PS2.0 Mikado, all functions work except sound - got it fixed thanks to GGG and the Forum's help

I have seen too many bad speakers from MTH. Try an ohm meter check. 

George T. , Detroit 3 Railers

troubleshooting needs to be methodical. The nice tools that techs can have sure helps. They could plug your boards into a rig and test them.

G will chime in about audio amps and yes, I've fried them too. Sometimes, it just needs a factory reset. 1w 5 bells

http://mthtrains.com/20-3287-1

2007 PS2

Do a continuity check on the volume pot to the board.  The pot uses pins 10-11-12 on the 12 pin connector.  Put an ohm meter on the speaker and look for about 4 ohm.  You have a 3 volt board set.  You seem to be a good trouble shooter and my guess is a bad audio amp.  I have GGG replace them often.  Below is a photo of what we are talking about.

Hey Greg,I would also suggest possibly calling Brian at Stock Yard Express.  He has help and fixed a few of my MTH engines and did a great job.  i hope the ohm meter finds the speaker faulty but FYI just in case.

Dave (Detroit Three Railers)

One last thing.  Check speaker wires for continuity to the board.  You need pins 6 and 7 on the 12 pin connector.

Also check the wires in the speaker, that run from the terminals into the coil.  They may be shorting on the frame.

Good point Robert.

I had the problem of sound going out when whistle was blown and not returning.  About 2 weeks ago GGG tipped me off about the internal speaker wire routing.  That was the problem.

All, thanks for the help.  I checked the speaker and it resistance is 4 ohms.  cannot see nicks on the wires to the speaker and pulled semi taut to ensure not shorting on frame - still no sound.  Marty will do the continuity checks in the next few days after work, thanks for the pic.  Marty/Joe, what usually causes the amp to go bad, short, fatigue, ....?  Dave, all,  will contact GGG or Stockyard if I have no luck.  

If I find the amp to be bad, what is everyone's thought about upgrading to PS3?  Would it be worth the effort, or just replace the amp?

Thanks again.

Audio amp repair will be a 1/4 of the cost of upgrade to PS-32.  For that engine, you need to confirm if speaker is aft in tender or under coal pile.  If under coal pile the PS-32 fit is tight, because of lack of head room.

Voltage spike and other issue can get the audio amp.

The good news is you can just ship me the PS-2 board set and I can repair.   G

Did we try turning  the  vol pot up & down a few times?  I know dcs over rules  conventional  volume but the connections at the pot must still be there.

Marty, finally got to check your suggestions for continuity on the Speaker and Sound pot.  All continuity is good.

GGG, I will be dropping you an email to send you a board to get the sound amp replaced.

All - thanks for your help.

All,

Just to let everyone know I got the Mikado repaired thanks to help from GGG, who repaired the audio amp.  I replaced the boards this evening and everything worked like a charm.

If anyone has any issues with their MTH boards I highly recommend GGG's work.  The work is impeccable, response very quick and fees quite reasonable.  

Everyone else, thanks for the recommendations and help, I am glad to get a favorite engine back up and running.  And best of all I learned a bunch of diagnostic tricks and repair techniques.

Thanks,

Agree about GGG's repairs.  He repaired some items for me.  Quick turnaround, reasonable fees, and high quality work.