HELP, MTH DD40AX smoke motors problem. UPDATE 7/11/2015

I just did an engine reset, twice, using my DCS, now the heating elements work but no sound and fans still not working. moves for and aft ok though

BTW, I was using a good known 9V alkaline battery, was this a problem?

Tried the volume off, on, up down on the remote, no cigar!!!

You need to get that speaker out of there NOW!  Those are infamous for killing the audio amp, it's a known issue.  I used to have a bunch of them lined up on the workbench leg, just to see how many I would collect, but I tossed all of them.

Since you have no sound, you may already be too late.  Don't run it anymore until you have a good speaker in it, "maybe" it'll come back.

I must admit I have not seen this speaker issue be that critical, and I had a big box of removed one and have replaced audio amps on 5V board that had good speakers.

But I agree, best to change it.  It is also disintegrating internally and will at some point prevent proper vibration.

If neither smoke fan working you may have a damaged fan fet.  Need to inspect the board. 

The battery test is not a good one. They can run on 9V but not on 5V.  Do they measure about 12 ohms?  If not the fan motors are bad.  If they do, it may be the 5V board.   G

I recently tossed one of those speakers that looked like that, the voice coil was internally shorted to the frame, I'm assumed it was because of the deterioration of the plating.  Could have been a coincidence, hard to say.

OK, Thx John. I'll get a new speaker asap, may be tonight form another loco that has a matching wattage and impedance speaker. (the speaker sounded perfect initially then it seems to have slowly went away then it died. I am using a Lionel 80w transformer that I just found in my stash, is this the problem? I have an MTH Z4000 I can use (I am moving stuff around in my room so the Z4000 was not easily accessible )

Thx GGG. The two smoke units are paralleled, motors together and elements together. I checked the two motors in parallel and they ohmed out at 5.5 ohms. The speaker ohms out at 16.1 ohm. All disconnected from the board.

How do I check the board? and which one? The one that the smoke units are connected to? I can DCS power the loco up w/o speaker connected and check output at the motors pins on the board? I can also run the motors at 5VDC using and MRC power supply? sorry to ask many questions, this is my first hard failure on an MTH PS2 board.

Anything else I can check?

When you put the 9V battery  to the fan motor,    George made a huge point about the voltage to the 5 V fan motors.  I do MTH and Lionel fan motors each week.  I have a worn down battery that reads 5.1 volts that I use to test fan motors.  Many BAD fan motors will spin when you kick them with 9 volts.

They (fan motors) are what they are and I feel we are stuck with them.  At York last October, I picked up a large number of speakers (16ohm/5W)  for the 5 volt boards and have used many.  To me it is still a small price to pay to have a great running PS2 locomotive with all the sounds and operation it has.

I go one step farther Marty.  I have a bench supply, and I set it to 2 volts and test motors that way.  If they don't spin slowly with 2V, they are almost always bad.

On the bottom of the board near where the 4 pin connector is for the smoke unit is a few fets that control the fans.  Look for a burned fet.  I will have to check a 5V board to see if the # is printed near by.   G

OK, I got it to Factory reset and now I get sound, full operation and heating elements work but of course the fans are still not working...those little buggers. The fan motors ohm at 5.5 ohms in parallel which means they are 12 ohms each but I'll separate them and measure again to make sure.

the speaker is not shorted and worked fine but is flaking badly and looks sad, so out it will go now, it I don't want a burned sound amp. Where do I buy one please? Is there a better speaker for better sound to upgrade to?

I'll try the motors on a 2VDC MRC power supply and let you know.

GGG, do I ohm out the FETS in or out of cct, and what do I look for? I have a solder sucker and a solder gun, I think I can repair it if I am told how.

I really like to get this running tops, I got it for a fantastic deal and I want to feel good fixing it

I'd start by testing the fans with a lower voltage, say a 2-3 volts DC.  If you have a meter, check the current they're drawing, they should only draw 40-50ma each.

Q306 and Q307 are the smoke motor drivers, they're a BSH101 FET.  I can't find any listing for them on the web, so they might be hard to come by.  However, if you feel these are bad, I can send you a couple of bad 5V boards that you can salvage some from, I have plenty of them in my board graveyard.  George may have them, and I see that MTH has them listed in my common parts listing, so they're available.

Thx John, you are the best. I am always amazed at how you continue to help others even though there are some "comments" thrown at you some times!!!!

Please keep up the great work...Cheers!

THe 5630 and the 352a are the upgrade replacements for them.  So they are readily available.

YOu can use a diode check.  They are head to head, so if the stop fet shorts it will prevent the fan from turning, or the 5630 does not pass current.

Many times the visual is also obvious if damaged.  G

Thanks George, I figured there was probably some newer parts that would drop in.  Here's the 352A at Digikey for 42 cents.

Cool, thx George, Marty and John...

Here are the main and only board and the speaker (looks OK and working but will change it):

EDIT: the two motors in parallel run smoothly at 2.85 VDC! does this mean the FETS are gone?

Are the fets under these heat sinks?

OPPS!!! Sears 65 in 1 tools, from $30 to $10...how can one resist...

The speaker looks ok, but will replace. Is there an upgrade to improve sound? where to buy?

 Which way does this white connector go in, I did not make a note thinking it is keyed!!

Or this way????

That speaker is not too bad.  Does it sound distorted?  It will get worse over time.

In your 2nd picture, closest area and to the left, you see the 3 lgs of the heat fet.  To the left is the 2 fan fets, lift up capon tape and inspect.

The connector has 3 holes that are closer to one edge than the other.  Make the holes closest to the frame, this allows the connector to be off the chassis more. Should be the last picture.   G

Hi George;

The speaker actually sounds really nice and clean, no distortion what so ever. This loco sat in my spare bedroom for a long time then in storage for a while (may be this is when it started flaking not having been in a controlled environment and due to aging too perhaps) and now it is being used again. Where do I get a replacement? I may buy a few since I have quite a few older PS2 locos.

OK, so the white connector is to be plugged as shown in the last photo, Great...Thx a bunch George!

The speaker flaking is a known issue with that vintage and brand speaker, I'll bet George has quite a collection by now!   I just tossed about a dozen of them that were stuck to my workbench leg.

I found the FETs, thx guys. They are SMT's and I am not equipped to replace them. My vision is also not the greatest even though I am using a magnifier. Since so far the only problem is the fans, I may decide to just let it be, or run the smoke fans from track voltage using an AC/DC rectifier with adjustable output? does that sound crazy? Else what are my options and cost. John and George??? ....cheers!

Most of the stuff on that board is SMT.  George will solder them on for you.

You could run the fan constantly from track power with a power supply, keep in mind that it'll dry out the smoke fluid if the smoke unit isn't on.

If I were going to "kludge" it, I'd probably power if from the smoke heater power, but the right way is to replace the FETs.  Of course, you should also identify why the FETs failed, there has to be a reason.

I am with John. Board gets tested separately to see if in fact fet bad.  May be one of the motors is bad going bad and it overloaded the fet.  This is a dual smoke unit.  G

I need to get a few of these 16 ohms speakers for this loco and other locos that I am working on.  I found another bad speaker that welded itself in a Dreyfuss steamer.

can some one  point me to where to get a few? perhaps even a better quality one?

This has been debated at length.  The MTH one is BF-0000033 $18MSRP and is 50mm dia x17mm Height 16ohm 5Watt.

Better speakers are taller or wider, and similar ones are not better, usually less Watts.

16ohm speakers are no longer as popular with new electronics.  So less in demand.

My recommendation is using MTH versions.   G

I've found some good and some bad speakers on eBay.  The problem is you have to kiss a few frogs to find your princess.

Thx George and John. I'll look into ebay and MTH. I don't know how many I need since I do not know which PS2 steam or diesel locos have this speaker. I think I will order 6-8.

I don't like kissing frogs in the hope of getting to kiss a princesses.  I look for a princess to kiss

Sometimes that's way more expensive.

Smoking well now. here it is with the old speaker and a temporary 9V alkaline. Took my time to tidy up the wiring, new traction tires, lubed. Runs smoothly down to 2 SMPH!

 Need the Caffeine first!

Sooo, what did you do to fix the smoke units?  My bag of tricks is nowhere near full.

Thanks,

Gene Anstine

Any STAR 16 ohms, 50 mm speakers for sale? . ebay does not have them.

EDIT: tried MTH online ordering, not working. Called in the MTH parts dpt, on hold a long time I hung up, don't want to email my CC info...Frustrated...I'd like to get these locos fixed

Still unable to locate 16 ohms speakers. MTH online ordering does not work and I am unable to call them at their time zone. Nothing on eBay. Any one can help me find them on line it would be greatly appreciated...

The speaker is MTH part #BF-0000033, 16 ohms, 5 W, 50mm or equivalent...Cheers!

Any one can help a little? Thx!

BigBoy4014,

Sent you an e-mail.

Joe Allen

Joe E., Thx for the speaker info.... Helps a lot...