Installing a sound decoder in Non Dcc ready K4

[richg]

Thee PC board really looks like first generation. It is quite crude compared to what is being produced today. I and others have posted photos here of the present PC boards.
This type of electronics is all hand wired as far as components go.
The newer generation PC boards are usually assembled, soldered and tested in a computer controlled machine. Wires added by hand.

It is common knowledge here the Bachmann does not use NMRA colors for the wires. That has been discussed a lot.
Take time to search the Bachmann forums.

Since the tender has the PC board and 8 pin connector, the motor is isolated. The loco is ready for a decoder.

I am going to be very blunt about this. If you insist on opening a loco and work at this level in DCC, get yourself a couple multimeter's and learn how to use them.
They cost about $5.00 online at Harbor Freight and I have had three of them for some years and compare very well to an expensive meter.

Rich

[uncbob]

Been using multimeters since 1958

But the replies here have simplified my task

[richg]

Things to remember.
Using  a multimeter helps reduce the LED and light bulb burnouts. Some have installed a decoder and connected the light outputs to 1.5 volt bulbs. Poof.
LED's do not show any resistance and can appear like an open circuit. With a couple clip leads and a 1k resistor, plus 12vdc, I can see if there is an LED and which polarity I need. Some use a 9 volt battery and 1k resistor. I have used both options.
A 12 volt bulb and 1.5 volt bulb will show resistance.
The red and black decoder pickup wires will show about 50 k resistance, at least with my Tsunami decoders.
Using a multimeter properly helps prevent decoder burnout, motor not completely isolated, as well and I have seen a fair amount of that in the different forums I belong to.
Besides a visual check, I check the isolation using the 200k resistance scale. It is possible for one tiny strand of wire to be still in place. Been there, done that, have the T shirt if you think that is ridiculous. Happened with a split frame mod.
A dangling uninsulated decoder wire because they are excited about running the new decoder. We are still kids.
Using the program track option with a new install. A defective install will usually show up in this test as the current is limited and the controller will tell you if your system has that option. My NCE Power Cab does and has protected me. The orange and red wires where swapped. The brand of red & orange DCC wire looked almost the same. I got rid of it and bought better looking red and orange wire.

Rich