Pioneer SX-2300 audio output problem

[skywalker999]

Pioneer Amplifier SX-2300

My stereo amplifier turns on but there is no sound output to the speakers and the headphones
Here’s what happen my brother decided to ad or connect another speaker on the B side
of amplifiers speaker output the A side output ad two speakers on it already as soon he
Connected the extra speaker bang no more sound of course he overloaded ohms capacity
Of the amplifier I know that you can connect as many speakers you want as long you respect
Te ohms capability that the receiver can handle
This receiver is rated (A or B 6 to 16 ohms ) ( A+B 12 to 32 ohms )
and with surround sound on 8 to 16 ohms
So my question where should I start to check or what parts could of gone bad

Direct link = http://s24.postimg.org/ada1t1sud/Pioneer2300_MB_front2.jpg
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direct link= http://s24.postimg.org/gghz23net/Pioneer_SX_2300_MB_back2.jpg
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[Terryl]

Only one speaker on the "B" side??? not a good idea.


He more then likley blew one or both of the output amps, or the drivers for the amps, I can't tell by the photos but do you see anything that looks like an output fuse of and internal fuse?

They would look like a little green resistor if they used one.

here is a link to a service manual for that one.

http://www.kallhovde.com/pioneer/tricomp/Audio/SX/SX-1300_2300_ARP1477.pdf

[skywalker999]

Terryl do you mean this on the pic

direct link= http://s17.postimg.org/6w81jh2tb/IMG_20130628_00035.jpg

18772

[Terryl]

No it should be on the main PCB, if they have some on there, or they could be external fuses, in a fuse holder.

They might not use them, the large transistors located on the back of the receiver are the power amps, then just before them are the pre-amps, they look like the main ones but do not have a heat sink on them..

But sence you do not have any audio on "A" "B" or the headphones the output IC could have been damaged, if that is the case and there are no fuses then it's time for a new one.

[nunoit]

ok skywalker this ones going to take a little time. i did not have much time to look at this just yet will look at it more later. like before you just want to see if you can do it right.

one thing we will need to start getting are part numbers off the chips like the big ones mounted on the back i will look at the schematic to see where is what.

terry thanks for the link great. i saw in the parts list there 4 fuses.

[skywalker999]

Thanks nunoit and you are correct know the big transistor chips number are there is two C3180N 0.9E and two green ones A1264N 0.8A and the four small ones two black and two green C2238 0.8A and A968 0.8A what's the correct way to test these
and Terryl here is a pic of the four transistors
18777

[Terryl]

After going over the parts list and schematic (what there is of one), I don't see an on board fuse for the audio.

So this means that ether the drivers are gone, or the finals are gone, (or they all have gone) you can contact Pioneer to see if they are still available.

I did find a like receiver on E-bay, you might want your brother to fork over the cash and get another one.


http://www.ebay.com/ctg/Pioneer-SX-2300-2-Channel-120-Watt-Receiver-/114211004


When he hooked up the "B" side to the speaker, did he use two speakers (L&R) or just one connected across L&R?

[skywalker999]

Terryl he only connected one to the right side and thanks for the link I will check it out

[nunoit]

before we go to far when plugged in when you power up do you get any thing at all. lights, radio display, tuner changing channels any thing. we could be looking in the wrong place to begin with. you don't need speakers connected at this time just minimize volume control for test.

with that said !!

sky those are npn and pnp transistors. think of them like to diodes in one package. you can use diode test function and test from base (b) to emitter (e) and base (b) to collector (c) then collector (c) to emitter (e) on board. if you get funny reading remove and test. (explained later)

ok when you look at them from mounting side left to right b c e (i posted a pic)

you have complementary pair pnp next to npn sorta matched black one with green one side of amp. the bigger the transistor the more power it can handle.

for a npn device
you connect red lead to (b) black to (e) take reading log it

then leave red on (b) move black to (c) take reading.

then put red on (e) leave black on (c) take reading

reverse leads and repeat tests above

for pnp device reverse leads and test like npn device.

if any read shorted or open device is most likely bad.

you could also remove it and use transistor function on tester to see if it is good. put leads in respective holes on tester.

pnp = positive negative positive.
npn = negative positive negative.

[skywalker999]

First the amp turns on just fine all the buttons on the front panel are working correctly
Tuner tunes in or on to right radio stations but no sound I have notice one thing do
The resistors on the small board where the speakers connect they are giving me nothing
don’t know if that’s important and now here is the results that I have taken from the four
Transistors connected to the heat sink



transistor 1 C3180
0.123 b-e
0.494 b-c
0.513 e-c

0.123 e-b
0.689 c-b
0.769 c-e

transistor 2 A1264
0.123 b-e
0.123 e-b
1.087 b-c
0.488 c-b
0.519 c-e
1.150 e-c

transistor 3 A1264
0.122 b-e
0.123 e-b
1.632 b-c
0.485 c-b
0.521 c-e
1.552 e-c

transistor 4 C3180
0.123 b-e
0.123 e-b
0.494 b-c
0.679 c-e
0.533 e-c

[nunoit]

those resistors should give you some kind of reading real low ohms i see 2.7 and 4.7 ohms worst case they might read shorted not open. if you get no reading at all i would think they are bad. just a note those look like wire wound power resistors (could be carbon). according to parts list r856, r857 are rs2lmf100j i am going to guess 4.7 ohm 1 watt and r854, r855 are rs3lmf2r7j 2.7 ohm 2 watt j indicates 5 %. i tried looking up those part numbers and got nil.

by the way the reading you got look confusing. b-e e-b should be different and b-c, c-b, e-c, c-e should show directional flow difference. now there is that big white dual resistor causing back feedback and according to schematic r527, r528, r537,and r538 also. so it is possible they are good the way to find out better would be to pull and test with tester. unless you had an in circuit tester. but lets not go there. if you want pull one and try your tester. i think they are good not 100% certain.

[skywalker999]

nunoit this is how did the test and that's the results i get

transistor 1 C3180
0.123 (+ red on b 1)-(e 3 - black )
0.494 (+ red on b 1)-(c 2 - black)
0.513 (+ red on e 3)-(c 2 - black)

0.123 (- black on e3)-(b 1 + red)
0.689 (- black on c 2)-(b 1 + red)
0.769 (- black on c 2)-(e 3 + red)

now for the resistors those are two resistors 2.7 ohms 3 watts one 10 ohms 2 watts and one 4.7 ohms 2 watts they all end with (J) i guess +5%
I'm going to remove one transistor and checked again and see if I get different results

[nunoit]

the only reason i am concerned with the readings is the b to e, e to b reading is the same which indicates bad, but like i pointed out there are resistors connected between those pins that could be why you read .123 both ways the other readings you are getting are the sign they are good.

did you get readings from those resistors. i did not see the 10 ohm unit in the pic.


also check out all the other transistors in that blocked out area. marked power amp. we will also be looking at the pre-amp section after we finish with this section. from what i see in the schematic there are 20 transistors in total to check 10 for each side.

if you look at the schematic section 5 block area c & d, 4 & 5. you will see all the components you need to find and test.

[skywalker999]

ok nunoit I removed all four transistors and these are the readings I get

Transistor1
C3181N R.8A

red on pin (1) black on pin (3) =.546
black on pin (1) red on pin (3) = OL
red on pin (1) black on pin (2) =.543
black on pin (1) red on pin (2) = OL
red on pin (2) black on pin (3) = OL
black on pin (2) red on pin (3) = OL

Transistor 2
A1264N R.8A

red on pin (1) black on pin (3) = OL
black on pin (1) red on pin (3) =.531
red on pin (1) black on pin (2) = OL
black on pin (1) red on pin (2) =.523
red on pin (2) black on pin (3) = OL
black on pin (2) red on pin (3) = OL

Transistor3
A1264N R.8A

red on pin (1) black on pin (3) = OL
black on pin (1) red on pin (3) =.519
red on pin (1) black on pin (2) = OL
black on pin (1) red on pin (2) =.511
red on pin (2) black on pin (3) = OL
black on pin (2) red on pin (3) = OL

Transistor4
C3180N R.8A

red on pin (1) black on pin (3) =.526
black on pin (1) red on pin (3) = OL
red on pin (1) black on pin (2) =.515
black on pin (1) red on pin (2) = OL
red on pin (2) black on pin (3) = OL
black on pin (2) red on pin (3) = OL

and yes there is a 10 ohm resistor there and what is the best settings on voltmeter mine goes from 2k to 200k i removed one and the best result i get .0003

[kijiji]

Unless your doing this as a hobby lets face it the pioneer sx-2300 is a 2 channel stereo receiver that about 20 yrs old now and was a dog at best.You can buy a used 7.1 audio receiver almost anywhere these days for about $50 but like i said if its a hobby good luck and have fun,if not move on to something else.

[skywalker999]

don't worry it's just a hobby project
used 7.1 audio receiver almost anywhere these days for about $50 is that on flebay

[kijiji]

don't worry it's just a hobby project
used 7.1 audio receiver almost anywhere these days for about $50 is that on flebay

kijiji,ebay or pawnshops.

[Terryl]

It looks like there is an overload detection circuit, it uses a relay to cut off the power to the audio amps, look for RY501 and see if it is stuck on/off or being turned on/off permanently by Q523 or Q524 being turn on, blown or shorted.

[skywalker999]

Terryl is that on the front panel because i don't see it on the amp board

[Terryl]

Look right next to the power supply transformer and close to one of the large caps.

18801

[skywalker999]

Thanks Terryl founded how do you turn that on is there a switch on that or something else turns that on

[Terryl]

That should be on when the stereo is on, it turns off when an overload is detected, if it has never been used then the circuit may have popped when your brother overloaded it.

The relay can only be tested when the stereo is on and connected, you can check for a DC voltage at R608, then on the other side of the relays coil there should be a low voltage, say around .6 volts or so, this can be measured at the second jumper over at the top of cap C607, you can see the trace in the photo I posted.

This relay will be on when one side is at (lets say) 12 volts, and the other side is at 0 volts, if both sides are at 12 volts or 0 volts then the relay will not turn on.

Now I am assuming that the relay is always on when the stereo is on, so one side will be a high voltage, the other a low, if both sides are the same then the circuit is ether on because it still detects an overload, or the circuit is popped.

Or the relay coil has gone bad, you can measure across it with an ohm meter, in circuit there should be some resistance across the coil, if you read an open then the relay is gone.

The coil resistance may be marked on the relay.

[nunoit]

those transistors look good they are hi power and will give readings like you got. re-install them. when you power up do you here a clicking noise. that would be the relay turning on. some times you can even feel it turn with your finger.

terry good call i was going to go there with the readings from the transistors.

for those resistors sky use the lowest reading on meter. 200 ohm

first of course re-install the transistors.

that relay if its bad is no longer available. pioneer no longer stocks it even the recommended # not available.

to test check for continuity where i put blue line. if good then pull relay and add jumpers that i marked in pic in red.

that will bypass the relay with jumpers (temp) and test receiver with speakers connected.

if that works your not out of the woods you will need to determine what went bad in the overload circuit.

if you have spare time and want to play some you could build this simple transistor tester (circuit posted) which will greatly improve and reduce testing time as you can test while in circuit. as you see parts count is small use bread board to mount and use mini grabbers for leads.

or you can get a kit from h**p://www.tequipment.net/ElencoDT-100K.html?Source=Google&gclid=CKOYnuOQkbgCFdB7QgodvDoAog
i have the same one works great. just change the clips to mini grabbers. they sell it for 20 bucks. should not take more than an hr or 2 to assemble.

[skywalker999]

Terryl and nunoit i get 48.2V on that resistor R608 but I'm getting no voltage on that coil
and other places close to that coil the other coil im getting 45.3V check pic
and connected two 8 ohm speakers on the amp to test but there is no clicking sound coming from
RY501

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[Terryl]

Use a real long screw driver, touch it to the relay then hold your ear to the handle of the screw driver, turn the power on and off, if you don't hear anything then the circuit driving the relay is dead, or the relay is gone.

[nunoit]

first check continuity across the coil of the relay. should read dead short if good, if not remove and find out voltage and replace.
yours is DPST (double pole single through) take to store to match pin out.

note: most relays come with 8 pins not 6 like yours. (normally open, common to both, normally closed and the coil) you need normally open contacts. once you find one, you may and will have to cut 2 pins (normally closed) flush to body to mount it.

if good then track down and test Q-601, Q-602, Q-604, then also look for Q-523 and Q-524, diodes are D-507 D-508, D-509, D-510 and zener D-610 also caps c-603, c-604, c-605, c-523, and c-524 those are all part of the overload circuit.

note: the zener diode is a voltage regulator the component # will aid you what voltage it regulates to. you need to look up specks for that info. that should tell you the coil voltage to.

my suspicion is the one mounted on the heat sink is bad, just my thought.

all those parts should be where marked on red on pic.

BTW: your doing great you will be done soon.

[Terryl]

OK, for that circuit the transistors Q523 and 524 are the overload detectors, they look for too much current or DC voltage across the power amp transistors Q1, 2, 3 and 4, if they detect to high a DC voltage or current they will turn on and cause Q601 and Q602 to do there thing and turn Q604 off, thus shutting off the relay RY501, as the DC voltage across the coil will be the same and that shuts off the sound to the speakers.

I would check with a small speaker at L501 and L502 (carefully, with the volume down low) (I would use an oscilloscope for this, but you might not have one of those)to see if you have any sound at that point, if you do then we are looking at the right circuit as it is keeping RY501 from closing and delivering the sound to the rear speaker terminals.

[skywalker999]

Thanks guys but that's a lot of home work for one day lol
thanks for the link nunoit but unfortunately don't think they ship north of the boarder (canada ) ad to by same exact one on ebay
40 dollars shipping included and I'm still waiting for my new cap tester to bad I couldn't get one capable of testing over 2000uf
will get back as soon as possible

[skywalker999]

NEC 78M12
8752J
I removed this part to test and fund that the heat sink was not soldered to the board
Here are the results
Red on pin 1 black on pin 3 = OL
Black on pin 1 red on pin 3 =.577
Red on pin 1 black on pin 2 = OL
Black on pin 1 red on pin 2 = .576
Black on pin 2 red on pin 3 =1.973
Red on pin 2 black on pin 3 = .634

So is this correct
I also removed RY501 will check at my local electronic parts store and see if they have that part or something similar
Terryl did that screwdriver test nothing no clicking noise
And nunoit there is five or six zener diodes on that spot are those tested just like a regular diode

[nunoit]

the 78m12 is a 12v regulator readings should be good. remount and check for 12v on pin 3. mounted and looking at front pins are left to right 1 input 2 ground 3 12 v output. test while mounted and powered up.
also my bad since its a 12 v regulator it has nothing to do with the over load circuit.

on the relay there are 6 pins 4 close together 2 on other end, the 2 by them self's are the coil. set you meter for ohms any one will do touch leads together. should read shorted.(continunity) now touch the 2 pins on the relay, you should read shorted. if not relay is bad. you can test the other 4 as well they should read open any combination of the 4 pins.

picture and schematics show the other zener diodes are for the power supply. according to the schematic the only zener diode for the relay is D-610, and is also 12 v regulator. from the side with the band you should get 12 v while powered up. as long as Q-601, Q-602, Q-604 and Q-605 (power off mute) transistors are working.

which leads to a mute circuit which could also be a problem, if there is one that is. so test all the transistors that i said in previous post.

just some FYI

on analyzing the circuit when power is turned on Q's 605 and 604 apply power to relay, now Q's Q-523 and Q-524 monitor the right and left channels of the output amp, if all is good they send signal to Q-601, Q-602, which allows Q-604 to continue to function correctly. if not the relay turns off to protect the power transistors from burning up.

terryl i did not realize you had made the same analysis on the circuit. don't want step on toes. did not read your post.

[nunoit]

it seems i have gotten stuck with the same dilemma weather to spend time and cash to repair or just buy new. i am swaying toward new. my spx audio pk06210/212 400w power amp suddenly died. i have looked for schematic to no avail. i already checked the power transistors and dual diodes for voltage doubbler, large electro caps i have not tested with power to follow and check zeners.

with ground connected and remote power red light turns on if i apply main power red led turns off green one does nothing it has an over temp circuit sensor works

seems when you apply power it turns on no sound. you can here the thump,no sound like the low level amp is dead or no power getting to the ic. replacing the ic's not worth it i think, considering a new pyle 1400w amp is only 60 bucks.

if i could find a schematic might help debugging. just to play with it.

[Terryl]

the 78m12 is a 12v regulator readings should be good. remount and check for 12v on pin 3. mounted and looking at front pins are left to right 1 input 2 ground 3 12 v output. test while mounted and powered up.
also my bad since its a 12 v regulator it has nothing to do with the over load circuit.

on the relay there are 6 pins 4 close together 2 on other end, the 2 by them self's are the coil. set you meter for ohms any one will do touch leads together. should read shorted.(continunity) now touch the 2 pins on the relay, you should read shorted. if not relay is bad. you can test the other 4 as well they should read open any combination of the 4 pins.

picture and schematics show the other zener diodes are for the power supply. according to the schematic the only zener diode for the relay is D-610, and is also 12 v regulator. from the side with the band you should get 12 v while powered up. as long as Q-601, Q-602, Q-604 and Q-605 (power off mute) transistors are working.

which leads to a mute circuit which could also be a problem, if there is one that is. so test all the transistors that i said in previous post.

just some FYI

on analyzing the circuit when power is turned on Q's 605 and 604 apply power to relay, now Q's Q-523 and Q-524 monitor the right and left channels of the output amp, if all is good they send signal to Q-601, Q-602, which allows Q-604 to continue to function correctly. if not the relay turns off to protect the power transistors from burning up.

terryl i did not realize you had made the same analysis on the circuit. don't want step on toes. did not read your post.

No problems we are all here to help out.

It looks like his mute circuit may not be working correctly as the relay is not turning on, looking at L501 and 502 with a speaker or a pair of head phones (with the headphones fed through a 330 ohm 1 watt resistor first) would tell if this is the case, he should hear something at those inductors (with the receiver set to a known radio station) as they feed the speaker outputs.

That relay does three job's, one to act as an overload preventer, two to act as a mute circuit when you press the mute button, and three to act as a power down/on mute so you don't hear a loud POP when the power is turned off or on.

There is a very small delay turning the relay on when the receiver turns on, and it shuts off the relay first when the power is shut off.

[Terryl]

it seems i have gotten stuck with the same dilemma weather to spend time and cash to repair or just buy new. i am swaying toward new. my spx audio pk06210/212 400w power amp suddenly died. i have looked for schematic to no avail. i already checked the power transistors and dual diodes for voltage doubbler, large electro caps i have not tested with power to follow and check zeners.

with ground connected and remote power red light turns on if i apply main power red led turns off green one does nothing it has an over temp circuit sensor works

seems when you apply power it turns on no sound. you can here the thump,no sound like the low level amp is dead or no power getting to the ic. replacing the ic's not worth it i think, considering a new pyle 1400w amp is only 60 bucks.

if i could find a schematic might help debugging. just to play with it.

SPX is a company in and made in Warsaw Poland try this for a contact
[email protected] use Google translate to make up a message to them, and ask for a schematic.

[skywalker999]

Terryl and nunoit unfortunately i have been to busy has of right know the pioneer SX_2300 is on hold when i have more free time and on top of that I think that pioneer is getting closer and closer to the recycle bin lol but lets see when my summer vacation comes maybe I'll have time to play with it again till then project is on hold

[nunoit]

terry thanks for the link i will try. skywalker don't worry when you get back to it post or pm to let us know when you are ready.
i have other things that i do as well. good luck

sent e-mail will see what there response will be.

[nunoit]

haven't heard any thing on the spx amp of mine. so its back burner for now ill go and buy a new one for now.

[nunoit]

good news on the spx amp. i had a few minutes so i decided to check the power flow.found what looked like a bad zener 16.5v. i pulled and tested was good so i am like what the heck is reading shorted. found a 220uf 6v cap bad for the pre-amp section. replaced and we are back in business.