Sony STR DB930 sound issues Fix

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Sony STR DB930 sound issues Fix

Post by Corp Dwayne Hicks on Fri Apr 01, 2016 11:10 am

Good Evening (well it is in the UK!) all. You'll be please to hear I have successfully repaired my amp this morning and it has since been running for two hours with my iPod connected to it without any hint of relays clicking or the dreaded "Protector" fault!

@maxxwire I did look at the board that you highlighted for me and touched up a couple of connections that didn't look too clever. I then found what I believe to be the problem and repaired it as you can hopefully see form the pictures below!

PLEASE UNPLUG FROM THE MAINS BEFORE STARTING!!!
Firstly here's pic of my 930 rag top, you can notice that the Heatsink is different to yours and the mains transformer too, (Mine is 240 against your 120 I suspect!)



Before I start a little how too, please read this post thoroughly if you are in the same situation. If you have no experience of working with electronics, you might want to think twice about attempting this repair! There are some very heavy duty components exposed which despite not being plugged in would love nothing more than to discharge and residual current through your body!

The fault with mine was a couple of dry joints on the relays that you will hear clicking in about 5 seconds after powering the amp on, or if you switch between the different speaker options.
There are 4 speaker relays in total

RY501 - Front Speakers CH A
RY502 - Front Speakers CH B
RY601 - Centre Speaker
RY701 - Rear Speakers

RY501, 502 and 601 are located on the main board and are visible with the lid off
RY701 is located on the rear amp board

As Rclarke said in an earlier post they are blue in colour and stand about an inch and a half tall.

The repair.

Remove the metal access grate on the bottom of the amp and you'll be greeted by the underside of the main board. I have coloured the relay pins, you need to heat up each leg and remove the existing solder, then re-tin each leg in turn. I did them one at a time, if you unsolder them all at once you run the risk of the relay becoming detached from the main board, which could be a problem!  Complete this for RY501, 502 and 601 on the main board. Do not try and look for dry jointed pins and only do them, you will struggle to see them, I did even under magnification! It only takes a few minutes to do all 18 legs.

RY501 legs in red, 502 in yellow and 601 in purple, the front of the amp is at 3 o'clock in this photo by the way.




(The output transistors that I resoldered earlier are at the top of the pic!)


Once that was done I decided that I would resolder the rear relay also.  Mine hadn't failed, but it though it good practice whilst I had the amp open.  This is located on the rear amp board and unless you are confident in your skillset, or your rears are clicking in and out I would not recommend attempting it as access is not easy!

Firstly you need to remove the digital board.  Disconnect all of the plugs and ribbon cables from the digital board, be careful here! Then there are 6 screws on the rear of the amp, one about each of the Toslink optical input/output sockets and 2 in between the 5.1ch inputs. There are also 2 screws on the top on the digital board, use a magnetic screwdriver for these to reduce the chance of you dropping a screw onto the mainboard and shorting something out!. There is also a plastic riser about 3" in length that supports the digital board, with the access grate underneath still removed, carefully unfasten it and remove the digital board. Your amp will look like this.  You will now see what I mean about access from this photo!




Disconnect all the plugs form the rear amp board and there are also 2 screws on the rear amp board to remove. You will NOT be able to remove the rear amp board because the output transistors are bolted and glues to the Heatsink! You can unfasten them from the Heatsink and I would of but I didn't have any thermal paste to reattach them with. Once the screws are removed and the cables are all unplugged and stowed out of the way (I used some of those metal twist fasteners that you use to seal up food bags) There is just about enough room to get your soldering iron and copper braid in!  It isn't easy and a gentle touch and a steady hand are needed!  You can see RY701 in the pic and the other three relays below it.



Once that is completed, rebuild your amp, carefully!  Remembering to reconnect all of the cables to the rear board, then refit the digital board, again remembering to reconnect all of the various cables and screw it all back together! Once this is done it's worth giving the amp a test before you refit the cover.  If I need to remind you about the danger of lethal voltages here then you shouldn't be attempting the repair yourself!  Connect up the audio source and your speakers first then plug it into the mains and test it.

Once you're happy, UNPLUG THE AMP and refit the top and bottom covers, Jump Up and down- you have fixed the Thing  bounce  bounce  bounce
If you've stumbled across this thread whilst looking for help as I did, please take the time (2 minutes!) to register and say thanks to the forum for helping you out! They're a nice bunch and don't bite!

Apologies for rubbish iPhone pics by the way!
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Corp Dwayne Hicks
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