major problem with my protosounds 2 board

No schematics.  Touching the 5V fan lead to AC chassis can cause havoc with both the PS and Processor board.  So you need someone with experience working these boards to troubleshoot and repair.

This type of casualty is one that can damage the processor beyond repair, so hopefully it did not go that far.   G

Unless someone has one in their scrap, bare boards are not available.  MTH is very possessive of their tech.

You end up paying more for the circuit board typically then you do for the whole conversion kit.  MSRP on the PS/2 3V board set is $200, the kit sells for $150 to MTH RR club members, $180 MSRP.

 I partially installed a PS2kit into a G gauge engine. After loading the soundset, there was a screeching noise coming out of the smoke fan. As I was prodding around, I must have accidently push the loose charging jack into ground or something like that. The board looked toast. The soundset was bugged out.

 I sent it to G and he luckily repaired it! Even he said it was lucky. The board was burned so bad we didn't think he'd be able to solder on a new piece. The engine still runs fine to this day. Although I never added ground lights to that engine. I decided not to tempt fate.

 I would send yours to G and give it a shot. Or at the least, send him a high quality photo of what's burned. He's saved me a few times now.

Was this Hudson an upgrade or board replacement?  Any MTH tech can put your boards in his test fixture and tell you where you are.  Having seen this before, I feel you are not in good shape.  I have boards on hand to R&R and send all my bad boards to George (GGG) to be repaired. 

Guys, any time you do board work, carefully check all wires before powering the new board.  If a board went bad, find out what took it out and don't just throw in a new board.  I have seen this happen with people loosing new boards.  Check things first or have someone check for you.

What is your MTH number.

PS2 3V boards are gold to repair guys and not usually found in the scrap box.

Can you can take a good photo of the bottom of the processor board?

I have boards on hand to R&R and send all my bad boards to George (GGG) to be repaired.

Given the very knowledgeable source (Marty KNOWS trains), that statement is quite a compliment to GGG's ability!

I purchased a new old stock MTH GP40 Proto2 recently and everything worked in conventional mode.  Then connected it to DCS and after about 15 seconds of letting it just sit there on the track with the DCS powered up, the loco started to smoke.

Found U5 (audio output chip) had burned up.  Ordered some new ones TPA2000D1PW) from Digi-Key and they arrived yesterday.  Installed a new chip today (oh I just love SMT components, NOT!) and the sound came back for about 30 seconds and the chip burned up again.

I removed the burnt chip to check the loco's other operations just I had done before when this happened the first time except now U8 caught fire and burned up.

I give up!  I've decided to convert this loco to operated as a slave unit off of a DCS board in another loco. I'm not happy with MTH's Proto-Anything right now but at least their tech dept did help me with the part numbers and where they can be purchased.

I don't know if the board was just defective or if there is a wiring intermittent/short going on or some other electrical problem with the chassis, just have to dismantle and check everything before slaving it lest another DCS board set gets toasted.

If you'd consider selling the engine as-is, please use the E-mail address in my profile to contact me with details and how much you'd want. I would have done this via E-mail except that your profile doesn't list an E-mail address.

Thanks!

Might still be repairable if you want to send it to me.  SOunds like you have a short in the speaker/wiring, and something with the lighting also.  G

Barry, thanks for your offer, but for now I'm hanging onto it until further notice.

Thanks, GGG.  As an experienced electronics engineer I did test the speaker as recommended by the MTH tech helping me out, and it registers 4 ohms on the DMM and it sounds great when connected to a power amp, so I'm sure the spkr is fine.  The lights also worked perfectly until this last bout with U8 burning up.

What bothers me is that there was some sparking at the trucks after (or possibly before) the chips burned up again.  I have checked the wires for pinches and exposed conductors as recommended by MTH's tech dept and did not find any such anomalies.

I don't know what U8 does, but it is now burnt toast as well.  The only thing that makes any sense to me is that the voltage regulator in the power supply section may have a bad connection in the reference circuit, or is intermittently shorting the input to the output.  When I tested the audio output chip +Vdd it was right at +5.00 volts, which is correct.

After the original audio out chip burned up and was removed from the board I tested the loco in both conventional and DCS mode, the loco ran and operated fine in both modes, just no sound, of course.  And then today we have another blown audio out chip and U8 went up in smoke, why?...I have to point back to the power supply being at fault, not much else makes sense right now.  And if the +V bus is going high and popping chips, any other chip connected to that bus is also now compromised.

This is why I'm abandoning any thoughts of repairing this board.  I don't mind the grueling labor of replacing SMT chips if I know the thing will work reliably afterwards, but there is obviously something bad wrong with this board and I'm not going to throw good money after bad.

  After following this post would a TVS across the red and black(or across the wire nuts) at the board helped with this problem?

Nope.  I believe replacing the boards is the only practical solution after seeing 3 chips go up in flames OR slave the motors, spkr and lights in this loco with another Proto2 loco with working electronics, of which the latter is my current choice at the moment.

I don't think a TVS would help here.  I'm with George, I think one of the speaker leads was shorted to the frame.

As indicated earlier I did verify the speaker is fine.  I even removed it and tested it and checked for frayed insulation, all is fine.  I had the volume set really low just in case it had a problem and the new chip burned up anyway.

Hey, I just got a lemon, it happens.  Of the couple dozen MTH Premier Proto locos I have this is the only one that has given me any guff so I can't complain too much.

I'm thinking more the speaker leads, not the actual speaker.

Thanks, but the spkr leads, to and from the connectors are all fine.  Now if someone could tell me what U8 does (it burned up after the audio chip was removed from the board) perhaps a common denominator might be found.  I'm still thinking its an issue with the power supply section, but w/o a schematic who knows?