Running issue w/ K-Line K2439-0269 GP38-2 LIRR Diesel Locomotive w/ RealSounds

Well, after some more testing, I’ve come to the conclusion there must be something creating a voltage loss in the call-in signal/voltage to the relays after I press the direction button on the transformer to switch directions. When I used my multimeter to check continuity on the forward and reverse triacs, the meter closed the circuit and the loco ran forward and reverse with full sounds. I’m wondering if the transformer (CW-80) has anything to do with it? Low initial voltage somehow causing the e-unit to malfunction and relays to chatter? I dunno. I’ll have to look at it again tomorrow. 

I believe once an engine has been run. It will start in forward. (non-Tmcc) that's how I remember those old conventional electronic E-units to work. 

If you're not having problems with any other engine I would think maybe it's the reversing unit.

TMCC stuff running in conventional mode will start up in neutral ONCE after running in command mode.  After than, they start up in forward.  I've seen conventional units work both ways, starting in neutral and starting in forward.

Interesting. This has conventional K-Line electronics (sound board & separate reversing unit). It appears to have a small motor speed sensor board as well? I can now cycle through F-N-R-N but the motors twitch when it cycles to F or R and causes the transformer light to flash as a short. I had a similar issue w/ a TMCC DCDS board because the insulator pad wore away allowing the MOSFET transistor’s pad to ground out. I wonder; if they used the MOFSET to amplify the voltage to close the motor driver relays, that would explain why the relays are clicking. Not enough power to hold them closed? Maybe that’s no bueno? I’ll have to look. I’m without power right now. We just got smacked by those big storms.

K-Line had a conventional cruise board as well as the command version.  Both versions were very prone to abrupt failures.

The FET's are the motor drivers.  I don't know what relays you're talking about, the K-Line cruise or the Lionel DCDS Odyssey boards have no relays.

GRJ,

The TMCC DCDR issue I was referring to was on a Lionel RS11 that I fixed previously. It had a similar issue when cycling between forward and reverse. The driver had a MOSFET grounding to the mount because the insulator pad had worn through.
The conventional K-Line board that I’m currently working on has 2 large relays at one end. They click when I attempt to cycle the e-unit to forward or reverse. They don’t act up when cycled to neutral. Here’s a pic of the electronic reversing unit I found online:

That's an ancient conventional reverse unit, there certainly isn't a speed sensor board in that engine working with that board!.  FWIW, I have had those boards from upgrades, and I'm pretty sure the normal is for them to start in forward when first powered up.

GRJ,

If your interested to know, I found the issue. It looks like this loco took a pretty big voltage spike that fried the bidirectional diode on the power PCB and smoked the flip-flop semiconductor (IC) on the driver board. The semiconductor is supposed to oscillate between 2 different outputs when the direction button is pressed.  They independently power the call in circuits to the relays. However, it was sending voltage to both outputs simultaneously which caused the relays to click because they were back feeding voltage to each other. I picked up the parts at my local electronics store for about $5.00 and it runs good as new. One more loco repaired!

I know this is an old post but I think I have the same problem. Do you have pics and info of the parts used for the repair? Thanks

@FabbDadd posted:

I know this is an old post but I think I have the same problem. Do you have pics and info of the parts used for the repair? Thanks

FabbDadd,

What loco are you working on? Same K-Line GP38-2 or similar? Can you provide more insight into its behavior? What does it do when powered up? Did you lose directional control? Does go through N-F-N-R functions? Are the relays click-clacking erratically?

I’ve done this same repair on many analog locos that have lost one or both PIC chips that control the forward and reverse directions. Are you comfortable doing the repair because there is soldering involved? A good adjustable heat soldering iron is recommended along with a sharp pair of flush-cut side cutters and desoldering wick. It’s not too complicated to do. I believe the PIC chip is a 14 pin flip-flop semi conductor. I picked mine up from Chester Electronics in Kenosha, WI which is near me. The have them in stock. The analog chips do not have any code to program. Just swap one for one. Post some pictures of the motor driver board so I can see what you’re working on.

Thanks,

DanVW

DanVW,

It's the same model. I have both the 256 and 269 GP 38-2. I ran the engine locked in forward and it ran fine for about a half hour. When I switched the e-unit to the on position is when I had problems. As soon as I hit the direction button or reduced the voltage to switch directions it would either stay in the same direction or not do anything. I just recently cleaned the track and I'm using an MTH Z1000. I took it off the track to see if the wheels were dirty but they were clean. Placed the engine on the track and turned the voltage up and it ran in forward. As soon as I hit the direction button it tripped. Know it will not run at all. The transformer trips all the time. Thanks for the response and yes I am willing to work on it if you can walk me through it. Greatly appreciate it.

@FabbDadd posted:

DanVW,

It's the same model. I have both the 256 and 269 GP 38-2. I ran the engine locked in forward and it ran fine for about a half hour. When I switched the e-unit to the on position is when I had problems. As soon as I hit the direction button or reduced the voltage to switch directions it would either stay in the same direction or not do anything. I just recently cleaned the track and I'm using an MTH Z1000. I took it off the track to see if the wheels were dirty but they were clean. Placed the engine on the track and turned the voltage up and it ran in forward. As soon as I hit the direction button it tripped. Know it will not run at all. The transformer trips all the time. Thanks for the response and yes I am willing to work on it if you can walk me through it. Greatly appreciate it.

FabbDadd,

The 1st and 3rd pics are of the audio board, so let’s disregard them for the moment. The last pic is of the roof fan driver board (if my memory serves me right) and not likely the issue.

First, you should isolate the audio board and roof fan driver board from the loco and retest just to make sure the symptoms remain. If they symptoms disappear, reconnect one board at a time to troubleshoot and isolate the problem board. ***Take pictures before you disconnect any wiring. If you run into trouble wiring things back up, you can go back to the photos later. Label like colored wires if needed.***

To me, it sounds like the 14 pin PIC failed based on your description of events. It’s clearly visible in the 2nd pic on the left side directly between your fingers mounted vertically on the motor driver board marked MC14013BCP.

The logic of this PIC chip is a flip-flopping action similar to a latching relay, but not entirely. The PIC chip is a low current/low voltage switch that controls the action of 2 transistors on the board. In turn, the transistors act as a slightly higher current/higher voltage switch which control the 6VDC relays. The circuit essentially takes a few current/voltage steps to switch the actions of the relays (2 large black boxes on the motor driver board labeled K1 & K2).

When you initially power up the AC track voltage, the loco should be in the FWD direction (1st relay is energized in the closed position which powers the forward direction of the loco).
•The first time you press the direction button, DC voltage switches the PIC to de-energize the 1st relay which opens the contacts and the loco rests in neutral.
•Press the direction button a 2nd time, the PIC energizes the 2nd relay into the closed position and the loco moves in reverse while leaving the 1st relay de-energized.
•Press the direction button a 3rd time, the 2nd relay returns to normally open and the loco rests in neutral.
•Press the direction button a 4th time, the PIC energizes the 1st relay again returning it to the closed position which then moves the loco fwd. The PIC functions as: 1-closed, 1-open, 2-closed, 2-open, repeat. 😮‍💨

Now, the question is, what happened to yours to cause the behavior you’re experiencing? The PIC has most likely failed and is allowing voltage to leak thru its #1 circuit so the forward relay (1st relay) never de-energizes. It’s like you’re closing both relays at once or trying to run the loco in both directions simultaneously when you press the direction button while the PIC tries to cycle. You’re getting opposite polarities converging at the outputs of both relays! The outputs of the relays are tied together at the motor connection. You can confirm this by removing the transistor labeled Q4. This should break the call in signal from the PIC to the 1st relay. You can then power it up and the loco should remain at rest on startup and 1st use of the direction button. Press the direction button a second time and it should move in reverse. There is a chance one of the transistors is at fault so I’d recommend replacing them along with the PIC. They’re cheap.

Here’s what I’d do: order a replacement PIC (MC14013BCP) and 2 transistors (labeled Q4 & Q5 on the PCB near the relays). All can be ordered on Mouser Electronics or Digi-Key. Hint: once you remove the components, use your phone’s zoom function to take a picture. It’s much easier to zoom in on an already enlarged picture to get the identification marks off of the hard to read parts. Using flush-cut side cutters, snip the pins at or near the pcb. Unsolder the pins and clear the PCB’s through-holes with desoldering wick or suction tool. Clean and prep the board. Install the new components using the least amount of heat possible and watch the excessive use of solder. ***Pay close attention to the orientation of the PIC on the PCB and reinstall the same way*** Reassemble and test.

Sorry for the long explanation. Let me know how it goes.

Thanks,

DanVW

DanVW,

Thanks for all the information. The detailed explanation is great and straightforward. As soon as things slow down at work I'll get started. I'll keep you informed. Thanks again.

DanVW,

What's your thoughts on a Proto 2 swap on the GP38? I'm asking because I have an engine I was going to sell but thought I can transplant the boards instead. Have several questions:

Can I use the existing motors from the K-line?

Can I somehow keep the spinning fans?

Can I use the existing lighting?

I would like to have the DCS capabilities but is it worth it?

Any input will be appreciated.

@FabbDadd posted:

DanVW,

What's your thoughts on a Proto 2 swap on the GP38? I'm asking because I have an engine I was going to sell but thought I can transplant the boards instead. Have several questions:

Can I use the existing motors from the K-line?

Can I somehow keep the spinning fans?

Can I use the existing lighting?

I would like to have the DCS capabilities but is it worth it?

Any input will be appreciated.

FabbDadd,

If you have PS2 parts laying around, it’s not a terrible idea nor a difficult one other than ProtoSound 2 is well known to fail and the parts are obsolete. Should something happen to your PS2 board down the road, you’re stuck. I’m currently in that position with my MTH P5a. The board took a hit and burned the traces within the layered pcb. It’s D-U-N (done). I’m waiting to see if MTH comes out with more PS3/2 boards for an upgrade. The newer boards are a little more robust. I’m sure someone like GGG can elaborate more given his expertise. If you’re looking to sell the PS2 loco, go for it. Maybe use the money to purchase an ERR Commander & RailSounds Commander? That’ll at least get you upgraded to TMCC which you can then run DCS via a TIU and TMCC interface (that’s if you have the equipment).

•”Can I use the existing motors from the K-Line?” - Yes. And most likely you will need to because of the motor’s worm gear. It’s highly unlikely the MTH motor will have a compatible gear. You’ll have to swap the flywheel & tach sensor over to 1 of the K-Line motors. This is accomplished by using a puller and then moving the tach bracket over before reinstalling the MTH flywheel onto the K-Line motor. ***DO NOT HAMMER THE FLYWHEEL ONTO THE ARMATURE SHAFT WITHOUT SUPPORTING THE SHAFT AT THE WORM GEAR END*** You’ll end up wrecking/moving the thrust bushings in the motor. This will cause the armature to walk up and down within the motor case and shred the brushes. I use a small drill press vise to press the flywheel back onto the shaft.

•”Can I somehow keep the spinning fans?” - Yes. I believe you can just reattach the power leads of the fan motor driver board to the center roller and ground. Trace them back to verify they’re connected this way from the factory. If I remember correctly, the power leads for all 3 boards have common wire nut connections for center rail power and ground. But verify this first.

•”Can I use the existing lighting?” - Unfortunately, you can’t use the K-Line bulbs. They’re 18V bulbs whereas MTH PS2 bulbs are 6V. I always convert my locos over to warm LEDs. You may want to do the same? There are many threads on this forum on how to do this.

•”I would like to have the DCS capabilities but is it worth it?” - In my opinion, digital control (regardless of system), is more enjoyable to run.

Since the loco requires repair and the original analog circuitry is unavailable, it might be a good time to either; a) install an ERR Commander w/ RailSounds or; b) wait for MTH to produce and sell PS3/2 kits again and go that route. If you end up selling your PS2 loco and later on you need an MTH harness, tach sensor, etc., I can send them to you. I have plenty laying around from conversions. I’m sure others on the forum do as well. Heck, MTH still has and is selling harnesses (depending on model of course). You can send the board out to have the flash code and sound file installed for whatever loco, road name, and road # you want.

Lemme know what you decide 👍🏻

DanVW

It's been some time but I finally upgraded the K-line GP38 to MTH Proto 2 and it works great. The next thing I would like to do is swap the lights to LED and connect the original fans. After that I would like to put in a smoke unit but I'm not sure if I can because the the Proto 2 came from an engine that didn't have it. Is it possible? Any input is greatly appreciated.

@FabbDadd posted:

It's been some time but I finally upgraded the K-line GP38 to MTH Proto 2 and it works great. The next thing I would like to do is swap the lights to LED and connect the original fans. After that I would like to put in a smoke unit but I'm not sure if I can because the the Proto 2 came from an engine that didn't have it. Is it possible? Any input is greatly appreciated.

Looks good. Did I spot a Greenport Scoot set on the upper level? I have one and added two more cars to it last year.

Bob

@FabbDadd posted:

The next thing I would like to do is swap the lights to LED and connect the original fans. After that I would like to put in a smoke unit but I'm not sure if I can because the the Proto 2 came from an engine that didn't have it. Is it possible? Any input is greatly appreciated.

You can replace any of the 6V bulbs with an LED and a 220 ohm resistor, they'll work perfectly.  I've done that a ton of times.  Just make sure the anode of the LED (long lead) goes to PV (purple lead).

Thanks RSJB18. Yes that is the Greenport Scoot. I will be purchasing the other two cars in the near future and would also like to add the 18" passenger set to my collection if I can find one.

Thanks for the info GunrunnerJohn. I'll keep you guys posted.

@FabbDadd posted:

Thanks RSJB18. Yes that is the Greenport Scoot. I will be purchasing the other two cars in the near future and would also like to add the 18" passenger set to my collection if I can find one.

Thanks for the info GunrunnerJohn. I'll keep you guys posted.

Here's my two. My set has passengers that were added by the original owner. I plan on converting the whole set to LED's and adding passengers to these cars also.

I'm also converting my Greenport cars to LED lighting.  I would love to add some brains to the MP15 that comes with the set, but I don't think that this is on the docket right now.  I also dream of swapping out the ALCo shell and putting it on a motorized frame, but I have been unable to find a suitable donor at a reasonable price.

I bought mine at at a toy store in Port Jefferson, about two blocks south of the ferry terminal.  My fiancée at the time loved the set, so we had to get it (for WAY TOO MUCH MONEY) and I just recently picked up one of the two sets of extra cars.  Now, all I need are the drunken passengers and perpetually grumpy conductors to make that set complete!