Help Troubleshooting a K Line Scale TMCC Hudson?

I have that engine and while I did get a kit to add cruise control, it did not come with cruise control. I would assume, from its behavior, that the TMCC board is failing.  Because it runs, the mechanical aspect of the engine are OK,  the electronics need to be repaired.  You could most likely run it still via transformer power and not under command control.   ERR does have a kit that would permit the replacement of those components and I have 5 of their kits (4 operating cars and an SMR engine) that run well and retain command capability.  I had my LHS replace my Kline electronics with MTH Proto 2 if you do not mind having another control system.

I have the scale K Line Hudson 5344W that came conventional.  I upgraded it with ERR TMCC and RS with no problems.  These are great looking engines, detailing is fantastic, motor pulls whatever I put behind it, including 10-12 MTH/Lionel/K Line NYC heavyweights.  I am not certain about the originally installed CC electronics in the scale Hudson.  However, I also have the scale Berk that had same K Line TMCC in it when introduced.  The Berk did give some problems in later years, but was easily corrected with ERR products, also.

Jesse    TCA   12-68275 

If this is the CC version, it has the K-Line cruise.  If not, and it has the ERR Cruise Commander M upgrade, try reprogramming the locomotive with a type of AUX1-4 and see if that gets it's mind right.

Of course, telling us exactly what you have, including exact model numbers, helps us to help you.

Hi- sorry it is a bone-stock K Line 3270-5343S, with factory TMCC in original condition. (I haven't fiddled with anything)

Any other thoughts are appreciated! I hate to go buying new chips and whatnot if it can be avoided. Everything else seems to be working fine. 

Are you "sure" it hasn't been upgraded in any way?  Are you the original owner?

The symptoms suggest a cruise board running away, which that particular model doesn't have.

K Line 3270-5343S is factory command control.

http://www.legacykline.com/app..._oem_sku=K3270-5343S

The latter models with "CC" suffix had cruise.

Jim, that's why I question the symptoms.  Runaway in that manner is rare for the non-cruise models.

Well, now I really screwed up. I went to remove and replace the two boards in the tender, just to make sure some contact was off. And here comes the lesson in not doing things without great lighting: I replaced the railsounds (I think for reasons you will soon learn) board a pin to the left without noticing. Predictably, I immediately fried the board upon giving the locomotive power. So now we have no sound and the acceleration issue...

It runs perfectly and controllable in analog with a ZW. Knowing that, where is the motor control board? In the tender or under the boiler? I tend to gave things one more look, then if I have to I will go the ERR route or just keep it for analog running as-is...

Well, the tender only has the sound boards, so you should have been looking in the locomotive.  The motor control board will be the one with the heatsink, and there's also the R2LC TMCC board plugged into a small motherboard.  I'd swap out the R2LC first, as it can cause this and it's a lot easier to test. 

I have RS4 boards, if you didn't cook the sound chips, I can probably get the sound going for you cheap.