Hornby Class 20 TTS Loco in Consist

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brammie
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Hornby Class 20 TTS Loco in Consist

Postby brammie » Fri Aug 17, 2018 10:26 am

For several years I ran a Lima Class 20 (00 gauge) Diesel fitted with a Lenz Silver DCC decoder, and was very satisfied with the operation as part of my mid`50s layout. More recently, I added a Hornby Class 20 fitted with TTS, having changed the body for a second Lima Class 20 body in the same livery as my other Lima. I very quickly felt the need to run the TTS Class 20 in consist with the Lima through my ECoS controller, so when Hornby introduced the Class 20 TTS Sound Decoder as a stand alone sale item, I booked one to fit to the Lima model. The part arrived, and was easily fitted; the following operational test of the Lima proved very satisfatory but when I started to configure the two for consist running, I noted that the Hornby ran some 40% faster than the Lima for the same throttle setting - clearly, unsuitable for consist operation. I have subsequently contacted Hornby (and other subscriber web sites) in the hope of establishing how I might speed match the two locos, but so far have not found an answer. The more that I learn about the limitations of the Hornby TTS stand alone decoder, the less confidence I have that my plan will come to fruition - albeit that given the price of the chip it seems a bargain. I have a second Lima Class 20 chassis in good running order, and am considering ordering a second stand alone TTS decoder - but my fear is that if the speed performance of the two Limas is anything other than very close, I will still be unable to run them in consist. The final solution, buy another Hornby Class 20 TTS Loco and switch the body for my spare? Perhaps, but I really don't want to shelve the two Lima chassis as they are both good runners.

Bigmet
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Re: Hornby Class 20 TTS Loco in Consist

Postby Bigmet » Fri Aug 17, 2018 1:40 pm

I take it that the TTS decoder doesn't offer any of start speed (CV2) maximum speed (CV5) and mid speed (CV6) settings, because if it did you would already have used these to speed match. (I know next to nothing about the TTS decoder.)

Since you are obviously confident fitting decoders there's a fairly simple decoder swap about option. Put the Lenz decoder in the Hornby mechanism and use its adjustments to slow down the Hornby to match whatever the TTS decoder does in the Lima mechanism.

Once satisfied with this, since it sounds like you want both locos with sound, a TTS decoder can be reinstalled in the loco with the Lenz to produce sound alone on the same address as the Lenz. You will have to make your own arrangements for the TTS decoder to obtain power, by connecting the red and black wires to the pick ups.

brammie
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Re: Hornby Class 20 TTS Loco in Consist

Postby brammie » Fri Aug 17, 2018 8:18 pm

Thank you kindly for your input Bigmet. You are quite right regarding the TTS CVs; 2, 5 and 6 are not referred to in the TTS Sound Decoder Manual, and read attempts show "Error" for all three. Your proposal concerning the decoder arrangement sounds interesting. Are you suggesting that the TTS decoder to be reinstalled in the loco with the Lenz decoder should only have the sound outputs connected? If I understand you corectly, the TTS decoder drive outputs would remain disconnected.

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Roger (RJ)
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Re: Hornby Class 20 TTS Loco in Consist

Postby Roger (RJ) » Fri Aug 17, 2018 8:25 pm

The TTS decoder needs to be connected to the motor as it relies on the bemf to alter the sounds depending on load and speed, that won't happen if you use a different decoder to power the motor.
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Bigmet
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Re: Hornby Class 20 TTS Loco in Consist

Postby Bigmet » Fri Aug 17, 2018 10:25 pm

brammie wrote:... Are you suggesting that the TTS decoder to be reinstalled in the loco with the Lenz decoder should only have the sound outputs connected? If I understand you corectly, the TTS decoder drive outputs would remain disconnected.

That would be the way. Since you have the pieces to hand, worth trying out to see if the effect is sufficiently satisfactory. If it isn't then further thought will be required.

For example, you still have two Lima mechanisms, and if those proved to be mechanically well matched you could run them as a pair with the TTS decoders.

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RAFHAAA96
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Re: Hornby Class 20 TTS Loco in Consist

Postby RAFHAAA96 » Sat Aug 18, 2018 9:40 am

Roger (RJ) wrote:The TTS decoder needs to be connected to the motor as it relies on the bemf to alter the sounds depending on load and speed, that won't happen if you use a different decoder to power the motor.


TTS steamers use BEMF to control the chuff rate and chuff/coast relationship hence require a motor, but TTS diesels rely upon set notch parameters using TTW CV values, much like the sport, normal and ice settings on your posh car. You can alter these CVs to change when the diesel notches up and down with the throttle if required but this doesn’t affect motor response just sound effects.

TTS decoders will work fine without a motor connected as seen in their single motored HST twin TTS set. Depending upon your controller will depend if you can program the trailer car address solo or if it needs to have the power car on the programming track as well.

Also remember if consisting Class 20s nose to nose you will have to reverse the motor control of one of them.

Rob
RAF Halton Brat - 96th Entry
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Roger (RJ)
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Re: Hornby Class 20 TTS Loco in Consist

Postby Roger (RJ) » Sat Aug 18, 2018 12:24 pm

Thanks for the clarification, Rob.
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brammie
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Re: Hornby Class 20 TTS Loco in Consist

Postby brammie » Sun Aug 19, 2018 8:46 pm

Thank you for enlightening me chaps. Bearing in mind the advice from RAFHAAA96 (what year was that entry?), I think I will go for driving the Hornby Class 20 with a second Lenz decoder, and leave the installed TTS decoder to supply the installed speaker for sound only as suggested by Bigmet. I'm struggling to come to terms with methodology for posting pics, but when I master it I will post some views of my 17ft x 10ft layout (Clackchester) now 13 years on from commencement!

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Bufferstop
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Re: Hornby Class 20 TTS Loco in Consist

Postby Bufferstop » Sun Aug 19, 2018 9:36 pm

Hi Grammie, there should be no problem posting pictures as long as it's from a pc.
Save your image to the desktop, have the bulletin board open in a window,not full screen,,
Write some text, leave the cursor on a new line,
Just below the editting window, click the attachment tab.
Click on the image file and drag it into the edit window.
Down below it's name will appear in the attachment tab.
Click on the link "place in line"
An attachment tab should appear in the edit window, if it's not on the new line put the cursor behind it and press enter.
At this point you should be able to click on preview and see how it will appear.
Continue editting your post. You can have up to five attachments in any post.

Hope this helps
John W
aka Bufferstop
Growing old, can't avoid it. Growing up, forget it!
My Layout, My Workbench Blog and My Opinions

brammie
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Re: Hornby Class 20 TTS Loco in Consist

Postby brammie » Mon Aug 20, 2018 5:01 am

Thank you for that Bufferstop. I'll give it a try once I get my blood sugar levels up later today.

brammie
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Re: Hornby Class 20 TTS Loco in Consist

Postby brammie » Mon Aug 20, 2018 6:53 pm

Update: Had a reply from Hornby - I am informed that I was correct in my assumption "no CV5 or CV6". Thank you for that Hornby.

Otherwise: Uploading of pictures mastered - see my thread "Clackwick" at Personal Layouts - Under Construction.

Class 20 progress: Plan to start modifications to locos in a day or two. Been tied up the last few days coming to terms with posting pics of my layout.

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RAFHAAA96
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Re: Hornby Class 20 TTS Loco in Consist

Postby RAFHAAA96 » Tue Aug 21, 2018 3:40 pm

brammie wrote:?..advice from RAFHAAA96 (what year was that entry?)...!


Joined RAF as an apprentice rigger Sept 1960, departed Halton July 1963 to join the grown up Air Force, departed RAF July 1984, gave up paid work July 2009.
Rob
RAF Halton Brat - 96th Entry
http://www.halton96th.co.uk

brammie
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Re: Hornby Class 20 TTS Loco in Consist

Postby brammie » Tue Aug 21, 2018 5:34 pm

Good man, Halton Brat. I was 36th B/E St Athan (Feb 59) A Mech E. Left on PVR after 25 years from Honington - history. Earned my corn as a CAA Multi X Licensed CAA Engineer until 2004. Retired and moved permanently to southern Germany, which is one of the few places where you can buy a property large enough to allow you a 17 x 14 ft room for your model railway without winning the lottery! Good to know you. Did you ever know Ray Goldsmith?

brammie
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Re: Hornby Class 20 TTS Loco in Consist

Postby brammie » Wed Aug 22, 2018 7:59 am

I'm hoping to complete the speed-matching of my two Class 20 Diesels today. The models involved are:

D8041 (address 8041) Lima of some age, but excellent runner. I removed the previously fitted Lenz decoder from this and fitted a Hornby TTS to facilitate sound.

D8024 (address 8024) Hornby TTS out-of-the-box. This runs significantly faster than D8041for the same throttle setting.

Plan: D8024 - disconnect the two TTS decoder outputs to the motor. Slave in the Lenz decoder, after re-programming address to 8024. Connect the Lenz to the TTS power pickups, and the outputs from the Lenz to the motor. Test 8024 for running.

With both models on my big outer loop, trial for speed and A and D matching, and adjust as required. When resolved, load on ECoS as consist.
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RAFHAAA96
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Re: Hornby Class 20 TTS Loco in Consist

Postby RAFHAAA96 » Wed Aug 22, 2018 9:29 am

Apologies to others for straying off topic for a while....

brammie wrote:Good man, Halton Brat. I was 36th B/E St Athan (Feb 59) A Mech E. Left on PVR after 25 years from Honington - history. Earned my corn as a CAA Multi X Licensed CAA Engineer until 2004. Retired and moved permanently to southern Germany, which is one of the few places where you can buy a property large enough to allow you a 17 x 14 ft room for your model railway without winning the lottery! Good to know you. Did you ever know Ray Goldsmith?


Didn’t know him. RAF was a small world but not that small that I knew everybody.

I had a mate in B/Es around the same time as you but he was a rigger. Arthur Young. He was my best man but I lost touch with him. His service number started 1942... I thought he was 39th but obviously he was earlier than that.

I went into industry after RAF mostly in Post Design Services for a variety of MoD contracts, ended up being responsible for Airfield Arrestor Gear, (RHAG and PAAG). Never even heard of the kit before I got lumbered with it.

Rob
RAF Halton Brat - 96th Entry
http://www.halton96th.co.uk


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