JVC RX8010 A/V Receiver with no sound

[djcmx49]

OK I have a JVC RX8010 receiver which has an intermittent no sound fault. When I turn on receiver for first time of the day I will have no sound any function. However if I select "line direct" I will get sound on front 2 channels. This feature bypasses Digital Proc. PCB. So you can guess where I am concentrating my troubleshooting, Digital Proc.board of course. However it's location makes it very difficult to take any voltages or scope it. Note, I don't have a scope.

All power supply voltages are correct, I have service manual, all 5 audio O/P amps are working fine, I can induce sound from touching input connectors and hear sound so I know it is not a mute/protection fault from O/P circuits. I have traced audio switching circuits and I found input to be OK right up to input of Digital PCB but no sound on O/P of this PCB.

Now here is the weird part. If I turn speakers 1 or 2 sw. on and off repeatedly I will eventually get sound through Digital PCB and all will be OK from that point on until turn off receiver for any length of time. Then I will have to to this all over again the next time I turn on receiver...

The Digital PCB has a slew of small SMD aluminum caps, only board which does, I am leaning to replacing all these but just not sure?? I know the poor history of these type of caps so it's a good guess but any suggestions would be very appreciated.

Note: I have been A/V bench repair tech for over 25 yrs so I am comfortable with any part replacement suggestions or specific help, you won't lose me with any tech talk...lol I no longer work in the A/V field but I still know my way around this stuff just looking to see if anyone has seen this issue or is familiar with JVC receivers...Thanks for any help

DJC

[Khron]

Re: JVC RX8010 A/V Receiver with no sound

What voltage inputs does the digital board have? I mean, does it receive 5v / 3.3v from the main power supply, or does it have voltage regulators on-board?

Digital stuff can create quite a bit of ripple on the supplies, maybe it "ate up" some caps(?).

Does it have a steel transformer, or a switching power supply?

[budm]

Re: JVC RX8010 A/V Receiver with no sound

I agree that the voltages on the DIGITAL board need to be checked when it is working and not working, since you lose all the sound, then it has to be someting that is common to all the channels, power supply is one of the common. Service manual? Do you also lose the sound at the Tpae monitor Rec out?

[djcmx49]

Re: JVC RX8010 A/V Receiver with no sound

Thanks for ideas...

Digital PCB receives +5,+13,-13. It has on board 3.3v reg. All voltages stay the same when not working or working...Can't tell if ripple is an issue without scope but no visible damage to any PS filter caps...

Amp uses Large metal transformer for main PS. When I first looked at unit it had cold solder areas and heat damage in power supply circuit which I repaired thinking this should solve issue, upon putting back together I found I was sadly mistaken...lol But I agree it still may be PS issue...

Voltages on Digital PCB are extremely difficult to measure due to its location, buried vertically at back of unit under large input/switching PCB...

Can't tell if I have audio O/P on tape rec.out jacks , don't have scope or cassette deck hooked up to them. I believe I do because low level signals on switching board are OK. And when on Line Direct sound is OK on front two channels...

[djcmx49]

Re: JVC RX8010 A/V Receiver with no sound

Update : Unit repaired !!! I finally received parts and installed them on the weekend. As I originally suspected the alum. caps on Digital Proc. Board. There were over 2 dozen on the board but I concentrated on the filter caps rather than signal coupling. After installing and powering up the receiver I now have audio restored immediately, no delay or warm up or speaker switching on/off required... Thanks for all the help

[budm]

Re: JVC RX8010 A/V Receiver with no sound

Thanks for the repair feedback, glad to know you fixed the problem.

[Greg Scruton]

Re: JVC RX8010 A/V Receiver with no sound

I'm a bit of a neophyte in electronics repair, but I'm having the same problem that djcmx49 had - the only sound that comes out is when "Line Direct" is active.

I can see all the SMD aluminum caps on the board & would like to try replacing them. I have a few questions:

- Where do I buy SMD aluminum caps?
- There appear to be a couple different types on the board- some are bigger and some are smaller. DJCMX 49 concentrated on the "Filter Caps." Are the bigger ones or smaller ones the "Filter Caps"? (Does this question make any sense?)
- Finally, is there a trick to getting them out of the board and putting new ones in? Do I need a special tool? Do they just pop out somehow?

Thanks in advance.

[Saxi]

Re: JVC RX8010 A/V Receiver with no sound

I'm having the exact same problem djcmx49 described. I'm not a tech at all but have some electronics knowledge and soldering experience. Is there anyway you can point me to the filter caps you mentioned? Even with the service manual I don't know to locate them physically.

[Khron]

Re: JVC RX8010 A/V Receiver with no sound

"Filter caps" = the capacitors between the supply rails (+/- and ground)
"Coupling caps" = the capacitors in series with the signal lines; basically DC-isolating various stages from one another.

If you have the service manual / schematics, they're marked with part numbers (usually C__ for capacitors), and more often than not, those markings are also on the silkscreen, on the circuit boards.

I've recently had to replace some SMD aluminium caps a few weeks ago, and i figured out a simple-ish method (that works especially if you're not hoping to recycle the ones you remove ). This type of caps is, more often than not, found on the digital / DSP boards, and as such, their negative leg is generally ground, and their other leg is on one of the positive rails (+5v or +3.3v or whatever). So, what you do, is heat up the positive leg (since the supply traces suck away a lot less heat than the huge ground planes) with your soldering iron - be patient, it might take a minute or two - and slowly try to pry up that side of the cap (stick the thin tip of a flathead screwdriver under the black plastic "foot"). When that cap leg is off the board, move over to the negative leg (the coloured/shaded side, on the top). Don't worry if you happen to pull off the cap and one or both legs break off and stay on the board, they're easily removed after the fact. Just be careful (or at least hope) you won't strip/tear off any traces

[Saxi]

Re: JVC RX8010 A/V Receiver with no sound

Thanks for the info, Khron666. I'll try and locate the capacitors between supply rails.

[bchtpc]

Re: JVC RX8010 A/V Receiver with no sound

I signed up to post that I had the same issue with my venerable RX-8010vbk which began failing to produce sound except in line direct mode. I wanted to post which caps I changed to fix the problem as it took me a while to figure it out.

Basically, on the DSP board, just change all the caps that are either 100 or 47 microfarad. I couldn't get 47's so I used 100 for all 12 of them and the amp worked immediately and has kept working since. The other thing is that I couldn't get the surface mount caps so I just used radial lead 10volt electrolytic caps and soldered them to the surface mount pads. Probably not the recommended method but the total cost for repair was around $4. Music to my ears.

bc

[Khron]

Re: JVC RX8010 A/V Receiver with no sound

Those surface-mount caps i had to replace were on the digital board in an Onkyo receiver. I also had no SMD caps at hand, but i laid my radials flat on the board, on top of strips of double-sided sticky-tape. The more "pro" way would've been using some RTV (room-temperature vulcanizing) rubber compound, but i had none of that.

But hey, necessity's the mother of invention, right?

[eelke83]

Re: JVC RX8010 A/V Receiver with no sound

Do you remember what voltage the caps were?
im having the same issue but cant figure out what voltage caps this should be.

in the parts list i have the caps arnt specified other than a serialnumber.
running that serialnumber through google i couldnt find any useful answer

[bugler13]

Re: JVC RX8010 A/V Receiver with no sound

Hi, just wanted to share my fix for the same no sound (everything else perfect) problem. On the DSP board, there are two regulators for the DSP chip. 3.3V - IC583 and 1.8875V - IC505. In my unit, the filter capacitor, C2535 (100uF/4V), for the 1.8875V regulator gone bad and the output (pin 3) waveform showed 0.5V peak to peak ripple. Just add another cap (had 47uF 35V) in parallel fix the problem and sound came back normal! Happy!