I have been trying to find the data sheet for the Sanyo STK0231 with no luck. I have a Sanyo DCX3300KA quad receiver that I recapped, but the right side has no output in stereo mode (front speakers) through the speakers or headphones (also has a hum through the right side). I suspect the IC chip, but need the data sheet to verify. Any help would be much appreciated, thanks!
here is my 2 cents without a schematic
if the IC is busted most likely the fault will trip the protector relay if existing inside and/or trip existing fuse inside ...so its not the IC ..Yet again you never know in such an old machine ...
from experience i may say to you that most quadrophonic amplifiers with the option to bridge for 2 channels fail in the switch that makes that selection Many weird things happen inside these switches since these have to do so many things ...
Normally i set for 4 CH discrete operation , use discrete 4CH tape input to make sure that my 4 CH are working properly in this mode , Then you see if its possible to be bridged
Obviously all other pots and switches are to be cleaned before putting the unit to more testings
Kind regards
Sakis
if the IC is busted most likely the fault will trip the protector relay if existing inside and/or trip existing fuse inside ...so its not the IC ..Yet again you never know in such an old machine ...
from experience i may say to you that most quadrophonic amplifiers with the option to bridge for 2 channels fail in the switch that makes that selection Many weird things happen inside these switches since these have to do so many things ...
Normally i set for 4 CH discrete operation , use discrete 4CH tape input to make sure that my 4 CH are working properly in this mode , Then you see if its possible to be bridged
Obviously all other pots and switches are to be cleaned before putting the unit to more testings
Kind regards
Sakis
Thank you for your response. Unfortunately, I do not have the schematic and it is not available on Hifi engine. I have cleaned all the pots with Deoxit and Faderlube. I will check them all again. I only tested the unit in stereo mode.
When I say stereo mode, I mean that the front channels in stereo mode and the rear channels in stereo, I have not tried four speakers at once. The rear channels work as advertised, but not the right front. All I hear from that channel is hum....loud hum. I recapped everything except the tuner and reflowed most of the solder joints, I will re-clean the stereo/quad select switch as suggested.
Normally i set for 4 CH discrete operation , use discrete 4CH tape input to make sure that my 4 CH are working individualy and properly in this mode , Then you see if its possible to be bridged
When you select stereo or 2 ch mode normally you expect 4 channels to be bridged in pairs to gain more power
Been looking at the 3000 schematic ...looks alike ( its the only one i could find ) you can brake the amps between pro and main amplifier at the ""spatial control volume pot ) i expect that you have one also
There you are going to find out if its a pre or main issue
There you are going to find out if its a pre or main issue
In the 3000 all 4 audio signals pass through the HP plug to divert between speakers or Headphones So the plug features 4 on on switches you need to check that also ...Any of the switches black or oxidized or dirty and you are in trouble
If anyone has the service manual for this (Sanyo DCX3300KA ), it would be much appreciated. It is difficult trying to troubleshoot without schematics.
I think you are correct in that the 3000 is similar to the 3300, I think I can download the manual for the 3000.
Sanyo DCX-3300KA hum problem
I know this is a very old post, but I am having the exact same hum/dead channel problem with my unit (except on the Left channel front).
GUNGNIR - Did you ever solve this? I've traced good audio (in 4 ch discrete mode) on all 4 channels right down to the input of the power amp board, but have strange voltage readings on the STK0231 AMP chip when comparing left vs right. Can't find any specs on this chip and also don't have a schematic to know what good readings are suppose to be. My voltages on the chip (lft vs right ) are:
PIN # LEFT RIGHT
0 GND GND
1 45.7 22.9
2 45.7 46.3
3 45.5 34.9
4 N/A N/A
5 N/A N/A
6 10.2 22.9
7 0 22.7
8 0 22.7
9 44.1 44.0
While I haven't done a recap on that board yet, I did a cursory check all the caps ESR and they all look good and given you already tried that and it didn't resolve it, it seems something else is the culprit.
Beyond the schematic I would like to know what expected voltages should be on those pins and also if there is a practical way to recreate the chip (in part or whole, depending is only half the chip is bad vs the whole chip is bad) since I suspect finding a replacement chip may not be practical (and probably very expensive even if it is available.) And help/guidance you guys can provide would be most appreciate, although I realize your're goign back a few years on this topic. Thanks.
I know this is a very old post, but I am having the exact same hum/dead channel problem with my unit (except on the Left channel front).
GUNGNIR - Did you ever solve this? I've traced good audio (in 4 ch discrete mode) on all 4 channels right down to the input of the power amp board, but have strange voltage readings on the STK0231 AMP chip when comparing left vs right. Can't find any specs on this chip and also don't have a schematic to know what good readings are suppose to be. My voltages on the chip (lft vs right ) are:
PIN # LEFT RIGHT
0 GND GND
1 45.7 22.9
2 45.7 46.3
3 45.5 34.9
4 N/A N/A
5 N/A N/A
6 10.2 22.9
7 0 22.7
8 0 22.7
9 44.1 44.0
While I haven't done a recap on that board yet, I did a cursory check all the caps ESR and they all look good and given you already tried that and it didn't resolve it, it seems something else is the culprit.
Beyond the schematic I would like to know what expected voltages should be on those pins and also if there is a practical way to recreate the chip (in part or whole, depending is only half the chip is bad vs the whole chip is bad) since I suspect finding a replacement chip may not be practical (and probably very expensive even if it is available.) And help/guidance you guys can provide would be most appreciate, although I realize your're goign back a few years on this topic. Thanks.
That's a single supply circuit, eh?
I would be guessing either 1 or 6 is the output (should be easy enough to find out if you know what the corresponding output coupling cap is), and 7/8 are the inputs. 3 could be a bootstrapped/filtered supply for the first stages or something.
Assuming all of this, there is something iffy going on on the left side (right looks sensible at first glance). The inputs are well outside usual permitted common-mode range (I don't think it's a ground-included input circuit à la LM358). Look for leaky electrolytics at the input or in the feedback network, as well as open resistors in feedback.
I would be guessing either 1 or 6 is the output (should be easy enough to find out if you know what the corresponding output coupling cap is), and 7/8 are the inputs. 3 could be a bootstrapped/filtered supply for the first stages or something.
Assuming all of this, there is something iffy going on on the left side (right looks sensible at first glance). The inputs are well outside usual permitted common-mode range (I don't think it's a ground-included input circuit à la LM358). Look for leaky electrolytics at the input or in the feedback network, as well as open resistors in feedback.
Yes single power to the center of the board. I took another pass through on all caps and resistors. All caps pass ESR and all resistors in spec. I could pull and replace all the caps but since the other user tried that and it didn't solve anything, I'm suspecting another cause. I've been searching high and low for a 3300 schematic to see if I'm missing something, but yet to come up with one. I'm having a tough time visualizing/tracing/debugging without one.
BTW My pin numbers where off by one - I redid and of coarse now come up with different results. I'm assuming I wasn't making good contact with a couple of pins when measuring. I may reflow them all just to make sure they are all making good contact but the readings now are:
Pin L R
1 GND GND
2 46.2 22.9 Pin to 1000uf coupling cap
3 46.3 46.3
4 46.1 35.1
5 N/A
6 N/A
7 10.1 23
8 45 23
9 26.5 22.9
10 44.5 44.5
Also no luck in finding a datasheet for this STK0231 amp, so all I have to go on is comparative values between L/R. No real knowledge/understanding of what each pin is used for and what expected values should be. I have found replacements, but quite expensive so I really want to be sure the chip is bad and not the circuit around it.
BTW My pin numbers where off by one - I redid and of coarse now come up with different results. I'm assuming I wasn't making good contact with a couple of pins when measuring. I may reflow them all just to make sure they are all making good contact but the readings now are:
Pin L R
1 GND GND
2 46.2 22.9 Pin to 1000uf coupling cap
3 46.3 46.3
4 46.1 35.1
5 N/A
6 N/A
7 10.1 23
8 45 23
9 26.5 22.9
10 44.5 44.5
Also no luck in finding a datasheet for this STK0231 amp, so all I have to go on is comparative values between L/R. No real knowledge/understanding of what each pin is used for and what expected values should be. I have found replacements, but quite expensive so I really want to be sure the chip is bad and not the circuit around it.
Broke down and bought a schematic. See attached excerpt of amp board below.
Good audio and voltage (12V) at the TR5 emitter output. But on the other side of C503 at input pin 8 of IC501, it jumps to 45.8v, when it should be 24v. Also with pins 2 & 4 also at 45.8V, it makes me think that IC501 is fried. Thoughts? I've checked all the resistors and caps and they all seem good and in spec. Also weird is the Pin 9/7 combo. Should be 24v on both but on Pin 9 is 18.9, then on the other side of R 513 it's 17.9, then on the other side of C511 it drops to 10.1v. R513 checks out ok and I even swapped C511 to be sure (no difference).
https://drive.google.com/file/d/0B_Yuh1ijNVjmZWd4X2pKZnhkS1k/view?usp=sharing
An externally hosted image should be here but it was not working when we last tested it.
Good audio and voltage (12V) at the TR5 emitter output. But on the other side of C503 at input pin 8 of IC501, it jumps to 45.8v, when it should be 24v. Also with pins 2 & 4 also at 45.8V, it makes me think that IC501 is fried. Thoughts? I've checked all the resistors and caps and they all seem good and in spec. Also weird is the Pin 9/7 combo. Should be 24v on both but on Pin 9 is 18.9, then on the other side of R 513 it's 17.9, then on the other side of C511 it drops to 10.1v. R513 checks out ok and I even swapped C511 to be sure (no difference).
https://drive.google.com/file/d/0B_Yuh1ijNVjmZWd4X2pKZnhkS1k/view?usp=sharing
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