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Fixing a buzzing transformer in a JX-3P
Old 14th March 2011
  #1
Gear Nut
 

Fixing a buzzing transformer in a JX-3P

I've recently picked up a JX-3P for a great price on ebay, but the PSU/transformer is buzzing like a fridge! I can only just about tolerate the sound of it for around 30-45 mins before i have to turn it off.

I've had a little search around and saw a few other threads regarding similar issues, and so far I've read about making sure that the transformer is secure and potentially stopping the buzz with some rubber grommets.

Would anyone be able to offer any advice on how to go about identifying the cause of the buzz and break down the area's of the transformer i should be looking at? I have some experience fixing data sliders, knobs, keys and the like, but am not familiar with power supply's at all. Keen to get stuck in though!

Would really apprciate any input.

Cheers guys,
Old 14th March 2011
  #2
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GoldMember's Avatar
Quote:
Originally Posted by polymono View Post
I've recently picked up a JX-3P for a great price on ebay, but the PSU/transformer is buzzing like a fridge! I can only just about tolerate the sound of it for around 30-45 mins before i have to turn it off.

I've had a little search around and saw a few other threads regarding similar issues, and so far I've read about making sure that the transformer is secure and potentially stopping the buzz with some rubber grommets.

Would anyone be able to offer any advice on how to go about identifying the cause of the buzz and break down the area's of the transformer i should be looking at? I have some experience fixing data sliders, knobs, keys and the like, but am not familiar with power supply's at all. Keen to get stuck in though!

Would really apprciate any input.

Cheers guys,
PS Audio - Humbuster III : More Info
Old 15th March 2011
  #3
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Xero's Avatar
probably bad capacitors/rectifiers....

cleaning the power ain't gonna do squat for failing components in vintage equipment, ignore that troll...
Old 15th March 2011
  #4
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LeeYoo's Avatar
 

Are we talking about mechanical transformer buzzing, or electrical buzzing in the sound..
Old 15th March 2011
  #5
transformers buzz because they are made of plates of metal held together with lacquer. the metal vibrates at the frequency of the incoming voltage. in a new transformer this is fine, but after a while the lacquer in-between the metal plates become less flexible, at which point the vibrating metal plates have room to move. sometimes the buzzing is the transformer block vibrating against the housing on the floor panel. and sometimes its due to the plates rubbing. in both cases the base plate and floor panel will amplify the sound

solutions are:
1) tighten the bolts holding down the transformer to the base plate

if that doenst help:

2) isolate the bolts from the base plate with grommets

OR:

3) take the transformer out, paint the plates a few times with varnish (which is supposed to rejuvenate the lacquer’s flexibility), wait a few days for the varnish to dry, put the transformer back in.

4) replace the transformer with a new one.
Old 15th March 2011
  #6
Gear Nut
 

sorry, yeah its definitely the mechanical transformer buzzing.

Golden beers, thats exactly what i'd hoped for and more! thanks again for such detailed advice, I really apreciate your time and expertise..

I'll try each of the steps you mentioned and let you know how i get on.

thanks again.
Old 15th March 2011
  #7
Oli
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Oli's Avatar
 

Sometimes this can be dampened with some adhesive applied to the outside edges of the laminae. It's not a real fix though, and may not do much. Really it is aging in the transformer.

It doesn't hurt to overhaul the rest of the power supply while you are in there.
Old 15th March 2011
  #8
oh word of warning,
if you see heat sink/fins anywhere in or on the keyboard physically connected to the base plate DO NOT isolate the transformer with grommets. you WILL cook the transformer in this case.

if it has no fins/heat sink, before you put grommets on, leave it switched on for a couple of hours. turn it off and feel the base plate. if it's burning hot you may not want to isolate it as the transformer may run too hot. if it's not burning hot. go for it.
Old 3rd May 2011
  #9
Gear Nut
 

Phew, finally got around to trying everything out, and the damn thing just won't stop buzzing. I've tried the grommets, the varnish, i think the old boy has had his chips!

Now replacing that transformer seems like it could be tricky. i found this one but its US only Roland JX-3P Transformer. Anyone have any idea on sourcing these in the UK or Europe? Or know how i can replace with a UK alternative?

Thanks again for all of your help.
Old 3rd May 2011
  #10
it's odd that the grommets didn't help, this is usually a major help. tell me, how did you use the grommets? please make a little diagram, perhaps you didnt isolate properly. it's no good using grommets if you allow vibrations to the chassis through the bolts, you have to completely isolate the bolts so no vibration gets through.
Old 3rd May 2011
  #11
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kreeper_6's Avatar
 

Have the same trouble with my matrix 1000.None of the hokus pokus tricks work and modern replacements do exist but I haven't been able to find anyone willing to find them.
Old 3rd May 2011
  #12
the grommets worked well for me in the past. though if the transformer is very loud you'll still hear it even if it isnt being amplified by the base plate. but this isolation trick will have have a very noticeable effect in any case

here's a diagram of what ive done in the past and has worked for me.




you can go further, because in my example a little vibration can still get transferred through the thread of the bolt. a way of isolating even more is to use bolts with narrower shafts so that the thread doesnt touch the housing at all, you would need additional smaller grommets to fill up the space between the narrow shaft and the housing holes in this case. ie the bolt is completely separated from any other metal by a cushion of rubber.
Attached Thumbnails
Fixing a buzzing transformer in a JX-3P-grommet-isolation.jpg  
Old 4th May 2011
  #13
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LeeYoo's Avatar
 

I always fix buzzing transformers with 2-part epoxy glue. The clear 10-minute stuff. Make sure the transformer is warm, so the glue is thinner. Mix up a small batch, and let it flow between the plastic bobin and the metal plates. You might have to remove it, so you can turn it, to let if flow inside. Less messy if you only do one side at the time.
Leo..
Old 9th May 2011
  #14
Gear Nut
 

Golden beers, once again you've come up trumps!

I followed your diagram and have reduced the buzz significantly, its much much quitier now. I can actually play the thing for more than an hour without going mad!!

After experimenting quite alot i did find that i needed to leave things screwed together loosely to reduce the vibrations, and i had to experiment with different grommmets, washers etc until i reached the optimum quite spot.

Here's some pics of the process:







Note to anyone else with the problem, I did actually go without the washers in the end as it seemed to make it less noisy, but you should experiment with different Bolts, Screws, Washers and Grommets until you find the quitest solution.

Once again thanks Golden Beers, i can't tell you how much you've helped me. Thats another one i owe for sure. Thanks to everyone else who contributed too

Polym,
Old 13th April 2014
  #15
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was silents's Avatar
Thanks for this thread.

I had an obnoxiously loud tranny in my 3P and tried to pad/grommit it but to no avail.

I ended up using plastic zip ties to squeeze the transformer tighter like squishing a hamburger to fit in a bite. The location and direction of your ties may have to be different.

Anyway, its totally silent now.

Hope this helps someone in the future.
Attached Thumbnails
Fixing a buzzing transformer in a JX-3P-img_1161.jpg  
Old 17th June 2014
  #16
Here for the gear
I have a Kurzweil K2000R with exactly this problem. I will definitely try these possible solutions. Thanks all.
Old 25th August 2016
  #17
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Gotta love cable ties (y)
Old 20th February 2017
  #18
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Ercole's Avatar
YES !!! This the thread I'm looking for !

One of my korg a3 has a psu humming and I knew I had found some infos about it involving golden beers. After an hour searching, yes ! it's there --> Bookmarked !
Old 20th February 2017
  #19
This is the best thread ever.
Old 21st February 2017
  #20
I have a JX8p doing the same thing - thanks for this !!

proftea
Old 21st February 2017
  #21
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Ercole's Avatar
This thread should be PINNED !!!

Don't have time to fix my fx but it will be most useful !

Now I have to find a thread about fixing the noisy headphones outputs of my mackie vlz pro... Never ending story...

To make music, learn to repair cars, or washing machines, or metal boats...
Old 22nd February 2017
  #22
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NebulaZero's Avatar
 

the external psu on my novation nova emits a high pitched whine i wonder if it might be the transformer?
Old 21st April 2018
  #23
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Nice thread. I have a Pioneer A-7 amplifier . And the transformer is pretty big as the amplifier is rated at 78 watts per channel . The transformer makes a very loud buzzing sound .
. It buzzes after it gets warm after about 45 mins so the buzz gradually increases . After 2 hours it's annoyingly loud . I opened the housing case of the PT and poured varnish while the PT was really hot. Let it dry over night . The buzz went away . But came back after two years .
I guess I should start a new thread ?
Old 22nd April 2018
  #24
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how much would it cost to get a power supply
completely refurbished? like, replacing transformer,
and whatever else is advised. can any electronics
tech do this, or would it want to be done specifically
by a synthesizer tech?
Old 22nd April 2018
  #25
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I took the system to a good technician. he said only rewinding of the power transformer coils can solve the issue and its too much of a risk to take . It may not even work he says .
Replacement is impossible unless you get the same model amplifier . In that case it is better to just buy that amplifier which is having the working power transformer.
I guess I know how it got bad . I used to have major power cuts in my residence back in 2009 . So I used to hate interrupted music playback . I used to connect the system to my home battery inverter and use it when we had no electricity . It used to work fine until 2013 . Power cuts stopped happening since that time too so now i use the system with electricity ONLY. I prefer to not connect it to a battery incase of a power cut .. anyway since 2013 the buzzing got really really loud like a treble buzz . . I poured hot varnish on the PT to solve this . It did solve the buzzing noise but it came back 2 years later . I've been trying to figure out many ways to solve this . In this case gormets and washers only eliminate chassis's vibration noise but the treble buzzing is from the internal part of the PT and it can never be minimized and it's gets annoyingly loud after 45 mins
Old 22nd April 2018
  #26
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Sorry I didn't answer your question. It cost 75usd to 80usd if a local winding shop does a rewind which is just not worth the risk said my technician.
Old 22nd April 2018
  #27
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daviddever's Avatar
Quote:
Originally Posted by allanmatters View Post
I took the system to a good technician. he said only rewinding of the power transformer coils can solve the issue and its too much of a risk to take . It may not even work he says .
Replacement is impossible unless you get the same model amplifier . In that case it is better to just buy that amplifier which is having the working power transformer.
I guess I know how it got bad . I used to have major power cuts in my residence back in 2009 . So I used to hate interrupted music playback . I used to connect the system to my home battery inverter and use it when we had no electricity . It used to work fine until 2013 . Power cuts stopped happening since that time too so now i use the system with electricity ONLY. I prefer to not connect it to a battery incase of a power cut .. anyway since 2013 the buzzing got really really loud like a treble buzz . . I poured hot varnish on the PT to solve this . It did solve the buzzing noise but it came back 2 years later . I've been trying to figure out many ways to solve this . In this case gormets and washers only eliminate chassis's vibration noise but the treble buzzing is from the internal part of the PT and it can never be minimized and it's gets annoyingly loud after 45 mins
I've dealt with this (and earned my wings, PTSD, etc.) in the specific case of hi-fi equipment, typically toroids (as an importer / distributor / distributor technician); often the best remediation is to locate the offending equipment in an adjacent room / closet, or to simply call out the manufacturer for poor QC.

For situations where the mains power distortion is high, the PS Audio power regeneration devices will work to a limited extent, but will not solve the worst cases (where even a synthesized, low-distortion mains waveform causes the transformer to physically hum). Additionally, these regenerators start to get quite expensive once you require a higher power rating (e.g., small power amps, mixing desks, etc.).

In the case of musical instruments, as long as you know what the secondaries should be rated at (unloaded), it's not unusual that you'd be able to find a common replacement, given that these companies were not typically making large enough quantities to justify a custom model / winding, etc.

One of the things that is on my personal TODO list is to sketch out the linear power supplies for all of the vintage equipment I've got, in the rare case that I need to find a replacement | stumble upon an identically-rated transformer, etc.
Old 23rd April 2018
  #28
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I found the problem. The housing steel case/frame which holds the power transformer tight from below has expanded from one side . I put a piece of wood below sandwiched between the chassis base and the underneath part of the PT on that particular side and tightened the screws accordingly until I was able to eliminate 90℅ of the high buzz . I don't know how the housing frame below got expanded a bit on once side as we I never even removed the transformer for any work in the last 30 years . System is silent since so many hours now .

Hope this helps someone with similar issues as my problem had a different solution . Thanks to all you have helped me
Old 19th January 2019
  #29
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buzz is back

unfortunately buzz is back after about a month. So i did a re-varnish process. Made sure the transformer was hot enough and submerged the entire thing in hot varnish until the bubbles stopped arising. Let it dry for 5 days , fired it up. silent as ever. kept it running for 2 hours and there was a gradual increase in buzz but not noticeable.
another interesting thing I found out was that after I give the system a break for about 15 minutes and then turn on the amplifier again, its silent as ever until after 2 mins that small buzz comes back almost quickly as ever.

When the was unbearably noisy before , I used to do the same thing . give it a break for about 15 mins and then turn it back on. But at that time when I used to switch on the system after a short break it used to buzz immediately and very loud as compared to now where it takes 3 mins to buzz (only immediately after the 3rd minute) at low freq after a short break.
Old 4th March 2019
  #30
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evosilica's Avatar
 

What kind of varnish did you use?
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