I recently purchased a used Marantz PM80 which arrived yesterday. The amp worked for only about 10 minutes then died. During the 10 minutes that I was able to listen to it, I though it sounded quite nice. Upon unpacking I first tried it in class A mode which sounded great. I then powered it off and switched to AB mode. This still sounded good, but not as refined. I powered off again and switched back to A. Sure enough, class A was much better. These were the 10 minutes or so that I mention. I then powered the amp off and left it. Later in the evening, I powered the amp up again and let it warm up for a while. When I cam back 15 mins or so later, and tried playing a CD, nothing happened. There was no sound at all. I switched to another input. Still nothing. I powered it off for 5 mins and switched it back on again. Still nothing. The amp was warm, but not hot. There was plenty of venitallation - there is a good 1.5cms between it and the CD player on top of it. There is also a good 2in of grille showing behind the CD player as it is nowhere near as deep. I cannot hear the characteristic click from the relays nor can I get any sound on the headphones. There is, in fact, no sound at all. I have contacted the seller responded by saying that I must have switched from A to AB mode without powereing off. I replied that I was aware that this should not be done and was very carefull about that and requested a refund which he is considering. The other option would be to repair the amp although if I open it up then I will probably void any right to ask for a refund (assuming there is one in the first place). I will wait for the seller to get back to me before doing anything, but I presume that the protection circuit has got stuck on for some reason. Is there anything obvious that I should do or try before returning or opeining up and repairing? Any reason why it would just fail like that? This doesn't make a lot of sense. I have another Marantz amp (pm350) which has never given me any such trouble.
It doesn't have MkII printed on it anywhere so I presume its a MkI. I'm not sure how to tell whether the loudspeaker relay relaxes in fault mode. Regarding the relays, there is an audible click on power up so I presume they are engaging on power up. However, if I wait a couple of minutes, I would expect them to relax but there are no further audible clicks while the amp is on. The relax only when I power off again.
It is a Mk1.
When in fault mode switch off and then back on. You should hear all 4 relays pull in. Use a long bladed screwdriver, place the handle end against your ear and the tip on each relay in turn. You will be able to hear them pull in in turn or not.
P851 has the mains power relay on it. LN01, LN02 and LN03 control the loudspeaker outputs.
When in fault mode switch off and then back on. You should hear all 4 relays pull in. Use a long bladed screwdriver, place the handle end against your ear and the tip on each relay in turn. You will be able to hear them pull in in turn or not.
P851 has the mains power relay on it. LN01, LN02 and LN03 control the loudspeaker outputs.
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Unlikely to be LN01-03 as I can't see all of them failing together and a failure in one of them would affect one speaker channel or headphone only. To affect all 3 simmultaneously would take a fault around the TA7317. The L851 seems to be the Class A/AB switch and located on the P851 board near the rear on the LHS of the amp. I can actually see the relay through the to grille. It was sufficient to place my ear to the top grille above it to hear it give a definite click.
You aren't going to learn much about the amplifier mode/protection operation from outside the case. As you can't touch it whilst there is a dispute to be settled, read the several existing threads about PM80+siblings - known issues here by using the forum search button at the top of this page or simply Google for it as a DIYaudio thread/post. These "half class A" models are not easy amplifiers to troubleshoot, as the thread lengths and setup procedures suggest.
With hot running amps, caps in the protection circuitry can dry out and become increasingly temp. sensitive, dropping out the speaker connection out as the amp. warms up. This is usually a considerable time in class AB but class A of course, means a constant toasting for anything near the heatsink and a much higher temperature plateau.
It seems inevitable, that with the narrow main PCB sandwiched tightly between the heatsinks, this or another heat related fault, is eventually going to show up. I'd assume your seller had noticed a problem but had retired the amplifier or was using it in class AB and decided to quit while he was ahead.
BTW, This model is from the Philips ownership period and a much more complex design compared to the PM350 from the Japanese Superscope ownership period. The protection in that model is only a basic current limiter IIRC.
Marantz followers probably know that they are now a budget brand of Kenwood and products from successive design/manufacturer regimes like Marantz has been through, can't really be compared any more than those from other manufacturers.
With hot running amps, caps in the protection circuitry can dry out and become increasingly temp. sensitive, dropping out the speaker connection out as the amp. warms up. This is usually a considerable time in class AB but class A of course, means a constant toasting for anything near the heatsink and a much higher temperature plateau.
It seems inevitable, that with the narrow main PCB sandwiched tightly between the heatsinks, this or another heat related fault, is eventually going to show up. I'd assume your seller had noticed a problem but had retired the amplifier or was using it in class AB and decided to quit while he was ahead.
BTW, This model is from the Philips ownership period and a much more complex design compared to the PM350 from the Japanese Superscope ownership period. The protection in that model is only a basic current limiter IIRC.
Marantz followers probably know that they are now a budget brand of Kenwood and products from successive design/manufacturer regimes like Marantz has been through, can't really be compared any more than those from other manufacturers.
I tend to agree and at the moment it is frustrating until I resolve this with the seller. I had reviewed some of the threads prior to purchase and discovered, amoung other things, that the STK3102 is a weakness in this amp while running in Class A and will benefit from attaching additional cooling fins to the heatsink, something which I indended to do. Little did I imagine it could fail after only a few minutes warm up. There seemed to be quite a bit of heat in both modes and the suggestion that it may be a heat related fault seems does seem most probable. In the meantime, I have been given to beleive that if I send the amp back by trackable means, then I will likely get a refund. The seller has been given the opposite information, namely, that as the amp was working when it arrived, he has fulfilled his side of the contract. If I send it back and get a refund, I will still be out of pocket by some £18-£25 for the postage by RM. Its quite possible that it could be repaired for less than or around that so a difficult decision really. I get the impression form your comments that the amp is not realy worth keeping, or did I mis-understand? The unit that I have has a label that says it was made in Japan. Not sure where Philips manufacture their kit. I was not aware that the Marantz brand is currently owned by Kenwood. Kenwood have a good reputation, but I was not overy impresseed by the Marantz 6000 series amp I heard in Richer Sounds a few months ago.
Hi
I don't single out the PM80 etc. models for criticism. If you have heard and like this one, that's what matters and it's worth the money you paid as long it works. The problem lies in its ageing and how much repair and maintenance work is needed. That much, I don't like. Some guys welcome any opportunity to fiddle with their equipment but when I close the lid, I like to think that is the finish of it and I'm onto the next project.
When owners press old products beyond a fair use-by date, the signs begins to appear in any model. Since heat is the major accelerator of that ageing and breakdown, different types and designs will fare accordingly. Unless suitable uprated parts are specified, tight layouts with poor air flow and parts directly facing heatsinks will fare worse.
For example, a cool running, low power class AB amp may last 40 years and then only require new electrolytics with a clean-up of exposed connectors but a tightly cased class A or high bias AB amp. may be ready for an overhaul within a nominal 10 year life cycle. When capacitors fail, normally stable voltages begin to fluctuate widely and apart from abnormal function, damage to other components can then occur too.
BTW, Philips' own brand models were made variously in Japan, Singapore and Taiwan with Japanese outsourced components IIRC, so I don't think there is any issue with where it was assembled. The product is conceived by the design team itself, and assembled to their specification apart from perhaps local parts/assembly issues beyond their control.
You may be a little over-optimistic with repair costs there. If you need professional help it will certainly cost more. Trying your luck by learning as you go may not prove simple or cheap either, so if it doesn't work now - get a refund whilst ever there is opportunity, whatever the courier cost because there is no assurance you will be able to resolve the problem yourself.
I don't single out the PM80 etc. models for criticism. If you have heard and like this one, that's what matters and it's worth the money you paid as long it works. The problem lies in its ageing and how much repair and maintenance work is needed. That much, I don't like. Some guys welcome any opportunity to fiddle with their equipment but when I close the lid, I like to think that is the finish of it and I'm onto the next project.
When owners press old products beyond a fair use-by date, the signs begins to appear in any model. Since heat is the major accelerator of that ageing and breakdown, different types and designs will fare accordingly. Unless suitable uprated parts are specified, tight layouts with poor air flow and parts directly facing heatsinks will fare worse.
For example, a cool running, low power class AB amp may last 40 years and then only require new electrolytics with a clean-up of exposed connectors but a tightly cased class A or high bias AB amp. may be ready for an overhaul within a nominal 10 year life cycle. When capacitors fail, normally stable voltages begin to fluctuate widely and apart from abnormal function, damage to other components can then occur too.
BTW, Philips' own brand models were made variously in Japan, Singapore and Taiwan with Japanese outsourced components IIRC, so I don't think there is any issue with where it was assembled. The product is conceived by the design team itself, and assembled to their specification apart from perhaps local parts/assembly issues beyond their control.
You may be a little over-optimistic with repair costs there. If you need professional help it will certainly cost more. Trying your luck by learning as you go may not prove simple or cheap either, so if it doesn't work now - get a refund whilst ever there is opportunity, whatever the courier cost because there is no assurance you will be able to resolve the problem yourself.
Ian, that makes a lot of sense. I was thinking worse case scenario is a failed STK3102, which can be sourced for about £20. It may be a lot worse or as simple as a dry joint. Replacing electrolitics, especially the big ones with quality parts can also be costly, so attempting a repair is a risk and I'm not not sure its one I wish to take. If I make every effort to get a refund and in the end I'm stuck with it, then I will have to make the best of the situation and repair myself, but I think I first need to do my best to try and get it refunded. What attracted me to it was the fact that I like the sound of older Marantz amps anyway, and that it has a MM and MC switcheable phono input, which was usefull for future upgrading of the turtable. That is only true if the amp lasts.... There is also the option of a good phono pre-amp. Thanks for your input.
Actually, Marantz isn't a budget brand, and not owned by Kenwood. It's part of DM Holdings (Denon/Marantz merger). There have even been identical Marantz and Denon models spotted recently.
Kenwood is owned by JVC Kenwood Holdings.
None of these old hifi makers really "exist" anymore, it seems. They're all pretty much umbrella brands, selling OEM models from random makers.
You are of course correct, Welcome.
My bad, perhaps if it was Denon I should have checked but a PM7004/ KI Pearl Lite amplifier I bought was apparently assembled and shipped from a Japanese Kenwood manufacturing facility. That may have been only a financial arrangement and the Kenwood association admittedly, was on verbal advice from the dealer's representative.
Otherwise, I have no idea of the claimed Japanese manufacturing origin of the "cheaper" Marantz products we now see. In stereo models, Denon is no longer the force it was, needing heavy discounting here and their "cheaper" models don't seem to enjoy the same enthusiastic reviews of the past in the UK either.
My bad, perhaps if it was Denon I should have checked but a PM7004/ KI Pearl Lite amplifier I bought was apparently assembled and shipped from a Japanese Kenwood manufacturing facility. That may have been only a financial arrangement and the Kenwood association admittedly, was on verbal advice from the dealer's representative.
Otherwise, I have no idea of the claimed Japanese manufacturing origin of the "cheaper" Marantz products we now see. In stereo models, Denon is no longer the force it was, needing heavy discounting here and their "cheaper" models don't seem to enjoy the same enthusiastic reviews of the past in the UK either.
After a couple of messages back and forth I managed to elicit a sympathetic response from the seller, who, apparently is a hifi enthusiast and who only reluctantly sold the amp. Mine was not the first offer either. He apparently had several at a similar price level before he finally decided to part with it. He says that the amp 'never put a foot wrong' and appears genuinely upset at the prospect of having to 'willingly accept the corpse of my old friend being returned to me'. I'm not sure that I would be quite that poetic, but I don't have the heart to return it to him...
It's more likely that's all just a load of BS, intended to make you feel reluctant to return it to him. An honest person would insist that you return it.
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I tend to agree this sentiment. Unless you are a charity for ignorant hi-fi traders and have deep pockets, don't accept sob stories as justification for not getting what you paid for.
Also, don't assume forum members will be able to bail you both out of the problem by talking you through repairs - repairs that are the prime responsibility of the seller. If the other offers were real, let the other guys sort them out. Perhaps they will even be aware of the problem and have a fix. Still, don''t accept this irresponsible reasoning from the seller anymore than paying for rotten food from a grocer because he hadn't checked his stock.
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Well I was in two minds, I have to admit, but en balance, it just seems overstated.
Personally I view a HiFi amp as a tool to produce high quality sound and that when working well and sounding sweet becomes is keeper until something else better comes along. I wouldn't get quite that attached and wax lyrical about it.
From a seller viewpoint, I have also had to recover a faulty item in the past, in this case one damaged in transit. I didn't get compensated by RM either so it was a write off, although I salvaged and sold some of the parts to offset my loss. In the end it was my responsibility to see the buyer right. As the buyer in this case I am therefore continuing to pursue a refund.
However, if I loose the dispute then I will have to come back for help.
Personally I view a HiFi amp as a tool to produce high quality sound and that when working well and sounding sweet becomes is keeper until something else better comes along. I wouldn't get quite that attached and wax lyrical about it.
From a seller viewpoint, I have also had to recover a faulty item in the past, in this case one damaged in transit. I didn't get compensated by RM either so it was a write off, although I salvaged and sold some of the parts to offset my loss. In the end it was my responsibility to see the buyer right. As the buyer in this case I am therefore continuing to pursue a refund.
However, if I loose the dispute then I will have to come back for help.
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Good luck. Was there shipping insurance? If so, keep the box and all packing materials in case you can make a damage claim if you cannot return it.
There will be a deadline on that also. You may want to go ahead with the damage claim, in case the seller refuses a refund, to meet the deadline.
You can also cancel the claim later, if necessary.
Well it seems that I am being blamed for pressing the mode button while the amp was running. I had read about this in a forum and was aware it was not recommended, so I was carefull. Would such an action have blown the amp? It this was true, it seems an odd design decision, especially as there is nothing to warn you. Maybe there is something in the manual, but since I don't have one, had I not read about it elsewhere, I would have been none the wiser. As it is, I was careful, so I do not beleive this to be the cause of the problem.
If you didn't do that, don't let it be an issue. Just state flatly that you did not.
If it was so dangerous to press that button, there would have likely been a warning about that on the back of the amplifier. Product "life-threatening" stuff like this tends to be written on the actual product, rather than in the manual.
And since it's not, it's probably not a big deal. And even if it is, you didn't do it so it's a non-issue.
Since he is apparently trying to put blame on you like that, it seems he may be dishonest. But it may also just be some sort of damage in transit issue.
And since it's not, it's probably not a big deal. And even if it is, you didn't do it so it's a non-issue.
Since he is apparently trying to put blame on you like that, it seems he may be dishonest. But it may also just be some sort of damage in transit issue.
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