Railsounds power supply board?

I have this, I don't know if other pins are active, but there's not much to the power supply.

Thanks. I have the 5 volts, so it looks like it's the sound board.

The board seems to have a lot of parts on it for just a 5 volt supply...but then I guess there is some on and off - ness for the conventional and command...the battery backup, etc.

But that helps,

Thanks again,

You can start looking at these pins.   I have some RS4 boards if you need one...

Well, you need to ensure you know which board is bad by swapping any other Power Supply in.  Or any RS4.0 Sound board.  I did fix one PS board that had a cold solder joint on the inductor.  Look for something simple.   G

John,

 The battery negative and chassis ground are the same pins, is that correct?

Battery is ground referenced on these, but not on the ERR RS Commander single board, everything is floating on that one.

I do have 5.06 VDC on the PS output. The RS board has 5 VDC on its pins. So looks like the RS board.

Subbing a new RS board will be next, but I only have a generic steam one coming.

Do you have a Mikado UP 1925 board that I could buy John?

I don't have that one, but you should be able to transplant the chips from your existing board into the new RS board, the chips usually are OK.  Remember, you MUST use the PLCC extraction tool, or you'll most likely break the PLCC socket and then you have bigger issues.  I've fixed a few of these, but the fix doesn't always work, depending on how bad the socket is damaged.

I'll try that. Thanks for reminding me about the extraction tool. I don't have access to them any more, so I just ordered one from DigiKey.

You'll thank me in the morning.   I just put an old RS 2.5 board back together, it has three corners broken, two on one side, and one on the other!  I first glue them with CA adhesive and let it dry.  Then I rough up the exterior of the break and use some JB-Weld to add some strength.  The board survived the experience and awaits installation.

Just because you have 5V what makes you believe you don't have another issue with the board?

Do you have any other RS 4.0 engines? Easy swap for steam.  G

I don't have much info on the PS or the RS board. So as you might imply, I will profit most by a substitute which will arrive in the morning mail tomorrow. I do feel tha the PS board seems to have a lot of parts on it for just a 5 volt supply. I'm no stranger to any variation of these kinds of applications, but no schematics, block diagrams, or even comprehensive pinouts of the boards, except for the helpful pin out provided by John, leaves me guessing and guessing is what I posted.

I'll post the results.

Not many of the pins on the RS P/S board are connected.  I recently tossed all the bad ones in the box or I'd have pulled the connector off to see if any others were connected on the top of the board.  I was always surprised how much it took just to generate power.  They do also manage the battery switchover, perhaps that's some of the parts.

Fixed!

Not the power supply or the sound board.

Rats...I tried twiddling the volume pot when it first happened and it didn't help.

So after trying both the new PS and the SB and neither worked...I was forced to try the volume pot again and after the 2nd or 3rd twiddle, the sound came to life.

So there you have it...

I tried to put a drop of Deoxit D5 by Caig Industries into the pot as best I could. Deoxit has been responsible for fixing a thousand Heathkits over the decades. So we'll see if it helps Lionel.

Thanks for all the help. I learned some things.

Chuck, I guess you missed my point.  Is this really the only RS 4.0 engine you have?  If you had any other engine diesel or steam doesn't matter, you could swap power supplies and RS boards.  Bad into good engine and vice versa.  At that point you would have know the boards were good, but the engine had issues.

Mother board trace, speaker, volume pot.

Glad you got it.

I do think the Power Supply board is more then a 5V voltage source.  It probably also amplifies the output to the speaker, may do voltage detection for off sets on bell and whistle, etc...  G

The RS4 audio board has a 1.1W amplifier for the speakers, the LM4861M is the output amp.  The P/S board does manage the battery backup power and generate the 5V.