Anyone have experience on the Harman Kardon AVR230 or equivalent AVR130 or 330?
The back-up battery on the digital board has failed and leaked electrolyte over the PCB.
If the digital controller board has problems then the entire amp is useless because there is no way just to input a simple analog signal to the power amp section.
The battery is soldered in and can't be replaced without substantial disassembly.
REALLY bad product.
I have done the disassembly, cleaned the board, replaced the soldered in battery with a battery holder and new battery.
Checked the new battery.
Previously, as the old battery failed, it would work for 30 or so seconds before the front display went dark and dead.
At this point it would not respond to any controls, could not alter the volume, switch channels etc.
Now the amp powers up, normal faint hiss from the speakers, but the front display, also part of the digital board, stays dead.
It responds to the remote control to power up and down.
Can't select any input, not even the "6/8 Direct" for pre-processed surround.
The digital PCB has a couple of SMT chips with about 100 pins each on sub millimetre pitch.
More or less impossible to replace the chips.
Have followed the instructions to reset the controller.
Any ideas appreciated.
Best wishes
David
The back-up battery on the digital board has failed and leaked electrolyte over the PCB.
If the digital controller board has problems then the entire amp is useless because there is no way just to input a simple analog signal to the power amp section.
The battery is soldered in and can't be replaced without substantial disassembly.
REALLY bad product.
I have done the disassembly, cleaned the board, replaced the soldered in battery with a battery holder and new battery.
Checked the new battery.
Previously, as the old battery failed, it would work for 30 or so seconds before the front display went dark and dead.
At this point it would not respond to any controls, could not alter the volume, switch channels etc.
Now the amp powers up, normal faint hiss from the speakers, but the front display, also part of the digital board, stays dead.
It responds to the remote control to power up and down.
Can't select any input, not even the "6/8 Direct" for pre-processed surround.
The digital PCB has a couple of SMT chips with about 100 pins each on sub millimetre pitch.
More or less impossible to replace the chips.
Have followed the instructions to reset the controller.
Any ideas appreciated.
Best wishes
David
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Hard to say without seeing it. I would wash the PCB with foam cleaner and hot water to get rid of all contamination.
If fine print has been damaged/eaten away then you are on to a loser tbh.
Unless the large IC's are damaged by contamination then I would not suspect them as such.
With the new battery removed and power removed try pressing tin foil over allthe PCB to remove charge and reset any micros. Even with a few 10's or 100's of millivolts they can lock up/stay locked up.
Does it need any regional coding/setup applying after battery replacement ?
If fine print has been damaged/eaten away then you are on to a loser tbh.
Unless the large IC's are damaged by contamination then I would not suspect them as such.
With the new battery removed and power removed try pressing tin foil over allthe PCB to remove charge and reset any micros. Even with a few 10's or 100's of millivolts they can lock up/stay locked up.
Does it need any regional coding/setup applying after battery replacement ?
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Beware of corroded vias (through hole plating connecting sides of pcb).
Can you post a pic of the cleaned pcb ?.
Dan.
Can you post a pic of the cleaned pcb ?.
Dan.
Thanks for the ideas.
I have cleaned the board and did check the tracks. The contamination was not in a fine track area, only on power tracks and they seem to be OK.
No set up AFAIK, and the reset procedure should have taken care of that anyway.
Come to think of it, the fact that the reset procedure works implies that part of the chip is OK - (you have to hold down some arbitrary button with the amp in stand by)
My concern about the chips was because I don't have the full static control set up. I am careful but don't have ESD safe wrist strap, whatever.
Best wishes for the New Year
David
It's a one sided board but thanks for the input.
I would have to pull the board for a picture and it's not made for frequent removal. MANY cheap connectors only intended for convenience as it is manufactured.
Fixed my HP office LaserJet printer recently. What a difference.
Made to be maintained rather than trashed.
Best wishes
David
my experience with this kind of thing is more from world of keyboards.if the back up battery fails it loses it's memory
you would have to boot load a new instruction set assuming you can obtain such a thing!
than again some device can be reset/re-initialized...
you would have to boot load a new instruction set assuming you can obtain such a thing!
than again some device can be reset/re-initialized...
Should be no problems with ESD as the chips are in circuit and so all inputs will be at (relatively) low impedances.
Anything with a battery/cap backup and volatile ROM can be a bit of an unknown when that supply is removed. Usually they revert to out of the box condition, but there's always the one that doesn't. I would definitely try the foil, perhaps leaving it for an hour or so, then power up with AC first and then fit the battery.
(Totally unrelated but the kind of thing that can happen... Sony VCR remotes (SLVE840??) frequently locked up. If your lucky removing the batteries for a few seconds fixes them, often they need to be left unpowered for up to a week). Even foil doesn't fix those, you just have to leave them. Not a one off, they all do it. Heating the PCB on a hot (really hot) radiator for a couple of hours accelerates the internal leakage and the remote works if you don't want to leave it... bizarre but true)
Anything with a battery/cap backup and volatile ROM can be a bit of an unknown when that supply is removed. Usually they revert to out of the box condition, but there's always the one that doesn't. I would definitely try the foil, perhaps leaving it for an hour or so, then power up with AC first and then fit the battery.
(Totally unrelated but the kind of thing that can happen... Sony VCR remotes (SLVE840??) frequently locked up. If your lucky removing the batteries for a few seconds fixes them, often they need to be left unpowered for up to a week). Even foil doesn't fix those, you just have to leave them. Not a one off, they all do it. Heating the PCB on a hot (really hot) radiator for a couple of hours accelerates the internal leakage and the remote works if you don't want to leave it... bizarre but true)
Yes, that was my rationale too, so I was careful but didn't feel the need to do the whole "certified ESD safe" carry on.
The Sony remote story was more or less what I had in mind.
Hoped someone would say "Oh yeah, on the AVR230 you need to ..."
Still a chance.
Best wishes
David
I think it should lose all the DSP presets, radio station frequencies and the like but not fail to function. That is what the reset procedure assumes.
Best wishes
David
The battery holds RAM memory probably CMOS. Before replacement it works for few seconds before display die, suppose battery can not hold instruction in RAM, CPU freezes. After replacement display is not working at all, like battery can not power RAM. Check replacement procedure again, maybe track are broken or bad solder. Measure voltage on memory chip if you can locate it.
I suppose CMOS holds some data important for display handling.
I suppose CMOS holds some data important for display handling.
The battery is supposed to maintain information like radio station presets rather than CPU code.
But I left it for 8 hours anyway, in the slim hope that the problem would vanish like in Mooly's Sony remote controls.
In the meantime rechecked every connector, retraced power supply tracks etc. etc. Could find no problem with my repairs.
Turned it on without any expectation, just my routine to confirm the problem before any more effort.
And it worked.
So it looks like my repair was fine, just corrupted CPU - despite the reset done as per factory manual.
Don't feel very satisfied about this, 12 wasted hours and I still don't trust it to stay functional, but at least it wasn't my mistake.
So, watch out for this trap in micro-controller based amps, probably most of them these days.
Thanks to everyone for ideas.
Best wishes
David
That's great news. We used to use the general term of "micro lockout" when this kind of thing happens.
I'm sure it will be fine from now on.
I'm sure it will be fine from now on.
No.😡
Ran it for an hour before I put the cover back on with a few screws for security.
Then ran it for another hour while I dismantled my old installation, ready for the new amp, before I finally reinstalled the last of the screws.
Now same problem, I didn't mess up the last screws, just Murphy's Law that it won't fail until you have wasted the time to reassemble it.
Now I know the uControllers are mostly OK.
Power rails out of limits? From mains fluctuations?
Over Volt so it takes a while disconnected to drop back to normal?
The power circuit is a tedious maze, don't even see yet how the standby power reaches the front board (not the problem but indicative of the unhelpful rat's nest of a harness.)
Back to the schematics and thanks anyway, useful to "think aloud", as it were.
Best wishes
David
That's close to what I said, four letters and the last two match.
Actually I didn't swear, just have to wait and see if it works after a while disconnected, so not much to do until then.
Best wishes
David
Power rails to the UController board are not in specification.
Maybe the backup battery failure was the result of a problem rather than a cause.
Maybe the backup battery failure was the result of a problem rather than a cause.
What is the voltage across the backup battery....with AC supplied, with soft switch off, and soft switch on ?.
Dan.
Dan.
Mains Voltage
What is your mains voltage ?
Have a lot of problems here in Brissie with all the electrical stuff , CFL's , washing machines , Set top box , DVD player , LCD TV's , computers , amps , you name it , they all break down due to high mains voltage , average 255 Volts here on a sunny day and we have lots of them 🙂, every one has Kilowatts of solar on their roof and feed in to the grid . I called energex a couple of times and they came over and said that everything was fine and my DMM's where uncalibrated 😕 and the voltage was fine .
One positive thing , my vintage "Blaupunkt Granada" tube radio loves the higher voltage and started playing again !
Cheers ,
Rens
What is your mains voltage ?
Have a lot of problems here in Brissie with all the electrical stuff , CFL's , washing machines , Set top box , DVD player , LCD TV's , computers , amps , you name it , they all break down due to high mains voltage , average 255 Volts here on a sunny day and we have lots of them 🙂, every one has Kilowatts of solar on their roof and feed in to the grid . I called energex a couple of times and they came over and said that everything was fine and my DMM's where uncalibrated 😕 and the voltage was fine .
One positive thing , my vintage "Blaupunkt Granada" tube radio loves the higher voltage and started playing again !
Cheers ,
Rens
One interesting thing, reset_in pin takes battery voltage, so reset can't carry out by empty battery.
BN81 connector, pin6, +5V is on battery, if it is higher could be the problem.
And if +5V is non or lower it is the problem.
BN81 connector, pin6, +5V is on battery, if it is higher could be the problem.
And if +5V is non or lower it is the problem.
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