ESU LokSound 5 58721, 58731, 58751, 58941 decoded

[dvescovoi]

I am assuming 58941 ... and correct me if you see differently. Aux 3 and 4 are ttl level coming from E24. the small amp in lower left corner must be a dual FET package?  any part number?
I am curious as to AUX 3 and 4 max current sink capability (assuming series resistor is bypassed).

[peteski]

I am assuming 58941 ... and correct me if you see differently. Aux 3 and 4 are ttl level coming from E24. the small amp in lower left corner must be a dual FET package?  any part number?
I am curious as to AUX 3 and 4 max current sink capability (assuming series resistor is bypassed).

That is correct.  The dual transistor converts logic level AUX outputs to standard "powered" AUX outputs.  No idea about the current sink capacity (as usual ESU doesn't seem to have that documented), and I assume it is  similar to standard "powered" AUX outputs on the decoder (that is documented in the ESU manuals).

I had that covered in my write-up for that decoder.

[dvescovoi]

Am I nuts or is the LED drawn wrong in the figure 58751 "Example function circuit". Polarity wrong!
Also wrong on the 58721 circuit.

[peteski]

Am I nuts or is the LED drawn wrong in the figure 58751 "Example function circuit". Polarity wrong!
Also wrong on the 58721 circuit.

Yes, the circuit diagram has the LED reversed - funny how I missed that. You aren't nuts - just observant. Most decoder installers and model railroaders in general looking at this info are not very familiar or interested in the actual schematic diagrams, so I don't think they noticed.  You seem to be more familiar with schematic diagrams.  Thanks for pointing it out. Will correct it.  Since I used the same basic drawings for other decoders (even LokSound 4), I have to check if that error is also in those diagrams.

[loddie]

This is an excellent thread. Thank-you for sharing this information. 10,000+ views!

Do you plan to also cover standard Loksound 5 decoders such as the 58420 & 58429?

[peteski]

This is an excellent thread. Thank-you for sharing this information. 10,000+ views!

Do you plan to also cover standard Loksound 5 decoders such as the 58420 & 58429?

Thanks loddie!  I'm modeling in N scale so no, I'm not planning on reviewing the larger decoders. This forum is very N-scale-centric, so I feel at home here.

All LokSound 5 decoders share the same basic electronic design. The differences are the board size, number of AUX outputs, and of course the current capacity. Some larger decoders also have voltages lower than U+ available as a common positive for AUX devices.  Larger decoders also sometimes have AUX resistors (which in some instances can be bypassed), and some have a built-in Keep Alive circuit.

[loddie]

Thanks loddie!  I'm modeling in N scale so no, I 'nm not planning on reviewing the larger decoders. This forum is very N-scale-centric, so I feel at home here.

All LokSound 5 decoders share the same basic electronic design. The differences are the board size, number of AUX outputs, and of course the current capacity. Some larger decoders also have voltages lower than U+ available as a common positive for AUX devices.  Larger decoders also sometimes have AUX resistors (which in some instances can be bypassed), and some have a built-in Keep Alive circuit.

My apologies, I was not aware of the N scale emphasis. The information is very helpful nonetheless, regardless of scale.

[peteski]

My apologies, I was not aware of the N scale emphasis. The information is very helpful nonetheless, regardless of scale.

No apologies needed.
The Railwire forum is multi-scale, but if you look at the number of posts in each section, most traffic N scale.  I was simply explaining that I model N scale, so I feel at home here.  And as you mentioned, smaller decoders are often used in largeer scale models, but the reverse is usually not physically possible. 

[kharstin]

Thanks for the comprehensive information.  Got an Atlas GP20 to add Keep Alives and SP lights too.

I use the Voltscooter keep alives as they are small enough to fit under the decoder on the back end with an additional 470uFd capacitor to bring the total capacitance up to 930uFd.

Ken Harstine

[peteski]

Thanks for the comprehensive information.  Got an Atlas GP20 to add Keep Alives and SP lights too.

I use the Voltscooter keep alives as they are small enough to fit under the decoder on the back end with an additional 470uFd capacitor to bring the total capacitance up to 930uFd.

Ken Harstine

I'm glad you found this informative Ken.
Most small ESU LokSound 5 or LokPilot decoders have nowhere close to 460µF on board.  At least that is what I can estimate visually looking at the on-board MLC type caps. So you are basically adding 470uF to maybe couple hundred of on-board µF.