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Help!!!!!! Yamaha pm700 question pm1000 Single-Channel Preamps
Old 20th February 2010
  #1
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Help!!!!!! Yamaha pm700 question pm1000

Whats goin on, Gearslutz??? I've been checkin the site out for a minute now & amazingly enough I never posted anything. I hate for my first post to be a technical question & it seems like the piece of gear in question never seems to get many replies on here, but hopefully someone can help.

Heres my situation: I recently obtained a Yamaha PM700 Mixer which, as some may know, was built along the same time as the Yamaha PM1000 and similar mixers. Please don't get on me for going after/spending time on an older unit as opposed to a new "Mackie" or the like: Aside from the fact that i'm a starving musician, i'm planning to use this as a summing mixer due to the transformers on the inputs/outputs (i'm going after that "huge"/colored sound that similar-designed mixers/pres seem to be famous for). Cosmetically, its in beautiful shape, and aside from one of the hinges on the built-in casing, it almost looks brand-new. ANYHOW, it powers up & all lights come on (vu meters, console light), but when I plug in/speak into a dynamic mic, none of the 4 vu meter needles move and I get no sound from the headphone jack. I also tried the talkback button/mic input and same thing (no sound, no needles moving).

We have a couple shops here that could work on it, but I would possibly end up spending more than what I paid for the mixer and I REALLY don't want to do that (ESPECIALLY if it ends up being a small/minor repair that I could have done myself with a soldering iron, some caps/resistors & some solder). Phoenix is a rather small market for music/etc, so you get raped alot here whenever you need a piece of audio gear repaired. Thus, i'm really hoping someone can give me some ideas or gradually walk me thru a repair as time allows. I would GREATLY appreciate it!!! The guy who sold it to me claims (suddenly/AFTER the fact) that back when he used it (for the few times that he did), he had to do something unusual to get it working. But its been so many years, he SUPPOSEDLY doesn't recall what had to be done...

I'm thinking it MUST be something simple because the mixer is in great shape cosmetically & I seriously doubt it had ever been dropped. I was thinking maybe an output transformer could cause this (of which I have access to several replacements as we speak)... However, while i'm NO expert at electronics/reading schematics, looking at the schematics it doesn't seem that the output transformers would have anything to do with no sound coming from the headphone out (&/or no movement from the vu meter needles). So i'm STUMPED!!! Visit http://www2.yamaha.co.jp/manual/pdf/...ers/PM700E.pdf to pull up the manual or see below (schematics are on pg. 9). I also included one picture of my unit below. If you need me to take more pictures, I can most certainly do that. I really hope someone can help me. I'll be checking back frequently for any replies. Thanks in advance!!!!
Attached Thumbnails
Help!!!!!! Yamaha pm700 question pm1000-pm700-021910.jpg  
Attached Files
File Type: pdf PM700E.pdf (1.13 MB, 384 views)
Old 21st February 2010
  #2
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BUMP

BUMP!!! Wow, did I post in the wrong section??? LOL SOMEONE must have some type of experience with this mixer. Any assistance would be GREATLY appreciated!!!
Old 4th March 2010
  #3
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BUMP!!!

BUMP!!!
Old 4th March 2010
  #4
Gear Addict
Okay...I'll bite.

We're gonna run a few tests. You're going to need a microphone, a CD player/iPod, some headphones and maybe a powered monitor of some sort. You're also going to need a variety of 1/4", RCA and XLR cables/adapters.

The first thing we need to do is to identify the shortest possible path from an input to an output of the board. To figure that out you need to open up that PDF in your first post and take a look at page 9 of the manual (11 of the PDF).

The simplest way to listen to the board is with heaphones so we'll find a fast path to the headphone output. The headphone amp has a selector switch (page 4 of the manual item 16) and we'll be using that to select which buss we want to monitor. Looking at the diagram on page 9 of the manual, there are some sub-ins that go straight to the mix busses and can be tapped to go to the headphone amp.

Page 6 of the manual shows you where the sub in jacks are. They're a clearly labeled group of four 1/4" jacks on the back. Let's plug the CD player/iPod into the program L/R sub in jacks, set the the headphone select switch to "PGM", turn the headphone volume all the way down. Get your CD player/iPod cranking and then start turning up the headphone volume. You should hear something now. If so...Life's good...Check the Mon1/2 inputs by plugging the in the iPod/CD player into the Mon1/2 inputs and flipping the headphone selector switch to the M1/M2 positions. Assuming that's good, you now know that your headphone amp works and that you can get signal into the board.

Now...What do you do if that doesn't work? If you can't get tunes cranking through your phones in the above scenario, then my guess is you've got a bad power supply. If you don't have a DMM/DVM then you either take it to someone who does and knows how to use it, or you buy one your self and learn how to use it. They're essential if you want to get into tech work. You'll want to tear into the board and test the power supply outputs. You need +-22V and +-15V according to the manual.

If you do decide to tear into this board you'll probably want a service manual with the schematics in it. Otherwise you're going to be tracing out stuff and probing blindly around the board.

Have fun up to this point and I'll check back in on your progress later. This will take you about 5 minutes to do and took me about 30 minutes to write.
Old 4th March 2010
  #5
Lives for gear
 

You can't troubleshoot a problem without the unit in hand or at least more info than "it doesn't work". You could have a pad part or you might even have a setting wrong. Get someone to help you there locally. Maybe get a sound person friend to at least see if you have it setup right.

One thing I did notice in the pic. The gains are set all the way down. Is this how you tested it with a mic?
Old 10th March 2010
  #6
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Smile UPDATE/@effitall

Quote:
Originally Posted by effitall View Post
Okay...I'll bite.

We're gonna run a few tests. You're going to need a microphone, a CD player/iPod, some headphones and maybe a powered monitor of some sort. You're also going to need a variety of 1/4", RCA and XLR cables/adapters.

The first thing we need to do is to identify the shortest possible path from an input to an output of the board. To figure that out you need to open up that PDF in your first post and take a look at page 9 of the manual (11 of the PDF).

The simplest way to listen to the board is with heaphones so we'll find a fast path to the headphone output. The headphone amp has a selector switch (page 4 of the manual item 16) and we'll be using that to select which buss we want to monitor. Looking at the diagram on page 9 of the manual, there are some sub-ins that go straight to the mix busses and can be tapped to go to the headphone amp.

Page 6 of the manual shows you where the sub in jacks are. They're a clearly labeled group of four 1/4" jacks on the back. Let's plug the CD player/iPod into the program L/R sub in jacks, set the the headphone select switch to "PGM", turn the headphone volume all the way down. Get your CD player/iPod cranking and then start turning up the headphone volume. You should hear something now. If so...Life's good...Check the Mon1/2 inputs by plugging the in the iPod/CD player into the Mon1/2 inputs and flipping the headphone selector switch to the M1/M2 positions. Assuming that's good, you now know that your headphone amp works and that you can get signal into the board.

Now...What do you do if that doesn't work? If you can't get tunes cranking through your phones in the above scenario, then my guess is you've got a bad power supply. If you don't have a DMM/DVM then you either take it to someone who does and knows how to use it, or you buy one your self and learn how to use it. They're essential if you want to get into tech work. You'll want to tear into the board and test the power supply outputs. You need +-22V and +-15V according to the manual.

If you do decide to tear into this board you'll probably want a service manual with the schematics in it. Otherwise you're going to be tracing out stuff and probing blindly around the board.

Have fun up to this point and I'll check back in on your progress later. This will take you about 5 minutes to do and took me about 30 minutes to write.
----------------

Man, you have no idea how much I appreciate the help!!!! Sorry for my delayed response: I had to wait a moment as one of the screw heads stripped during my first attempt to get inside the unit... I'll give a final/brief summary w/ pictures in a moment (which will hopefully help someone else in the future), but it turns out that the screw that was stripped wasn't even a screw that was necessary to open the unit (DOOOPH lol)... Bought a new power drill+screw extractor bit & none of the above was really needed... Woulda known that had I had a service manual that explained the proper way to get this thing open...

Anyhow, $70 (+) dollars and some bumps/bruises/scratches later, I got inside the unit and came to learn that 2 out of 5 internal fuses were blown. Of course I had no idea that this model even had fuses in it (aside from the externally-accessible main power fuse), but you live & learn. Replaced the 2 fuses & PROBLEM RESOLVED... I now have sound & moving vu needles :-)... Will post some pics & a short summary of the fix AND the PROPER way to get inside this unit shortly. Thanks again for your time man, I REALLY appreciate it!!!!
Old 10th March 2010
  #7
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Wink UPDATE/@mixedupsteve

Quote:
Originally Posted by mixedupsteve View Post
You can't troubleshoot a problem without the unit in hand or at least more info than "it doesn't work". You could have a pad part or you might even have a setting wrong. Get someone to help you there locally. Maybe get a sound person friend to at least see if you have it setup right.

One thing I did notice in the pic. The gains are set all the way down. Is this how you tested it with a mic?
----------

My apologies, Steve!!! Aside from the simple fact that I felt I typed somewhat of a novel, I do believe I gave a little more information other than a simple "it doesn't work" (or at least I TRIED to :-). After quietly observing the posts on this site for several years, one of my biggest fears in regards to posting on the site was the fear that if I asked certain types of questions, some people would automatically assume that i'm a "newbie" to everything and it would be downhill from there. Case-in-point: No, I did not test the board with the gains set all the way down (lol). I tested it with all faders/gains up, each channel, with the input gain selector in every available position. I'm no expert, but I do know how to perform basic troubleshooting at least up to the point when you have to start dealing with complex electronic parts/terminology/etc.

In any event, it turned out to be a simple solution (2 blown fuses on the internal power supply board), as stated. I'll be posting a brief summary w/ pictures in a moment that will hopefully help someone else in the future. Thanks for stopping by and leaving some comments! For a minute, I was worried that I was posting in the wrong section :-) Until next time, have a great one!!!
Old 10th March 2010
  #8
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Update summary/yamaha pm700 "how-to"

So i'm on a time-crunch, but wanted to post a brief update/summary to my findings with this mixer... As stated in the original post, I was having an issue where it would power up but the VU meter needles did not move and no sound would come thru.... I tested thoroughly and initially could not figure out what was wrong... LONNNG story short: It turned out to be 2 blown 1.5AMP 250V fuses INSIDE the mixer (go figure). Of course I had no idea that this model had 5 fuses inside of it (aside from the externally-accessible main power fuse), but you live & learn. Replaced the 2 fuses & PROBLEM RESOLVED... I now have sound & moving vu needles :-).

The main problem I ran into when getting inside the unit is that I absolutely DID NOT know the proper way to open it up. The standard owners manual sadly does not include this info and I did not have access to a service manual. I went about it COMPLETELY wrong on the 1st attempt, unscrewing screws that had NOTHING to do with opening this unit, buying $70+ dollars worth of materials (power drill, screw extractor [for a screw that had a stripped head]), and I spent a whole lot more time on it than I would have had I known the PROPER way to access the internals (which, embarrassingly enough is VERY simple). Hopefully this information (with included pictures) will save someone some time in the future:

HOW TO ACCESS THE INTERNALS OF A YAMAHA PM700 MIXER:

VERY basic: There are four bolts underneath the front end of the unit (2 on each side [see picture])... These bolts hold the top portion in place, so when you remove them, the top opens up like a car hood (you have to lift it from the wooden sidings). Once open, you'll notice that there are brass metal brackets on each side of the unit that will prop the top up for you, as seen in the picture.

Inside, you'll notice the power supply circuit board with the 5 fuses (see picture). In my case/as stated, 2 of these 5 fuses had blown (there are 3 1.5AMP 250V fuses and 2 1.0AMP 250V fuses)... I'm no expert in electronics, but this was actually THE source of why I had no sound & no movement from the VU meter needles. Take a look at the close-up shot for a better view of the power supply circuit board.

Finally, take a look at the picture of the hinges on the back of the unit. One hinge type (4 total) supports the top as you open up the unit, and the other (2 total) supports the removable console "flight case" lid.

There you have it folks!!!! Checked every channel & while the pots are scratchy, every channel is working and the "talkback" channel is SOO cool!!! I'm so happy that I didn't have to take this guy to the repair shop. I'm so glad it was something as simple as a blown fuse... Sadly, my ProTools hard drive went out shortly after resolving this issue (just my luck, lol)... But once i'm back up & running, I can't wait to start running my mixes thru this!!!! I'll also be using one channel as my mic tracking channel until I can afford a Neve 1073. I'll keep everyone updated & i'll try to post more often!!!!! If anyone else has this mixer and can share some thoughts, i'd LOVE to hear (hit me up :-)... Till next time, have a great one!!!!
Attached Thumbnails
Help!!!!!! Yamaha pm700 question pm1000-cimg1814-info.jpg   Help!!!!!! Yamaha pm700 question pm1000-cimg1802-info.jpg   Help!!!!!! Yamaha pm700 question pm1000-cimg1804-info.jpg   Help!!!!!! Yamaha pm700 question pm1000-cimg1816-info.jpg  

Last edited by traxkeyzvox; 10th March 2010 at 10:26 PM.. Reason: typo
Old 10th March 2010
  #9
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Smile Update summary/yamaha pm700 "how-to"

ALSO: If ANYONE has a service manual for this mixer, please let me know! I'd love to have one. Thanks (see summary above)
Old 27th October 2011
  #10
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10/27/11 update****

FYI: This mixer has been SOLD... Actually sold it a few months ago... Kinda miss it but had to let it go... Thanks!!!! -trax
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