mth ps2 3 volt boards.

I would email GGG.  It's his area of expertise.  His prices for the work are reasonable, and he may point you to some things to check first.

With the 3V PS2 locomotives, there was a rash of bad 4-ohm speakers (coils opened up). A quick way to test is to use an Ohm meter on the speaker. If it indicates 4-Ohms resistance (there's usually also a slight click or chirp), the speaker is OK and off to George it goes.

If you get infinite resistance (open coil) your speaker is bad and needs a replacement. I'd go onto eBay and find some 2" 4-Ohm 3-watt speakers as they're pretty inexpensive (about $4-$8 per pair). You'll have saved money and time over shipping the locomotive.

hi I would also try a conventional  reset just to make sure it's not something simple like a reset 1W5B 1/2 SEC INTERVALS FROM A z4000 mth transformer reset in conventional mode!. you can also try a reset from DCS if you use remote operation!

Alan

p.s. also someone mentioned checking the speaker for 4 ohms, you also need to check speaker terminals to ground of the speaker some of those speakers have been known to short to ground and that will blow the sound chip

Hi Guys, Thanks for your input on the speaker and resets - I should have mention that the ps2 boards that have no sound do show signs of overheating on the sound chip, that is why I am looking for a replacement for the chip or an ic chip no. so that I can replace it with a new one, hope someone out there can help. I am also wondering if anyone knows why these amp chips go bad, is it due to age of the boards or a short  Thanks Frank H.

Unless you have the equipment and know how, send it to George.  

mthonca posted:

...the ps2 boards that have no sound do show signs of overheating on the sound chip...

Since you apparently know the chip in question, if you're asking how to translate the chip marking 2000D1, that's a TPA2000D1PW available at DigiKey for about $3 (plus shipping):

http://www.digikey.com/product...296-7009-5-ND/374561

The chip has thermal shutdown protection so presumably you checked as suggested previously about shorts in the speaker and/or speaker wiring.  But if the chip overheats even with the 12-pin harness (with the 2 speaker wires in the middle) pulled out, then changing the chip seems a logical next step.

Obviously since you're seeing the chip you know what you're getting in to.  It does take some soldering finesse to replace it.

That chip replacement "usually" brings back the sound.  However, I recently had one that the audio chip was toasted with an obvious bubble, and replacing it did not bring back the sound.  I think I'm 4 of 5 on them, before I had a perfect record, don't know what other damage was done to the last board that resulted in no sound with the new amp.

Audio chips can go and seems to be a frequent issue on a derailment or if some other board failure occurs.  The longer you power up the board with a shorted audio amp (can be down to near 0 ohms), the more damage you will do to other sections of the board or the power supply which are not meant to carry that kind of current.   There is also a high chance when you replace this that the engine won't have speed control either.  That is another chip on the Power Supply board.  All depends on what caused the fault.  G

GGG posted:

...There is also a high chance when you replace this that the engine won't have speed control either.  That is another chip on the Power Supply board.

Good idea.  If putting together a DigiKey order for the audio amps, why not toss in a couple speed control chips...U12 on the power supply board LMV358M, 89 cents at DigiKey:

http://www.digikey.com/product...58M%2FNOPB-ND/270692

U12 (has silkscreen designator) is on the bottom of the power supply board.  Should be easier to replace (if needed) than the audio amp chip.

If you use the OGR Search feature on "TPA2000D1PW" or "LMV358M" you will find previous threads with possibly relevant troubleshooting tips.

Thanks for the info. on the chip nos. I will put an order into DiGi-Key for both the chips and will let you know how I make out.. Thanks again for the help !!   Frank H.

I see many of these go when guys run old lionel transformers without protection.   Fuses are cheap, PS2 boards are not.