gavind Posted December 29, 2013 Share Posted December 29, 2013 So I have the large capacitor across the rectifier bridge as shown in Martin's picture above (blue wire is positive) and the small capacitor between pins 20(GND) and 12(+Vcc) (pin 20 should be the same as the black wire in Martin's pic. pin 12 is the 'odd' pin at one end of the 21 pin layout and pin 20 is the third pin from the opposite end on that side of the grid (there's no pin 11). Layout can be seen here: http://www.dccconcepts.com/index_files/DCCdecoderfunctionsdesc.htm Following on from the discussion with Nigel, I was surprised it needed such a large capacitor to make it work, as the Hornby decoders seem to benefit from something as small as 1000uF. Gavin Link to post Share on other sites More sharing options...
chaz Posted December 29, 2013 Share Posted December 29, 2013 Sorry if I'm missing something, but can someone confirm where on a Loksound 3.5 the connections need to be made? cheers Ian If and when I get my loco's keep-alive to work as it should I will post full details here but until I do there seems little point in in my commenting - however have a look at.... http://www.rmweb.co.uk/community/index.php?/topic/80078-keep-alive-has-no-effect/ ....there's a link offered in the last post of that topic BUT it relates a a LOKpilot V3 decoder, NOT a LokSound V3.5. Whether they are similar enough to make the same approach possible I don't know. Chaz Link to post Share on other sites More sharing options...
chaz Posted January 4, 2014 Share Posted January 4, 2014 No luck I'm afraid. Despite rewiring with two capacitors as per the circuit in the link referred to above I have had no success. Not sure what to try next and am thinking that the decoder will need replacing if the trick can't be found. Chaz Link to post Share on other sites More sharing options...
gavind Posted January 5, 2014 Share Posted January 5, 2014 Chaz, My apologies, I thought I had this sorted, but after some further tests following your post yesterday, I'm no longer convinced…. It seems that the small cap on Vcc discharges very swiftly when the power is cut, and the output wire for an active function (headlamp) goes to HIGH at this point, staying at +15V as long as the large cap takes to discharge. This would seem to imply that the trigger is the loss of the DCC command signal itself, rather than the loss of the driving voltage. From some more digging elsewhere, Ive seen talk of CV 111 being used to set the timeout for a loss of the signal, but the 3.5 doesn't appear to support that. The loksound 4.0 manual says this is stored in CV113 on that decoder, but on the 3.5 CV113 is a function configuration. -So if there is any benefit to be had from having the capacitors in at all, it may only last for whatever hardwired value that timeout is set to... There's a tantalising question left in my mind based on ESUs statement somewhere that the 3.5 can be firmware upgraded to a 4.0, but I don't have access to a programmer, or really to technical support as I picked mine up secondhand. Gavin Link to post Share on other sites More sharing options...
Suzie Posted January 5, 2014 Share Posted January 5, 2014 It is important to make sure when testing that you are not pressing the stop button to remove the power. Pressing the stop button will send a stop command to the decoder before removing the power. You must use a switch to disconnect power to get a valid test. Link to post Share on other sites More sharing options...
chaz Posted January 5, 2014 Share Posted January 5, 2014 It is important to make sure when testing that you are not pressing the stop button to remove the power. Pressing the stop button will send a stop command to the decoder before removing the power. You must use a switch to disconnect power to get a valid test. Thanks for that Suzie, but I am not using the STOP button during testing. I am lifting the loco from the track for, as I said above, this seems to me to be equivalent to a break in the current path due to dirt on track or wheels. I wonder if you would mind confirming what wiring and components you have used (I believe I read a posting of yours where you said you had a successful installation on a Loksound 3.5?) and what CV settings are needed. I would prefer not to have to discard the decoder as I like the sound project that's in it (a V3.5 download that I edited). Chaz Link to post Share on other sites More sharing options...
gavind Posted January 5, 2014 Share Posted January 5, 2014 Thanks for that Suzie, but I am not using the STOP button during testing. I am lifting the loco from the track for, as I said above, this seems to me to be equivalent to a break in the current path due to dirt on track or wheels. I wonder if you would mind confirming what wiring and components you have used (I believe I read a posting of yours where you said you had a successful installation on a Loksound 3.5?) and what CV settings are needed. I would prefer not to have to discard the decoder as I like the sound project that's in it (a V3.5 download that I edited). Chaz I tried to follow Suzie's suggestion exactly, so I wired a kill-switch into one of the power feeds to the decoder and took the whole thing off the track so the motor is running freely. I then found that I had recovered the effect I was looking for, in that the lights fade slowly (sic) when I kill the power. However, I realised in the course of cross-checking that I'd managed to disconnect the 0V line to the large capacitor, and when I reconnect this everything is back to an instantaneous cut-off. This feels like the potential of progress, but I'm still confused!!! Link to post Share on other sites More sharing options...
gavind Posted January 5, 2014 Share Posted January 5, 2014 I tried to follow Suzie's suggestion exactly, so I wired a kill-switch into one of the power feeds to the decoder and took the whole thing off the track so the motor is running freely. I then found that I had recovered the effect I was looking for, in that the lights fade slowly (sic) when I kill the power. However, I realised in the course of cross-checking that I'd managed to disconnect the 0V line to the large capacitor, and when I reconnect this everything is back to an instantaneous cut-off. This feels like the potential of progress, but I'm still confused!!! OK, now I have success… -that last discovery made me think that perhaps there just wasn't enough juice in the Vcc cap to last out, so I swapped out the 1000uF I had there for a 4700uF (I hope I can get away with less than this ultimately…). The white wire attached to one of the decoder diodes is 16V+, and the 100Ohm charging resistor is just visible with a diode at lower right. The blue/white wire coming off pin 20 is the common ground for both caps. The Orange wire coming from pin 12 is the +Vcc wire to the 4700uF cap just visible upright at the left. Ignore the PCB that's sitting in front of the speaker at left, as that's something else entirely... With the 25V cap disconnected this gives a definite fade on the lights. If I now reconnect the 25V cap (which I have at 2200uF), then I get a clear continuation of the motor when I cut the power. I think this just means that the decoder is quite hungry in itself. This would also explain why I thought I was getting some slight improvement before. I've attached a photo of the test setup. Now when I kill the power with the sound on there's a reassuring fizzle out of the engine noise. I have some video: Gavin Link to post Share on other sites More sharing options...
chaz Posted January 5, 2014 Share Posted January 5, 2014 Thanks for posting that Gavin. It looks like we need to use the highest value capacitors that will fit into the model. Could you please just confirm what CV settings you have on 29, 50 & 124 please? Chaz Link to post Share on other sites More sharing options...
gavind Posted January 5, 2014 Share Posted January 5, 2014 Thanks for posting that Gavin. It looks like we need to use the highest value capacitors that will fit into the model. Could you please just confirm what CV settings you have on 29, 50 & 124 please? Chaz 29 is set to 2 49 set to 3 50 set to 0 51 set to 0 124 set to 6 In the end I'm not sure there was a lot of difference in the setting of 50, provided that 29 is set right. I'm sure there must be a lower value for the Vcc cap that will work OK, maybe 2200 there. Gavin Link to post Share on other sites More sharing options...
gavind Posted January 5, 2014 Share Posted January 5, 2014 Thanks for posting that Gavin. It looks like we need to use the highest value capacitors that will fit into the model. Could you please just confirm what CV settings you have on 29, 50 & 124 please? Chaz P.S. thanks for encouraging me to persevere! Link to post Share on other sites More sharing options...
Grovenor Posted January 5, 2014 Share Posted January 5, 2014 I think this just means that the decoder is quite hungry in itself. Sounds like the lights are on the decoder supply. probably would last longer with the lights turned off. Keith Link to post Share on other sites More sharing options...
chaz Posted January 5, 2014 Share Posted January 5, 2014 Sounds like the lights are on the decoder supply. probably would last longer with the lights turned off. Keith if you are right Keith that is good news to me, my Peckett saddle tank has no lights.... Link to post Share on other sites More sharing options...
gavind Posted January 5, 2014 Share Posted January 5, 2014 Sounds like the lights are on the decoder supply. probably would last longer with the lights turned off. Keith That may be true, which to me would be surprising since the function outputs are all clearly 15V, not Vcc, although on 10k resistors they shouldn't be drawing more than about 1.5mA. At 5V the charge in the small cap should have been about 5mC, so the headlamp LED on its own should last about 3 seconds on the smaller cap (if anything it was lasting about 1/50th, if at all before). I can't believe that's going to dominate the power drain compared to anything going through the speaker… -I'll give it a try with the lights out and only the sound (when it's not going to wake the kids up), but I doubt it will make a significant difference... Gavin Link to post Share on other sites More sharing options...
chaz Posted January 6, 2014 Share Posted January 6, 2014 I'm going to put a 2200uf on to the 5V keep-alive and will also set the CVs to the settings listed by Gavin. That will be sometime today. Will report the result this evening. Fingers crossed! Chaz Link to post Share on other sites More sharing options...
chaz Posted January 6, 2014 Share Posted January 6, 2014 Success at last! Just to clarify what I have done I have wired two capacitors to the chip as detailed here... 51978_LokPilot_V30_Familie_ESUKG_EN_User_Manual_Edition_7_eBook.pdf Look at page 19 (thanks Keith) In fact I used a 25V 3300uf and a 25V 2200uf as they are what I had. The latter is rated at a much higher voltage than needed and is therefore rather bulky but in 7mm this is less of a problem. Both capacitors have diodes (I used 1N4001) and 100R resistors. Under test if the loco is lifted from the track whilst under power it noticeably runs on for a moment - probably about half a second (although this is very difficult to gauge accurately). That's not much but it's probably enough to see it over any likely stall. When I have had the chance to test the loco in service I will post again. Incidentally the loco could be programmed with the capacitors connected. I used Gavin's CV settings (Thanks Gavin) which are... 29 is set to 2 49 set to 3 50 set to 0 51 set to 0 124 set to 6 So that problem is now sorted although I will experiment with other, larger, capacitor values and with a lower voltage rating for the second capacitor for the next loco I do. it's a pity that nobody knows how to do a similar job on the Loksound V3.5XL. Chaz Link to post Share on other sites More sharing options...
GoingUnderground Posted January 7, 2014 Share Posted January 7, 2014 Chaz, My apologies, I thought I had this sorted, but after some further tests following your post yesterday, I'm no longer convinced…. It seems that the small cap on Vcc discharges very swiftly when the power is cut, and the output wire for an active function (headlamp) goes to HIGH at this point, staying at +15V as long as the large cap takes to discharge. This would seem to imply that the trigger is the loss of the DCC command signal itself, rather than the loss of the driving voltage. From some more digging elsewhere, Ive seen talk of CV 111 being used to set the timeout for a loss of the signal, but the 3.5 doesn't appear to support that. The loksound 4.0 manual says this is stored in CV113 on that decoder, but on the 3.5 CV113 is a function configuration. -So if there is any benefit to be had from having the capacitors in at all, it may only last for whatever hardwired value that timeout is set to... There's a tantalising question left in my mind based on ESUs statement somewhere that the 3.5 can be firmware upgraded to a 4.0, but I don't have access to a programmer, or really to technical support as I picked mine up secondhand. Gavin i have never seen any statement from ESU that any LS 3.5 model can be upgraded to a 4 with a firmware change, so I think you are probably wrong. However it was possible to upgrade the 3.0 to a 3.5 with the relevant firmware upgrade. EDIT: According to the latest published Loksound V3.5 and V4.0 manuals neither use CV111. Also both manuals do not show CV11 in their respective lists of supported CV. On the LS V4 series only CV113 sets the time that the power pack will supply power to the decoder/the decoder will accept power from the power pack, with the aim of limiting the "run-on" as if you hit the stop button and the base station turns off track power the motor will still keep running. The idea is to limit the run on time as you may have hit the stop button because the loco is about to dive off the baseboard and you don't necessarily want the motor to keep turning until the capacitor is depleted as that might just be long enough for the loco to make that nosedive on to the floor. On the LS V3.5 CV113 has a totally different function, setting light brightness. Link to post Share on other sites More sharing options...
GoingUnderground Posted January 7, 2014 Share Posted January 7, 2014 It is important to make sure when testing that you are not pressing the stop button to remove the power. Pressing the stop button will send a stop command to the decoder before removing the power. You must use a switch to disconnect power to get a valid test. That isn't necessarily true as it depends on what your system actually does when you first press the stop button. Some systems, such as the ECoS, do cut the track power immediately whilst others send out an "all stop" command but leave the track live. Link to post Share on other sites More sharing options...
Crosland Posted January 7, 2014 Share Posted January 7, 2014 This would seem to imply that the trigger is the loss of the DCC command signal itself, rather than the loss of the driving voltage. From some more digging elsewhere, Ive seen talk of CV 111 being used to set the timeout for a loss of the signal, but the 3.5 doesn't appear to support that. The loksound 4.0 manual says this is stored in CV113 on that decoder, but on the 3.5 CV113 is a function configuration. Gavin CV 11 (not 111) is the NMRA standard recommended CV for the packet timeout. Andrew Link to post Share on other sites More sharing options...
gavind Posted January 7, 2014 Share Posted January 7, 2014 CV 11 (not 111) is the NMRA standard recommended CV for the packet timeout. Andrew Thanks... I thought that was correct… the 3.5 doesn't appear to support this anyway. Gavin Link to post Share on other sites More sharing options...
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