
ongtw75
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Hi WeakEars, The blue capacitor is for EMC filtering and doesn't affect the function nor the sound quality of the speakers. Since the same power supply board is used in various models (Bar48, Cinema 600/800 etc), there is going to be slight variance in the components they used on each model, depending on the EMC compliance result.
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Hi Furry, +5V to VDD, GND to GND and you can leave STB unconnected (do insulate it with tape). STB only works on the original power supply board.
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Hi @njlandry90, referring to the photo below I've drawn a red line that divides the high/low voltage sections. Generally you would want to avoid touching the capacitors on the left side until the power board has been left sitting idle for some time, i.e 30 mins or more. The capacitors at C05 and C06 are the culprit. You can replace them with better known brands of low ESR (equivalent series resistance). I'm using Chemi-Con KZE series capacitors, 220uF 16V (diameter 6.3mm, height 12mm). While the old capacitors are out, you may want to remove as much of the surrounding glue as possible. That will aid cooling. Alternative capacitors: https://www.digikey.com/short/75ff0hbm https://mou.sr/4dJcXXT Good luck!
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Hi @SteadyDropsofWater , glad that my solution works for you. Yes, kind of funny how this thread has evolved from Bar 48 to Cinema 800. 😄 Cheers!
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So, finally someone with the Cinema 800 requested my help to fix his. Just like everyone's 600/700/800/1200, the soundbar was dead, no power, no lights whatsoever. As you can see from the photos below, the 800 has the same power supply board as the 700 and 1200 (at least visually). Most interesting that I saw the same bulged capacitor as in Skunk's. I do have some spare capacitors that will fit within the footprint.... replaced them and problem solved! 😁 New capacitors: United Chemi-Con KZJ low ESR series, 1000uF 16V To replace at C5 and C28 Alternative: https://www.digikey.com/short/bf43j7p0 https://mou.sr/3XB8SyT When the old capacitors are desoldered, do try to remove as much glue as you can below them as that will aid in cooling for the new capacitors. When the power board is working, VCC will be 5.2V. STB will go from 0V to 2.8V when the soundbar is powered on. It is an enable signal to turn on the high voltage circuit (2 prong plug) and that in turn will give 24.5V. In many ways, the 800 power board is very similar to the Bar48 and Cinema 600 boards. I didn't measure the current consumption of it, but looking at the 5V regulator chip (FT8370C) specifications, it is capable of 5V 3A. So a replacement board from Amazon/Aliexpress ought to have 5V/3A and 24V/4A dual output. Hope the above info is helpful.
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I think they both are of the same capacitor specs and yes, I would change both since we're already here. The high voltage capacitors and circuit are at the top half of your photo, an imaginary horizontal line dividing the 2 yellow transformers, top half is the 'live' or 'hot' high voltage circuit and you'll want to avoid touching any part of it while troubleshooting. The high voltage capacitors may take a couple of minutes to be totally discharged when power is removed. No such worries for the bottom half.
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Hi Skunkworks, I don't own a 700 or 800 but have fixed the power boards of Bar48 and Cinema 600 a couple of times, and they all suffered the same capacitor failure. The photo that you've attached seems to show the same capacitor failure (red box), with the top of the capacitor bulging. That's not a good sign. You may change them to see if that's the cause of the problem. Do get some capacitors of the same rating and of low ESR (equivalent series resistance) specification. I have good experience with those from NCC KZE series. The 5 and 2 prong plugs are very similar to the 600. With a multimeter, VCC should measure at least 5V wrt GND. There won't be any voltage at the 2 prong until the soundbar has powered up. The microcontroller chip at the amplifier board side will signal the STB pin 'high' (>2.5V), only then will the main power circuit be turned on. For the 600, the 2 prong plug measures 24V. Hope this is useful.
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Hi Karan, You may try to disconnect the STB wire from the new power supply and use electrical tape to insulate it. This wire is only needed if you are still using the original power supply board. STB is a signal thrown out by the microcontroller chip. It tells the rest of the speaker system to wake up (3.3V) or power down (0V), so if it is permanently connected to 5V on the new power supply, it could mean the speaker system never goes to standby/sleep.
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Hi Klement, The STB cable need not be connected if you're using the Amazon replacement. STB is a signal output from the controller chip towards the original power supply unit, without the latter there isn't any need to keep it connected. You may try disconnecting it to check if you'll regain the power off function.
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Hi DrewKrew, Yes, the symptoms point to a power supply that is about to give up completely.
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Hello everyone! Following on from my 1st post back in 3/10/2022, I've since fixed a few Cinema 600 power supply boards for other owners. They all had the same failure with capacitors C05 and C06. I replaced them with 220uF 16V part from NCC (Nippon Chemi-Con) KZE series. This is not a common size part. You may use 220uF 25V instead but it'll be a tight fit. As some others have noted here, the +5V and ground cable colors seem to deviate from set to set. For those having problem with their power units from Amazon, do trace the respective cables back to the amplifier board (left most connector) and wire them accordingly. I've attached a photo here for reference. STB need not be connected, it's only needed with the original power board. You can safely insulate it with electrical tape and tuck it away.
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Hi, I'm from Singapore too and have helped a couple of owners fixed their Promedia 2.1 Bluetooth units. The thing about our local 230V version of this speaker is that it uses a different volume control circuit board and has an additional SMPS board within the subwoofer as compared to the US 120V version. Very often, the cause of failure (blinking blue LED light) is due to the faulty SMPS board, not due to the bluetooth chip being hijacked. You can look for me in Carousell should you need help in fixing it. Search for "promedia repair".
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It looks like your set uses a completely different chipset and module for the bluetooth. From what I can see, there are 2 voltage regulator chips on onboard. 1 of them should be 5V and the other 3.3V, the latter is the power source for the bluetooth module. If you have a multimeter, you can probably trace the connection to 3.3V and disconnect it. Good luck!
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Hi. You will need a power supply that outputs 24V and 5V. 12V will damage the digital/amplifier board. Cheers!
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Well done! Thanks for the verification. Seems like this is a common weakness for this PSU, intentional or not.