Sir TophamHatt Posted August 24, 2018 Share Posted August 24, 2018 (edited) Quick question: What 8-pin decoders do Zimo produce that can accept Stay Alive? Turns out it'll be the MX633 for a start. I have a few locos that have the MX621 and some have MX600 but that's only because I didn't know the difference between them! Is there a simple list of what decoders have what features/pins/whatever? I looked in the manual but it's still a little clunky to understand. Perhaps I should re-write it, take out all the extra info that isn't really needed, as I guess then I'll get to know the decoders and their features! Managed to understand the manual as far as I need. Although it's still confusing. The MX600 doesn't say it has reduced features, compared with the MX622, which states it has full features. So does it have reduced or full features - whatever that means?! For my own remembering: MX600/MX600R: 4 functions MX621/MX621R: 2 functions, reduced features MX622/MX622R: 2 functions (plus 2 function "ready pads), full Zimo features. MX623/MX623R: 2 functions (plus 4 "ready" pads). MX630/MX630R: 4 functions (plus 2 "ready" pads). MX633/MX633R: 4 functions (plus 6 "ready" pads), stay alive capable. Edited August 24, 2018 by Sir TophamHatt Link to post Share on other sites More sharing options...
michaelp Posted August 24, 2018 Share Posted August 24, 2018 (edited) The one I use is MX645 used with stay alive but I am sure there will be other Zimo decoders.. Edited August 24, 2018 by michaelp Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 24, 2018 RMweb Premium Share Posted August 24, 2018 (edited) On the MX600 and also on the MX612 you have to solder the ground cable on a position on the chip - but the position is clearly described in the manual. I did do it for all my MX600 (and those are 10 if I am nor wrong - as they are cheap ). I never did it on a 621, which is a bit smaller. In any case to do so you need a very fine soldering iron (I use 6 Watt), a fine solder wire (preferably 0.5mm) and if you do not have perfect eyesight also a magnifying glass or an optivisor (what I do, as then I have hands free....) The shrink foil cover on the chip has to be partially removed, and after soldering I normally seal the soldering point with a drop of hotmelt so that the soldering doesn't see mechanical threats if the wire is moved. I didn't ruin a single chip so far and all my stay alive locos run fine. I suppose you have downloaded the Zimo manual - if not find it here. http://www.zimo.at/web2010/documents/MX-KleineDecoder_E.pdf see page 6 And finally: good luck! Edited August 24, 2018 by Vecchio Link to post Share on other sites More sharing options...
ianjeffery Posted August 24, 2018 Share Posted August 24, 2018 does this mean i can add stay alive caps to my mx600R's ?????? have you got any pictures? Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 24, 2018 RMweb Premium Share Posted August 24, 2018 does this mean i can add stay alive caps to my mx600R's ?????? have you got any pictures? Yes you can. I can send you a picture in the evening (company computer doesn't like flickr....) Link to post Share on other sites More sharing options...
ianjeffery Posted August 24, 2018 Share Posted August 24, 2018 (edited) that would be fantastic. what size caps do you use? how do they actually attach.... the manual on page 7 says "makeshift ground terminal if required between the diodes and the capacitor"... so the negative goes where, what about the positive leg ??? I have a load of 50v 100uf ones lying around. Edited August 24, 2018 by ianjeffery Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 24, 2018 RMweb Premium Share Posted August 24, 2018 (edited) The positive is the blue wire. (don't ask me why, but this is standardised on all decoders) 100uF will be a little low to see an effect. I normally use 1000uF or 1500uF and if there is space enough I even put some in parallel to increase capacity. Old Lima's were a perfect place for stay alives - first they really need it because of bad performance, second there is enough space above the dummy bogie. Try to find 25V types on the internet, for instance at Conrad (called Rapid electronics here on the island.). Look carefully at the size, there are quite some differences. for instance 1000uF radial 25V 10x21mm 16pence (min quantity 5). For my experience it is easier to find space for 2 with 10mm diameter than for one with 14 or 16mm diameter. By the way - no space for capacitors? See what I did 15 years ago... This was an Austrian page, but no fear it is in 2 languages...This was with a Zimo MX63 - this decoder model is long time gone and replaced by others. But my loco with the MX63 runs today like on the first day. Hats off to Zimo. http://atw.huebsch.at/modell/h0/LIMA_2061_V20.htm Edited August 24, 2018 by Vecchio Link to post Share on other sites More sharing options...
Sir TophamHatt Posted August 24, 2018 Author Share Posted August 24, 2018 (edited) Thanks. Although it's still not entirely clear where to put the blue or black wire from the stay alive I'll have to zoom in a little. Could you also draw out (simply) how to daisy chain some together? Edited August 24, 2018 by Sir TophamHatt Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 24, 2018 RMweb Premium Share Posted August 24, 2018 To increase the capacity you have to connect the capacitors in parallel. Means you connect all the + poles together and all the - poles together. Doing so you just have to add up the capacities to get to your new total value. Ctotal = C1 + C2 + Cn Example: 3 x 1000uF 25v = 3000uF. The maximum voltage stays unchanged at 25Volt If you connect capacitors in series you will decrease the capacity but increase the maximum operating voltage the capacity will be: 1/Ctotal= 1/C1 + 1/C2 + 1/Cn and the voltage will be Utotal =U1 +U2 +Un Example: 3 capacitors of 1000uF 25V in series 1/Ctotal = 1/1000 + 1/1000 + 1/1000 = 1/0.003 = 333uF Utotal = 25 + 25 + 25 = 75Volt This will be used in case of supercaps which have a rather low maximum voltage. Blue and black wire on Zimo decoders with stay alive circuit built in: also for the stay alive capacitor blue is plus and has therefore to be connected with the plus pole of the capacitor and black is ground. Drawings / pictures come later. 1 Link to post Share on other sites More sharing options...
ianjeffery Posted August 24, 2018 Share Posted August 24, 2018 The positive is the blue wire. (don't ask me why, but this is standardised on all decoders) 100uF will be a little low to see an effect. I normally use 1000uF or 1500uF and if there is space enough I even put some in parallel to increase capacity. Old Lima's were a perfect place for stay alives - first they really need it because of bad performance, second there is enough space above the dummy bogie. Try to find 25V types on the internet, for instance at Conrad (called Rapid electronics here on the island.). Look carefully at the size, there are quite some differences. for instance 1000uF radial 25V 10x21mm 16pence (min quantity 5). For my experience it is easier to find space for 2 with 10mm diameter than for one with 14 or 16mm diameter. By the way - no space for capacitors? See what I did 15 years ago... This was an Austrian page, but no fear it is in 2 languages...This was with a Zimo MX63 - this decoder model is long time gone and replaced by others. But my loco with the MX63 runs today like on the first day. Hats off to Zimo. http://atw.huebsch.at/modell/h0/LIMA_2061_V20.htm so the negative lead goes to the two small pads on the chip, and the positive connects to the positive blue wire ? ok, that sounds easy. Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 24, 2018 RMweb Premium Share Posted August 24, 2018 Yes it is not complicated, but, especially for bigger capacitors, you need a resistor to limit the charging current, otherwise your DCC controller will tell you "short circuit" This resistor is rather a low value, you want to limit to a current the decoder can easily handle. Zimo recommends 33Ohm for capacitors up to 2200uF or 68Ohm for bigger capacitors. In the latter case you need also a diode so that the energy from the capacitor goes to your decoder without being limited by the resistor. See page 60 of the manual (liknk further up this thread) So here are some pictures: First 3 already modified decoders as described before. 20180824_171357 Now the position for the ground connection. Note that the shrink foil is already removed. Sorry for the picture quality - I was to lazy to get a proper camera out. This is all what my rather dated Samsung can offer.... 20180824_172034 Now how to connect capacitors together: First 2 1000uF capacitors parallel to get 2000uF. This is just for the picture - please consider insulation tubes to avoid short circuits. Especially in larger capacitors there is quite a bit of energy. So better no short circuits.... 20180824_172836 Now a few in series (these are supercaps) 20180824_172321 And we spoke in another thread of Sir Topham Hatt about soldering - this is what I use for fine stuff. Contains lead and is only 0.5mm. Flux is inside the wire. 20180824_172640 So keep all the naughty trucks well sorted in the yard and happy soldering! Link to post Share on other sites More sharing options...
ianjeffery Posted August 24, 2018 Share Posted August 24, 2018 i cant really see where its soldered to on the picture. do you have any more? Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 24, 2018 RMweb Premium Share Posted August 24, 2018 Not today. Probably after the weekend. Social program starting.... 1 Link to post Share on other sites More sharing options...
ianjeffery Posted August 24, 2018 Share Posted August 24, 2018 is it between the two small diodes at the side of the board? Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted August 31, 2018 RMweb Premium Share Posted August 31, 2018 is it between the two small diodes at the side of the board? Yes it is. To get this sorted I need to go for some serious kit... 20180831_090538 First the decoder as it is and the position marked by a pin. DSC_0076 Next I cut a window into the shrink sleeve DSC_0086 Even I did this with a new scalpel blade it doesn't look nice under this magnification. Now comes the soldering. DSC_0089 And now sealed with hotmelt glue. DSC_0093 As mentioned if you use a larger capacitor (or a few small ones in series) you need to limit the charging current. On the other hand you want full power when needed. So you need a resistor to limit the current and a diode to allow discharge without the resistor. I use 47 Ohm (could be a bit larger, but this is what I have) which limits the current to 340mA (at 16V). With this the control station has no problem and there will be no short circuit detected. The diode is 1N4007, a 1Ampere type. DSC_0090 To avoid short circuits I pack the arrangement into a shrink tube. DSC_0094 So. Now the whole thing need to go into a loco. I have one on order, it is a tiny permanent way "draisine" (light auxiliary rail vehicle for crew and material transport) Because of it's size it will need a stay alive. Will see how it goes. Small picture of the X 626 below. liliput X 626 Hope this was of help! 2 Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted September 11, 2018 RMweb Premium Share Posted September 11, 2018 Correction. As this famous little loco has a next 18 interface I will use a decoder which fits without fiddling. The only fact that speaks against this plug and play method is the new MX 659 (also this is next 18 direct plug in) which is too long for the available space but may fit after modification. Especially as I saw that there is a sound project for this little loco existing which I can download for free.... Will download it and try it on a test loco with an MX645 before I decide. Vecchio Link to post Share on other sites More sharing options...
shelton Posted October 18, 2018 Share Posted October 18, 2018 Hi Vecchio 1. Do you have a photo where it shows the resistor and diode and capacitor and Zimo decoder all connected together? 2. Also I have a soldering station with variable temperature will this be okay to use to solder the home-made keep alive? ThanksShelton Link to post Share on other sites More sharing options...
Nigelcliffe Posted October 19, 2018 Share Posted October 19, 2018 1. Do you have a photo where it shows the resistor and diode and capacitor and Zimo decoder all connected together? 2. Also I have a soldering station with variable temperature will this be okay to use to solder the home-made keep alive? There are diagrams in the Zimo manuals, towards the back, which show how the components fit together. Essentially, diode+resistor in series with one lead (noting orientation of diode - that is really important!), and then capacitors between decoder positive (blue) and decoder ground (the new wire). The components Vecchio is using are on the larger size of what's needed - my units use surface mount resistor and diode as they are a fraction of the size shown. Soldering is a matter of small tip, holding the decoder down so it doesn't move, limited time with heat applied, and good hand control. Link to post Share on other sites More sharing options...
RMweb Premium Vecchio Posted October 19, 2018 RMweb Premium Share Posted October 19, 2018 Attention. Diode and resistor in parallel. Not in series as you want to limit the charging current but you want full current for the chip (and motor) in case of loss of track voltage. Rest ok. For the diode you need a 1 ampere type or bigger depending on decoder and model as the complete current will run over it. Cheers from the train to London. Delayed as usual and not enough seats.... Link to post Share on other sites More sharing options...
Nigelcliffe Posted October 19, 2018 Share Posted October 19, 2018 Attention. Diode and resistor in parallel. Not in series as you want to limit the charging current but you want full current for the chip (and motor) in case of loss of track voltage. Rest ok. For the diode you need a 1 ampere type or bigger depending on decoder and model as the complete current will run over it. Cheers from the train to London. Delayed as usual and not enough seats.... Depends how you parse my sentence above.... I can see there are two readings. It is (Parallel diode and resistor) in series of the lead between decoder positive and capacitors..... - Nigel Link to post Share on other sites More sharing options...
RMweb Premium Torper Posted November 8, 2020 RMweb Premium Share Posted November 8, 2020 Here's an even easier way of adding a Stay-alive to a Zimo MX600: 1 Link to post Share on other sites More sharing options...
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