The SV mallet again

Neil Robinson

Neil Robinson

Registered
Country flag
Just to confirm, with the LGB decoders removed and the motor blocks powered via the LGB board does everything work as it should?
Is dip switch 1 on the sound board set appropriately for the mode of operation?
If so your plan should work well and, IMHO, be a worthwhile upgrade.
 
remove the bord.. get a xls.. ???
 
kimbrit said:
Hi Neil,
The front drive train doesn't run on dc via the original board with the dip switches set for dc operation but everyting else does, obviously burnt something out there. Dip switches now set back to digital settings, just in case I forget ;)
Click to expand...

My guess is one of the motor wires/PCB tracks to the front drive train has gone open circuit. If so when on the rails the rear train will try and push the dead front one causing a heavy load and current draw on the rear unit.
You could try putting the loco on rollers and swapping the connections to the drive trains over at the board connectors. This should reveal if the trouble lies within the motor block wiring or the board.
I have little experience of DCC but I suspect if the decoder isn't connected to the power (as opposed to sound) board you won't have digital control over any sounds.

Mike's idea is fine and was my first instinct but costs a bit more and could be a bit fiddly to connect some features such as the flickering firebox effect
 
Depending on the vintage of the engine, you may find you a quite tight for space to fit a Massoth if you leave the original boards in place.
Other than that, if you are *sure* the motors are good, then an XLS would replace the whole lot.. You can combine function outputs to get a 'pseudo random' flicker effect if necessary.
 
Your high amperage may well be coming from the old board having a fault - as others have alluded to above. The double decofer method often gave problems. Stripping out the oud board and replacing with an XLS sound a pretty good option to me.
 
kimbrit said:
But, thinking this through, itr's an old board of circa 1994 and was built around a dc feed, so I will have to leave a decoder attached to the rear drive unit and feed the board from the motor side of the decoder. My head hurts.

Again thoughts please.
Click to expand...

Probably little point in retaining the board with a decent twin motor decoder but if you have to could you use the decoder + and decoder - terminals as the dc feed?
 
try the xl, like you surgested kim, then fall back to a S module if its not good enough/dosnt work..
 
Wire the motors direct to the XL and your track supply (not from the XL) to the old board.
You now have your motors on Massoth and your old board at full voltage for smoke, lights and sound.
I did this with my FrankS (because of the connecting wires to the tender) and it work fine.
 
I'm following this thread with interest in case I discover the answer to something that's been puzzling me for a while. The Uintah sound boards that I have bought from ebay ( http://www.gscalecentral.net/sounds/lgb-sumpteruintah-soundboard-now-in-place-in-bachmann-annie-and-it-works-for-30!/ ) have six connections from the main board but only two (5 & 6) are needed to power the board with power direct from the track for analogue operation.
What function do the other four serve? I'm guessing they may be sound triggers if a decoder (or two) are connected to the main board.
 
Kim,
read of my exploits in a 'recent thread' on my Uintah mallett. It was an analogue version. I purchased the digital sound board complete with wheel/chuff sensor and bell/whistle reed switches. When hooked up basically nothing worked, but when the analogue board was refitted all was fine. I sussed that there was something strange amiss in the digital board as applying power resulted in a short circuit when the two original motor block four pin connectors were used on the digital board. A multi check of where the pin blocks connect to the main board showed that track power and motor power pins were short circuiting even when the MTS DIP switches were set to digital. A new replacement board had the same 'problem'.

After a lot of head scratching I found that using the main board only for sound input and separately wiring the motor blocks (not using the main board connectors) to a decoder bypassed the problem with the perceived short circuit in the motor block receptacles on the main board. Perhaps there was a batch of faulty boards released years ago. Note while I mention connection to a decoder, as yet I simply ganged the track power and motor wires together to get continuity and everything worked fine on analogue. Thus I cannot see why a decoder could not be fitted to my 'ganged' wires and use the decoder functions to power lights, smoke, etc. This way you would not use the six wire decoder interface that LGB recommends. The decoder would pass track power to the main board and thus power would flow to the sound board.

Link to my original thread - http://www.gscalecentral.net/digital-(dcc)/lgb-uintah-mallett/

Link to my originally original thread - http://www.gscalecentral.net/digital-(dcc)/lgb-uintahsumpter-valley-sound-decoder/
 
Kim,
my new sound board and main board came from the earlier #20892 German version of the SV Mallet, made around the late 1990's. There was a later German release around 2004. This may have had more compact boards. Like you I should have ditched the stock analogue Uintah board and fitted an XLS, but as I previously owned a SV mallett, I wanted that particular sound and that is why I tortured myself with this route. The loco works fine on analogue. When I feel inspired I will fit an XL decoder and use the stock sound board that I have. When I rerouted the wiring to avoid the main board for motor control, I wired it to enable later fitting of a motor/function decoder.
 
your rich in freind kim.. good man, nicely sorted..
 
Kim,
glad to see that there is a light at the end of the tunnel. As regards board differences, the Uintah mallet was available as an analogue only and an analogue model with analogue sound. In both cases the boards were singular only, with the analogue sound components fitted to a large single piece analogue motor control board.

The Sumpter Valley mallett came as digital sound (#20892) only and this consisted of a two piece board connected by an umbilical cable. The front board controlled motor, lights and DIP switches and the rear board contained the sound components plus capacitors. I believe that the later release German version circa-2004 was factory fitted with a decoder and thus capacitors would have been ommitted.

I believe that ultimately you took the better option and bypassed the factory boards by using the XLS (I wish that I had of). The sound is undoubtedly better and hopefully less head scratching involved.
 
You must log in or register to reply here.
Back
Top Bottom