Figured I'd try here first...

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  • Alaric
    Ultra Senior Member
    • Jan 2006
    • 4143

    Figured I'd try here first...

    My beloved PM7200 has begun to exhibit an issue. At higher volume levels it starts dropping out, like a CD skipping. It does this regardless of source or input selection so I'm assuming it's a problem with the output/amplification. It sat in its box in a basement for 3 years or so before I got it back. Would that have affected the capacitors? When the amp is exercised vigorously () it just cuts out, like the signal is being dropped several times and eventually just stops altogether. Front panel lights stay on, no flickering or indication of a problem there, and if I turn down the volume down a little it goes away immediately.

    So does anyone have an idea what may be up?
    Lee

    Marantz PM7200-RIP
    Marantz PM-KI Pearl
    Schiit Modi 3
    Marantz CD5005
    Paradigm Studio 60 v.3
  • Kevin P
    Member
    • Aug 2000
    • 10809

    #2
    Open it up and inspect the electrolytic capacitors for bulging or leaking.

    Comment

    • JonMarsh
      Mad Max Moderator
      • Aug 2000
      • 15259

      #3
      Also, that sounds more like protection circuit behavior to me... double check your speaker leads and connections, make sure there are no stray bits of wire.
      the AudioWorx
      Natalie P
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      Resistance is not futile, it is Volts divided by Amperes...
      Just ask Mr. Ohm....

      Comment

      • Alaric
        Ultra Senior Member
        • Jan 2006
        • 4143

        #4
        Originally posted by Kevin P
        Open it up and inspect the electrolytic capacitors for bulging or leaking.
        Caps were all good on recent visual inspection, I was just wondering if there was something I might be missing there.

        Also, that sounds more like protection circuit behavior to me... double check your speaker leads and connections, make sure there are no stray bits of wire.
        Banana plugs on both ends, but I'll check. I still have to get my SACD player fixed, too. (Doesn't like to read discs all the time).
        Lee

        Marantz PM7200-RIP
        Marantz PM-KI Pearl
        Schiit Modi 3
        Marantz CD5005
        Paradigm Studio 60 v.3

        Comment

        • Alaric
          Ultra Senior Member
          • Jan 2006
          • 4143

          #5
          OK, no stray wires. I did find I had the selector set to Class A (25 watts) and turning that off helped. It still goes silent at the top of the volume range, but here's where it gets sticky. I'm using my motherboard as a pre preamp (CD player rarely works anymore. ) and the volume knob on the Marantz is only at about the 1:00 o'clock position. So I still think the issue is the Marantz, as it fails at volume levels it previously attained in effortless fashion. I suppose I can change the motherboard op amp (currently a LM4562) and see if that's the issue or contributing to it.
          Lee

          Marantz PM7200-RIP
          Marantz PM-KI Pearl
          Schiit Modi 3
          Marantz CD5005
          Paradigm Studio 60 v.3

          Comment

          • Kevin P
            Member
            • Aug 2000
            • 10809

            #6
            Maybe your motherboard is overdriving the Marantz? Do you have another component to try, like a CD, DVD, BD player or other device with a standard line out RCA?... or coax/toslink digital?

            Comment

            • Alaric
              Ultra Senior Member
              • Jan 2006
              • 4143

              #7
              It does the same thing with my SACD player. It's just getting more difficult to get said disc player to read discs and takes a while sometimes.
              Lee

              Marantz PM7200-RIP
              Marantz PM-KI Pearl
              Schiit Modi 3
              Marantz CD5005
              Paradigm Studio 60 v.3

              Comment

              • Alaric
                Ultra Senior Member
                • Jan 2006
                • 4143

                #8
                Looked inside and nothing obvious like bulging caps, cleaned the (minimal) dust out of it. Tried headphone outs and same thing. It cuts out when the bass kicks in at any volume above mid level. Anyone know a good repair place?

                Tried another computer, same thing. The amp cuts out under any appreciable load and it sucks to be me.

                Edit/update: If I try the right or left channel with the Balance knob the amp is a little more tolerant, but will still drop out when the load goes up, coming back in when the signal drops off. This is across all inputs and with different sources. Could a speaker crossover going south put too high a load on the amp and cause the protection circuit to kick in? I replaced the tweeter domes a few months ago; is there a chance that I screwed up the install?
                Last edited by Alaric; 28 August 2019, 01:35 Wednesday.
                Lee

                Marantz PM7200-RIP
                Marantz PM-KI Pearl
                Schiit Modi 3
                Marantz CD5005
                Paradigm Studio 60 v.3

                Comment

                • Kevin P
                  Member
                  • Aug 2000
                  • 10809

                  #9
                  If it were the crossover, it would only be happening on one channel, unless both crossovers are bad. Also if you're using headphones and not speakers, the crossovers would be moot.

                  Sounds to me like a power supply issue. It's not supplying enough current to drive the amps under load. If you have a multimeter and can locate the power rails, check the voltages on them while the amp is playing. Turning the balance control to one side reduces the load on one channel, allowing more power to reach the other, hence the "increased tolerance".

                  Comment

                  • Alaric
                    Ultra Senior Member
                    • Jan 2006
                    • 4143

                    #10
                    Yeah, the transformer has some discoloration in the resin at the corners of the base-it's black. I guess I'll see how much Marantz wants for a new transformer. I can easily see the connections so it would be a simple desolder/resolder job.

                    Hey, Kev! I think I found a fix for your DVD player issue! I'll post it in the thread as soon as I find it. LOL
                    Lee

                    Marantz PM7200-RIP
                    Marantz PM-KI Pearl
                    Schiit Modi 3
                    Marantz CD5005
                    Paradigm Studio 60 v.3

                    Comment

                    • Alaric
                      Ultra Senior Member
                      • Jan 2006
                      • 4143

                      #11
                      I'm open to any tips for checking my amp. I picked up a couple 100w/8 ohm resistors and some banana plugs to make dummy loads so I can start checking things with a meter, but I'm not sure what/where to check or what I'm looking for. I'll pull it out of the system when (if) my Cambridge Audio amp arrives today.
                      Lee

                      Marantz PM7200-RIP
                      Marantz PM-KI Pearl
                      Schiit Modi 3
                      Marantz CD5005
                      Paradigm Studio 60 v.3

                      Comment

                      • Alaric
                        Ultra Senior Member
                        • Jan 2006
                        • 4143

                        #12
                        OK, update time. The closest Marantz service center to me is Huntington friggin' Beach, CA. S early next month I'll be shipping my 30 lb. wounded music warrior there (Adam's Electronics). Reviews seem to be positive by a good margin and they will use Marantz parts (And I will verify that afterwards.)

                        I know when I'm in over my head and that time is now. LOL I'm very much hoping I'll get my old SQ back with a freshened up/repaired amp. I might look in to an upgrade next year, after Christmas and birthdays, and pass it along to my daughter then. She's already drooling.

                        edit: Can you believe I'm talking about my 19 year old daughter??? She'll be 20 in February. She was 6 years old when I signed up here. I remember telling you guys about her wanting me to play The Beatles White Album when she was 8, so she could stand on my feet and dance with me. She can't do that anymore, she's about 5'9" tall! Where in Hell does the time go??? When did my little girl grow up??? You guys with youngsters, read this paragraph over and over until it sinks in. Trust me on this.
                        Lee

                        Marantz PM7200-RIP
                        Marantz PM-KI Pearl
                        Schiit Modi 3
                        Marantz CD5005
                        Paradigm Studio 60 v.3

                        Comment

                        • ergo
                          Senior Member
                          • Mar 2005
                          • 675

                          #13
                          This is wise if you have only little experience. There is the mains voltage and also secondary voltages for amps are also relative high, so one needs to be careful in there

                          My suggestion would have been to follow to instructions on Page 34 of service manual for re-adjusting the DC offset and bias voltages.


                          Page 16 bottom right shows the protection circuit based on TA7317P. Thats a specialized chip for the job. From schematic I see it monitoring the current through the power transistors and a DC in output. No over temperature sensor. So DC offset and bias voltages might both influence the working of this part.

                          Comment

                          • Alaric
                            Ultra Senior Member
                            • Jan 2006
                            • 4143

                            #14
                            My temperature concerns are the potential for having overheated the amp and caused damage. What appears to be some kind of resin around the EI transformer is black and burnt looking, and I assume the resin came from the transformer itself.

                            While I can handle a lot of minor electrical and electronic repairs, my most useful skill is knowing when my skills run out. At this point I'm better off letting a factory trained professional bring it up to snuff and then caring for it until I pass it on. My daughter and I have a lot of memories in that amp and I'd like her to get many years of enjoyment out of it. And maybe think of her old Dad when a Beatles song comes on.
                            Lee

                            Marantz PM7200-RIP
                            Marantz PM-KI Pearl
                            Schiit Modi 3
                            Marantz CD5005
                            Paradigm Studio 60 v.3

                            Comment

                            • Alaric
                              Ultra Senior Member
                              • Jan 2006
                              • 4143

                              #15
                              Status update:
                              My girlfriend really liked the Cambridge AM5. So much, in fact, that it's now hers. LOL And she wants to build a speaker kit. Wish I'd met her years ago. That left me in need of amplification, so I went back to Cambridge Audio. Well, Audiogon actually, but I picked up the now discontinued Topaz SR20 for $300. It seems underrated at 100 wpc, AM/FM receiver and integrated DAC. It sounds great, very clean and technically outstanding but it lacks the body and smoothness of the Marantz. I could happily live with the Cambridge for life if I hadn't gotten very revealing speakers. The Marantz knocked the sharp edges off them without sacrificing detail, a very synergistic pairing.
                              However, repairing the Marantz is on hold for several months so I can handle Christmas and birthdays. I can definitely make do with the British powerhouse for that long. It's a new take on my music and I'm thoroughly enjoying the discovery at this late stage. Imagine! Surprises from my music collection!

                              If anyone is looking for a second system without breaking the bank I can heartily recommend either one. The AM5 has the sweeter sound, very musical if your speakers can be bright or "shouty". I think it would be a great pairing with some Klipsch horns. It's also very forgiving of less than stellar material. The SR20 is less forgiving, but it grabs the drivers by the scruff of the neck and bends them to it's considerable will.

                              For your edification, my girlfriend approving of this amp is epic. I had to talk her in to the $27 Lepai she's been using. "$25 for an amplifier!? Are you crazy???" "$50 for SPEAKERS???" When she heard the little Topaz AM5 she said "OK, that amp is worth $100". I almost fell off the couch. Or ravaged her. It was touch and go for a few moments. In the end I just gave her the amp.
                              Lee

                              Marantz PM7200-RIP
                              Marantz PM-KI Pearl
                              Schiit Modi 3
                              Marantz CD5005
                              Paradigm Studio 60 v.3

                              Comment

                              • Alaric
                                Ultra Senior Member
                                • Jan 2006
                                • 4143

                                #16
                                Update on the replacement amps. The SR20 receiver is much more likely to show flaws in your equipment chain or (especially) source material. It's been so long since I had any gear at home to do a comparison that I forgot one of my favorite music genres is rife with bad recordings, bad production, bad mixing, and worst of all D) All of the above. The 100 watter will make those issues very evident, where the 25 watt AM5 is much more forgiving. It doesn't seem to lack detail, but you do have to work a little harder to hear that last few percent. It makes a lot of low SQ music fun to listen to for the music's sake while the SR20 seems more willing to criticize your choices. I could happily live with both and split critical listening and fun time between them. The Marantz will be back, though. It combines the best traits of both the CA amps for me. More than enough raw power, detailed, and lets marginal recordings sound their best.
                                Lee

                                Marantz PM7200-RIP
                                Marantz PM-KI Pearl
                                Schiit Modi 3
                                Marantz CD5005
                                Paradigm Studio 60 v.3

                                Comment

                                • Alaric
                                  Ultra Senior Member
                                  • Jan 2006
                                  • 4143

                                  #17
                                  Old thread, but I have new info. Jon nailed it-the speaker protection board had 3 of 4 bad caps. The PCB was thin and way too delicate and my junk soldering iron and skills were not up to the task. So I made a hash of the board, which is long since made unavailable from Marantz. So the PM 7200 is dead.
                                  Being a fan of the Marantz "house sound" I went looking for an affordable replacement. I didn't exactly hit "affordable" but I pulled the trigger on a used PM-KI Pearl. Big and heavy beast of an amp, but it provides everything I loved about the PM 7200 and none of the things I....didn't love as much. LOL Paired with a Schiit Modi 3 it has me going through music I haven't listened to in a long time. The big Cambridge receiver about soured me on music. It worked great, plenty of power, but it had an almost Bryston like quality. Dry, emotionless, but lots of detail. It was just a poor match with my speakers and my preferences. It just sounded two dimensional. The new (to me) Marantz sounds alive, happy to be playing music. It doesn't want to critically examine every note, even though it outshines the Cambridge by a wide margin in detail and clarity.
                                  So, until I can find a solution to the PM 7200 issue it's in a box in my closet. RIP, buddy. We had a lot of good times together.
                                  Lee

                                  Marantz PM7200-RIP
                                  Marantz PM-KI Pearl
                                  Schiit Modi 3
                                  Marantz CD5005
                                  Paradigm Studio 60 v.3

                                  Comment

                                  • JonMarsh
                                    Mad Max Moderator
                                    • Aug 2000
                                    • 15259

                                    #18
                                    Originally posted by Alaric
                                    Old thread, but I have new info. Jon nailed it-the speaker protection board had 3 of 4 bad caps. The PCB was thin and way too delicate and my junk soldering iron and skills were not up to the task. So I made a hash of the board, which is long since made unavailable from Marantz. So the PM 7200 is dead.
                                    Being a fan of the Marantz "house sound" I went looking for an affordable replacement. I didn't exactly hit "affordable" but I pulled the trigger on a used PM-KI Pearl. Big and heavy beast of an amp, but it provides everything I loved about the PM 7200 and none of the things I....didn't love as much. LOL Paired with a Schiit Modi 3 it has me going through music I haven't listened to in a long time. The big Cambridge receiver about soured me on music. It worked great, plenty of power, but it had an almost Bryston like quality. Dry, emotionless, but lots of detail. It was just a poor match with my speakers and my preferences. It just sounded two dimensional. The new (to me) Marantz sounds alive, happy to be playing music. It doesn't want to critically examine every note, even though it outshines the Cambridge by a wide margin in detail and clarity.
                                    So, until I can find a solution to the PM 7200 issue it's in a box in my closet. RIP, buddy. We had a lot of good times together.

                                    Well, that's very good news Alaric, that you have a new performer that is making you happy!
                                    Isn't it funny how electronics can have such an impact on dimensionality and engagement in playback? I've been wrestling with that since the mid 70's, but many folks still haven't heard a system that does some of that stuff "right".

                                    I've got a lot of stuff to sort through and figure out how I want to setup, and it's looking like I'll be putting together three systems, of a sort- one for the living room with a minimal visual footprint to keep Liubov happy, one for a music learning/rehearsal room to handle monitoring and playback chores, and a higher end one for evaluating components and speakers. Where that is going to go I haven't quite figured out yet- probably won't until we get around to buying a house, not in the rental we've got now.

                                    I've got a Marantz SACD player I need to dust off and listen to with components I'm familiar with to see how it fits in the pantheon of performance.

                                    Oh, and probably both the living room system and rehearsal system will be line arrays- two way. Sensitivity and power handling being the marquee features, as well as LF extension (this array design will likely have a crossover frequency of about 300Hz).
                                    the AudioWorx
                                    Natalie P
                                    M8ta
                                    Modula Neo DCC
                                    Modula MT XE
                                    Modula Xtreme
                                    Isiris
                                    Wavecor Ardent

                                    SMJ
                                    Minerva Monitor
                                    Calliope
                                    Ardent D

                                    In Development...
                                    Isiris Mk II updates- in final test stage!
                                    Obi-Wan
                                    Saint-Saƫns Symphonique/AKA SMJ-40
                                    Modula PWB
                                    Calliope CC Supreme
                                    Natalie P Ultra
                                    Natalie P Supreme
                                    Janus BP1 Sub


                                    Resistance is not futile, it is Volts divided by Amperes...
                                    Just ask Mr. Ohm....

                                    Comment

                                    • Alaric
                                      Ultra Senior Member
                                      • Jan 2006
                                      • 4143

                                      #19
                                      Ah, my Marantz SACD player! Also in a closet. It has the dreaded "no disc" syndrome. I think I read the fix is a simple resistor across two pins of a ribbon cable connector. Considering the mess I made of the amp, I'm more than a little reluctant to dive in to it. The SA8260 was such a wonderful sounding little unit, too. With a shockingly good headphone section with volume control.
                                      My daughter was supposed to get my PM 7200, so I'm pretty disappointed about that. In the interim I got her a Marantz PM5005. She may have to settle for inheriting the Pearl someday. Although, if my tinnitus continues current trends she may get it sooner. The noise floor is starting to intrude on my regular hearing instead of just keeping me awake at night. Old age is not for the weak.

                                      Line arrays-oooooh. Power handling and sensitivity? Now I'm curious as to what you'll be driving them with. SET? Parasound JC5? Just those two little descriptors make for extremely versatile speakers.

                                      It's good to see retirement hasn't made you too sedentary. I think the only dust in your vicinity will be the cloud kicked up behind you. :alol:
                                      Lee

                                      Marantz PM7200-RIP
                                      Marantz PM-KI Pearl
                                      Schiit Modi 3
                                      Marantz CD5005
                                      Paradigm Studio 60 v.3

                                      Comment

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