amp only partially working! no surround ????

[sparkymarky]

my yam rxv795a is driving me nuts!

It has always worked pefectly and has hardly been used really.
but now it will not decode any surround sound.
by this i mean it will not put out any sound from my player (via optical lead).

it won't even do pro logic from skybox (fed via 2 phono cables)


The amp will output 2 channel (i.e all surround sound types off)
from Sky but as soon as you move it to pro logic it outputs no sound.

the dsp program effects like church/stadium etc still work but as soon as you get to pro logic/dd/dts nothing works.


(btw, when you turn on dvd player the orange dts sign lights up on amp and can't get it off dts. Can't remember if this is normal or not???)


any ideas please???


i have tried: unplugging speakers in turn
-switchin impedance selector
-tryed a phono lead in the external decoder ports
in case they are dirty and they player thinks that
there is offboard decoding going on

but still am stuck??????????????????? Hellllllllllpppppp!!!!

[sparkymarky]

test tones also do not work on any channel.


come on guys!

[sparkymarky]

just realosed that the first post was not clear.

basically the amp will only act as a 2 channel stereo amp.

it wont output anything through the centre or rear channels (although you can 'hear' that the amp is on through the speaker if you know what i mean)



does anyone know if the centre and rear channels are in fact one amplified channel? unlikely that 2 or three channels have all blown isn't it??

[bob1]

Try reseting the amp.

[sparkymarky]

btw not sure whether i did the putting phono leads into external decoder ports right or not. do you have to have the amp set to anything special or input anything to it (i don't have any external decoder)

[sparkymarky]

how do you reset it bob??

[bob1]

I don't know but on mine it's just a matter of pressing a button while turning on.

[lynx]

I don't think this is what you want to hear, however i had similar symptoms (i didn't the amp did) and it turned out to be a blown IC. The two stereo channels worked but the centre and surrounds were down. Of course this may not be the same fault on yours,just an other option to explore if all else fails.

[sparkymarky]

sounds bad.

what is an I C lynx???

[lynx]

Integrated circuit.

[sparkymarky]

thought so.

i reckon it may be the analogue to digital converter as obviously it works fine with 2 analogue sources but as soon as you select something that needs digital processing like DD or pro logic (which i believe had to go through the same stage) it stops working.

i have had my x box on top of the amp and whilst some vents were left uncovered some were covered. i know that ics are heat sensitive.

how much do you reckon to get it fixed??


thanks for the replies

[lynx]

Originally posted by sparkymarky

how much do you reckon to get it fixed??

The ic cost around £20, however if you need one and can get the id code check out somwhere like cpc as they stock hundreds of ic's for a few quid.

[hornydragon]

Best bet is take it to a service centre that will have (get hold of) the main Schematic for the AMP and identify the DSP Chip thats knackered and replace it for you. I would expect £40-50 for a pro repair depending on Chip cost.

[sparkymarky]

thanks hornydragon.

i think i will do that.

the nearest service centre is about 80 miles so i will take it there i think.


if your estimate is accurate then £50 plus £15 petrol should be ok.

i know its a fairly old reciever now and i have to weigh up getting repaired against a new one, but it does everything that i need. i'm not really interested in 6.1/7.1 or dpl2 so a new reciever would not benefit me , so i think i would rather get this one fixed.

thanks guys for all your efforts

[hornydragon]

Best to call service centre first before such a long trip mate £50 is guestimate but shouldnt be much more unless Yamaha charge a fortune for the Chip! Get an estimate gone firdt,this should be FOC.