hello all,
my first post here. requesting for your assistance.
have a problem with my marantz pm 7200 amplifier.
amplifier was on when an electric iron was plugged into another outlet. the inverter shut down and restarted. heard a sound from the equipment rack but could not figure out which unit made the sound.
then on playing music, i find, that the volume levels have dropped drastically. i need to position the volume at 12:00 clock position, which is normally unbearably loud. normal volume position is around 8:00 to 10:00 clock position. the bass is also much reduced.
however, both channels ARE producing music. there is no hiss, crackle or any other interference.
opened up the amplifier, but could not see anything specific that looked damaged. my friend says either one of the fuses or one of the output stages could have gone kaput.
need your opinion guys, before I take it in and have it looked at.
additionally, as a matter of curiosity, when I opened it up, it did not look to be like a dual-mono design. however, in most places on the net, including some marantz sites, this is advertised as a dual-mono amplifier. I am attaching a pic of amp internal. What do you guys think this is ??
thanks in advance. eagerly awaiting your inputs.
my first post here. requesting for your assistance.
have a problem with my marantz pm 7200 amplifier.
amplifier was on when an electric iron was plugged into another outlet. the inverter shut down and restarted. heard a sound from the equipment rack but could not figure out which unit made the sound.
then on playing music, i find, that the volume levels have dropped drastically. i need to position the volume at 12:00 clock position, which is normally unbearably loud. normal volume position is around 8:00 to 10:00 clock position. the bass is also much reduced.
however, both channels ARE producing music. there is no hiss, crackle or any other interference.
opened up the amplifier, but could not see anything specific that looked damaged. my friend says either one of the fuses or one of the output stages could have gone kaput.
need your opinion guys, before I take it in and have it looked at.
additionally, as a matter of curiosity, when I opened it up, it did not look to be like a dual-mono design. however, in most places on the net, including some marantz sites, this is advertised as a dual-mono amplifier. I am attaching a pic of amp internal. What do you guys think this is ??
thanks in advance. eagerly awaiting your inputs.
Attachments
Another Marantz amp that's kissed its *** goodbye.
This is truly abominable.
Wh t happened to th e good old days of Marantz quality?
I guess once Philips bought them, it was downhill all the way.
Clearly Dennon have done nothing to try to rectify the issue.
Lets all spread the word: Marantz is JUNK.
Maybe the owners will try to sort it out then.
This is truly abominable.
Wh t happened to th e good old days of Marantz quality?
I guess once Philips bought them, it was downhill all the way.
Clearly Dennon have done nothing to try to rectify the issue.
Lets all spread the word: Marantz is JUNK.
Maybe the owners will try to sort it out then.
@Bonsai: I find this a rather baseless remark. Yes, I have had Marantz equipment that failed, but no more or less often than other brands I had or still have.
Sudden mains failure can damage any equipment attached to it. I've seen it happen to very expensive measuring equipment. Doesn't matter what brand is on the casing.
Please, refrain from throwing mud on this forum.
@diy_lost: the power supply is the first thing I'd go over considering what happened. Measure all power rails to check if they're still working properly.
If the sound you heard was a click, it might just have been the speaker relay falling off.
Did you try other line inputs? Did you swap the speakers to channel B?
About the dual-mono thing: audiophiles usually only consider something dual mono if both channels are built up completely separate from eachother (often including the power transformers). In essence stereo is dual mono, so the term dual mono might be 'abused' a little for marketing purposes.
Sudden mains failure can damage any equipment attached to it. I've seen it happen to very expensive measuring equipment. Doesn't matter what brand is on the casing.
Please, refrain from throwing mud on this forum.
@diy_lost: the power supply is the first thing I'd go over considering what happened. Measure all power rails to check if they're still working properly.
If the sound you heard was a click, it might just have been the speaker relay falling off.
Did you try other line inputs? Did you swap the speakers to channel B?
About the dual-mono thing: audiophiles usually only consider something dual mono if both channels are built up completely separate from eachother (often including the power transformers). In essence stereo is dual mono, so the term dual mono might be 'abused' a little for marketing purposes.
jitter,
first off, to clarify on the nature of the sound I heard. It was not a click, more like a *phat*.
I did the following tests :
1. Connected speakers to "Speaker B" outputs. no difference.
2. Connected RCA from CDP to other inputs (Aux1, Aux2). no difference.
3. Connected my Ipod to Aux2. no difference.
The problem still remains. Volume is drastically reduced. In fact I could take the volume knob to 2:00 clock position. It was just comfortably loud. Normally I could never do that. In fact I have never taken it that high in so many years of using the amp.
To re-iterate :
1. Drastic reduction in volume levels is the only problem.
2. Left and Right output is still perfectly okay, in the sense all the musical information is being reproduced.
3. There is no other static, hissing or other interference noise.
4. Also the traditional click and thump when the amplifier is started is also there.
With respect to the other thing you wanted me to check :
Checking power rails :
I regret to inform you I am a total ignorant in this field. However, if you can guide me step by step and tell me the tools I will need to test, I wil go about acquiring them and follow your instructions to test the needful. (My username is diy_lost !!! is it not clear ??
)
do let me know how I proceed next.
Thanks again for your help.
ciao.
first off, to clarify on the nature of the sound I heard. It was not a click, more like a *phat*.
I did the following tests :
1. Connected speakers to "Speaker B" outputs. no difference.
2. Connected RCA from CDP to other inputs (Aux1, Aux2). no difference.
3. Connected my Ipod to Aux2. no difference.
The problem still remains. Volume is drastically reduced. In fact I could take the volume knob to 2:00 clock position. It was just comfortably loud. Normally I could never do that. In fact I have never taken it that high in so many years of using the amp.
To re-iterate :
1. Drastic reduction in volume levels is the only problem.
2. Left and Right output is still perfectly okay, in the sense all the musical information is being reproduced.
3. There is no other static, hissing or other interference noise.
4. Also the traditional click and thump when the amplifier is started is also there.
With respect to the other thing you wanted me to check :
Checking power rails :
I regret to inform you I am a total ignorant in this field. However, if you can guide me step by step and tell me the tools I will need to test, I wil go about acquiring them and follow your instructions to test the needful. (My username is diy_lost !!! is it not clear ??
)do let me know how I proceed next.
Thanks again for your help.
ciao.
IMO a phat-sound could indicate that a component blew up. Usually this is accompanied by a little smoke and a bad smell, but not always.
To check the power supply circuits you need a (digital) multimeter set to measure DC voltage. But don't go running off to the nearest electronics store to get one because although I'd gladly talk you through it, I am unfamiliar with this amplifier. Therefore I won't be able to give you specific instructions on where to measure what value.
That means you have to find the power supply circuits and determine if they still function correctly on your own, which might be a bit difficult for someone without knowledge of electronics.
I'm sorry, but this is where my ability to help you falls short. Good luck anyway.
One last tip: check if the fuses are still in one piece.
To check the power supply circuits you need a (digital) multimeter set to measure DC voltage. But don't go running off to the nearest electronics store to get one because although I'd gladly talk you through it, I am unfamiliar with this amplifier. Therefore I won't be able to give you specific instructions on where to measure what value.
That means you have to find the power supply circuits and determine if they still function correctly on your own, which might be a bit difficult for someone without knowledge of electronics.
I'm sorry, but this is where my ability to help you falls short. Good luck anyway.
One last tip: check if the fuses are still in one piece.
Jitter,
no. Its about time consumers let rip on poor quality products. Marantz have no excuse on this one - zero.
I've had a CD Recorder which stopped working 1 week after it came out of warranty and they refused to fix it (Philips).
These companies make bad quality products and then expect consumers to take on expensive 'warranty extensions' to pay for sloppy design and engineering.
In my view, there needs to be some legislation against this nonsense - its exploitation plain and simple.
I will not be buying a Marantz product anytime soon I can assure you and if anyone asks my opionion, they will get it straight. Ditto a few other brands with the same problem.
no. Its about time consumers let rip on poor quality products. Marantz have no excuse on this one - zero.
I've had a CD Recorder which stopped working 1 week after it came out of warranty and they refused to fix it (Philips).
These companies make bad quality products and then expect consumers to take on expensive 'warranty extensions' to pay for sloppy design and engineering.
In my view, there needs to be some legislation against this nonsense - its exploitation plain and simple.
I will not be buying a Marantz product anytime soon I can assure you and if anyone asks my opionion, they will get it straight. Ditto a few other brands with the same problem.
This doesn't make sense unless I have missed something along the way.
Does the amp have remote control ? Whatever has happened it doesn't sound like an output stage problem, they don't fail like this - the gain changing etc and certainly not on both channels.
You run it off an invertor ? Mains voltage to the amp OK ?
If it has remote what functions can you control. What I am getting at is whether there is any electronic gain/muting/tone etc.
unless I have missed something along the way.Does the amp have remote control ? Whatever has happened it doesn't sound like an output stage problem, they don't fail like this - the gain changing etc and certainly not on both channels.
You run it off an invertor ? Mains voltage to the amp OK ?
If it has remote what functions can you control. What I am getting at is whether there is any electronic gain/muting/tone etc.
Yes, all the R/C and input switching logic are handled by a controller and its located on the board behind the front panel.
There is an auxilliary +-15V supply to the pre-amp board - you should check this is ok (looking from the top of the amp with front panel facing you, the regualtors are on the right hand side on the pre-amp board.
Other things to check are that there are no burnt or o/cct resistors in the signal path between t h e rear connectors and th e volume control. I mention the resistors because they are really bad quality and I had 2 go open circuit on my first amp.
This amp could be so damn good, if only.
There is an auxilliary +-15V supply to the pre-amp board - you should check this is ok (looking from the top of the amp with front panel facing you, the regualtors are on the right hand side on the pre-amp board.
Other things to check are that there are no burnt or o/cct resistors in the signal path between t h e rear connectors and th e volume control. I mention the resistors because they are really bad quality and I had 2 go open circuit on my first amp.
This amp could be so damn good, if only.
I have worked on way to many devices that have "weird" software faults that go away when left unplugged or with the backup supply disconnected.
I usually disconnect the battery ( if it has one ) or discharge the cap with a 220 ohm or similar. Those 1F caps take a long time to discharge to. And then get some aluminium cooking foil and press that over the panel to short everything out. You have to be ABSOLUTELY certain that there are no PSU caps still charged before you do this. Leave it for an hour or two like that.
I have had PIC type chips in remotes ( Sony actually ) that lock up. They had to be left for at least 72 hours with no batteries in, then they work correctly.
I think it's something like this that has happened.
I usually disconnect the battery ( if it has one ) or discharge the cap with a 220 ohm or similar. Those 1F caps take a long time to discharge to. And then
get some aluminium cooking foil and press that over the panel to short everything out. You have to be ABSOLUTELY certain that there are no PSU caps still charged before you do this. Leave it for an hour or two like that.I have had PIC type chips in remotes ( Sony actually ) that lock up. They had to be left for at least 72 hours with no batteries in, then they work correctly.
I think it's something like this that has happened.
jitter...
i could see two fuses, the small transparent cylindrical ones at the top left of the amp. they seem to be okay. the wire inside seems to be intact.
anyways, thanks for your help. will take it in to one of my contacts for a look see and/or the marantz service center after hunting it up.
thanks for all your help in any case. i understand there isn't much you ca do more what with me being literally illiterate in this area.
in any case once i get the problem resolved, i'll report back to let you know what exactly was wrong.
thanks and regards once again.
i could see two fuses, the small transparent cylindrical ones at the top left of the amp. they seem to be okay. the wire inside seems to be intact.
anyways, thanks for your help. will take it in to one of my contacts for a look see and/or the marantz service center after hunting it up.
thanks for all your help in any case. i understand there isn't much you ca do more what with me being literally illiterate in this area.
in any case once i get the problem resolved, i'll report back to let you know what exactly was wrong.
thanks and regards once again.
Mooly,
thanks for your response.
Yes. The amp has a ful function remote control. In fact i control the CD player too with the remote, which is also a marantz. (CD6000 OSE LE)
Remote has functions to switch on / standby, change source, volume control and other CD player functions as well.
The amp is a 95 WPC Class AB mode and 25WPC Class A mode.
Has a dedicated button to switch on Class A.
It has tone controls and also a Source Direct Button to bypass the tone controls.
However Class A button and Souce Direct are only present on the unit and not on the remote control.
links to amplifier page on marantz site.
http://www.marantz.com/new/index.cfm?fuseaction=Products.ArchProduct&cont=eu&bus=hf&prod_id=2401
http://ca.marantz.com/Products/584.asp
I spoke to a Marantz dealer here who was of the opinion there might be a problem with the Volume IC.
Unfortunately they will ony service units which have been purchased from them. I had purchased my unit from Malaysia when I was based there. There are no "authorised Marantz service centres here".
With respect to the inverter :
=====================
It does not always run off the inverter. When there is a voltage fluctuation or a voltage drop automatically all appliances and devices (including fans, lights etc) switch over to the inverter. I basically run the inverter on UPS mode so that even if there is voltage fluctuation, all appliances run off the inverter. I have had it properly installed and the thing has been working fine for close to 2 years not without any problems. The inverter is pretty large capacity ( the batteries i.e.) can comfortably run over a day with all appliances running off it.
Mains voltage must be OK as all of my other stuff too runs the same way, my home PC, Pioneer HTIB amp, T.V., DVD player etc, both our laptops etc
thanks and regards.
thanks for your response.
Yes. The amp has a ful function remote control. In fact i control the CD player too with the remote, which is also a marantz. (CD6000 OSE LE)
Remote has functions to switch on / standby, change source, volume control and other CD player functions as well.
The amp is a 95 WPC Class AB mode and 25WPC Class A mode.
Has a dedicated button to switch on Class A.
It has tone controls and also a Source Direct Button to bypass the tone controls.
However Class A button and Souce Direct are only present on the unit and not on the remote control.
links to amplifier page on marantz site.
http://www.marantz.com/new/index.cfm?fuseaction=Products.ArchProduct&cont=eu&bus=hf&prod_id=2401
http://ca.marantz.com/Products/584.asp
I spoke to a Marantz dealer here who was of the opinion there might be a problem with the Volume IC.
Unfortunately they will ony service units which have been purchased from them. I had purchased my unit from Malaysia when I was based there. There are no "authorised Marantz service centres here".
With respect to the inverter :
=====================
It does not always run off the inverter. When there is a voltage fluctuation or a voltage drop automatically all appliances and devices (including fans, lights etc) switch over to the inverter. I basically run the inverter on UPS mode so that even if there is voltage fluctuation, all appliances run off the inverter. I have had it properly installed and the thing has been working fine for close to 2 years not without any problems. The inverter is pretty large capacity ( the batteries i.e.) can comfortably run over a day with all appliances running off it.
Mains voltage must be OK as all of my other stuff too runs the same way, my home PC, Pioneer HTIB amp, T.V., DVD player etc, both our laptops etc
thanks and regards.
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