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PostPosted: Wed Dec 17, 2008 1:53 am    Post subject:

Smile Okay: lots of folks experience these type of problems after a move. and they do just what you did which results in the same kind of damage to their equipment. weather it is moisture or vibration or altitude or humidity....all of this can effect your time park the equipment in your home and wait about 72 hours before you power it on, then leave it on for a few days to accalmate it to your new surroundings.
But for what has already happened:
first off : what level of electronics education do you have
what type of test equipment do you know how to use
Do you know what your looking for when you make a visual inspection of your equipments PCB's.
You will need to know what a blown Capacitor looks like and have available the solder removal equipment.
You can attempt this at your kitchen table if you need to but I don't advise it.
you need good lighting and a work bench
you need a solder re-work station
you need a good DMV with Transistor and Capacitor reading ability
you need an expendable speaker for testing
you need hand tools like screw drivers and pliers
you need the ability to read a schmetic and understand the theory implyed.
with that said:
it has been my experience that most failed stereo systems exibit:
loss of left or right signal >>>sound
distorted sound
fail to power on
........What you described...... as the first issue a minium loss of specific frequency... IE... bass tone in the sub-woofer circuit
this has happened more then once in my experience ....the consumer is getting ready to move they dis assemble their audio system and while they are doing this they do not relize that the Sub-woofer contains LARGE CAPACITORS a capacitor is kind of like a battery and it will hold a charge capable of electronic damage and shock... disconnecting it improperly will damage your system and possibly shock you in the process.
depends on what kind of Tonal component your sound system has.
if it is a newer Digital or IC (integrated circuit) type of component you will have to replace the IC which controls your tone output typically these components also integrate the amplification as well. if it is an older unit with discreet components you will be looking for a blown Transistor probably mounted on some type of heat sink if it is a larger watt output system these transistors are mounted in a configuration of 2 paired components one pair for the left side one pair for the right
Always give Capacitor respect learn to discharge them before you begin poking around inside the cabinet.
during your visual inspection look for signs of BURNNING, lifted leads leaking fluid DON't try to clean stuff up just look with the power off
with the [power ON] look for smoke SMELL listenand then turn it off
if you have a remote temp sensor use it to analys the suspected PCB don't touch it TAKE DIGITAL PHOTOGRAPHS OF THE OPEN CABINET
locate wire harnesses solder connections and the color of system leeds.
if your confident you understand what your looking for begin by discahrging the main CAP's then with the power supply UNPLUGGED read your cap values your not so much looking for specifics as your looking for response an unresponsive cap is a typical indication of failure.
if that checks out then look at DIODES specifically in your BASS tonal block because your initial issue was with BASS Tone
if that checks out
locate your TONAL IC could be a flat black chip mounted on a heat sink some thing like STK8066 in white stamped on it's body maybe 8 to 10 leeds soldered to the BCP .....go to your electronics supply store and purchase the exact same component ... desolder the installed components and install the new ones....
TYPICAL FIX IS UNDER $50.00 and take about 2 hours including trobbleshooting process.
HINT: replacement in sequence will save you money and digital photos will keep things where they were when you opened the box!
replace the suspect turn on the unit test the sound if it it good put it all back together if not DISCHARGE THE CAPS and UNPLUG the unit and try again.
I have an oscillascope and a huntron tracker an frequency generator and advanced DMV's my shop is ESD epuipped with floor amts and bench pads I have cameras for Microscopic digital displays on flat panel monitors including computer interface for quick reference to schmetics and parts lists I also used a solder re-work station. several decades of experience have brought me to this understanding and it all started by blowing the right channel out of a friends stereo by accident.
PostPosted: Sat Dec 13, 2008 4:00 am    Post subject:

ryanc wrote:
Anyone at all? Is it likely a blown resistor? Or a capacitor? Or transistor? If I could get someone to tell me what to look for, I have a DMM I can use to test stuff out. Thanks!


While it may be a simple problem, It could be many things; what you need to do is to first isolate the circuit, do a visual check and then do some measurements to be able to tell further. It may necessitate a schematic of some sort. There is no magical way to detrmine that. You may have anything from a blown output, etc to a control issue--there are too many variables.
PostPosted: Sat Dec 13, 2008 2:57 am    Post subject:

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PostPosted: Sat Dec 13, 2008 2:23 am    Post subject:

Anyone at all? Is it likely a blown resistor? Or a capacitor? Or transistor? If I could get someone to tell me what to look for, I have a DMM I can use to test stuff out. Thanks!

PostPosted: Fri Dec 12, 2008 1:14 am    Post subject:

minnie wrote:
Got a model #?

Oh yeah sorry!

The model # is VSX-515. It is about 3 years old.


PostPosted: Thu Dec 11, 2008 11:50 pm    Post subject:

Got a model #?
PostPosted: Thu Dec 11, 2008 4:31 pm    Post subject: Pioneer 6.1ch receiver subwoofer out repair

I have a pioneer 6.1 Chanel receiver and the subwoofer output no longer works. I want to try to fix it because the rest of the receiver functions great! I am trying to do this on the cheap (myself or a cheap repair guy) because it is not that expensive of a receiver. Any ideas on what to look for/check? No, it is not user error - I know how to set up my receiver and it was working fine.

It was working fine but then we moved from Wisconsin to Indiana. When I set my system up in the new house, I noticed the subwoofer was not getting loud. I thought it might have something to do with the larger new house so I bumped up the level on the sub amp. This helped for a bit but then it wasn't loud anymore. So I increased the level on the sub-out on the receiver. Each time I bumped something up, it would help for a short while and I'd have to bump it up again. Eventually I had my sub-out at +10, which is the max. Shortly after that point, I got no sound. The amp on the sub wasn't even turning on when set to "auto-on". I then tried an old kenwiod receiver on the sub amp and it was turning on butonly a very faint sound would come out of the subwoofer. I then realized that the amp was bad, and by this time in the process I had managed to fry the subwoofer out on my "good" receiver. Any help would be greatly appreciated.


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