Rotel RSX1057 - buzzing

TrevorMcW

Novice Member
Hi Folks,
Glad to see this forum is still going, was a member a few years ago and just rejoined.
I have an old Rotel rsx1057 which is 'buzzing' internally - not through speakers and the system is still functioning OK.
I have explored internally and found a blown capacitor on the Digital PCB 016E-1449A00. Its C430 which is a Samsung SCDA5R5104V. (See attached)

I'd like to know the function of the capacitor so does anyone know where I can get a circuit diagram of this board or through some light on the function?
Also, I've tried to locate a replacement part but can only find one through Alibaba - will take 30days they say. Can anyone help with a suitable alternative?

Any other help resolving the internal buzzing also appreciated.

Regards
 

Attachments

  • Rotel1057DigPCB.jpg
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shug4476

Active Member
You probably have found the culprit - buzzing is usually (not always) a failed or failing capacitor.
 

TrevorMcW

Novice Member
Thanks Shug4476, Yeah thats why I need to replace that capacitor before looking further.
Have found a replacement through RS at reasonable cost which should arrive today . . . in fact it's just arrived! I'll break out the soldering iron and sucker and see if it makes a difference and post back later.

Cheers
 

TrevorMcW

Novice Member
Hmmm, well I've replaced the SuperCapacitor but the buzz is still there Bah!!!
I'm gonna have to investigate further, any direction is welcome.

Regards
 

TrevorMcW

Novice Member
Just found that the buzzing tone is effected when I touch the trigger relays on the Digital Board. They are likely bouncing due to age.
I'm gonna see what price these are, I don't use the 12V trigger but that buzz is really annoying!!!
 

shug4476

Active Member
Can you check the capacitors beside the power supply? There should be four large ones. PSU buzz usually means one (or more) of these are getting long in the tooth.

Rotel can probably repair it?
 

TrevorMcW

Novice Member
Hi Shug 4476,
The buzz definitely isn't coming from the main PSU filter caps and its not cap scream either.
If I'd just heard the noise alone I'd have said it was small transformer or similar. I've tracked it to the digital board and can effect a tonal change when I press on any of the three 12V trigger relays (Takamisawa A12W-K) but I haven't found a supplier yet.

Just for clarity there is no buzz eminating from the speakers this is purely a noise from a component in the 1057 housing.

Thanks for interest Shug, all thoughts welcome.
Oh with regard to Rotel fixing - I've investigated this and they charge £100 just to take the unit then time and components on top. This 1057 is a second hand replacement for my old 1055 which has major audible 'cracking' problems . . probably the output caps. But I found this 1057 for £75 which was advertised as 'all good'. Turns out it works but has this buzz so I'm having a bash at resolving.

Cheers
 

TrevorMcW

Novice Member
Ok so have found the relays but they have to come from our oriental friends in China, estimated 29th of July. But good news is that I get 5 for £7 (that'll replace all of them in the 1057 if required)
I'll post back here when they arrive and report on progress. TBH I'll be surprised if this doesn't fix it as the noise is just like a buzzing relay.

Cheers
 

John7

Well-known Member
If you don't use the triggers, just unsolder and remove the relays, problem eliminated!
 

TrevorMcW

Novice Member
John7, thanks for that. I did wonder which way they would be configured and if the absence would effect me. I've just put it all back together now !!!!!!! and the missus has me on another job but will get back to this asap.

Cheers
 

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