HO ( OO ) Decoders on G tracks, anyone had success?

Brixham

Brixham

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As the title suggests...I have a low power motorised unit that I would like to fit dcc. The motor only draws a just over a hundred milli Amps whilst running, and about 0.8 amps on stall.
Theoretically, I could use an HO decoder, but wonder if the higher voltage on G tracks will kill the decoder.

Normally, HO decoders run on 14-16 volts, and G tracks can ( with Massoth ) vary from 18-24 volts. HO decoders are around £17...and G ones...well..£40 up

I think the maximum voltage in the NMRA specs for an HO decoder is 27 volts. I'm wondering if inserting a chain of back to back diodes would reduce the voltage enough to stop the HO decoder ending up as toast. Four diodes in each leg would drop around 2.5 volts....and if the command station wasn't set to more than 22v, the voltage to the decoder would be under 20....enough to be safe? Maybe add a transient snubber circuit and/or 24v zeners

Has anyone had success? Or a box of smoke

Malcolm
 
I looked into this area briefly but I was told by the retailer I approached that they could not offer any warranty so if it went up in smoke it would be my loss.
I was looking at HO/OO Dietz/Uhlenbrock sound decoders. I didn't proceed,
You can get a Massoth M for a little over £30.
In short, if it works you've saved yourself £17, if it doesn't you've lost £17 and possible damage to the loco, so try it on the workbench first!
 
Some dealers or decoder manufacturers offer a full no quibble warranty....TCS decoders used to be 'goof proof', not sure if they still have that pledge,

Malcolm
 
Brixham said:
Some dealers or decoder manufacturers offer a full no quibble warranty....TCS decoders used to be 'goof proof', not sure if they still have that pledge,

Malcolm
Click to expand...

All the TCS HO decoders say 16V max. on track and programming..
 
While I don't have much experience of decoders made for the smaller scales, I believe you will find a lot (most?) of them are not capable of handling typical G scale voltages.... if you want a physically small decoder that will definitely be OK then I'd second Dave's suggestion of a Massoth M.

Jon.
 
You could always try a cheep one and see what happens? Like a Hornby sub £10 on offer or second hand or even a Hornby Xero one. These can be had for almost nowt. Actually I have a Sero One One somewhere, might give it a try!
JonD
 
Yep, can be done... and if you do have an issue, you can truthfully tell the supplier that it was not presented with "over xx" volts ...

Quality HO decoders will take higher voltages, like Zimo.

Here's an inexpensive and easily-tunable way to do your "bidirectional voltage dropper"

dropper.jpg


Read about "tuning" the voltage drop: https://elmassian.com/index.php?opt...ctronics&catid=19:trainelectronics&Itemid=353

Greg
 
Greg Elmassian said:
Yep, can be done... and if you do have an issue, you can truthfully tell the supplier that it was not presented with "over xx" volts ...

Quality HO decoders will take higher voltages, like Zimo.

Here's an inexpensive and easily-tunable way to do your "bidirectional voltage dropper"

dropper.jpg


Read about "tuning" the voltage drop: https://elmassian.com/index.php?opt...ctronics&catid=19:trainelectronics&Itemid=353

Greg
Click to expand...
Fascinating Webb Site, bookmarked for future reference.
JonD
 
Brixham said:
As the title suggests...I have a low power motorised unit that I would like to fit dcc. The motor only draws a just over a hundred milli Amps whilst running, and about 0.8 amps on stall.
Theoretically, I could use an HO decoder, but wonder if the higher voltage on G tracks will kill the decoder.

Normally, HO decoders run on 14-16 volts, and G tracks can ( with Massoth ) vary from 18-24 volts. HO decoders are around £17...and G ones...well..£40 up

I think the maximum voltage in the NMRA specs for an HO decoder is 27 volts. I'm wondering if inserting a chain of back to back diodes would reduce the voltage enough to stop the HO decoder ending up as toast. Four diodes in each leg would drop around 2.5 volts....and if the command station wasn't set to more than 22v, the voltage to the decoder would be under 20....enough to be safe? Maybe add a transient snubber circuit and/or 24v zeners

Has anyone had success? Or a box of smoke

Malcolm
Click to expand...
All my playmobil locos (9) are fitted with MRC HO 1731/1730 Universal Steam/diesel Decoder with Bell and Whistle. Whilst basic, there cheap and I haven't had any problems. Massoth 1200 set to 18v/7a.
 
Yeah, some MRC will go higher voltages, and some blow up easily at around 21 volts. Ask me how I know, I have a handful of AD322's that I use for temporary installations. They blow up pretty often.

Be sure of the max voltage they can take. I run full 24 volts because I have large locos that are geared down, like the Aristo 3 axle diesels.

Greg
 
I've used "high power HO" decoders on some of my smaller locos. being careful to choose decoders rated at 24V or more. I ran my line using NCE gear at around 18V.

According to my notes, I have the following installed somewhere in the roster!

CT Electronik DCX 51
TCS T1
Zimo MX64H
 
dunnyrail said:
... I have a Zero One [decoder] somewhere, might give it a try!
JonD
Click to expand...
Zero-One wasn't NMRA DCC protocol, so it won't understand the commands from a modern DCC system.
 
Found this on the NMRA specs for dcc...

"Digital Decoders intended for "N" and smaller scales shall be designed to withstand a DC voltage of at least 24 volts as measured at the track. Digital Decoders intended for scales larger than "N" shall be designed to withstand a DC voltage of at least 27 volts measured at the track"

So.....turning down a massoth central to 18 volts may well be fine. I'm tempted to try with a used Digitrax DH126 which I already have, along with a diode volt dropper using a bridge rectifier as shown above.

Malcolm
 
I blew a big hole in the middle of a Digitrax decoder, (164, I think) running it on Massoth at 23 volts, haven't had the courage to try again with a diode bridge.
Please , Malcolm, (Brixham) post how you get on with what you propose, I have several Digitrax decoders for 'Thomas' and friends and would like to get them all DCC
Thanks
Dave
 
I blew up a TCS 17 quid decoder. It ran my stainz for about 5 minutes and then the smoke came out. It didn't smoke actually - it just stopped.
 
TCS are junk, stopped using them... they have firmware issues, especially in the custom speed table. The new WoWSound is likewise poorly implemented.

I've found several firmware bugs in it...

They say their decoders will take 24 volts, and then promptly tell you to adjust track voltage to 12... hmm... but the max voltage is not specified in the manual, this info was from their FAQ section.

Greg
 
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