor part # 140-XRL16V100-RC @ $0.08 ea
Q7 2sc1384 (ecb) transistor part # 522-ZTX694b @ $1.41 ea lead layout (ebc)
and an additional part added for longevity
1n4004 diode part # 512-1N4004 @ $0.05 ea

a zetex ztx1056 would be preferred, but they are out of stock until the end of th year. the 694b should suffice.

mouser.com has replacements for these parts, with no minimum order and if first class mail shipping is specified, the shipping costs can be kept low too.

The additional diode will be connected to pins 9 and 10 on the board, which go to the relay. Pin 10 will be connected to the diode's cathode, which is the end with the band painted on it, while the other side of the diode, the anode, will be connected to pin 9.

WARNING:
The transistor lead arrangements are different, the original is eCB and the replacement is eBC, so the flat on the transistor will face in a different direction from the original's direction.

Let's get it working first, and not complicate the diagnosis by doing anything to the power supply right now.
 
Thanks Markthefixer
I will get these parts on order with mouser on monday as we have a business account with them.
Observation: have been listening to the 1010 for an hour now.
Lost tuner after 15 minutes sprayed PS board with freeze (ESD safe) and has been fine now for 45 minutes
Relay clicked out a couple of times, When it clicks off pin 3 goes to OL on meter ,i hit it with freeze spray and it lasted for about 30 minutes.
I believe there is a problem with both boards. I will rebuild the protection circuit when the parts arrive and test again. I will post results when available.
Do you know the value of the resistors or P/N on the resistors across the elna 18000uf caps?
Thanks Mark
 
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