Hello everyone. Been here a while but first post here. Just looking for some advice on a possible repair.
I have recently been given an Samsung HT-C450N 5.1 Home Theatre System which is perfect for what I want but I have a hissing issue in the satellite speakers. When it is standby the hiss is very quiet as expected, but as soon as it detects a signal and becomes active the hiss becomes significantly louder to the point of irritation, especially at night with lower volume. I have seen online that others have had this issue with both this and other systems, so was hoping I could replace or upgrade something in there, or even add some shielding to at least bring it down a bit.
The hiss is around 7kHz and doesn't change with volume change, balance adjustment, nor input type and I have tried different plug sockets around the house to rule out ground. I would have thought the fact it is not affected by audio volume might point to the possible culprit.
I have swapped out all the main caps for better brands to make sure that wasn't the problem, but it has made little difference. At a bit of a loss as to where to go from here.
I do have a schematic and photos if that might help.
Any help at all would be very much appreciated.
I have recently been given an Samsung HT-C450N 5.1 Home Theatre System which is perfect for what I want but I have a hissing issue in the satellite speakers. When it is standby the hiss is very quiet as expected, but as soon as it detects a signal and becomes active the hiss becomes significantly louder to the point of irritation, especially at night with lower volume. I have seen online that others have had this issue with both this and other systems, so was hoping I could replace or upgrade something in there, or even add some shielding to at least bring it down a bit.
The hiss is around 7kHz and doesn't change with volume change, balance adjustment, nor input type and I have tried different plug sockets around the house to rule out ground. I would have thought the fact it is not affected by audio volume might point to the possible culprit.
I have swapped out all the main caps for better brands to make sure that wasn't the problem, but it has made little difference. At a bit of a loss as to where to go from here.
I do have a schematic and photos if that might help.
Any help at all would be very much appreciated.
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The solution is very difficult. It depends on the amplifier manufacture: quality of components, layout of pcb, etc. Also depends on your skill and intruments available by you.
Thanks for your reply. I had a feeling it might not be an easy job. I have repaired both discreet and integrated circuits before (guitar amps, IEM Transmitter, iPod Nano 3, GPUs. et al) but only really have soldering stuff, heat gun, and multimeter in terms of equipment. I thought if I could figure out where the problem is coming from I can decide if I would be able to fix, even if it means buying some equipment unless it is going to cost significantly more than replacing the amplifier. I would rather exhaust efforts to fix than just write it off.
Remember the first Samsung Syncmaster 3 still working at home (CRT PC moni). Those were good enough products.
Which parts would I recap? I am assuming anything before the volume is ruled out otherwise the volume would affect it wouldn't it?
I know it was a cheap unit back when it came out ~2010 but it was free and is only to hook up to my laptop to stream movies so the sound is fine for what I need it for...besides the hiss. I wouldn't know what to look for in a replacement unit as wouldn't want to be spending much, likely something off eBay.
I know it was a cheap unit back when it came out ~2010 but it was free and is only to hook up to my laptop to stream movies so the sound is fine for what I need it for...besides the hiss. I wouldn't know what to look for in a replacement unit as wouldn't want to be spending much, likely something off eBay.
Samsung sold their capacitor business to Samhwa, both are terrible in terms of quality.
Change all the electrolytic caps to a reputed brand...Any Japanese, Vishay, Epcos, Sprague, others of that rank.
And put a 10 pf or so between signal in and ground to reduce stray signal pickup.
Change all the electrolytic caps to a reputed brand...Any Japanese, Vishay, Epcos, Sprague, others of that rank.
And put a 10 pf or so between signal in and ground to reduce stray signal pickup.
Ah brilliant, thank you for that.
I'm going to show my newbiness and ask if I am right to assume the dark grey things are solid capacitors?
The caps are all SAM YOUNG, SAM WNA and JIANGHAI so will look at getting them swapped out.
I'll check the schematics to find where all the signal in's converge with there being multiple ins (I mainly use optical)
I'm going to show my newbiness and ask if I am right to assume the dark grey things are solid capacitors?
The caps are all SAM YOUNG, SAM WNA and JIANGHAI so will look at getting them swapped out.
I'll check the schematics to find where all the signal in's converge with there being multiple ins (I mainly use optical)
It's entirely possible that the hiss is coming from the nearby laptop's power supply or its processor or modem/wireless transmissions - an RF type of interference.
If I put a cellphone on top of my clock radio, an annoying hiss is generated into the clock radio when it's turned on.
And certain things like even a turntable are disrupted by a nearby cellphone too.
The Dual 616Q turntable will lift its tonearm and speed will go crazy if a cellphone near it rings.
Another interference is from those flourescent light bulbs and some LED bulbs - the invisible "flickering" makes a TV set in the room change channels, effect the volume, and keep the remote from working.
Unfortunately I have already ruled those out - the laptop is docked and connected via ethernet so not using WiFi, and tried connecting an iPod, an Out from my audio interface, as well as both DVD and USB, all with my laptop being the other side of the room. Tried different monitors (via HDMI)mand no monitor too, and even tried turning everything else in the room off. Even the test tone in the unit itself causes it. I am assuming it is the luck of the quality-control draw and mine is one of the bad ones. A cap change or new unit seem to be the main options.
Ah yeah, the classic cellphone "dut dut-dut-dut dut-dut-dut" too! I figured out a lot about audio interference setting up my first home studio many a moon ago, so made sure I ruled out all of the obvious before posting here. Thank you for the suggestions though - they could have easily slipped my mind especially while I am trying to fix this effing iPod Nano 3 again (after weeks of thinking I had it fixed it now looks like the charging circuit has been the fault, and non-repairable, from the start
)
Hahaha that is crazy it can have such an effect on a turntable. As for the rest...are you sure you aren't haunted?
😂
It is very strange what RF and EMF can do to electronic equipment though.
Ah yeah, the classic cellphone "dut dut-dut-dut dut-dut-dut" too! I figured out a lot about audio interference setting up my first home studio many a moon ago, so made sure I ruled out all of the obvious before posting here. Thank you for the suggestions though - they could have easily slipped my mind especially while I am trying to fix this effing iPod Nano 3 again (after weeks of thinking I had it fixed it now looks like the charging circuit has been the fault, and non-repairable, from the start
)Hahaha that is crazy it can have such an effect on a turntable. As for the rest...are you sure you aren't haunted?
😂It is very strange what RF and EMF can do to electronic equipment though.
I use a 5V charger and a resistor or diode to charge lithium batteries.
Old Nokia charger....
You can rig it up...leave the unit off, or put a switching jack, so power is cut to the unit while charging.
Use a low ampere charger, and charge less than needed.
That should keep your device in service.
Old Nokia charger....
You can rig it up...leave the unit off, or put a switching jack, so power is cut to the unit while charging.
Use a low ampere charger, and charge less than needed.
That should keep your device in service.
Update
So I've swapped out the main capacitors plus a few in other curcuits with Nichicon caps on the tan board and Panasonic caps on the green (all marked in red), and it doesn't seem to have made a huge difference. I have now noticed however, that it does only seem to be the left, right, and rear left channels that have the loud hiss, so it is at least narrowed down.
Any suggestions of the next step? Could it be those grey things (not sure what they are?) or is it more likely to be something surface mounted? I'm going to open it up again tomorrow.
Regards
So I've swapped out the main capacitors plus a few in other curcuits with Nichicon caps on the tan board and Panasonic caps on the green (all marked in red), and it doesn't seem to have made a huge difference. I have now noticed however, that it does only seem to be the left, right, and rear left channels that have the loud hiss, so it is at least narrowed down.
Any suggestions of the next step? Could it be those grey things (not sure what they are?) or is it more likely to be something surface mounted? I'm going to open it up again tomorrow.
Regards
For clarity I have highlighted the bad channels in red and good in white incase there is something obvious it could be in their signal paths.
Trying to get a Volkswagon Beetle's performance up to the level of a luxury limosine is impossible.
But I guess trying such a thing is good excersize for the brain, and kills some time when you're bored.
But I guess trying such a thing is good excersize for the brain, and kills some time when you're bored.
It's more a case of being happy with a VW Beetle but wanting to get rid of that annoying squeaking. Caps cost £40 so it is a bit frustrating they have had little effect, but at least I know they are not an issue now and given it new legs. Pretty sure it is something between the inductor choke coils (figured out what they are) and the connectors.
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Those grey things are inductors - coils, and hardly defective or worthy of considerations.
Samsung produces junk if you ask me, and has an ongoing terrible reputation for their products and customer satisfaction.
In fact, there are literally hundreds of complaints, damage to homes and people, and many class action lawsuits against the company.
Samsung produces junk if you ask me, and has an ongoing terrible reputation for their products and customer satisfaction.
In fact, there are literally hundreds of complaints, damage to homes and people, and many class action lawsuits against the company.
@StarfireBlack Consider cleaning off the green board if you have not done so already. I believe the pics are showing a layer of fuzzy "stuff" on the components, particularly nearby the output connectors. Might help, can't hurt.
Place it in nearest junk can, then the hiss will go away.