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MRC Tech 4 280 problems

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  • Member since
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  • From: northeast ohio
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MRC Tech 4 280 problems
Posted by 0-6-0 on Wednesday, May 3, 2017 8:28 PM

Hello I have had this tech 4 dual control for a while not really sure how long. The only thing that ever gave me trouble was the direction switch for cab 2. Sometime's you have switch it twice to get it change. Now when running cab 2 the trains slow to a stop no matter witch train or where it's at on the layout or direction. Is this the beginning of the end for it or can they be repaired. Thanks Frank

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Wednesday, May 3, 2017 8:49 PM

I might be repairable. They have a transformer, full wave rectifier, a pot, a resistor, cap and the voltage regulator.

I opened a different model many years ago and I thought the MRC had security screws for the case. I had to buy something that looked like a screwdriver with a different style tip.

One fellow here repaired that model some years ago.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
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  • From: Shenandoah Valley
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Posted by BigDaddy on Wednesday, May 3, 2017 8:51 PM

The electrical gurus here, that have oscilloscopes and Fluke meters, probably could but where else can us non electrical geeks get anything repaired these days? 

I went to Radio Shack on Saturday and it is now a Sprint cell phone store.

Ebay has your model at the mid $40's though some current auctions have much lower bids.  Caveat Emptor over there.

 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by zstripe on Thursday, May 4, 2017 6:43 AM

Get Yourself a can of CRC 2-26 Lube & Electrical cleaner and with the small nozzle (make sure the can has one, usually taped to side of can) attached to the end of the spray.....spray directly in all the slide switches, while working the switch back and forth. Do that a few times on all the slide switches. Having that reverse switch having intermittant contact will stop the rest of the unit from working properly as though it's not on. If You can get the cover off, You can also spray both potentiometers (pots) with it. That unit should have two separate transformers in it for each cab. Cleaning it throughly should get it working again. If not let us know.... there are some tests that can be done simply to find if there is another problem. But normally it is just plain ole' corroded contacts.

https://www.walmart.com/ip/CRC-2-26-Multi-Purpose-Precision-Lubricants-2-26-16oz-dries-moisture-Set-of-12/21068182?wmlspartner=wlpa&selectedSellerId=1122&adid=22222222227016782965&wl0=&wl1=g&wl2=c&wl3=52576465511&wl4=pla-60240488251&wl5=9021618&wl6=&wl7=&wl8=&wl9=pla&wl10=101593696&wl11=online&wl12=21068182&wl13=&veh=sem

Don't be afraid to spray it liberlly.....won't harm anything.

 

Good Luck! Big Smile

Frank

 

  • Member since
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  • From: northeast ohio
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Posted by 0-6-0 on Thursday, May 4, 2017 7:46 PM

Hello yep it has those weird screw's I was just going to drill them out and replace them with something else. If can't fix this one then I'll check with the hobby shop first. I have not shopped on ebay in a long time. 

Frank I dont have that but I do have this

I also have some deox? it's electrical grease. This what I have on hand if these wont work then Ill get what you showed me. Just by looking it over I am going to have to open it up to get to anything. Thanks Frank

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Thursday, May 4, 2017 8:12 PM

Search the internet for security screwdrivers. You will see what the tips look like in different links. I had a manual before the Internet that showed different tips designs is how I found what I needed. All the different tips have a designation. I was fortunate that a tool distributor in West Springfield, Ma had a catalog. As I recall, the piece fit in my screw driver handle.

Possibly search for mrc power pack security screw might work.

A retired machine mechanic and I seriously doubt I could ever find the tip in all my tools.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by BigDaddy on Thursday, May 4, 2017 8:20 PM

Dunno what screws they use, but Harbor Freight has a cheap security bit set.  OTOH drilling them out and using standard screws might be cheaper.  I picked up left handed drill bits on Amazon, which is even better for drilling out stuff especially stuck screws.

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Thursday, May 4, 2017 8:42 PM

As I recall, they are hardened screws and look like a Torx but with a small diameter pin in the center to prevent using a standard Torx.

Grainger is a tool comp-any in my location that I use to buy from when I worked as a mechanic in a local company. They are online. Even, McMaster Carr is another good tool company.

Many searches people saying nothing replaceable but that is for the average model railroader who might not have electrical, electronic experience. MRC would not want the liability for someone working on it with the cord still plugged into an outlet. Even the Bachmann forums have said that about there DC power packs. I posted a couple pictures of the inside of there older power packs and the powers that be removed them.

I have seen warnings here over the years about working in old power packs or old computer power supplies.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
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  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Thursday, May 4, 2017 9:26 PM

Torx Security bits are readily available at big box stores. 
 
 
I bought a good assortment at Harbor Freight.
 
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
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Posted by richg1998 on Thursday, May 4, 2017 9:44 PM

Good suggestion. I hope 0-6-0 will take some pictures and post them. I am curious. Might help someone else.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
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Posted by zstripe on Friday, May 5, 2017 4:30 AM

Yeah..MRC over the yrs. had a lot of different security screws over the yrs. From dome shaped to torx etc. I have found that most all of them, (that I worked on anyway) were not really too tight and have used all kinds of tricks to get them off.

Years ago I bought those security torx sockets from a Automotive supply store in My area.....at the time they were not cheap. I had a 85 Crown Victoria 4dr Secretary of State, IL. Police interceptor and it had a variable ventura carb on it that was loaded with those security torx screws....what a nightmare to rebuild. But I got it going......what a fast car on the highway. Just looked like a plain Jane 4dr from the outside with big wide tires. Inside added on to the dash were all types of gauges, trans. temp,oil temp, etc. etc.... the suspension was all heavy duty. Speedo went up to 150 mph, with a 5 speed auto trans. I happened to buy it at Auction for 320.00..it had 46,000 miles on it. Kept it for two yrs. painted the body a nicer light Blue Metallic and it was sold for 1800.

Good Luck, on the MRC! Big Smile

Frank

 

  • Member since
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  • From: northeast ohio
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Posted by 0-6-0 on Friday, May 5, 2017 12:01 PM

Hello well I got it open. I have a set of security torx but could not find one that fit. It looked more like a allen key but they would not fit either so I just drilled them out. They were not hard. The first one I drilled out I almost drilled thourgh the front. I looked over the parts inside and I didn't see anything that looked broken or burnt. Here are some photos of the inside and it is unpluged. This is the front

this is the back.

And I was wrong about the deox I have dielectric silicone compound for electronic systems. I'll try the cleaner and see what happens Thanks Frank

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Friday, May 5, 2017 1:03 PM

I would suspect the three terminal device right now. Can you read a part number on those? Probably a power transistor or voltage regulator.

I see the full wave bridge diodes and electrolytic filter caps, plus the yellow bypass caps.

Does the pack have momentum capability?

The pots and switches are easy to clean.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    January 2010
  • From: Chi-Town
  • 7,712 posts
Posted by zstripe on Friday, May 5, 2017 3:58 PM

They are voltage regulators and that would be one of the first things that you would have problems with.......assuming of course that voltage Vin is constant. Looks like there is some writing on them. Hopefully there is a LM number on them. Also hopefully a good cleaning is all You need.

Good Luck! Big Smile

Frank

 

  • Member since
    June 2006
  • From: northeast ohio
  • 966 posts
Posted by 0-6-0 on Friday, May 5, 2017 7:35 PM

Hello   It works. I took it out side a gave it a good spraying. It only took a few min to dry. It's still unpluged and I took a meter and set it to beep and tested all the connections and diode's. Everything I touched from the input side beeped. I put That dielectric silicone in the switch's and in the bottom of the knob's? Not sure what they are called.

You can see it above the contacts are above the black disc. It went right back together just fine. Some new screw's and plug it in and see what happens. Everything is moving smooth and so far no power loss. The train has been running for an hour now. I keep slowing down and changing directions. So far it seem's fine.  Thank you guy's for helping me with this. Have a nice day Frank

  • Member since
    January 2010
  • From: Chi-Town
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Posted by zstripe on Saturday, May 6, 2017 5:19 AM

Good for You....glad it was that simple........usually that is the number one cause for those not working...just plain old corroded contacts.

Yrs. ago...I repaired TV sets, tube/hybrid....number one cause for them not working properly......dirty tuner. LOL

Take Care! Big Smile

Frank

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