Massoth S DCC/DC Sound Only Decoder - DC Analog Operation Challenges

[Greg Elmassian]

So, reading the original post, his issue is length of standing sounds. How long will your soundcard run with a fully charged battery? Maybe this is a future solution for a similar installation.

He's trying to do it with supercaps. Just not storing enough energy as I see it.

Greg

 

[LGB333]

A customer's LGB 2019S Mogul needed repairs and the old factory sound board in the tender had also failed. I installed into the tender a Massoth S Sound Decoder with volume controller and Massoth Maxi PowerCaps. The decoder's sounds work fine except in the DC analog operation the Power Caps won't charge up well to power the decoder's standing sounds when the locomotive comes to a stop.......lasts only about 15 seconds even with making some CV adjustments to the power caps for longer holding charge. If I charge up the power caps by placing the tender alone on the track at 18v. high voltage, the power caps will charge up nicely after a few minutes but then when operating again with the locomotive on the track they will obviously not recharge well again. If I test the decoder on a DCC test track, the power caps charge up super nicely since the decoder's receiving continuous 20v. DCC to the track. So, here's the challenge operating DCC sound decoders in DC Analog: How to get the power caps to charge up well while operating the Mogul & Tender at normal speeds on the track? Are there any electronic devices I could install onto the decoder or power caps to compensate for the lack of sufficient DC power being provided to the decoder? I don't think running the track power through a DC Adjustable Voltage Regulator with Bridge Diode Rectifier to the decoder would do the trick since the continuous 18 volts it could provide the decoder would mess up the chuff sounds which adjust their sync speed based upon the amount of DC voltage the Mogul receives. Thoughts?

Maybe I should convince my customer to switch to DCC!

Okay, I've played around with all the CVs that even remotely relate to the power caps or start up of the S decoder's sounds. None of them overcome the issue of the power caps not charging well when the Mogul is running at normal speed on the DC analog powered track. But I did find adjusting CV 193 Trigger Threshold Sound Output Analog Operation from its default setting of 2 to 1. That at least gets the sound on about the same time as the Mogul starts to move. Before, the Mogul would start moving down the track a ways before the increased voltage would finally activate the sound unit's chuff. I also tried the 0 setting, and that worked even better but then when the Mogul would stop, the power caps slighyt charge would cause the chuff sounds to continue. So, the 1 setting is the best option.

When my customer came yesterday to pick up his Mogul (and pay the bill!), I demonstrated on my DC Test Stand how the S decoder works and he was thrilled compared to this the sound quality of his other LGB 2019S Mogul with the old factory sound board. I had set the S decoder's three standing sounds to the sequence I wanted and time length, and advised him to hear them to do this: Turn off the power switch to the Mogul, then turn up his DC throttle to full blast for 2 minutes. The S decoder will make some distorted chuff sounds while he does this. Then turn the Mogul's power switch back on, and the power caps will be fully charged, and he can hear the standing sounds go through their 3-sound sequence.

I'm waiting for someone to advise in detail how to connect some electrical device to the power caps that will provide a supplemental charge to them during the Mogul's normal operating speed, and not mess up the S decoder or its chuff sound output. I've sent a inquiry to the Massoth Hotline in Germany for their advice. Otherwise, what I've done with the customer's Mogul is as good as it gets........without installing some other method to provide sound to his DCC analog Mogul.

 

[Greg Elmassian]

I think the issue is finding a boost converter that can keep a common ground with the keepalive/normal power internal to the decoder.

If this could be done, it would be like taking positive and negative off the full wave bridge in the decoder, connecting a boost converter, and then connecting the output negative to the same negative (actually redundant) and the the positive from the boost would go through a protection diode to the positive side of the keepalive array.

Possible problems:
the boost converter would draw additional current since it is converting a low voltage to a higher voltage, and could burn up the FW bridge diodes on the decoder.
the boost converter might not have a common ground between the input and output
electrical switching noise from the boost converter might feed back into the decoder and cause issues with the microprocessor
the higher voltage on the capacitor bank might cause some issues with any logic associated with the decoder supplying voltage (probably not)

In any case, if they get one of their electrical engineers to answer the question, I would bet dollars to doughnuts they would say no.... if you are willing to experiment I would try it, although I would certainly characterize the boost unit first, and look seriously at higher current diodes for the FW bridge on the decoder.

Greg

 

[LGB333]

I think the issue is finding a boost converter that can keep a common ground with the keepalive/normal power internal to the decoder.

If this could be done, it would be like taking positive and negative off the full wave bridge in the decoder, connecting a boost converter, and then connecting the output negative to the same negative (actually redundant) and the the positive from the boost would go through a protection diode to the positive side of the keepalive array.

Possible problems:
the boost converter would draw additional current since it is converting a low voltage to a higher voltage, and could burn up the FW bridge diodes on the decoder.
the boost converter might not have a common ground between the input and output
electrical switching noise from the boost converter might feed back into the decoder and cause issues with the microprocessor
the higher voltage on the capacitor bank might cause some issues with any logic associated with the decoder supplying voltage (probably not)

In any case, if they get one of their electrical engineers to answer the question, I would bet dollars to doughnuts they would say no.... if you are willing to experiment I would try it, although I would certainly characterize the boost unit first, and look seriously at higher current diodes for the FW bridge on the decoder.

Greg

Greg - Your electronics knowledge is superb! I'll let you know what Frank Noller at Massoth Technical Shop says probably after his holiday return.

 

[Greg Elmassian]

Will be interested, but I will not blame them if they take a conservative approach. They are a business after all.

(thank you for a compliment, apparently my college education was worth something ha ha)

 

[phils2um]

Tom doesn't want to convert the loco to DCC so this comment isn't for him. Thinking about it overnight I realized just converting the loco to DCC with analog enabled would probably help significantly. Nothing will happen in analog operation until the track voltage is at least high enough to power up the decoder. This should allow more energy to be stored in the powercap.

 

[LGB333]

Okay, I've played around with all the CVs that even remotely relate to the power caps or start up of the S decoder's sounds. None of them overcome the issue of the power caps not charging well when the Mogul is running at normal speed on the DC analog powered track. But I did find adjusting CV 193 Trigger Threshold Sound Output Analog Operation from its default setting of 2 to 1. That at least gets the sound on about the same time as the Mogul starts to move. Before, the Mogul would start moving down the track a ways before the increased voltage would finally activate the sound unit's chuff. I also tried the 0 setting, and that worked even better but then when the Mogul would stop, the power caps slighyt charge would cause the chuff sounds to continue. So, the 1 setting is the best option.

When my customer came yesterday to pick up his Mogul (and pay the bill!), I demonstrated on my DC Test Stand how the S decoder works and he was thrilled compared to this the sound quality of his other LGB 2019S Mogul with the old factory sound board. I had set the S decoder's three standing sounds to the sequence I wanted and time length, and advised him to hear them to do this: Turn off the power switch to the Mogul, then turn up his DC throttle to full blast for 2 minutes. The S decoder will make some distorted chuff sounds while he does this. Then turn the Mogul's power switch back on, and the power caps will be fully charged, and he can hear the standing sounds go through their 3-sound sequence.

I'm waiting for someone to advise in detail how to connect some electrical device to the power caps that will provide a supplemental charge to them during the Mogul's normal operating speed, and not mess up the S decoder or its chuff sound output. I've sent a inquiry to the Massoth Hotline in Germany for their advice. Otherwise, what I've done with the customer's Mogul is as good as it gets........without installing some other method to provide sound to his DCC analog Mogul.

Final comment about this issue. I did today hear back from Massoth Technical Shop Germany. Frank Noller suggests setting CV47 Buffer Runtime (analog/digital) from the default 10 to the max setting of 240. He says that should keep the sound on for a long time. I had tried that setting previously but didn't help with the low voltage charging challenge. In fact, that's the later message I sent Massoth about the charging issue. I'll post his response to that issue once I receive it. Of course, I no longer have the Mogul to test it, the customer now has it.