No voltage on pins 8-19 on SX-1050 awr 103 board????!!!!

My SX 1050 hsa no sound and the function indicator lights seem brighter than they should be. I checked the voltages on the AWR 103 board and there are no voltages on pins 9 thru 19. Im not sure what happened, is it possable to rebuild this board from scratch?

Wooaa Steve. First, Welcome to AK. Second, tell us some more about the unit's history. Did it just go out, or started having problems, or just "dead" when you got it?

So you joined AK more than 2 years ago and this is your first post? No need to be so shy.

Function lamps are powered by a regulated 5.4V supply, measure at pin 18 or 19 of that board. You say the function lights are lit, so either you're measuring wrong or your meter is wonky.

Replacing all those small lamps is a truly sucky job. If you measure a voltage (possibly with a meter that works) more than 5.4V on 18 and 19, I'd take out the FU3 and FU4 fuses until you get it worked out.

Sorry about not posting sooner but my 1050 has been in the closet for a while just pulled it out a couple of days ago. I got the schematics from Sams photo facts so I could Have them for just this eventuality. my meter is a Fluke 77. I have a pretty good understanding of electronics as it has been a hobby for approx. 30 yrs.

Any chance you were using it as an amp and left the jumpers out?

all jumpers are in place. headphone jack dead too, tuning meters ar working normally, all selection switches for phono, am.fm, aux work as lights for selected input are working.

sorry voltage readings on pins 18,19 are good

Sounds like you need the schematics. I rebuilt most of the power supply board on a 1080. I know that's a different animal, but it wasn't too difficult, and I'm not the sharpest tool in the shed. I believe I left all the resistors in, and changed the diodes, caps, and transistors. Does the speaker relay click in after you turn it on? The schematic might be in the Pioneer database, (sticky) at the top of this forum.

I Have Schematics Relays are clicking.

Guys, Ive got to go to bed. (got to be fresh for my real job(auto mechanic)
I will check back in tomorrow about 8:00 P.M. PST.

I'm sure some more Pioneer fans will be along later today. The SX-1050 is a sweet receiver, BTW.

awr103 voltages

First, there IS a 39 MB sx-1050 service manual .pdf file in the manual database that members can download, and if you prefer a high quality Pioneer reproduction paper manual, they are available from (no affiliation) Rick at http://www.stereomanuals.com/ .

Ok, let's address a few cockpit questions.

First there is the "soft start" relay, which operates within a second or so of power up, to tame the huge inrush of current charging up the main capacitors when it is turned on.

Then there is the protection relay which should operate a few seconds later, which connects the speakers to the amplifier outputs.

But since you said relayS.....

There is one other gotcha waiting, if ALL THREE speaker switches are turned on at the same time, NO SPEAKERS are connected. BUT the headphones stay live.......

I have included a list of all the voltages on the power supply board. Troubleshooting must be approached methodically... so, what are all of the voltages on these pins, referenced to a metal chassis ground?

Power supply regulator board AWR-103 voltages:

1 +24v raw dc
2 +76v raw dc
3 -76v raw dc
4 ground
5 +13v regulated
6 +13v regulated
7 -13v zener diode
8 -60v regulated
9 -30v regulated
10 -25v regulated resistor dropped from -30v
11 -25v regulated resistor dropped from -30v
12 ground
13 +25v regulated, zener dropped from +30
14 +25v regulated, zener dropped from +30
15 +30v regulated
16 +60v regulated
17 +60v regulated
18 +5.4v regulated
19 +5.4v regulated

The loss of some of the lower voltages could shut down your control and tone amps. Does bypassing the tone controls make any difference?

Then of course there are the usual issues, such as the positions of the switches and the presence of the pre out / power in jumpers.

When starting out cold troubleshooting with both an unknown piece of equipment, as well as an unknown troubleshooter, you must forgive me for assuming NOTHING....

Can you induce hum into the power amps with the power in jumpers? (or another signal source??)

Can you read the tuner or phono out at any of the rear jacks?

Voltages on pins 1=24v
pin2=80v
pin3=-80v
pin4=0v
pin5=13v
pin6= -13V
pin7= 0V
pin8= 1v
pin9=0v
pin10= 0v
pin11=0v
pin12=0v
pin13= 0v
pin14= 0v
pin15= 0v
pin16= 1v
pin17= 1v
pin18=8.75v
pin19= 8.75v

Power supply regulator board AWR-103 voltages:

1 +24v raw dc pin 1=24v ok
2 +76v raw dc pin 2=80v ok
3 -76v raw dc pin3=-80v ok
4 ground
5 +13v regulated
6 +13v regulated
7 -13v zener diode
8 -60v regulated
9 -30v regulated
10 -25v regulated resistor dropped from -30v
11 -25v regulated resistor dropped from -30v
12 ground
13 +25v regulated, zener dropped from +30
14 +25v regulated, zener dropped from +30
15 +30v regulated
16 +60v regulated
17 +60v regulated
18 +5.4v regulated pin18=8.75v
19 +5.4v regulated pin19= 8.75v


Wow, the WHOLE board is BLOWN up. This will take a while to reference across to mouser.com 's Fairchild transistors... It will probably be best to replace all the transistors, most likely all the power pass transistors ( the ones that cost more) are gone, and the smaller ones will be really cheap. While the board is being worked on, it will be a good idea to replace the electrolytic capacitors as well.

On the bright side, when you are done, you will have the equivalent of a brand new power supply.

The green represents the power being supplied to the regulator board, and it's ok.

The magenta represents a questionable area, as pins 5 and 6 are connected together, and pin 7 is supposed to be -13v.

The red area is just plain gone... although if the 13 volts is on pins 5 & 6, then all we have to do is figure out why the 5.4v supply is putting out 8.75v, as it might be partially regulating the voltage, unless the voltage drop is solely due to R21's voltage drop and Q12 is either shorted or turned on hard.

You will want to protect your lamps in the unit by doing as EchoWars recommended and pull the FU3 and FU4 fuses until the voltages are correct.
The next question after that is how it got that way.... and more importantly, is it going to happen again.

like I tried to post earlier the unit has been in a closet for about two yrs as i had another reciever and the 1050 was overkill for the system I was running at the time. I'm not sure but I seem to remember some fluid being spilled onto the reciever. I forgot about it at the time because it was not being used. possibly fried the board on powerup. as I stated I did not hear any unusual sounds, no smoke,no odors, etc.

I kind of thought that the reg board was fried. Let me say that I love this reciever and would love to get her up and running again as iI have 3 reel to reel tape decks and a Dual turntable I wish to hook up. My Speakers are Vandersteen Model2 C and i wish to get the best out of them.

sx1050 power supply awr-103 awr103 recap rebuild

Here is a list of the parts to do an almost complete rebuild of the power supply regulator board:

q1 2sd313 to-220 bce npn 60v 3a 30w 5mhz
replacement part # 512-KSC2073TU_Q @ $0.53 ea (bce, same layout)
q2, q3 2sc869 to-92 bce npn 50v 30mA .2w 150mhz
replacement part # 512-KSC2310YBU @ $0.11 ea (ecb, opposite layout)
q4 2sc1318 to-92 ecb npn 50v .5a .6w 200mhz
replacement part # 512-KSC2682YS @ $0.31 ea * to-123 case (ecb to ecb, same layout, different case)
q5 2sb507 to-220 bce pnp 60v 3a 30w 5mhz
replacement part # 512-KSA940TU_Q @ $0.54 ea (bce, same layout)
q6,q7 2sa628 to-92 ??? pnp 25v .1a .15w 100mhz
replacement part # 512-ksa733Clta @ $0.05 ea (ebc layout) wrong!!! (ECB, SAME layout)
q8 2sa720 to-92 ecb pnp 60v .5a .625w 200mhz
replacement part # 512-ksa1142ystu @ $0.28 ea * to-123 case (ecb to ecb, same layout, different case)
q9,q12 2sd325 to-220 bce npn 35v 3a 10w 8mhz
replacement part # 512-ksc2073tu_q @ $0.53 ea (bce, same layout)
q10,q11,q13 2sc945 to-92 ecb npn 50v .1A .25w 150mhz
replacement part # 512-ksc945Clta @ $0.06 ea (ecb to ebc, different layout) WRONG!!! (ECB, SAME layout)

d1 wz-140 mouser.com part # 512-1n5244b @ $0.04 ea
d2 wz-130 mouser.com part # 512-1n5243b @ $0.04 ea
d3,d4 wz-061 mouser.com part # 512-1n5234b @ $0.04 ea


nichicon:
c1,c9 220uF 80v mouser.com part # 647-UPW2A221MHD 220uf/100v $1.48ea
c3,c12 47uF 16v mouser.com part # 647-UPW1E470MDD 47uf/25v $0.31ea
c6,c14 47uF 35v mouser.com part # 647-UPW1H470MED 47uf/50v $0.34ea
c7 10uF 35v mouser.com part # 647-UPW1H100MDD 10uf/50v $0.25ea
c8 1uF 50v mouser.com part # 647-upw1h010mdd 1uf/50v $0.23ea
c15 100uF 35v mouser.com part # 647-UPW1H101MPD 100uf/50v $0.50ea
c16 220uF 25v mouser.com part # 647-UPW1V221MPD 220uf/35v $0.56ea
c17 47uF 10v mouser.com part # 647-UPW1E470MDD 47uf/25v $0.31ea
c20 100uF 25v mouser.com part # 647-UPW1V101MPD 100uf/35v $0.15ea
c22 47uF 10v mouser.com part # 647-UPW1E470MDD 47uf/25v $0.31ea
c23 2.2uF 50v mouser.com part # 647-UPW1H2R2MDD 2.2uf/50v $0.23ea
c24 220uF 16v mouser.com part # 647-UPW1V221MPD 220uf/35v $0.56ea


Sharp eyes will notice that Q4 and Q8 have been substituted with transistors with different, larger cases. They can handle more power, and will not be straining even under reasonable overload conditions.

Also the voltage ranges of the electrolytic capacitors has been increased, most specified caps now have a 50 volt rating. The difference is just a few pennies at most and are better suited to survival under fault conditions as well.

I will edit this post in a day or two, to contain the full lead designations and changes in the lead arrangements on the original transistors to the lead arrangements on the replacements, there will be time between when these parts are ordered and when they arrive.

You can specify first class mail shipping in the checkout procedure to keep the shipping costs down if you wish.

edit: xicon cap numbers removed, if you're going to this much trouble, use the (darn) Nichicons!!!!

Slow evening there Mark? :scratch2:

EchoWars said:

Slow evening there Mark? :scratch2:

Click to expand...

:lmao:

All my hammering in the bathroom was giving me a headache, and I'm tired of my diet of sawdust and cement board dust.

Of course when the wall studs are all FINALLY closed, then I get to tape everything and SAND the joint compound (oh.... sneeze ...joy)

I have a sx-1050 on the shelf that might benefit from a power supply regulator rebuild eventually, so I'm keeping a copy of the above for myself too.

mark thats some list but I am definatly up for this job. I await your next post with baited breath. thanks for the info all. as I posted earlier Iwant to use this recieverto set up my music room again. I have the factory schematics and board pics so now it just a matter of time and patience.