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Noisy MRC 2500

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  • Member since
    June 2011
  • 15 posts
Noisy MRC 2500
Posted by Longtrain on Wednesday, April 12, 2023 4:25 PM

Hi All!
I'm wondering if a smoothing capacitor could be used to remove the pulses that cause the annoying buzzing on my MRC 2500? If so, what would be the procedure to do this? Thanks!

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Wednesday, April 12, 2023 7:53 PM

The same thing happened on mine.There are 2 adjustment pots inside which may help. Scribe a mark before you adjust them.

I ended up putting a large cap across the output terminals inside the pack which did make mine useable for another couple of years. Zero motor noise. Cannot remember the value.

Once the pack failed, I purchased a 2400 which has a pulse off switch.

To gain acess, the security screws use a T 10 anti tamper torx extended shank bit or a T 10 anti tamper torx screwdriver.

Jim

  • Member since
    April 2021
  • From: saskabush
  • 127 posts
Posted by wvgca on Wednesday, April 12, 2023 8:13 PM

the large internal capacitor could be starting to go bad ....you can find a direct replacement on ebay or one of the electronics supplier ..

you will need a safety torx to get the thing apart, unless it has been apart before and the case screws changed out ..

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Friday, April 14, 2023 3:42 PM

Thanks for the good info!

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Friday, April 14, 2023 3:45 PM

Is there possibly a way to wire the right size cap to the external outputs of the power pack?

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Friday, April 14, 2023 7:51 PM

Wiring it to the teminals on the outside is the same as attaching them on the inside. The difference is the cap is protected on the inside and out of the way. Other than saving the cost of a the bit set, not sure why you would want to.

Jim

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,278 posts
Posted by gmpullman on Friday, April 14, 2023 8:29 PM

Shouldn't the capacitor be upstream of the reverse switch? Simply wiring to the output terminal will not sit well with the cap when you reverse the polarity to it.

Just askin'

Regards, Ed

  • Member since
    April 2021
  • From: saskabush
  • 127 posts
Posted by wvgca on Friday, April 14, 2023 8:47 PM

gmpullman

Shouldn't the capacitor be upstream of the reverse switch? Simply wiring to the output terminal will not sit well with the cap when you reverse the polarity to it.

Just askin'

Regards, Ed

 

quite correct .. you would need two capacitors and associated diodes to function properly

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Friday, April 14, 2023 9:10 PM

I used a non polarized capacitor at the output terminals, worked great for over 2 years.

Jim

  • Member since
    April 2021
  • From: saskabush
  • 127 posts
Posted by wvgca on Saturday, April 15, 2023 8:00 AM

mot people don't have ready access to non polarized capacitors [ which is basically two ordinary capacitos back to back, with associated diodes], but a non polarized would work okay on the DC outputs at the back of the controller, polarity reversal wouldn't matter with a non polarized capacitor.

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Sunday, April 16, 2023 11:10 AM

Hi! Thanks for all the great advice! The links to where non-polarized capacitors can be obtained is especially helpful. The only reason I want to wire the capacitors to the output terminals is it would save me from having to open the case. And my soldering is definately not up to snuff! Haven't soldered in years! Maybe once I find the setup that works and I've practiced soldering I will put it inside the case. So what would be the range of specs to use to find the right size capacitor for this project? Thanks again for the help! Arvin

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Sunday, April 16, 2023 7:01 PM

Arvin,

Understood. I looked around and found the capacitor I used. It is a 50v / 500uf axial non polar.

The output as shown on the MRC spec sheet is 20v no load.

Jim

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Wednesday, April 19, 2023 1:08 AM

Awe now I shall purchase one and try it out! Thank you very much Jim! Arvin

  • Member since
    June 2011
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Posted by Longtrain on Wednesday, April 26, 2023 1:20 PM

Longtrain

Awe now I shall purchase one and try it out! Thank you very much Jim! Arvin

 

 
Jim, I'm having some trouble sourcing a capacitor with those exact specs. Do you think this one would work?
 
 
Thanks!
Arvin

 

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Friday, April 28, 2023 6:44 PM

Soo Line fan

Hi again Jim

The trouble is I live in Canada and that company wants $18US to ship it to me! eBay Canada does not have that listing, and I haven't yet been able to find anyone on eBay Canada (or Amazon Canada either) that sells that particular capacitor. I've phoned my local electronics parts store and they couldn't find one, but would call me back if they could get it. They never called me back! So that's my sad tale for today! That link I sent you was from Amazon Canada, and that's probably why it seems so expensive to you! Haha. I can find a few, but none that say non-polarized. I will keep looking, but I'm not hopeful!

Thanks!

Arvin

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Sunday, April 30, 2023 2:07 PM

Hi all,

Since I can't seem to find a 50v/500uf non polarized capacitor available to me in Canada (but I can find plenty that are polarized), couldn't I use a polarized capacitor by disabling the reverse switch on the powerpack and using a reversing switch that is placed after the capacitor?

Thanks!

Arvin

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Sunday, April 30, 2023 4:48 PM

Can you find a 50v 470uf?

If not, then no reason adding a second direction switch would not work. You could put the cap and switch into a project box.

The manual is here: https://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Tech%202%202500%20AF130.pdf

 

 

Jim

  • Member since
    June 2011
  • 15 posts
Posted by Longtrain on Monday, May 1, 2023 10:09 AM

Soo Line fan

Can you find a 50v 470uf?

If not, then no reason adding a second direction switch would not work. You could put the cap and switch into a project box.

The manual is here: https://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Tech%202%202500%20AF130.pdf

 

 

 

Thanks Jim for the info. 

Yes I saw a 470uf listing. Can't remember at the moment whether it was non polarized or not. I will check when I get a chance. 

Arvin

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