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DCC decoder chips

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richrua

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richrua Mentor

richrua

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Yo dudes,

 

Is there any difference between 8 pin and 21 pin chips as far as functionality goes? I dont know whether to get 21 pin chips or adapters and 8 pins for my Murphys.

 

Also. Hattons do own brand decoder chips at a good price. Any experience of these? Any good?

 

Many thanks

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skinner75 Mentor

skinner75

Posted
Posted

The number of pins used to connect them to the loco? ;-)

I'd go for the 21pin one, as that what the Murphys locos use.

 

I picked up a couple of different decoder chips from Hattons there last week, just to try em out, but haven't fitted them yet.

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Noel Grand Master

Noel

Posted
Posted

I'm fairly new myself to DCC, but as I understand it the number of pins is more of importance when using 'direct fitting' decoders (i.e. decoders that plug directly onto a circuit board in the loco or into a lead already fitted into the loco). If using bare wire decoders than I don't think the number of pins/wires matters too much if using basic four function decoders (i.e. loco drive plus a few lights). 21pin decoders seem to support more functions (i.e. lights, fire box flicker, simulated steam module, sound/speaker connections).

 

There are wiser and more experienced owls on here who I'm sure can give a much better explanation. I'm about to embark on a phased programme to install decoders in about 30 of my old locos, mainly LMS, GWR, BR (exLMS/exGWR) and a few LNER steam. None of these are DCC ready (i.e. don't have DCC sockets), so I will be fitting basic drive only or four function wire decoders in most of them, but I plan to use 8pin plugs and harnesses for ease during future maintenance and in case I ever need to change the decoders. I've bought a few test samples so far and have found some are better than others for slow speed running especially with older style motors. Some of the budget decoders don't seem to run locos as slow speeds as smoothly as others.

 

The recent Murphy Models GM locos I have collected take 21pin direct fitting decoders so no choice there as regards pins. So far I'm impressed with LokPilot 4, LokSound 4, Lenz Silver and surprisingly the Bachman 36-557 (rebadged Soundtrax). Have a few more yet to try.

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richrua Mentor

richrua

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Thanks for the replies and advice. I have taken the plunge and went for the Hornby DCC E-LINK and railmaster system. It should arrive any day now.

I was tempted by NCE but I like the fact that I can use existing laptop/android to run the latout. I mucked about with the trial version and it certainly has plenty to offer. Also, it is a very visual system, so that should help me get my head round it all.

 

Better order a test decoder or two to go with it!!! ☺

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Dhu Varren Proficient

Dhu Varren

Posted
Posted

The main difference between 8 pin and 21 pin is the number of functions available through the pins. An 8 pin socket will only support 3 functions, although 4 function decoders with an 8 pin plug will have an extra 9th wire which requires connecting separately for the 4th function. 21 pin connectors will support 6 functions. If using sound decoders, an 8 pin setup will also require speaker connections, whereas a 21 pin setup has the connections built in.

I would agree with skinner75 that it is a good idea to fit pre-DCC locos with 8 pin sockets instead of directly wiring into the loco, providing there is enough space inside for a socket and a decoder.

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irishthump Veteran

irishthump

Posted
Posted

The amount of pins on the decoder is mainly to do with the amount of functions. 8 pin has a maximum of 3 functions which can be used without any modifications. The word "function" does not cover motor control, it's normally lights, sound or even smoke generators or couplers. Many 8 pin decoders will have a seperate purple wire which can be connected to power an extra function but this has to be wired in seperate from the decoder socket.

 

Having said that, Murphy's 141's have a 21 pin socket but actually don't require it. The loco only uses 2 functions (forward and backward lights) so an 8 pin decoder can be used with a 21-8 pin adaptor. To be honest though, there's no benefit as the cost of the decoder plus adaptor is close enough to the cost of a 21 pin decoder! You might even run into problems squeezing the decoder+adaptor+wires under the body of a 141....

 

The 071's and 201's actually need a 21 pin chip that supports 6 functions to allow you use all the lighting features on the loco. You can use a cheaper decoder (which usually have 4 functions) but the cab lights won't work.

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irishthump Veteran

irishthump

Posted
Posted
The main difference between 8 pin and 21 pin is the number of functions available through the pins. An 8 pin socket will only support 3 functions, although 4 function decoders with an 8 pin plug will have an extra 9th wire which requires connecting separately for the 4th function. 21 pin connectors will support 6 functions. If using sound decoders, an 8 pin setup will also require speaker connections, whereas a 21 pin setup has the connections built in.

I would agree with skinner75 that it is a good idea to fit pre-DCC locos with 8 pin sockets instead of directly wiring into the loco, providing there is enough space inside for a socket and a decoder.

 

Sorry Dhu Varren, we must have been typing at the same time! :-bd

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richrua Mentor

richrua

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Many many thanks. So a hattons 21 pin will do the141/181 , but Ineed something with 6 functions for the 071. I presume a murphy sound chip does all these functions plus sound?

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Noel Grand Master

Noel

Posted
Posted

I've used a mix of Lenz Silver 21pin and Bachman 36-557 21pin in Murphy Models 141/181s. The low cost 36-557 performs remarkably well with MM141 crawling smoothly without any juddering.

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irishthump Veteran

irishthump

Posted
Posted
I've used a mix of Lenz Silver 21pin and Bachman 36-557 21pin in Murphy Models 141/181s. The low cost 36-557 performs remarkably well with MM141 crawling smoothly without any juddering.

 

Never used Bachmann but I have to agree on the Lenz decoders. I just installed Lenz chips in a couple of old Athearn locos and they are running sweet as a nut, even with the crappy old Athearn motor!

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Noel Grand Master

Noel

Posted
Posted (edited)
Never used Bachmann but I have to agree on the Lenz decoders. I just installed Lenz chips in a couple of old Athearn locos and they are running sweet as a nut, even with the crappy old Athearn motor!

 

Agree about Lenz. The Bachman 36-557 is actually a rebadged SoundTrax M1. It does seem worth a few extra bob to put a reasonable decoder in older locos rather than budget decoders. They seem to have better features for driving old motors smoothly. Spent a few hours this evening dismantling the first batch of my older steam locos for a pre DCC service and DC test run. Also allows me to evaluate what space is available to fit decoders, pick ups, etc. It doesn't seem worth fitting DCC to a loco unless there are pickups on at least 3 axles, and preferably 4 axles. Some of my old BR diesels have pickups on only two axels on one bogie!

Edited by Noel
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skinner75 Mentor

skinner75

Posted
Posted

Interesting vid comparing the 36-557 to the Lenz 10321. Could just be a dodgy Bachmann decoder he got - Noel, you don't have any issue with slow running?

Good channel this guy has for tips on all aspects of the hobby

 

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Noel Grand Master

Noel

Posted
Posted
Interesting vid comparing the 36-557 to the Lenz 10321. Could just be a dodgy Bachmann decoder he got - Noel, you don't have any issue with slow running?

Good channel this guy has for tips on all aspects of the hobby

 

 

Thanks Skinner75. Very enjoyable video. I haven't had any of those problems with the 36-557s in my MM141/181s. Just powered up the layout to double check, but no chip noise when stopped, acceleration/deceleration is good, and they stop immediately the 'STOP' button is pressed. I have a Lenz Silver 21pin in a MM181 and the performance seems identical to the 36-557, if anything the 36-557 has slightly smoother crawl speed but that could be a difference in the two MM motors. I wonder if there were different production batches and I got lucky with my 36-557 stock.

 

I posted this comment on his youtube:

Thanks for the excellent video clip. Interesting experience you've had with your chips. I have a mix of Lenz Silver 21s and Bachman 36-557 in my Murphy Model Irish GMs (141/181 class) and have been surprised how good the 36-557s have been in my 141/181s. After watching this video, I have just double checked the locos running the 36-557 and they all stop immediately when 'stop' is pressed. No noise either when idle, and their slow running and acceleration is fine. I wonder if there are different versions or batches of the 36-557 chips produced and I've been lucky with mine (so far). The Lenz have performed well too. The MM141 and MM181 ultra slow running with the Bachmann has been impressive. I think they are rebadged SoundTrax M1s. Bachmann don't actually make decoders.

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Noel Grand Master

Noel

Posted
Posted (edited)
He does mention that his 36-557 was the latest revision - you probably got a previous revision that the retailer had in their stock

 

Yes, I'm not sure which way around! :) Who got the latest, etc. I purchased mine only last month, his video was posted last may, but made when I don't know. I will check the version no on DCC programmer.

 

BTW, Thank you for the link to the amazing series of how-to videos on Everade Junction. An absolute gold mine of info for me after 15 years break from the hobby.

Edited by Noel
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Dhu Varren Proficient

Dhu Varren

Posted
Posted
Sorry Dhu Varren, we must have been typing at the same time! :-bd

 

Great minds think alike irishthump, but your reply is much more comprehensive than mine.

 

Whilst on the subject of space for fitting decoders, I have just been shoe-horning a 21 pin sound decoder + speaker + lighting circuit board + headlights, marker & tail lights + associated wiring into an already crowded NIR MV. Would really have been struggling if I had tried to fit an 8 pin and adaptor. The loco is powered by a Hornby Class 56 motor with two flywheels, driving a Hornby Class 20 drive unit. This leaves very little room inside for ballast without encroaching into the cabs. I had planned to have two drive units, but could not fit a decent motor in between the two bogies.

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trainboy Contributor

trainboy

Posted
Posted

Hi all, I have a general question on doc chips for the 071 class. Can I use any 21 pin dcc decoder for the loco? I got a 21 pin TCS 6 function decoder (eu621x) and tried programming it using prodigy Express unit without success. Are there only certain chips that work, such as the Murphy mm0005 or Bachmann 36-557.....thanks, Brendan

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Noel Grand Master

Noel

Posted
Posted (edited)

Any 21 pin decoder should work. A four function one can operate the running lights and the headlights. A six function decoder can also operate the cab lights. Make sure you know what address your decoder is set to. Factory default for most is 3. Put loco on the DCC test track circuit and see if you can write AND read back CVs. That will tell you if the decoder is working or not. CV8=8 on the test track will reset the decoder back to its factory default settings.

 

Ps. I've used 7 different 21 pin decoders types ok with MM 071s (zimo, ESU, lenz, bachmann 557/554, MM, tcs)

Edited by Noel
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burnthebox Veteran

burnthebox

Posted
Posted (edited)

For the techies on here & those who want EXTREME SLOW & and to add to the present topic, here's a couple of Tube vids on DCC I have just come accross, from beginners to experts. Tube 2 has talks about something called " Unstoppable Signal Processing Device " or Power 1, for SLOW ! & I mean SLOW .....

 

No. 1, https://m.youtube.com/watch?v=PRynyMy9bYU

 

No. 2 https://m.youtube.com/watch?v=_gTEG2ImLKo

 

Forgot to mention they're a bit long, 3hrs

Edited by burnthebox
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Noel Grand Master

Noel

Posted
Posted (edited)
i have recently purchased and fitted a Mr Sound Guy decoder for a 141, My query is, " Does any body know how to turn the sound up, or is it set to a preset level that cant be adjusted". Any advice welcome. TDR

 

Hi TDR, hop this helps.

 

On Zimo MX644D decoders:

 

CV266 is master volume level (0-64) I used 40 as I find 64 too loud

CV523 is the sound level of brake hiss (i.e. when F4 brake is applied on the move)

CV287 is the duration of brake sound as loco stops - I increased mine to 44 instead of default 22 because the brakes only sounded for a moment

 

BTW, on some DCC controllers you may need to set CV31 and CV32 appropriately to write to CV values above 255 like these, but I had no problem with the NCE.

 

Noel

Edited by Noel
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Noel Grand Master

Noel

Posted
Posted (edited)
Noel thanks for the help. Im operating a Gaugemaster Prodigy Advance2 and I've never ventured into CV's so this will be new territory/experience for me, so fingers crossed I dont balls it up. TDR

 

Hope it helps. IrishThump has a Gaugemaster Prodigy Advance2 so if there are any issues he may be able to help. From memory CV31 should be left at 16, but CV32 set to 1 before attempting to write to CV266, 523, 287, etc, as they are all >255.

 

BTW, Out of the box MrSoundGuy's Zimo decoder limited the top speed of my 141 loco because CV5 (max voltage/speed) was set to a default of only 140 out of a max value of 255. I changed mine to 255 and the loco then was able to run at a faster scale top speed of 74mph.

 

That Zimo decoder by MrSoundGuy is my favourite to drive because of the 'coasting' and 'braking' features. Enjoy.

 

Attached CV settings I have used on an MM141 with this sound chip:

 

DCC_Sound_141_Zimo_MrSoundguy.pdf

Edited by Noel

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