'smoked' a Spectrum 2-8-0 DC circuit board

Model Railroader Electronics and DCC
1

Ok, probably an obvious thing, but I was curious if this is common or not.

I’ve had this lil’ 2-8-0 HO Spectrum for about 4 years. It’s been packed back in the box (the nice black foam lined box) for about a year since I disassembled the test ‘L’ layout and am working on finishing a room at the back of the garage for a new layout.

I just finished building a manual turntable for the end of one staging yard and wanted to test the connections, so I got the old steamer out of the box.

Spectrum 2-8-0 DC (DCC ready). Using an old MRC Tech II DC pack. Track is perfectly straight and level.

She ran perfectly before it was packed away, but now forward is very slow: at full throttle she’s only going about the equivalent of 1/4 throttle. Reverse works fine, full sweep from dead slow to good top speed. On the forward selection sometimes the overload light will come on. Also I smelled ozone. NOT GOOD!

I did some searching here and found the thread about the RF filtering cap soldered at C1 (mine has a double cap linked together). I noticed that the red motor lead was tucked in very close to the 8 pin connector and some of the insulation was melted, but not all the way through, so I repositioned the wire. I then clipped one cap lead, moved the clipped end slightly to avoid contact, and took it out to the garage to try running again (shell still off).

This time, forward worked very slightly better until a plume of smoke began emanating from the center of the circuit board under the D4 resistor or whatever it is. Quickly shut off power and blew on the board until it co

2

It sounds like binding in the mechanism.

When using some decoders, you should clip the capacitor. Only reason.

Does not sound normal. Your best bet is to return the loco for a replacement if you cannot work on the loco. The board is not available as far as I know. Check the Bachmann page and Bachmann forums.

Use a multimeter to check the continuity on the PC board. A item with a D such as D4 is a diode. Check the foil on the PC board for any evidence of burning.

Check the two inductors for continuity. One might be burned out. There is a inductor in series with each motor lead. Some coils have thin wire wound on a form. Some coils have a green body with colored bands. They look similar to resistors. There will be two inductors for a PC board.

Here is a copy of the schematic of the USAR medium tender I think is used with the 2-8-0. I bought the tender to be used with a different loco and traced out the wiring on the PC board. At least this is correct for my application. All I had to add is a 1k resistor for a LED headlight. The wiring is correct for a 12 volt light bulb type headlight.

Rich

3

I don’t know about the replacement board, but R is a resistor, D is a diode. It seems more likely that you smoked a diode which is now open. Probably 2 diodes. The reason they give you a parts list with the engine is so you can order replacements. Contact Bachmann.

4

My 2-8-0 did the same thing. Since I converted it to DCC when I got it it smoked a decoder and the light board. It was on a shelf for about 1 1/2 years. Ran great before sitting. There is a cogged drive belt and a plastic gear between the motor and flywheel. The gear was slipping on the motor shaft and the drive belt took a hard set and lost its flexibility. I have not fixed it yet. I have been kicking the idea of putting a Bowser drive system in it. The decoder that got smoked was a soundtraxx LC280 that plugged into the original board and had a speaker mounted on it. Before I disassembled it I put a DC plug in and tested the amp draw on DC. At 10 volts it drew 2.4 amps in forward before the light board fried. I could hear the motor spin wildly and the loco just moved about 3 inches and was jerky. With out the motor and belt the drive mechanism is smooth when pushed back and forth. Before sitting for so long it was the sweetest running loco you could ask for.

Pete

5

Did you run the engine on track before you got to the turn table? If it was fine before the turn table, I would look at the turn table.

I woud all so look at the drive as well, if it is binding going forward that could cook the board as well.

Last time I looked Bachmann will repair or replaces any steam engine for $15.00.

Have you done the quater test on the turn table? I am not sure if this appliess to DC, but if a bus wire is to thin it will keep the breaker of the power supply from shutting down. I BBQ $120.00 to $200.00 in decoders before I under stood this test. I know that smell well I must add.

Smoke them if you got them Ken.

6

Thanks for the replies, guys.

I guess I’ll have to check the drive, I also thought I should try to run the motor with the power leads clipped directly to the motor lead solder joints on the end of the pc board.

After that, I’ll contact Bachmann to see about buying whatever parts I need.

7

I don’t think Bachmann sells any replacement parts for this loco – you send the whole shebang to them and they will repair if possible, or replace it if they have any left in stock.

We had a club member send one back, and he received a DCC On-Board replacement. If you don’t use DCC, this could be a problem.

8

I’d really rather not ship the whole thing when all I need is a small part.

Warranty is not a big deal, I don’t mind buying the parts, and the installation is pretty simple.

I’ll be using DCC eventually, but as the room’s not anywhere near done yet, it won’t be for a while. I figure on making a DCC system a very late purchase in the grand scheme of things, since I’ll be the only operator I can run one loco on DC for a while at first.

9

I had a similar problem with a Spectrum 2-10-0 Decapod i purchased from Micromark. It would run great in reverse but very sluggish in forward. A friend told me which was in the instructions if I bothered to read them, to run the engine fro a break in period. I ran it backwards on the dc layout for about 15 minutes and then would switch direction I keo this up for about an hour or so increasing and decreasing speed. It finally worked it’s self in and now runs like a top. You can send it back to Bachmann for repair or if it’s like what happened to my N&W J class a defect right out of the box (drivers out of sink) they will give you a replacement. Bachmann isn’t too keen on selling any small parts. I have a second Decapod that I broke of one of the front steps I asked for replacement part and they told me to send it back. They sent back a brand new locomotive I couldn’t ask for better service then that. One thing I will warn you of though, Bachmann takes their sweet time getting stuff back to you. Remember the N&W J class loco I mentioned it only took them four months to get the new one to me so you will need to be patient unless you feel like driving to Philadelphia.

10

Rich, Not the only reason. I have done extensive testing and have a large fleet of Bachmann Spectrum locos on my DC layout. I use Aristo Craft Train Engineer throttles which have a pulse width modulated output.

Removing the noise filter caps dramaticly improves the slow speed operation of the Spectrum 2-8-0 and 4-6-0 in particular, and improved all Spectrum locos in my fleet (4-8-2’s, 2-6-6-2’s, GE44T, GE70T) as well.

AND, improvements where seen on a number of different conventional power packs as well as on the Train Engineer.

I have also noted this problem/solution on the new Intermountain FP7’s. Slowest speed was very fast with the TE until the noise filter cap was removed from those as well.

To the OP, Bachmann still makes those, but has updated them with LED headlights. If you return it they will likey replace the whole tender or give you a whole new loco.

Sheldon

11

Hello Atlantic Central

I was answering the OP’s question. He did not indicate he was using DCC. Yes, I know, DCC and your method is the same. PWM. Both need the capacitor removed. Still the only reason to remove the capacitor.

Rich

12

Thanks again for the feedback, I do appreciate the help.

For any that may eventually have a similar problem, I found the culprit in my case:

After a considerable amount of blue language, I got the loco disassembled, the instructions I could find were sketchy, maybe they made several shell styles with differing attachment points, I don’t know. In my case I had to (after the obvious pilot truck and screw removal step) separate the tops of the forward ladders, separate the valve gear on the right side (found out the hard way), and do a LOT of wiggling. Managed to snap off the valve gear and one ladder which slipped back into it’s attachment hole while wigglng was in progress. Well, that’s what they make glue for.

Unscrewed the weight which houses the motor, and separated the two halves.

The belt is fine, motor and running gear turn freely, so I thought it must just be the circuit board, which is now fully toast. It was the D2 diode that cooked, and it’s now split in half, and the number two pin in the 4 pin connector has melted somewhat. This is the yellow wire from the connector which goes to the green lead to the front headlight.

NOW, after starting to gently reassemble the weight/motor/gear assembly and making sure that it still turns freely, I noticed on the worm gear, the second tooth from the rear of the loco has a chunk missing, so must have been the root of the problem.

Why this didn’t show up earlier, I have no idea. The driver axle gear is delrin or a similar type of acetal plastic and the worm is brass. It must be a manufacturing defect, since this is certainly the first time I’ve disassembled the loco, unless I’ve been sold a return. The back of the loco shell has always been loose (lifted up freely), I found this to be due to the rear shell attachment screw housing tube was sheared off, which I glued back in place, so one

13

Thanks for explaining what you found by taking the engine apart. Unfortunately, I don’t think Bachmann sells replacement parts. Their warranty says they will “repair or replace the item at their discretion” or some such verbiage.

I ran into a problem with a G-scale 2-truck Shay having a broken part. The exploded drawings that came with the model even showed the part number. It should not have cost more than $1, but when I contacted Bachmann they said, “No, you have to purchase the entire Shay engine assembly for $75, or send it to us and we will repair or replace it under warranty.”

14

Hello Offlinekcole4001

The not so obvious solution has been to send the loco back to Bachmann. A few have said that The Bachmann forums have covered this issue a lot. You should really join. You can make your email address not seen when you join. There is a Bachmann rep, yeah you guessed it, named the Bach Man there.

A few people have been able to get parts but it is a hit and miss situation. I got two DCC connectors for my Spectrum 4-4-0 that I cut too short.

http://www.bachmanntrains.com/home-usa/board/index.php

You do not have to leave this forums as there are maybe three or four here that are on the Bachmann forums. Both forums can benefit from each other.

Rich

15

Hi,

Thanks for the link.

Ill wait to see what their reply is, and if I have to return it, then so be it. The layout wont be built for a while yet anyway, so time isnt a factor, but I dont see any economy in shipping a heavier box twice when I could just replace the parts myself at less cost.

It might even end up being cheaper to just get another engine and keep this one for parts, it`s undecorated and unweathered yet.

It also seems odd that theyd include a blow up diagram and parts list with numbers included with their product if they wont sell you the parts.

It`s not like I want something for free, I emailed them that I would just like to buy some parts, plus a spare belt or two for when the original belt breaks or wears out.

Anyway, I`ll wait and see what happens.

16

You have to remember, Bachmann is run by Bean Counters. I really wonder how many are model railroad enthusiast? The stuff is made in China also. I think the paper work is a feel good thing for customers.

I buy Roundhouse locos and the same thing there. Run by Bean Counters. Made in China with parts lists. I have been able to get some parts from Athearn/Roundhouse though.

Bachmann are coming with SoundTraxx decoders which is a USA company and Roundhouse is going to have them also. Don’t know how they have the decoders installed, here or there?

Roundhouse is going to have a revamped Genesis 4-6-2 with sound.

Rich

17

Rich and Kevin,

It is my understanding that Bachmann may not actually be able get parts on an “ala carte” basis. Bachmann is and American company but is wholely owned by Kader, the Company in China that does the manufacturing. It has been said by several people with knowledge of such matters, that Kader may actually be limited by laws in China that control what they export. And/or they have simply concluded it is not cost effective to handle parts.

Some parts are brought in to the US as “repair assemblies” but many of the parts that are supplied to customers are simply salvaged from returns. They are very good about trying to give you what you want and are very free about simply replacing problem locos. During busy fall/winter season they can be a little slow, but they will take care of you.

Many of the other American companies in our hobby using China for production actually have more control over such matters becuse they specify with each production run a set amount of parts. OR, in some cases all or some of the parts are actually made here and are sent to China for assembly. I believe this is still the case with most/all Intermountain products and was or still may be true with at least some Athearn/Roundhouse products. This is likely the case with Bowser’s new RTR stuff as well, and possibly others. As for sound decoders, it would not surprise me if they are made here and shipped to China for installation in the locos.

The manufacture of products by making part of it in one country and sending it to another country for assembly and then sending it back or elsewhere for sale is not new or unusual. Many years ago, MATCO tools had its sockets made by ALLEN manufacturing. After developing a new process to make sockets, they needed a grade of steel that was much cheaper to buy in Germany. But total production costs there where too high. So, the steel was made in Germany, a

18

Thanks Sheldon, you’re probably very right about the parts stock, this is a more common issue for many companies in varied types of business, as large inventories make no money, so they’re cut back more and more.

I live in Canada, so cross border shipments are more expensive than interstate shipents, not to mention the exchange rate.

The more I think about the problem, the less significant it becomes, however.

I could most likely dispense with the circuit board altogether and run the motor wires direct from the pickup leads, and I don’t think the worm gear fault actually contacts the drive axle gear, so there should be no real operational issues. I just won’t have directional lighting until I install a decoder, which I will have to learn to hard wire as with an older style of engine.

No big deal really, just so long as the engine runs, I’ll be happy.

19

My guess on the circuit board would be that you might have had one of the trucks turned the wrong way around when you put it on the track, causing enough of a short circuit to fry something in the lightboard. Luckily if you’re in DC the lightboard is optional, before converting to DCC I removed several lightboards from DC engines and just hardwired everything together. It will run fine, and use less power since the lightboard soaks up power for the constant lighting circuit.

If you want to go DCC later, you can just do a hardwire install to the existing wiring, no problem.

20

Kevin,

One other important note. They sell that tender seperately with the old style circuit board installed. So if you come across one of those at the right price, that would be a quick fix as well.

Sheldon