Joined: Sep 23, 2009
Posts: 1
From: United Kingdom
Posted: 2009-09-23 16:38
My Sony Amplifier STR DB390 keeps losing the sound & chatter badly, then the sound comes back does anybody know a fix as it is a great AMP. My local Sony dealer doesnt know a fix but want to sell me another
Maxxwire Moderator Premium Member Rank: Sony Adept
Joined: Aug 29, 2002
Posts: 25726
From: Portland, Oregon - USA
Posted: 2009-09-23 17:33
morgan34- Welcome to Agoraquest. As the picture below of my DB 930 will attest Sony no longer makes a Receiver with this high of a build quality so it is well worth your while to have your ailing DB 930 repaired.
After 10 years of faithful service I had to take my Sony DB930 over to my Audio Tech's house to have some cold solder joints touched up which were causing the output relays to chatter and the Receiver to loose sound intermittently.
The solder joints that need to be touched up are located on the circuit board with the blue arrow pointing to it. My tech also touched up most of the other solder joints on this board because in his opinion they were not done with quality workmanship in the first place.
Hopefully you will be able to find a skilled solder slinger within your local Audio Enthusiast community who will be able to touch up these cold solder joints and get your DB930 performing once again.
I had exact same problem a few years ago, it's easy to fix.
The board that maxxwire indicates has the relays for the rears on it. If it's the centre speaker thats playing up, you'll need to remove the access panel on the bottom of the unit to get access to the underside of the circuit board. Don't recall which board has the relays for the fronts, but it's one of those two.
If you're reasonably handy with a soldering iron you can do it yourself otherwise visit your local tech and ask him to resolder all the relay joints. The relays are the blue rectangular compents which are about an inch and a half high. They each have six pins into the circuit board, all of whch you should resolder.
cheers,
rob (switzerland)
Maxxwire Moderator Premium Member Rank: Sony Adept
Joined: Aug 29, 2002
Posts: 25726
From: Portland, Oregon - USA
Posted: 2009-09-24 07:36
rclarke1- The cold solder joints that my Tech resoldered were all located on that same circuit board. I can't say for sure exactly which ones belonged to which channels because as I said he redid almost all of them because he was not satisfied with the original soldering job on any of them.
morgan34- Unless you have the proper equipment and know exactly what you are doing I would suggest taking your DB930 to an experienced Audio equipment Technician who does. For example my Tech has all of the latest diagnostic equipment and been making a living working on every brand of Audio equipment from Audio Research to Krell plus all of the more popularly owned consumer brands along with building all of the ModWright Indusrties Audio equipment from the ground up. Some of the most reputable Audiophiles in the world hail from the United Kingdom and I am confident that you will be able to find an Audio equipment technician who can fix the problems that your DB930 is currently having.
~Maxx~
----------------- A Satisfied Sony Fan Since 1974!
Firstly apologies for a noob digging up an old thread, google led me here and the rest is history! I too have a str db930 that gave up last summer following almost 10 years of loyal service! I replaced it with a newer Sony model str dh810 which is a good little amp and also takes care of my HDMI switching needs (thanks Pioneer for only putting one HDMI input on my plasma!). This happened about 2 weeks before my daughter was due to be born so i didn't have time to attempt a repair on the 930. It was put away in the spare room to await its chance.
Finally 9 months later I have got round to looking into the problem! It is essentially what the OP had, when you power it on and feed it an input, (analogue or digital) all you can hear in the relays chattering and clicking with no sound coming out. I have since found the service guide after a quick search, which whild providing some faurly useful schematics, wasn't of much use!
So after a little bit of google action I founf this thread and registered here to seek the advice of folk more knowledgable than this callsign!
I have removed the lid and the access panel underside, and removed and resoldered all of the output transistors that are bolted to the heatsink, however that didn't fix the fault. None of the fuses have blown either and I can't see any visual evidence of componant failure, (bulging caps and the like) so where do I go next?
I'm no stranger to electronics but have never stripped an amp like this before!
This amp is great and the main reason I bought it was because it sounded great in 5.1 and very good in 2ch stereo also, which none of its competition at the time came close to doing! So the old girl deserves a second chance, I refuse to take it to some joker in a sony shop who'll only try and rape my wallet for repairs or a newer model!
It does look slightly different to yours maxxwire, might be due to mine being UK spec i'm guessing.
Also being a noob I didn't want to post a link to the service guide incase it offends the mods! If it's ok, then let me know and I'll put up a link.
Great fourm by the way!
Maxxwire Moderator Premium Member Rank: Sony Adept
Joined: Aug 29, 2002
Posts: 25726
From: Portland, Oregon - USA
Posted: 2010-04-07 12:15
Member Quote
On 2010-04-07 09:08, rob-the-viking wrote:
This amp is great and the main reason I bought it was because it sounded great in 5.1 and very good in 2ch stereo also, which none of its competition at the time came close to doing! So the old girl deserves a second chance.
rob- You're certainly right about that! All it took to bring that wonderful sound back to my DB930 was touching up the cold solder joints located on the fairly easily accessible circuit board indicated below-
Have you touched up this board yet? Doing so brought my DB930 back to life to celebrate its 10th anniversary with a with a sonic excellence commensurate with its amazing build quality which can no longer be found in current production models selling for 2X-3X its 1999 pricepoint.
~Maxx~
----------------- A Satisfied Sony Fan Since 1974!
Maximus, thanks for getting back to me mate. I did look at the board in your earlier photo, but couldn't see anything obvious that was dry jointed there. I'll attack it with the Iron and re-tin everything there tomorrow, I've left the amp at work as we've got proper ESSD handling benches in the building which is great for me to fix my own kit in!
As for the credentials of the 930, you're damn right mate! It's replacement, (DH810) does lack some of the depth that the 930 had, but HDMI switching is a godsend and means I don't need one of those seperate switching units! If I get the 930 fixed up then I have a spare pair of B&W 601's (that also need some repair work on one of the crossovers) that it will get mated to and it will be used purely for music.
When I bought it I looked as a Pioneer a Yamaha and a Denon, the Yammy was ok and if I hadn't heard the Sony demo'd I would probably have ended up buying it. The Pioneer and the Denon left me feeling very underwelmed! Although a mate has since bought a Denon 3505 which is a damn good amp!
I'll let you knwo how I get on mate.
Rob.
Maxxwire Moderator Premium Member Rank: Sony Adept
Joined: Aug 29, 2002
Posts: 25726
From: Portland, Oregon - USA
Posted: 2010-04-08 01:03
I haven't put my DB930 up against a Denon Receiver, but I did A/B listening test it side by side with a Class A Stereophile Magazine Recommended Creek 5350SE dedicated Stereo Integrated Amp at 3X the pricepoint of the DB930 and the Sony Receiver sounded every bit as good as the Audiophile darling in every aspect and area of sound quality with the single exception of the retrieval of inner detail where the Creek had a very slight advantage.
~Maxx~
----------------- A Satisfied Sony Fan Since 1974!
Good Evening (well it is in the UK!) all. You'll be please to hear I havesucessfully repaired my amp this morning and it has since been running for twohours 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 highlited for me and touched up acouple of connections that didn't look too clever. I then found what I believeto be the problem and repaired it as you can hopefully see form the picturesbelow!
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 componants 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 Sepakers 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 aninch 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 exisitng 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 ofthe 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. Thisis 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 inbetween 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 fastners 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 attempring 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, robert is your fathers's brother!
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!
Rob.
[ This message was edited by: rob-the-viking on 2010-04-09 02:38 ]
I been repairing pc boards for 34 years now. One of the most common problems are cold solder joints. An interrmittent failure is a tech's worst nightmare. When solder joints are suspect and not seen by the naked eye, I spray and brush the area with Chemtronics ES1035B Flux Off. The bad joint now becomes visible. I prefer this brand because it does not discolor plastics. Some brands will turn plastics white. (overspraying) I then remove the old solder with a solder sucker. I then use a fiberglass eraser brush and thoroughly clean the component lead. Be careful with these brushes because the tiny fiberglass bristles break off and can stick in your fingers and become splinters that are near impossible to see and remove. I then resolder the component.
I suspect the cause of cold solder joints are 2 reasons. The first is that the component lead was tarnished when it was originally soldered. The other is that not enough heat was applied. Or a combination of both.
Joined: Mar 13, 2003
Posts: 13788
From: Sewell, NJ
Posted: 2010-04-09 21:42
Outstanding photos and repair instructions. Cold solder connections to the speaker relays are often the problem. I know that I have posted on this subject in the past. can remember posts on this in the past. If you use the Advanced search feature at the bottom of the Forums page and search for "cold solder joints" and author "jehill" you will find a few.
Joined: Feb 28, 2003
Posts: 9156
From: Chicago,IL, USA
Posted: 2010-04-09 22:42
Hello rob-the-viking.
Greetings and welcome. Thank you for taking the time to take and share your pictures and step by step repairs of your DB930. Hopeful that it will help other forum members now and in the future.
I look forward to many more of your posts in the future. BTW, I just read today that the iPhone is coming out with the 4.0 operating system this June and it will upgrade the camera to a 5 mega pixel camera. So we have that going for us.
Joe
Maxxwire Moderator Premium Member Rank: Sony Adept
Joined: Aug 29, 2002
Posts: 25726
From: Portland, Oregon - USA
Posted: 2010-04-10 00:32
rob- Another thing that really improved the sound quality of my DB930 was replacing the molded nickel bladed plug on its power cord with a Leviton 8215-C Hospital Grade Plug...
After noting a substantial improvement in performance with the higher conductivity of the Leviton's brass blades I bumped the quality of the DB930's power cord plug up several notches by replacing it with a Furutech FI-11 plug which uses cryogenically treated Pure Copper blades along with access to power from a Tice Micro Block Line Conditioner which improved the sound quality of the DB930 an order of magnitude over what it sounded like when it merely e qualed the performance of the Class A Audiophile quality Creek 5350SE.
~Maxx~
----------------- A Satisfied Sony Fan Since 1974!
Thanks for your replies. I just hope this thread might help someone else out in the future!
@maxx. I like the plug mod mate, I intend to replace the volume LED soon so when it's apart I might do this mod!
@jehill I have read many of your posts mate and you've probably forgotten more than i will ever know! keep up the good work helping out noobs like me!
@jttar You are very welcome. This forum pointed me in the right direction so it was the least I could do! I do hope what you say about the iPhone camera is true also, even on my 3gs it is pretty crap!
Maxxwire Moderator Premium Member Rank: Sony Adept
Joined: Aug 29, 2002
Posts: 25726
From: Portland, Oregon - USA
Posted: 2010-04-17 14:55
Member Quote
On 2010-04-16 15:37, rob-the-viking wrote: @maxx. I like the plug mod mate, I intend to replace the volume LED soon so when it's apart I might do this mod!
Many people don't yet realize the benefits that an improved AC Power connection can make in the performance and sound quality of their AV gear, but there are very positive improvements that can be realized for a relatively small investment.
~Maxx~
----------------- A Satisfied Sony Fan Since 1974!
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