repair Lionel railsounds 2.5 card. 589-699

Sending you a note via e-mail. I've had pretty good luck bringing RailSounds 2.5 boards back to life.

TRW

Is there a common part on the board that fails?

I responded to Jeffrey's question directly to him, but for the record, the Lionel RailSounds 2.5 boards themselves are fairly reliable.

The failures I've found over the years tend to be in the "back end" where the switching power supply and voltage regulator reside (the two components attached to the heat sink) or at the "front end" connected to the speaker and volume control pot. Problems there usually take out one or both of the audio amplifiers, audio pre-amp and/or the PIC and ROM chips if the problem is particularly severe. With the exceptions of the PIC and ROM (programmed replacements aren't typically available), all the other components are replaceable.

TRW

Thank you for responding to my question.  I am just going to upgrade the sound system to module from ERR by 3rd rail.  Technology has changed a little since 1995.  The sounds from the original module were very limited thus not really worth repairing. 

PaperTRW posted:

I responded to Jeffrey's question directly to him, but for the record, the Lionel RailSounds 2.5 boards themselves are fairly reliable.

The failures I've found over the years tend to be in the "back end" where the switching power supply and voltage regulator reside (the two components attached to the heat sink) or at the "front end" connected to the speaker and volume control pot. Problems there usually take out one or both of the audio amplifiers, audio pre-amp and/or the PIC and ROM chips if the problem is particularly severe. With the exceptions of the PIC and ROM (programmed replacements aren't typically available), all the other components are replaceable.

TRW

Neat info.   I think I saved one way back with audio amp change, but later had another that that did not work.  In general they are robust units.  Why did they use 2 audio amps on these.  Going from memory but it had two chips of the same type.  G

GGG posted:

Neat info.   I think I saved one way back with audio amp change, but later had another that that did not work.  In general they are robust units.  Why did they use 2 audio amps on these.  Going from memory but it had two chips of the same type.  G

If replacing the pair of audio amps didn't fix things, try replacing the lm4861 pre-amp on the other side of the board. That's usually the next part to go. I have one board that still isn't back to life after replacing those components, and tracking down the cause isn't trivial at that point.

I'm not 100% certain why Lionel used the audio amps as a pair, but I believe it has something to do with driving both sides of the speaker. Both the predecessor RS2.0 and successor RS3 boards use the exact same set-up, before moving to more efficient designs on RS4 and above.

TRW

I never did get the dual audio amps, but I never bothered to track down how they were being used.

I have a Lionel 6-18045 Commodore Vanderbilt Hudson with no sounds.  I measured about 40 volts on one large electrolytic capacitor and 14 on the other.  The screw to the stud mount in the middle of the board is very hot.  Are the voltages OK?  I assume some component has shorted to make the screw so hot, but have not pulled to board to see what component is heating it.  Do these symptoms suggest anything to anyone?   Thanks.

Find another RS 2.5 board and replace it.  If the chips are still good, you can transplant them to the new board.