Got a MTH 20-2169-1 E-8 Rock Island. It had green battery that didn't want to hold a charge, so I tested the unit with a regular 9 volt and the engine starts up and runs fine. Next I put in a BCR and no joy. Checked the voltage at the 9v plug and was 1.3 or so volts. Charged BCR externally, checked about 8.3 volts, put it in and started up ok. but the voltage was going down at the 9v plug. Any ideas why the PS-1 board isn't charging the BCR / battery ?
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There are a number of components in the charging circuit, the LM337 regulator on the bottom side of the board heatsinked to the chassis is one possible failure, there is also a resistor near the connector, but I'm sure there are also other components involved.
I take the bad board out, take a good tested one from the working pile from upgraded engines, put the bad board into a pile for rainy day to repair.
FWIW, a common failure is people remove the board to change a battery- in some the battery is under the board, and then fail to properly insulate that regulator when mounting the board. Bad things happen when it's shorted even partially to frame.
Also realized- this is showing that resistor in series with the battery that often gets burned or charred.
@Vernon Barry posted:FWIW, a common failure is people remove the board to change a battery- in some the battery is under the board, and then fail to properly insulate that regulator when mounting the board. Bad things happen when it's shorted even partially to frame.
Also realized- this is showing that resistor in series with the battery that often gets burned or charred.
Interesting, battery is in the back, but it does appear the regulator both vertical and horizontally may have gotten hot at some point.
I've had this repaired years ago, can't remember what for, but never disassembled it myself, hum what to do...
Thank you sir !
Your using a piece of paper under the screw head, where normally is a Teflon washer that also keeps the screw centered and insulated from contacting the inside edge of the transistor tab as it passes through. Make sure the transistor tab is not shorted to the screw.
If the regulator failed the top board would not have power for operation and or it would see over voltage. The resistor is a prime suspect. Then there are several other parts on the opposite side of the board related to battery function. Replacing bottom board is best option. G
Thanks guys, I'm going to look at it some more tomorrow, but right now, I'm not sure if I'm going to get it fixed or just upgrade it to PS-3
Just a curious question for @gunrunnerjohn, would this be a candidate for a YLB to workaround and fix the problem?
One can spend lots of time, troubleshooting and repairing this when a self-charging component like the YLB could be a potential solution.
@H1000 posted:Just a curious question for @gunrunnerjohn, would this be a candidate for a YLB to workaround and fix the problem?
One can spend lots of time, troubleshooting and repairing this when a self-charging component like the YLB could be a potential solution.
One minor detail. The YLB charging aspect assumes that DC and AC common or ground are the same, and that charging is in reference to the DC negative lead.
PS1 uses an LM337- a negative voltage regulator. I don't claim to know the schematic of the PS1 lower board, but my concern is that the negative lead of the battery connection could be at a different potential compared to AC frame ground. Maybe I'm wrong, but again, how the YLB and really even the competing charging circuit from J&W BCRs, this dependency and assumption of the DC negative lead could be a problem?
Hi the bottom board is available from mthpartsand sales.com part number is AD4500001 sells for $60.00 plus shipping n tax!
MTH Electric Trains (mthpartsandsales.com)
Alan
The picture of your bottom board shows red wire next to the resistor which can burn out if the battery is installed backwards, there were 2 different harnesses! !
Before you go buying a board, I have a set of PS1 MTH NP F3s that I wanted to convert to TMCC. I put it on the track, it moved three feet, then when I cycled the power, started the clank. My two brothers that are MTH fanbois said I should replace the battery, so I bought a Tenergy 9V. Still clanks. Based on what I have read, the chip needs to be reset.
I am now stuck on what are the four wires that pass thru the connectors. Two are the rear coil coupler, but what are the other two, and could I convert one of them to center rail, and if so, where would I put a polyfuse. Kinda stuck on should I get a reset kit, trace out the wires, or just go for it. Wild guess is they have something to do with the lighting. Also need to take apart the middle B unit to see what happens in there. Also what if someone in the future hooks up a non-converted.
Once I get past that, you can have the boards.
If the trail F3 is powered 3 of the wires are for slave board control. If it is a dummy, they run coupler and control of reverse light on Trail CV board. G
@H1000 posted:Just a curious question for @gunrunnerjohn, would this be a candidate for a YLB to workaround and fix the problem?
One can spend lots of time, troubleshooting and repairing this when a self-charging component like the YLB could be a potential solution.
Like Vernon says, I don't know that the grounds work out without looking. The YLB depends on either frame ground or a diode between frame ground for it's negative reference. I designed the board with all versions of Lionel Railsounds board specifically in mind. Without analyzing the charging circuit, I don't know if that board meets that requirement
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