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Recapping and modding a Yamaha PM1000 - lots of advice, please Consoles
Old 16th September 2011
  #1
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Recapping and modding a Yamaha PM1000 - lots of advice, please

I recently bought a Yamaha PM1000 from a friend for $50. I am planning to recap and mod this console myself since I've been reading that it's fairly straightforward in its design, thus being a great way to learn. I am a complete newb at this stuff, though, so I have a couple of questions and points/issues where I need opinions from folks who know more than me:

1) After being off for about a month (maybe even more, I'm not sure), the console powered up fine and didn't have any noise or buzzing the first time I tested it. It did, however, become increasingly noisy and buzzy when I had it in on in my studio for longer. Am I right in assuming that this is likely an issue with old caps.

2) See #1. It seems like the noise and buzz is coming from the master section. The buzz/noise increases and reduces as I pulled the master faders up and down. The input channels didn't add or reduce any buzzing when turned up or down while the master faders were left at unity ("7", according to the manual). Does this seem correct? Would I be correct in assuming that it would be best to recap the master section first?

3) The phantom power doesn't seem to be working. Nothing happens when I flip the switch to the "on" position, so I'm not sure if it's an issue with the switch or if there is something else wrong.

4) Should it be OK if I just recapped the input- and master/monitor-sections or do I need to recap the power supply, talkback/oscillator and headphone sections too?

5) On one of the input-modules (Ch 11) I get only buzz and a very quiet, thin-sounding signal. When I'm turning the EQ-knobs and work the fader they all seem to do what they are supposed to, though. What could this be?

6) I want to add direct outs to the first 8 input channels. I know very little about transformers at this point (although I'm learning...), but I've seen the transformer in the link recommended for the direct outs. Will it work?

http://www.edcorusa.com/products/143-wsm600-600.aspx

7) Lastly, there are a few scratchy pots and faders (although I already know the faders in this console are really just pots). Should normal contact cleaner work for this?

I've modded mics and a couple of pedals and things before but, while I'm pretty excited about doing this, I do feel a little overwhelmed. I would really appreciate any advice a lot.
Old 16th September 2011
  #2
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Bump
Old 17th September 2011
  #3
Gear Nut
 

Haven't been here in ages.

I'm really busy with my R&D day gig, but I'll throw you a couple bones:

First, see if your friend has a $50 oscilloscope to see you.

Actually, scratch that. If you're going to use it to get the PM1000 running, you probably want a scope that's working to at least 85%...it's hard to troubleshoot a scope when your only scope is glitchy.

Quote:
The phantom power doesn't seem to be working.
Is there 48V at the supply? Is there 48V at the switch?

Quote:
On one of the input-modules (Ch 11) I get only buzz and a very quiet, thin-sounding signal.
The rotary switch for gain is the first suspect.

Quote:
Should it be OK if I just recapped the input- and master/monitor-sections or do I need to recap the power supply, talkback/oscillator and headphone sections too?
Recapping the power supply will probably have the most benefit. It's the component that all of the other pieces have in common. The better it is, the better they are.

Quote:
Should normal contact cleaner work for this?
Contact cleaner is a two-edged sword. It might get things working in the short term, but it can cause long term problems. The lubricant in some of them seems to cause more dirt to stick. Once you start, you kinda have to keep using it.

Quote:
I've seen the transformer in the link recommended for the direct outs. Will it work?
Sure. Almost any 600:600 transformer will work. Some are better than others. How good you need is entirely up to you. If you want really gooey, low headroom, and bandwidth constrained, the Edcor might be a little too good.
Old 17th September 2011
  #4
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Thanks for the reply. Much appreciated!!!

I've opened the console and it looks like the power supply is all but original. In fact, I'm not seeing anything that resembles the power supply I see in photo's of this console that I've found on the internet. Very crappy-looking work too. Am I correct in assuming that I might just have to get a completely new power supply? If so, where do I begin to look? Any links?
Old 18th September 2011
  #5
Gear Nut
 

Very hard to tell anything about the supply from the description. Are there any kind of markings regarding manufacturer, ratings, etc?

Measure the Voltage on its outputs - both AC and DC. The DC value should be a solid 44V. The AC value should be 0V.

If there's a current rating, I think you need 2A @ 44V for a 16 input PM1000...double that for a 32. If it's not up to the task, it might be responsible for some of your symptoms.

The original PM1000 supply is pretty primitive, and you can get better, more modern ones from several manufacturers. Power One, Acopian and Condor come to mind off the top of my head. To get 44V, you'd probably start with a 48V supply, and adjust the trimmer down to 44V.
Old 19th September 2011
  #6
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CZ101's Avatar
 

Quote:
Originally Posted by KillerV View Post
Thanks for the reply. Much appreciated!!!

I've opened the console and it looks like the power supply is all but original. In fact, I'm not seeing anything that resembles the power supply I see in photo's of this console that I've found on the internet. Very crappy-looking work too. Am I correct in assuming that I might just have to get a completely new power supply? If so, where do I begin to look? Any links?
There are lots of options for upgrading from the stock PSU, and after toying with the idea of using a Condor + Power-One combo, I ended up throwing in the towel and going all Acopian.

Right now I'm in the process of racking and wiring up four separate Acopian "goldbox" linear regulated PSU's for the PM-1000's 44VDC, 48VDC, 12VDC and 13VDC rails.

I got these supplies off eBay for around $200 total (minus AC/DC wiring, empty rack enclosure, replacement 'lytic caps and other parts), and to get anywhere near an equivalent multi-output rig directly from Acopian - they quoted over 3 grand and this would have been minus cool perks like ampere and voltage meters (not to mention a 6A rather than 15A rating for the 44V supply heh)!

Acopian seems like a good company to deal with though - buying direct would definitely be worth it if money were no object. They were very helpful in explaining how to lower output voltage from 48V to 44V. So for the 44V supply, it will require this plus one more simple mod (removal of C7).
Old 19th September 2011
  #7
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Thanks again for all the advice so far. Quick update:

I checked the voltages at the power rails and the phantom power switch. It really look quite bad. There is nothing at the phantom power swith and only about 22V at the rails. I say "about" because the readings kept changing. At one point it was as low as 12V. The power to the headphone section and meter bulbs seems to have been disconnected.

I've ordered a new power supply, which should arrive by the end of the week. A tech is going to install it for me, after which I'll start on the rest of the work I originally planned.
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