Sound-chipping An Older Frank S.....?

Zerogee

Zerogee

Clencher's Bogleman
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I'm currently searching (in the Wanted section) for an original green Frank S (LGB22261), and I've got a couple that I'm looking at or have been offered.... while I'm still making a decision, I thought I'd ask the question in advance about DCC chipping.
I already have an original blue Nicki & Frank, bought from a fellow forumite, which was chipped with two separate decoders - an L or XL in the loco and an XLS in the tender, I believe - and has had the connection cable between loco and tender removed completely. I also have a much newer black DR version with factory-installed DCC and sound, which has TWO plug and cable connections between loco and tender.

Now, as I understand it, the original DC version uses the cable connection for two things - to share pickups between loco and tender, but also (via some electrical gubbins) to equalise the running speed between tender and loco motors, as I gather that otherwise the tender can tend to "push" the loco by running faster...... on my blue N&F, the CVs of the two decoders were apparently tweaked by trial-and-error to get both units running at about the same speed.

My question prior to buying an old green version is this: is it possible to make the loco work with just a single XLS, and if so how do you wire it (and are there still problems with speed variantion between the two gearboxes)? Or is it essential to use two decoders to get round the problem?

Any advice, suggestions and personal experiences welcome! :)

Jon.
 
My experience of DCC is very limited so I suggest you confirm any of my comments with the supplier of your chip(s) before purchase.

I suspect on some early versions with four wire tender loco connections one pair was for pickups (also connected to a lighting socket) and the other pair for the rear light. The light, if 5V, would need access to a voltage regulator and the tender may not have one.

Whatever you choose I would recommend linking all pickups on each side together so this would mean at least one pair of wires. If you were to use two chips there would be no need for motor or light wires between the two units. You could also adjust the speed curves independently. However I don't see any theoretical difference between the Nikki and Frank with any other two motor twin bogie loco so one twin motor decoder should suffice but you'd need the two extra pairs of wires.
 
Thanks Neil. My question about the loco/tender speed differential is from reading several comments to this effect in the past.... I can only assume that it's down to the fact that rather than being two identical power units (as you'd get on most twin-bogie locos), the tender motor is driving just a basic 4-wheel gearbox with no rods or motion, while the loco one is instead driving a 6-wheel chassis plus all the outside motion rods, which must put some (small but measurable) extra drag on that motor. There is also the weight issue, in that the loco is going to be a LOT heavier than the tender which again must have some effect on the running speed at the wheels. Anyway, as I understand it, this was got round at the factory by adding some circuitry to the tender which actually slows the tender motor VERY SLIGHTLY compared with the loco motor to even out the speed between the units - hence the need to fiddle with the CVs if using the two-decoder solution.

Jon.
 
You may find the loco and tender run at identical speeds in which case a single XLS would suffice to run both motors.
If you were to use two decoders and the motors were slightly out the method I would use to equalise speeds would be to vary the top speed CV of the faster motor. The max (and factory setting) is 220 I think so by trial and error change the faster motor to 210 and see how it compares until you get both motors (in situ) running at the same speed.
 
The tender drives on these often seem to be a bit faster - if its small i would not worry about it.
As Paul said, I would go for an XLS. Twin decoders is now old hat.
 
Thanks Alan and Paul - what I was trying to get at is that if fitting a single decoder (eg an XLS) how do you wire it, given the connecting cable and the speed-balancing circuitry that exists in the old DC version?
Anyone on here who has actually done one and can remember how they did it?

Jon.
 
O.K. here's a plan, offered as a basis for discussion.
Remove all existing electronics from both units. Decide location of speaker and mount large sound decoder in the same vehicle. Link pickups from both units with one pair of connecting wires with another pair to feed the motor in the non decoder fitted unit. Add additional connections for relevant features such as lighting. Adjust decoder output voltages to match additional features (lighting, smoke) and/or replace with full voltage examples.
 
Yes, that may well prove to be the best way, Neil - the "rip-it-all-out-and-start-from-scratch" approach is often the simplest, I agree! ;)

Jon.
 
I would copy the layout that Märklin have installed in the 24265 model Jon - pretty much as Neil says above.
 
Zerogee said:
Thanks Alan and Paul - what I was trying to get at is that if fitting a single decoder (eg an XLS) how do you wire it, given the connecting cable and the speed-balancing circuitry that exists in the old DC version?
Anyone on here who has actually done one and can remember how they did it?

Jon.
Click to expand...
Yep, I did mine a few years ago. I ripped out everything in the loco and tender and fitted a XLS in the loco, its a bit tight for a speaker though. I still use the connecting cable between loco and tender as 2 x track power to chip and 2 x motor drive from chip. The loco and tender run at the same speed without any problems and if I was to acquire another one I would wire the same way again. The only (minor) issue is with this system the rear lights do not work unless you string two more wires across to the tender from the chip, but I didn't bother as to me its only a very minor issue.
 
Thanks Steve, good to hear from somebody who has actually done one! Very useful to know that the speed variation wasn't a factor with your loco - maybe I'm worrying too much over that, but the reason I've been asking about it is that the forum member who sold me his blue N&F told me that it HAD been a problem for him on that particular model, and that quite a bit of fiddling with the two decoders he installed was necessary before the tender stopped trying to push the loco along.....
I'm guessing that the slightly easier way is to put both chip and speaker in the tender (where there is more room) rather than in the loco, but I know some folks don't like to hear the sound coming from the tender (and in G scale, if you are close to the loco you CAN sometimes hear where the speaker is....). Not something that really worries me unduly, so an installation in the tender would be OK for me.

Jon.
 
If the decoder is in the tender..
You need the following wires to the loco:
2 x track
2 x motor
1 x common for lights / functions
1 x for cab light
1 x front light(s)
1 x smoke
So, eight wires minimum. - I say minimum, as you might find problems with a single 'common' for everything.
 
Thanks Phil, good point re the large number of wires....

One of the examples I've been offered already has 2 x MTS chips (I assume 55021s), might be easiest to just to go with that, leave them alone and simply add an S and a speaker! ;)

Jon.
 
Zerogee said:
Thanks Steve, good to hear from somebody who has actually done one! Very useful to know that the speed variation wasn't a factor with your loco - maybe I'm worrying too much over that, but the reason I've been asking about it is that the forum member who sold me his blue N&F told me that it HAD been a problem for him on that particular model, and that quite a bit of fiddling with the two decoders he installed was necessary before the tender stopped trying to push the loco along.....
I'm guessing that the slightly easier way is to put both chip and speaker in the tender (where there is more room) rather than in the loco, but I know some folks don't like to hear the sound coming from the tender (and in G scale, if you are close to the loco you CAN sometimes hear where the speaker is....). Not something that really worries me unduly, so an installation in the tender would be OK for me.

Jon.
Click to expand...
Mine is also the older blue loco as well. I placed the decoder and speaker in the loco because I like the sound to come from the engine, I've heard a Frank S with sound in the tender and to me it just doesn't sound right as the loco passes then the tender chuffs by. Plus the extra wires that's Phils spoke about between loco and tender. On the motor speed side of things I think if its just one chip (XLS) then the output to both motors will be the same, so in theory both motors should turn together and run at the same speed, the gearing is the same on both loco and tender, so the only reason (I can think of) is if one motor is older than the other and more worn giving more/ less resistance, but I don't really understand things like that. Neil's the expert when it comes to motors.
 
I chipped a blue one using a Zimo MX695 in the tender for motor control of both motors with the speaker in the tender. I then fitted a Zimo MX623 accessory decoder in the loco and programmed the outputs to get proportional smoke, auto on/off cab lighting with movement and put a couple of leds in the firebox to get a flicker when the coal shovelling sound is played.
I kept the original 4 wire connection for all wheel pick up and motor supply to the loco.
 
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Unless the two units are of very differing age.. Running speeds should be near enough to not be a problem.. If you have a motor decoder in each, then place then a foot apart, and run them in both directions.. As long as one does not take off like a scalded rabbit and they stay roughly the same distance, then you will be fine.

If you get one with two (motor) decoders in, then an 'S' would be a possibility..
There are alternatives to Massoth speakers, which are smaller, and possibly better quality?? as well.
 
I generally use Visaton speakers for most applications, bought from Rapid and then fitted with the Massoth-type CT plugs from Muns (GRO); they do the tiny 25mm type that Massoth sell, but also a very useful 36mm diameter version that Massoth don't list....

Jon.
 
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