Power buffer used with Massoth 'LS' decoder

[Tim Brien]

I am currently planning installation of a Massoth 'LS' decoder in a LGB Stainz loco. I intend fitting a power buffer. The Massoth power buffer has three wires, with the white wire being the charging current wire. The 'LS' has three solder pads, Gnd, +24V and BC. 'BC' is the connector pad that senses/provides charging current and if programming in process, shuts off the charge process.

Now comes the problem. I have purchased a power buffer from an American manufacturer that uses two wires only (Gnd and +24V). The unit has onboard electronics that self senses programming current and shuts off the buffer to allow programming to occur. I am hoping that the unit will work when connected just to the Massoth 'LS' decoder Gnd and +24V solder pads (not using the 'BC' pad).

Any thoughts???????

 

[muns]

Tim,

I would need to read the instructions/specs for the power buffer, specifically on how it detects programming. Can you provide manufacturer & part number for the buffer please (and possibly point me to their website?).

 

[Tim Brien]

Mark,
this is the link to the unit. The manufacturer states that the programming current detection/shutdown software/electronics is patent pending, but gives no details.

http://www.shourtline.swl4.com/SL-6101047_4,700uF_Automatic_Power_Buffer_EBAY.html

 

[ntpntpntp]

Looks interesting. It specifically states it works with all Massoth decoders, and they even sell a Massoth L prewired with one of their units.

Let us know how you get on with it?

 

[Tim Brien]

Nick,
I am awaiting receipt of the unit this week. I purchased two units. One is destined for the Stainz, with the other to be fitted to a LGB #20761 Spremberg loco that I recently fitted a type '1' LGB decoder and LGB digital sound to. I fitted the stock LGB sound storgage capacitors to the sound board and want the power buffer for the decoder. This hopefully will handle power outages over frogs.

For the Stainz, I am still in the planning works. I have disassembled the loco to get an idea of available space for the decoder, plus power buffer, plus Massoth flickering firebox and a suitable, small (470uF) power buffer for it. I have already fitted the 57mm low profile speaker in the cab roof. The loco is a base starter set green Stainz from their 30th Anniversary set. A very basic loco with 24 volt lighting, no smoke and definately basic electronics (no circuit board to remove).

 

[muns]

Tim,

I would go with connecting it direct to the +24v & GND as the manufaturer says and ignore the BC output on the decoder.

Keep us updated on how it goes as they look "interesting".

 

[Tim Brien]

Mark,
many thanks. I would have liked the 8300uF unit, but overall size limitations had me choosing the smaller unit. I have been advised that buffers can possibly lead to pitting of the wheel surface as current inrush recharges the capacitor. This may be an old wive's tale as current inrush would be limited by onboard resistor value. A higher resistor value would increase the recharge time. I suppose it is all a compromise.

 

[whatlep]

I have been advised that buffers can possibly lead to pitting of the wheel surface as current inrush recharges the capacitor.

Unlikely Tim. Maximum charging current stated by Shourt Line is 200 milliamps. Peanuts compared to what a loco working hard will draw.
This looks like a very interesting product. Please let us know how you get on with it.

 

[Railfan]

Tim, I would just follow the instructions given with the buffer. As stated on the web site "The Shourt Line is Massoth's Number 1 FACTORY Authorized Dealer in the USA for the last 5 years running." He knows Massoth's products. I have met with James Shourt at a couple of the train shows here in California and he seemed pretty knowledgable. He even gave a seminar on DCC at one show. I have some DCC items from him without problems. I don't think that you will either.

 

[Tim Brien]

George,
I have no issues with the product line. My concern is that Massoth makes no reference to the use of power buffers on their product listing in relation to the 'LS' decoder. They specifically mention the other decoders, but not the 'LS'. One needs to go to the download for the 'LS' to see reference to the use of power buffers. That download specifically mentions using the three wire Massoth buffer connected to the three solder pads on the 'LS' decoder board.

The third wire (white) is connected to a function pad that disables the power buffer when programming the decoder. The Shourtline product has this capability built into its electronics and so, hopefully, negates the need for the third wire to operate normally.

 

[Tim Brien]

Shourtline power buffers arrived today. I purchased the 4700uF version. I cannot praise the unit highly enough. The buffer has changed my tempermental short wheelbase loco (LGB #20761 Spremberg) into a charmer. Ideally, the larger buffer (8300uF) would be preferred, however, due space limitations, I went with the 4700uF model. Loco works brilliantly over my trackwork.

I have twelve frogs on my mainline. At a moderately slow speed the loco performs beautifully. The buffer has enough charge for two to three frogs in a row at very low speed. This is an excellent product.

Prior installing the buffer, I programmed the decoder (LGB #55020) to disable analogue operation. I have not attempted to read the decoder since installing the buffer. Will try later. Installation takes only a few minutes and is just a two wire procedure.

 

[bunnyrabbit03]

For your next loco installation you could also consider a decoder with a built in power buffer (ESU Lokpilot XL V3.0) or one where you can simply buy the required capacitator(s) for a few dollars/pounds and wire them directly to the decoder (the new Zimo 695 - here, the decoder has the charging circuit etc. built in).

 

[beavercreek]

Neil Robinson posted a circuit diagram for a do it yourself power buffer, for the LGB digital sound units 65000 series, as a replacement for the LGB buffer 65011. http://www.gscalecentral.net/m26063 post number 5.
I wonder if a version of this could be used with the the Massoth decoder (or others). The Neil version was rated at 9v as the LGB 65000 series uses a 9v battery if no buffer is used. I am not sure what voltage the Massoth decoders use for the buffer recharge but perhaps Neils circuit would just need the appropriate voltaged regulator to match the voltage of the decoder's needs....... I am also thinking of the Aristo TE Revolution receivers and their power buffer needs (instead of the retail product buffer).
Perhaps I am totally wrong with this and Neil's design is not appropriate for this type of use.....

 

[beavercreek]

Just had a pm from the guru himself (Neil). He has said that there is probably different circuitry involved and he would need to see the innards for the Massoth or the Revolution buffers to see what their configurations are. The power protection needs of the boards may, as well knowing what the charging voltage given out by them, need consideration.

Oh well t'was a thought.............

 

[Tim Brien]

A basic power buffer is simply a suitably sized capacitor, an inrush resistor to control charging rate and a diode. One could definately make one with very little trouble, BUT, one would need to install an on/off switch to switch off the capacitor when programming the decoder.

The later version Massoth decoders have the 'switch' built into the decoder and use the third wire to control the capacitor charging by way of a decoder function pad.

A decoder with a built in capacitor (power buffer) in reality would be of little use. The capacitor size needed is almost the size of the decoder itself. I feel a minimum 8300uF capacitor is required for smooth operation.

The benefit of the Shourtline buffer is that it has the decoder programming shutdown circuit inbuilt in its electronics and secondly, the capacitor and electronics are separate, thus the capacitor may be positioned separately to the electronics, convenient when space is at a premium. It is a simple two wire installation - red wire to dek+ and black wire to GND.

In so far as voltage input, the buffer requires full track voltage. I use the LGB #65011 sound storage capacitor for the digital sound onboard as that unit only requires around 5 volts to operate. Remember that the buffer stored energy is driving the locomotive in a power loss situation, so relatively higher voltage is required.

Before you start skimping your pennies to build your own unit, I suggest that you research the subject. The largescale guru, George Schreyer, gave up on power buffers as he considered that wheel pitting was not a compromise to poor power pickup situations. He went to battery operation on smaller locomotives.

I am very happy with my unit's performance. It is not the same as strapping on a huge nicad battery pack, but it does afford me smooth operation over a couple of frogs before it depletes its stored energy. Ideally, I would start at the 8300uF size as a minimum for reliable on tap power backup. Even the small Massoth buffer is capable of only 0.5 seconds operation.

Basic circuit diagram for a power buffer (drawn by Bob Brashear and posted on MLS forum from memory) -

 

[beavercreek]

I was only hazarding a guess as to what home spun power buffer might be built for decoders.
I have built the type to be used with LGB sound modules, following Neil's schematic as it is a very specific design that works at 9v and was just wondering if they could be 'adapted' to work with Massoth decoders etc.

NEILS DESIGN FOR BUFFER FOR LGB 65000 sound modules

My real interest was in what extra would need to be taken into account when building a buffer to be the same or larger in place of the Aristocraft Revolution capacitor board. The Revolution CRE 57076 capacitor board is rated at 12000mf and 35v, not sure of the charging specs.. But as these are only about £20 (from Dragon) it is probably not worth it anyway!

 

[Tim Brien]

As a power supply for the LGB sound unit, I found that capacitor packs have a limited operating time. Rather than a capacitor storage unit, where access was possible, I opted for four Ni-cad or similar cells giving 4.8 volts. This was connected directly to the common and positive terminals of the LGB sound board (the variable connector is not used).

The advantage of using a battery pack was unlimited slow speed operation sound. If the sound board does not have stabilised minimum voltage then it shuts down. I generally drive steam locomotives at very slow speeds and I tired of the sound constantly cutting out once the capacitors had released their energy. The battery pack solved this problem.

For a buffer you need full track voltage (no voltage regulator in the circuit), plus current limiting resistor and a diode to prevent the capacitor discharging when external power is applied from the decoder.

 

[bunnyrabbit03]

Tim,

The ESU decoder I mentioned above has gold cap buffers, which have a significantly higher capacity than standard capacitators and are very small. And the Zimo MX695 does not require any resistors, diodes or a switch - you simply wire up the capacitator(s) to it and the decoder does the rest. This is not a question of skimping to do a self-built, but buying high quality advanced decoders (trust me, the Zimo is not cheap - quite the opposite).

Marc