mth locos losing sound

For the 3V board it's U5 on the processor board, a TPA2000D1PW SMT chip.  For the 5V board, it's the 9-pin SIP next to all the connectors, a TDA7056A.

Here is the 3V board.   Are you using the correct speakers from MTH? When you put in new speakers, did the sound restore?  We know you are aware of the volume control for conventional operation and the DCS remote  can raise and lower volume.

Thank you so much Mr.Marty, I am aware of the volume control, and yes I did use exact replacement mth speakers for the repair, the ps2 RS11 I was able to restore sound, that speaker had crumbled apart. The other two, a premier J class and a premier SD50 will not make even a crackle, but I never lost operations. ..all still run perfect (I run conventional)....I'm Juding by other posts on here that the sound amp gets wiped out by a bad speaker......but before I go condemning the sound amp I should test the volume control..?

I guess the next question begs, can I send these PS2 boards to you for repair Mr. Marty?...or would it be better to convert the dead ones to PS3?.....I'm new to the whole MTH thing as I always had Lionel with railsounds....any advise you can give would be greatly appreciated and thanks so much for your time

thanks for the info too, gunrunnerjohn

Once you are sure it's the amplifier chip and not wiring, volume control, or speakers, the go-to guy for board repairs of MTH stuff is George (GGG) on the forum here.  I think Marty sends him his boards to repair.

very cool, thanks for the tip....do you guys think it would be wise to go straight to PS3, or just try to fix these PS2's?

after checking the N&W J premier,...I now have whistle and bell, but no start up sounds or steam chuff. it operates as it should, forward, neutral and reverse. I picked up this piece used and the guy before me (tried) to install  a PS2 upgrade kit in this loco that was already PS2...all the lights work, and the smoke unit works in rhythm like it should....I don't run DCS or TMCC, I run off old school KW's....thanks again...these mth engines are a mess.... 

start with a factory reset using your transformer.

I'm gonna try that right now Joe, I will let you guys know the outcome.....thanks for the tips

trying to get that j to reset with a lionel CW80 is miserable.............

Some things you describe seem to change?

I thought you were using KWs?

in my little shop, I have a test track set up with a cw80.....I couldn't get it to reset with the kw's or the cw80....I have sound buttons on the kw's....pretty sure its me not hitting the buttons in sequence correctly

The button timing can be tricky - I realize this video is of the Z-4000 and Z-750 but it might get to closer to hearing the double-toot acknowledgement...

IMO if the only issue is the audio amplifier chip replacement, I don't see any compelling reason to spend the $ to convert to PS3.  As suggested above, GGG is to go-to guy for these kinds of repairs.

I would be mindful to ask yourself why the audio amp chip (again, assuming that's the problem) blew in the first place.  I suppose you can send the entire engine and have GGG check all the wiring, etc. but if just sending in the PS2 board-set note that one cause of the blown audio chip is some kind of wiring short in the harness/speaker wiring - for example a speaker wire touching the chassis.

Very true, a bad speaker or a wire touching the frame can take out the audio amp in short order.  Before sacrificing another audio amplifier, be sure to eliminate any possibility of those issues.  I've seen several speakers where the connection to the speaker has the braided wire to the cone laying on the speaker frame, not good!

It's nice to load the board set into a test rig to see if it's a board problem. Sometimes, it's the chassis, tether, wiring, or speaker. It's best to narrow it down on where to look.

That's great if you have a test set, and it's clearly the way I troubleshoot boards!

I would also tell you to send the boards to George.

Right.  It appears these engine(s) were "built" from upgrade kits so who knows what attention was paid to that errant strand of a speaker wire touching the chassis.  I've replaced that ~$2 audio amp chip myself but I can see the dilemma of sending in just the board-set which only weighs a few ounces vs. the entire engine which can be 10 lbs or whatever. 

I've replaced a few of the amplifiers as well, but they're a bit of a PITA with the finer pitch leads.  I did finally hit upon a decent technique to get them on, but it's still not fun.  That's the reason I limit myself to a certain size SMT part when I lay out boards.

as Joe said before, I need to better explain what is going on with these locos, ..........so I will try to make it brief as possible....I  bought a bunch of mth premier locos from a fella, 3 of which have/had problems....the RS11 ran but had no sound, I got a new speaker for it and that one got fixed. the old speaker had crumbled. the second is an SD50. I put anew speaker in it, but nothing....it runs fine, smokes and all the lights work. the speaker outward appearance wise, looks ok....the j I thought had no sound until I turned up the volume, but it only has whistle and bell. I tried the factory reset with my kw and sound buttons, but I couldn't get the timing right, so I tried it on my cw80 in my workshop. it took a bunch of tries but finally got it to acknowledge a reset....just a few minutes ago...so now it has start up sounds, but still no chuff.... 

also, let me mention the j is originally equipped with ps2 , when I got all the stuff from him, there was a opened ps2 steam upgrade kit in all the stuff. the fella I got it all from said he was trying to fix a dcs control problem he said the loco had. but I didn't get the dcs system. in conventional mode the loco runs fine, smokes and all the lights work as advertised...

If a steam engine has other engine sounds (such as the compressor which is typically part of the start up and idle sound) but NO chuffing, it could be from a mis-aligned, loose, defective tach sensor.  Since you only operate conventional, you should notice that for the SAME throttle setting a PS2 engine with a broken tach sensor will run much faster than one that has a functional tach sensor.  So, for example, you can place two engines on the track at the same time (even mixing diesel and steam) and in conventional mode both PS2 engines should run roughly at the same speed...say within 10% or whatever.  If one is grossly faster than the other, then you likely have a tach issue - especially on a steamer if there is no chuffing sound.

If the smoke is functional on the steamer, does it puff when going slowly?  If the smoke is steadily streaming (rather than puffing distinctly) at slow engine speeds this is another indicator your have a tach issue.  A tach issue is something you might be able to adjust/fix yourself...or send it to GGG but this means postage for the entire engine.

the smoke distinctly puffs as if it were in rhythm with a chuff....I did notice that...I will open this loco up tomorrow when I get home from work and let y'all know what I see....I might find a mess in there cause looking up into loco, I can already see a rats nest, and lots of tape.... 

I took the loco body and the tender body off today.....its a total mess inside....the wiring looks like a hacked up massacre....not sure why, the board swap should have been plug and play...I will take some pictures and post them up. evidently the fella before me must have been chasing a problem......I really appreciate all of your help...im gonna sit and first straighten out all this wiring and then start investigating.......  

Have you replaced battery with good charged ones?  The older engines with 8.4V rechargeable batteries only last 4-5 years.  The newer PS-2 3V enignes use a 2.4V type battery and can last 5-7 years.

If you run conventional, you need a good battery.  Get a good Pure Sine wave transformer or a MTH Z-1000 set up with a good bell whistle button.  It is a must for conventional ops.  The CW-80 is not really compatible.

Once you get a reset done, and sound do not come back, I can test and repair boards.  E-mail in profile.  G

gunrunnerjohn posted:

That's great if you have a test set, and it's clearly the way I troubleshoot boards!

John, Do you really need the arrow on the Motor?  Don't your forward green and red reverse motor lights work?   G

I will check the battery, and do as you suggested George...........and if that don't work, I will get up with you and send them to you....THANKS! I really appreciate everyone's help and input!....great group ya'll have!

and the saga of the premier N&W J continues..... I straightened up the wiring. Soldered up the loose and twisted together connections and used heat shrink where needed.....I took the loco over to  a buddy's house who has MTH's DCS on his layout....he got the engine to move under his command, but it had no low speed control. It would kinda just start taking off, like it has no tach sensor.....but the smoke unit puffed in rhythm with the drivers, as if it were getting the signal from the tach. He did a factory reset with his hand held and was able to get the start up sounds to come on but still no chuff...that's where we stopped. just now, I tried it again on my conventional layout, I lost start up sounds that I did have before, I still have whistle and bell sounds (no chuff) and the loco runs fine on my conventional layout slow speeds are fine...this is MTH's premier no. 20-3364-1 PS2 loco. it has the 3v board and a fully charged battery..... as mentioned before the guy that owned it before me replaced the board with a new one from a ps2 upgrade kit...

GGG posted:

John, Do you really need the arrow on the Motor?  Don't your forward green and red reverse motor lights work?   G

Yep, I just put it on there one day, I'm not sure why.

harmonyards posted:

and the saga of the premier N&W J continues..... I straightened up the wiring. Soldered up the loose and twisted together connections and used heat shrink where needed.....I took the loco over to  a buddy's house who has MTH's DCS on his layout....he got the engine to move under his command, but it had no low speed control. It would kinda just start taking off, like it has no tach sensor.....but the smoke unit puffed in rhythm with the drivers, as if it were getting the signal from the tach. He did a factory reset with his hand held and was able to get the start up sounds to come on but still no chuff...that's where we stopped. just now, I tried it again on my conventional layout, I lost start up sounds that I did have before, I still have whistle and bell sounds (no chuff) and the loco runs fine on my conventional layout slow speeds are fine...this is MTH's premier no. 20-3364-1 PS2 loco. it has the 3v board and a fully charged battery..... as mentioned before the guy that owned it before me replaced the board with a new one from a ps2 upgrade kit...

Fully charged and working battery?  Power it up so sounds are playing and turn track power off.  If it does not play shutdown sounds the battery is dead or the battery circuit on the PS-2 board failed.

No speed control but puffing smoke seems odd, unless the motor driver FET shorted.  When track power is applied in DCS does it start moving immediately?  These symptoms are odd.  Need to send to a tech who can test boards out of engine and go from there.  G

we put in a fully charged battery from one of my buddy's stock .....he pulled a battery from another loco that he had just charged up and was operating his loco perfectly. when he applied track power to my loco sitting on his layout, it would sit there until he started increasing the thumbwheel, as soon as it got moving, it would just start taking off like a rocket. have to quickly thumbwheel down to get it to stop.....its like cruise control I cant control....my question is do you need this whole loco or just the boards?.......ima let you fix it George, its gotta be worth the cost.....

I can probably answer for George, I suspect he'll say it would be best to have the whole thing.  While that kinda' sounds like it's likely the board, you never know.  I'm having trouble figuring out how it can chuff and not have speed control.  The board is obviously receiving the tach signal or you wouldn't get chuffing.  But, you seem to have control of the FET as it doesn't take off until you give it throttle.  Can't say I've ever seen those exact symptoms with a PS/2 board before.

believe me John, I wish it weren't true either..........nobodies more frustrated with this thing than me! I wish it ran ok....1000 dollar loco that wont say a word other than ding ding and toot toot...perhaps a video of what this thing does? or just box it up and carry it to George?

I'd just take it to George, he'll beat it into submission.

agreed, I can rebuild and restore prewar and postwar lionels with the best of them.....but this one is above my pay grade....with out the proper equipment, I might as well throw darts.....shotgun approach I could see getting very expensive very fast.....

GGG will figure it out. 

Please update us when you get it resolved.

absolutely!....I cant wait to be updated myself, Stan!

I sent an e-mail to George, time to pass this loco up to the pros