RMB-1077 amp problems, Help!

[hery19]

Currently have the 1077 amp connected to a 1069 in a 5.1 channel set up and 2 remaining channels powering zone 2. Using a 12v trigger to power the amp. The problem is that when I power on my system there is sound only coming from the right front, right surround speakers and sub, no sound from the center channel or left speakers. I did a test tone thru the 1069 to confirm this.

Powered the system off, disconnected the amp and so forth and nothing solved the issue. Later powered the system on and the problem was gone all speakers working. Then this morning the problem again. What I've noticed is that when the system is powered on the amps red protection lights are not coming on or off like they normally do.

Any suggestions, this is driving me crazy!

[1oldguy]

Question for those who would know.

If a preamp has a bass and treble control but is configured to only be active in the signal path once it's out of the 12 o'clock position,would that not be the best of both worlds?Especially for recordings that are less than stiller?
But again if left in the 12 o'clock position it bypasses the bass and treble control altogether.
Are there compromises in designing such a unit?


Also could someone go into (trim) decibel control?What are the uses for such a option? I saw it on a unit where minus 6DB,0 DB,plus 6 DB and 12 DB were the options.Would it give more power for low level listening?Is that it;s purpose?

[hifiguymi]

Currently have the 1077 amp connected to a 1069 in a 5.1 channel set up and 2 remaining channels powering zone 2. Using a 12v trigger to power the amp. The problem is that when I power on my system there is sound only coming from the right front, right surround speakers and sub, no sound from the center channel or left speakers. I did a test tone thru the 1069 to confirm this.

Powered the system off, disconnected the amp and so forth and nothing solved the issue. Later powered the system on and the problem was gone all speakers working. Then this morning the problem again. What I've noticed is that when the system is powered on the amps red protection lights are not coming on or off like they normally do.

Any suggestions, this is driving me crazy!

If all of the speaker connections are solid and no speaker is damaged, I'd say there is something wrong with the amp. The only time I've seen an amp start working after it's been disconnected and then stop again is if there is a short in a wire or voice coil. If that is not the case, it sounds like it needs service.

Eric

[hery19]

If all of the speaker connections are solid and no speaker is damaged, I'd say there is something wrong with the amp. The only time I've seen an amp start working after it's been disconnected and then stop again is if there is a short in a wire or voice coil. If that is not the case, it sounds like it needs service.

Eric

Ya the connections seem to be fine, that's what I was afraid of that it would need servicing because the issue comes up with different sources.

[hifiguymi]

It wouldn't be a source issue. You may try disconnecting all of the speakers except the front left and right and see what happens. If the issue shows up, try just the right one and then add the center. Just keep adding speakers until the problem shows up and see if that speaker is OK. Sometimes a voice coil in a speaker is going bad but it's hard to hear but shows a short to the amp. That's the last think I could think to have you try.

Eric

[hery19]

It wouldn't be a source issue. You may try disconnecting all of the speakers except the front left and right and see what happens. If the issue shows up, try just the right one and then add the center. Just keep adding speakers until the problem shows up and see if that speaker is OK. Sometimes a voice coil in a speaker is going bad but it's hard to hear but shows a short to the amp. That's the last think I could think to have you try.

Eric

I will give that a try Eric. I truly believe that it is the amp, from what I remember whenever it power on the red protection light would light up and that isn't happening now. There was an instance where it worked for a while yesterday and I ran a the processor test tone thru each speaker and they all seem to be working fine. While was messed up only the right speakers were working. Guess I'll have to call BMW group support and see what they suggest. Thanks for you help Eric

[srb]

Question for those who would know.

If a preamp has a bass and treble control but is configured to only be active in the signal path once it's out of the 12 o'clock position,would that not be the best of both worlds?Especially for recordings that are less than stiller?
But again if left in the 12 o'clock position it bypasses the bass and treble control altogether.
Are there compromises in designing such a unit?


Also could someone go into (trim) decibel control?What are the uses for such a option? I saw it on a unit where minus 6DB,0 DB,plus 6 DB and 12 DB were the options.Would it give more power for low level listening?Is that it;s purpose?

I pretty sure you have posted in the wrong thread.

Steve

[hery19]

It wouldn't be a source issue. You may try disconnecting all of the speakers except the front left and right and see what happens. If the issue shows up, try just the right one and then add the center. Just keep adding speakers until the problem shows up and see if that speaker is OK. Sometimes a voice coil in a speaker is going bad but it's hard to hear but shows a short to the amp. That's the last think I could think to have you try.

Eric

I am happy to report that after trying your suggestion of disconnecting everything and adding the left and right speakers then the center and finally the surrounds everything seems to be working fine so far. I had already called B&W support group and was ready to ship it out. But thanks to your help I am back in business. Again, Thanks for your help :T You saved me the headache of shipping it in for service and repair money ;x(

[hery19]

I am happy to report that after trying your suggestion of disconnecting everything and adding the left and right speakers then the center and finally the surrounds everything seems to be working fine so far. I had already called B&W support group and was ready to ship it out. But thanks to your help I am back in business. Again, Thanks for your help :T You saved me the headache of shipping it in for service and repair money ;x(

Well, I spoke too early. This morning powered up the system to see the news and the same problem again. Getting audio only from the right front and rear speakers.

[hifiguymi]

When you hooked up the speakers did you let it play for a little while to see if it will exhibit the problem before you added the others. That is the easiest way to find out if it's a speaker causing the problem. It does sound like it needs to go in for repair but it's better to be sure then to have it come back no problem found if it is a speaker causing it.

Eric

[hery19]

When you hooked up the speakers did you let it play for a little while to see if it will exhibit the problem before you added the others. That is the easiest way to find out if it's a speaker causing the problem. It does sound like it needs to go in for repair but it's better to be sure then to have it come back no problem found if it is a speaker causing it.

Eric

Yes Eric, I connected one pair at a time starting with the mains, then center channel, and lastly the rears, it played fine all evening after connecting them and I even shut if on and off to test the 12V trigger and everything was fine until this morning.

[hifiguymi]

That's frustrating. It does sound like it will have to go in for service. Hopefully they can turn it around quickly for you.

Eric

[hery19]

That's frustrating. It does sound like it will have to go in for service. Hopefully they can turn it around quickly for you.

Eric

Yes very frustrating, luckily I have a 2 ch amp to use while its in the shop.
Appreciate all your help! :T

[Carrotman]

It's most likely a problem with the 250ASP-module for the front left channel because that powers the other channels that shut down for you.


/U.

[hery19]

It's most likely a problem with the 250ASP-module for the front left channel because that powers the other channels that shut down for you.


/U.

I take it that's something only an authorized service shop can handle? How would a module go suddenly go bad, just curious I wasn't sold a dud.

[lotones]

This may have already been suggested or tried (I couldn't tell from reading the thread), but have you tried switching the right left channels into the amp when you're having the problem? If the problem switches channels then the problem is in the pre/pro.

When my digital board went bad in my 1068 it only effected one channel also. I'd hate for you to send the amp in for repair only to have it be the pre/pro.

[hery19]

This may have already been suggested or tried (I couldn't tell from reading the thread), but have you tried switching the right left channels into the amp when you're having the problem? If the problem switches channels then the problem is in the pre/pro.

When my digital board went bad in my 1068 it only effected one channel also. I'd hate for you to send the amp in for repair only to have it be the pre/pro.

Thats a good idea to try but I currently have a 2 channel amp hooked up to the front left and right channels and audio is fine, so I'm assuming the pre/pro is OK. What I can do is test the remaining channels in the pre/pro with the working amp to rule out the pre/pro and speakers completely as the problem. Also planning on testing the fuzes in the 1077 amp to see if they are OK. Thanks for the suggestion lotones :T

[Carrotman]

I take it that's something only an authorized service shop can handle? How would a module go suddenly go bad, just curious I wasn't sold a dud.

Yes, they need to replace the module. I can't point to any particular reason why it would suddenly become unstable except to say that "it happens" with electronics (not that that helps you I know).

/U.