Converting Accucraft K-27 to battery r/c

[maxi-model]

If you want the Sierra sounds to be triggered by remote use a relay output R/C switch, rather than a solid state R/C switch, on any spare channel.
The relays isolate the Sierra from the ESC circuit.
MRW dual relay switch

Hi Tony. Looking only at its the operational description, in the link you provided, it sounds similar to the "2 way switcher" that Fosworks list. I have used that successfully on another installation but using a Spectrum R/X, Mac 5 esc and a "My Loco Sound" card. However, that device will not work, specifically noted in the installation manual, with the Rx2 receiver that Fosworks supply to work with their Omni branded T/X. As I understand it most of the Fosworks range is derived/rebranded from the Peter Spoerer range of R/C products. I will raise your suggestion with Steve at Fosworks when I speak to him today. I think the key component is "relay" and I cannot confirm if that bit is present on either of the Fosworks supplied products for this purpose. Max

P.S. As a point of note I dialled the phone number on the back of one of the manuals supplied by Fosworks to get some clarification (I'd in ignorance ordered the wrong switcher for the presently discussed installation , see above) and found I had dialled the number for Peter Spoerer - What I got was a patient recorded message telling me he no longer supplied his R/C equipment range and suggests calling Fosworks, who now market that range

 

[Deleted member 4232]

Moved

 

[maxi-model]

Will do John. And many thanks for your assistance with this. Would you like me to make Steve at Fosworks aware of your interest and skills or shall I stay schtum ? Max

 

[Rhinochugger]

I would only install a DPDT CO if the need is to maintain Battery and Track Power. That has nothing to do with turning the Battery on or off or the charging circuit that requires the battery to be off to charge. A Smart Charger will tell you if it is in Charge Mode ie off. Why a Centre Off? Well to stop any possible flash over, just a belt and braces thing really.

Gotcha

I don't think I've considered battery and track power in one loco - I live too simply

 

[Deleted member 4232]

Moved

 

[maxi-model]

I have just spoken to Steve at Fosworks and got everything sorted out. It would seem it was not clear from the information I gave him at the outset that the Sierra Soundtraxx card, that is installed in my Accucraft K-27 was an older non-DCC version. One vital component, an Rx3 receiver, will be substituted for the supplied Rx2. My apologies to Steve for any impression I may have given that there may have been any lack of understanding and knowledge on Fosworks part in any of my posts. I have decided after discussions with Steve to go ahead, on my own account, and have incorporated a PWC/PWM linear converter (have I got that right John ?) between the Cobra esc and Sierra card. We now have the way forward.

John S - it looks as though Fosworks has the right "old school" switches in stock, though not listed, to operate the 2 sounds on the card that would benefit from manual r/c operation from the Omni transmitter rather than via reed switches. So there will be no need to incorporate those into the PWC/PWM linear converter that you are building.

 

[Greg Elmassian]

None of the Sierra's are DCC, just for future reference. It's a very old design. Sound is good though!

 

[Tony Walsham]

If you want to hear the "at idle" sounds of a Sierra sound (Fireman Fred etc) and you are connecting any solid state trigger to the Sierra, you will need a common ground with the trigger and therefore must use an opto coupler on pins # 7 & 8.

Or it can be done as shown above by John S. One opto coupler per sound trigger.
Sierra themselves showed a circuit on how to do it.

 

[dunnyrail]

Gotcha

I don't think I've considered battery and track power in one loco - I live too simply

It does make a lot of sence if you are doing a DCC Loco to Battery Power as then you can use a DCC System to do any CV Revisions, also will work on a DCC Line if you want it to. My first DCC Conversion will not have the option as it is a rubbish runner on DCC Track Power anyway ( Train Line Pffifi), but subsequent ones will have the dual option.

 

[Deleted member 4232]

Moved

 

[maxi-model]

If you want to hear the "at idle" sounds of a Sierra sound (Fireman Fred etc) and you are connecting any solid state trigger to the Sierra, you will need a common ground with the trigger and therefore must use an opto coupler on pins # 7 & 8.

Or it can be done as shown above by John S. One opto coupler per sound trigger.
Sierra themselves showed a circuit on how to do it.

Hi Tony very much appreciate your suggestions. However, I am a simple soul and the terms - "common ground", "solid state trigger" and "opto coupler" are meaningless to me . And I do not posses or know where to find Sierra's schematic to do this.

I know what I want to achieve - converting my track powered Accucraft K-27 to r/c controlled battery power, while retaining all the sounds, at idle or voltage induced and otherwise and to overcome some operational shortcomings that have shown up on my line as built that are not exhibited by any other of my track powered locos. Hopefully without messing around too much. If that cannot be done then I will just bin the conversion and live with it as a DC track powered loco. Max

Board constructed, passed voltage tests, motor test have to be done tomorrow, have a weather warning in these parts, restricted vehicle access on the A38 across the Tamar Bridge, long and convoluted detour around the A30, day job beckons with an earlier start time.

View attachment 245331

Wow ! Great stuff. Thank you, very much appreciated. No hurries. Max

 

[Deleted member 4232]

Moved

 

[maxi-model]

John that is wonderful. Thank you. However, I have returned the switches you are showing at Fosworks suggestion as I'm told they will not work with the Rx3 (or the Rx2 for that matter) in this application. Alternative connectors, "of an older type", are being sent by Fosworks for use with the Rx3 to connect directly to the Sierra card. Or that is what I understand. These are not listed on their site so I cannot tell you what they are or how they work. I'll post pictures here when I receive them. I am becoming very confused. Max

 

[Deleted member 4232]

Moved

 

[Deleted member 4232]

Moved

 

[maxi-model]

Thank you John. You are going to have to give me a little time to inwardly digest this

First thing that meets my eye is it appears we are doing away with the Sierra's 6v lead acid power supply and replacing with the loco's 18v as a common supply. Is that so ? This will do away with the Sierra's tender mounted switch and mean I can get rid of its wiring, grounded on the tender's chassis at one of the speaker mounts. I will also need to replumb the voltage controller in the tender, for the rear facing light, that is similarly grounded on the same speaker. I think I can work that all out.

There are 2 pairs of wires on the MOT outputs on the Cobra, 1 pair can go to motor, 1 pair to the Sierra. There are 2 pairs of wires on the +ve & -ve input terminals on the Cobra, 1 pair are the inputs from the battery, the other pair are in effect "tapped in" wires (in parallel to those from the battery) that can be wired as shown, via the card you have supplied to provide 18v power (instead of 6v at present) to the Sierra - so there is no need for the additional wires to tap into the as you have shown in the first image. Am I right ? Deep breath.

I'm somewhat filled with trepidation with regards the "Puff the magic dragon" metaphor but I'm not planning to change anything there as one wire on the volume control is on 4 (as well as 1 & 3). I shall gird my loins and proceed with caution. Max

 

[Rhinochugger]

Thank you John. You are going to have to give me a little time to inwardly digest this First thing that meets my eye is it appears we are doing away with the Sierra's 6v lead acid power supply and replacing with the loco's 18v as a common supply. Is that so ? This will do away with the Sierra's tender mounted switch and mean I can get rid of its wiring, grounded on the tender's chassis at one of the speaker mounts. I will also need to replumb the voltage controller in the tender, for the rear facing light, that is similarly grounded on the same speaker. I think I can work that all out. I'm somewhat filled with trepidation with regards the "Puff the magic dragon" metaphor . I shall gird my loins and proceed with caution. Max

Never let the magic smoke escape

 

[Tony Walsham]

BIG SNIP!!
There is a reference on the t'internet to use the connections marked 2 & 4 to connect up an external supply, only one result is guaranteed if this is followed!

Puff the Magic Dragon will look tame compared to the amount of smoke that will bellow out of the Sierra Card!

SNIP

Yes, that can happen if the battery supply is over 12 volts.
The # SSI-12v5 after market Opto coupler device I used to make for Sierra sound pcb's was designed by Sierra and permitted up to 12 volts to be fed into the Sierra pcb to replace the 6 volt battery. PDF instructions The 12 volts was provided by a proper 12 v regulator.
+ 12v on terminal # 4 and - on terminal # 2.
If you used only 6 volts you could not get a Sierra diesel sound to ramp up to notch 8.

 

[maxi-model]

So we are reinforcing the warning - do not use terminals #2 & #4 on the Sierra's board to apply power from an 18v source ? As I have mentioned there is not much risk of this in my mind as they are already taken up with another function, along with #3, to provide for the Sierra's volume switch. But as John has set it up on the card he is supplying me with, to pass and then input power at the point shown on the schematic, it is perfectly ok ? Max

 

[Deleted member 4232]

Moved