Pioneer SX-2300 audio output problem

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.

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Originally Posted by 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.

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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.

Quote:

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Originally Posted by 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.

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SPX is a company in and made in Warsaw Poland try this for a contact

Code:

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[email protected]

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use Google translate to make up a message to them, and ask for a schematic.

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

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.

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.

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.