Good morning,
I'm actually facing a problem with my HK home theater unit, then hope You could assist me in that.
Since a couple of mounts ago, it all began, while the AVR was properly working, playing a film, just having the AVR get in stand by mode, without any reason. Las week this failure occurred to happen say every time I was attempting tu turn the unit ON, just before any input was selected for the AVR: I mean, I push the main power switch in so as to get ON the stand-by orange light just below it; then I push the stand-by button in order to make the AVR start working, but no any actions by the AVR, even trying by the remote, no way and if try again and again both by the remote and the stand-by pus-button. I also tried. to set the main power button ON and OFF twice without any improvement Time to time it happens, while attempting to turn it ON by the stand-by button or by the remote, the AVR display gets magically ON, but it is just for a while, then the AVR gets OFF again with the orange light of the stand-by button ON. any further attempts, sequentially performed, results in a frozen condition of the unit, having the main power button ON and the orange light of the stand-by button ON.
I can only get rid of this trouble if, after having turn the main power switch ON, I wait for about 15 -minutes 20, before to switch the stand-by button ON....say that about 8 attempts over 10 get success.
I have tried to clean it up inside, opening the metal cover and blowing it using specific dry PC compressed air....that seemed to improve a bit the situation, at least for the reduced number of unsuccessful attempts before tho get the unit working, even always leaving the unit to somehow settle for a certain time in stand-by mode and the main power button depressed.
Once the AVR is eventually able to stably work, say after the "voodoo initializing procedure" has successfully been performed, the Harman Kardon keeps on properly functioning without any interruption, until you decide to turn it OFF.
Note: during the first trials to get the AVR ON I noticed, when it was shutting ON and OFF by itself, the settings for the selected input player were lost and I had to enter them manually again. This lack of setting parameters at the last positive power turn ON, I mean stable working situation, always occurs for all attempts procedure.
Hope this my description of the power-ON failure is sufficiently accurate to let You drive me through the appropriate troubleshooting to fix the problem.
Meanwhile I thank You, have, please, my Best Regards.
Franco
hello:a távirányítót ellenőrizted, működik, ad ki jelet?
Itt vannak rajzok, ellenőrizni kell a feszültségeket
https://elektrotanya.com/showresult?what=Harman%20Kardon%20AVR%20330&kat...
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Hi!
Cleaning the dust will not be enough to solve the problem.
The 3.6 Volt battery labeled BAT-1 should be replaced on the front panel.
Since it is submerged, it confuses the central processor.
Hifista.
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Thanks You, Mr. Hifista, what do You mean by submerged battery? Is It anyway a replaceable one?
Thks
Franky
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Thanks You, dear Hifista, but what do You mean by "submerged battery"? Is It anyway a replaceable one?
Thks
Franco
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Hi!
This is a 3 X 1.2 Volt NiMh battery pack.
Due to aging, it cannot be charged to the correct voltage and cannot maintain the correct voltage level.
Therefore, the voltage oscillates at the margin of error.
The solution is replacement.
The original GP40BBVH3A3H. In principle, the GP80 series is good instead, it has double capacity.
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Dear Hifista, I went through the replacement of the battery, but that wasn't fixing my issue. The AVR power-ON is still time to time self switching to stand-by mode at the first time I set It to work. As already said, It then happens I can't immediately turn It on by pressing the orange stand-by button or ON on my remote. The battery had to anyway be replaced, since its voltage was around 2,2V under charge.
I thank You for any other further advises on this matter.
Best regards
Franco
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Good morning, just to complete my report, I noticed even after having successfully replaced the battery, (its voltage under charge Is now abt. 3.9V, while it before was 2,2V), the setting parameters got lost when I turn the AVR On after few hours it was Off in standby mode....
Thank You for this useful support You are providing me with.
Have a nice day.
Franco
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Hi!
Let's clarify that it can't even be turned on, or does it turn on, but turns off after a few seconds?
Since the settings are lost, even after the battery is replaced, there may even be a faulty capacitor around the battery.
Possibly IC 85 Reset IC capacitors.
If something drains the battery, its voltage may drop below 1.5 V, which activates the reset IC and turns off the device.
Hifista.
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Yes, May be a little confusione in my description....I meant I have to wait say one minute to be sure It then works, but could even be just few seconds. Only matter that sometimes, in a random way, my AVR start immediately working without waiting at all. But there Is a morning update: today, starting my unit, I noticed the setting parameters were still in memory and everithing was properly functionning....don't know...I Will check in the next coming days.
As usual, many thanks dear Hifista!
Let's keep in touch for any...
Franco
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Hi Franco,
I don't know about this particular one, but most AV receivers shut off when one of the supply voltages is out of the specified range, e.g. too low.
So I would open the service manual look for and measure all regulated supply voltages first (these are usually supplied by 78xx and 79xx regulators, but lower voltages may be supplied by LDO regulators). These supply voltages are often accessible at some connectors within the AVR. You can also measure the main supply voltages of the amplifier (usually denoted by "+B", "-B"), but those are rarely problematic.
Such intermittent faults are often caused by cracked solder joints. They crack circularly around the throgh-hole component legs on the PCB, so the contact becomes unreliable. Repeated heating and cooling of the components facilitate the cracking. The green soldermask lacquer on the bottom of the PCB changes to brownish where there has been a lot of heat. Check those brownish PCB areas and reinforce the solder joints using flux (e.g. rosin) and new solder. Typically it happens around the regulators.
Hope this helps, but generally speaking, it takes a lot of time to repair faults, one needs to study the service manual, think, measure, think, then study the service manual, think, measure, think, etc. until the problem is resolved.
István
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