Working on a M&S Systems Model DMC1 Master Station

The M&S Systems DMC1 (music & sound) Master Station is essentially the same Model as a NuTone NM200 Master Station.
Both of these Models share a lot of design aspects with the M&S DMC3-4 and NuTone NM100.
This DMC1 was sent in with a specific problem, a very pronounced and constant hum or buzz on the System.
The source of this problem was typical, but unexpected for a 7 year old unit
Here's a Link to our Repair Request Form:
docs.google.co...
For more detailed information about NuTone Door Chimes and Intercom Systems:
You Can:
Visit our web site: northsideforyou...
Or you can email use at: [e-mail]
Or you can call us at: 925-743-8236

[@northsideservicecompany3567]

Our Experience with both NuTone NM Series and M&S (music & sound) DMC Series of Intercom repairs is growing. Some of the more common problems are revealing themselves and are becoming easier to repair (somewhat ~ sometimes). We are still on the uphill part of the learning curve on these models - however each repair brings us closer to the top of the hill. All we have to do is, make sure that really big rock - that we're pushing up the hill, doesn't roll back on us, crushing our progress (and me) at the same time (ahhhhhhh) - Chris

[@marcyhendrickson8088]

Thanks for the shoutout! Getting ready to reinstall the master station...Thank you again!

[@northsideservicecompany3567]

Hi Marcy: Thanks - Don't forget to turn the Circuit Breaker OFF before connecting the DMC1 to the Transformer - so you don't blow the Fuse n the Transformer - Chris

[@2packs4sure]

Nice job but if it were my intercom I would have requested that you recap that tuner module and hopefully that would repair it because the new factory tuner is gonna have the junk capacitors in it...

[@northsideservicecompany3567]

Hi 2paks4sure: Not actually repairing the Tuner was a cost choice. A replacement Tuner Module was less expensive than attempting a repair on the original unit - Chris

[@2packs4sure]

@@northsideservicecompany3567 Understood, I assumed that was the reason but my thinking would be if it were mine that while it's in the hands of the master let's just get it all done with quality caps...

[@northsideservicecompany3567]

@@2packs4sure It very well become part of the "Standard Rebuild" work that gets done on DMC and NM Series of Master Stations - Chris

[@zx8401ztv]

Wow that is one bad design, Nicely cooked and it didn't even go Ding!! to show it was done :-D Cheap ass capacitors didn't help, they should have been 105 degrees switchmode spec. When you said buzzing i thought rectifiers/smoothing/regulators and overloading causing ripple related problems. I was mentally using a blunderbust fire arm, i hit a lot in one go lol. I tend to use panasonic capacitors for switchmode repairs, 105 deg, low esr and reliable. But they are not cheap. Stick to well known brands, no china sounding names at all. Pity the trasformer could not be relocated to make the cavity slightly cooler. Ive seen lots of products that have capacitors right close to heatsinks, wonderful cook the caps!!. I bet you have seen this way of premature device death (Done on purpose). Sorry long waffle :-(

[@northsideservicecompany3567]

Hi zx8401ztv: I used Nichicon brand capacitors rated at 105 degrees. I also use Panasonic for certain models. I would have preferred to go up 1 voltage range (from 35 to 50) but I couldn't find any in stock that would fit into the allotted space. I have always found that trying to overcome a poor design is challenging, as I tell customers with models like this - "there's only so much that can be done with a poor design" - Chris

[@Brandon__Stone]

I’m attempt to get a customer to Mail you his unit. What’s cost on this ?

[@northsideservicecompany3567]

Hi Brandon: You or your customer will need to either fill out our on-line Repair Request Form (here's a link: docs.google.com/forms/d/e/1FAIpQLSdQHT6fVgm25twaXFeCkkgeITEfAE_zlRBry6B8-GbIs19wcQ/viewform?formkey=dF9RVjBQMFQ5S0xYbTBHMHRoNkVkRFE6MQ ) or, either of you can contact us directly about the M&S DMC System - Please be aware, I will have questions about the System - Chris