 Joined: 30/04/2013(UTC) Posts: 11 Location: Porto
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  Here are two snapshots of the silicon diodes inside the Faller AMS 4030 and 4702. Paulo Barbosa
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 1 user liked this useful post by pamgb1963
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Joined: 30/04/2013(UTC) Posts: 11 Location: Porto
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There are not any silicone diodes made by Faller, the original diodes that Faller used were made with selenium which was cheap and nasty. The selenium diodes have a voltage drop between the cathode and the anode higher, almost 2.5 times higher than the silicon diodes, which means the motors will have less voltage available to work, so the cars will run slower. Another problem is the reverse current that is also much higher in the selenium diodes, which means the hand-controllers will be interfering with each other because of lack of isolation. If you want the hand-controllers completely isolated and the cars runing at top speed then you must replace all the selenium diodes with silicon diodes. For each hand controller you need one diode, so if you use four hand controllers then you will need four diodes. For each car you also need one diode, so if you use four cars then you will need another four diodes, in total you will be replacing eight diodes, four in the hand-controllers and four in the cars. Good luck! Paulo Barbosa Edited by moderator 02 November 2019 07:28:15(UTC)
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1 user liked this useful post by pamgb1963
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 Joined: 12/01/2002(UTC) Posts: 2,578 Location: Sweden
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It is a very long time since I was running Faller AMS cars, but I remember I had some device with diodes, that was intended to allow you to run two cars independently on each track. In total 4 cars independently. This was in the late 60's. I noticed that the cars did not run independently. The first attempt to fix it was to replace the selenium diodes with silicon ones. But it did not fix the problem. So I analyzed the wiring inside the device and concluded that it was designed incorrectly. This was the major reason for the non-independence even though the low quality of the selenium diodes made it even worse.
I built my own device instead. It worked well. Maybe there are different versions and maybe there are original Faller devices where the wiring mistake is fixed. But at least the device I had was non-functional by design.
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2 users liked this useful post by perz
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 Joined: 31/12/2010(UTC) Posts: 4,010 Location: Paremata, Wellington
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Originally Posted by: perz  It is a very long time since I was running Faller AMS cars, but I remember I had some device with diodes, that was intended to allow you to run two cars independently on each track. In total 4 cars independently. This was in the late 60's. I noticed that the cars did not run independently. The first attempt to fix it was to replace the selenium diodes with silicon ones. But it did not fix the problem. So I analyzed the wiring inside the device and concluded that it was designed incorrectly. This was the major reason for the non-independence even though the low quality of the selenium diodes made it even worse.
I built my own device instead. It worked well. Maybe there are different versions and maybe there are original Faller devices where the wiring mistake is fixed. But at least the device I had was non-functional by design. There have been various attempts at installing decoders into Faller AMS vehicles , infact it's been talked about for easily 15-20 years. Early attempts could only be done on vehicles with enough space for one, usually LKW trucks etc. There were problems with the quality of the signal due to the constant track sparking but newer decoders may be more tolerant of that (and sometimes it's worse). But of course, Decoders have got smaller, and smaller and smarter. Going to the trouble of discarding the selenium plates in favour of silicon diodes seems to me that adapting to a decoder could achieve the same thing and a whole lot more? It's something I've kept an eye on waiting for someone dedicated enough to do the ground-breaking. This is one example... And here's one with what appears to be the decoder externally on the tray |
Cookee Wellington  |
1 user liked this useful post by cookee_nz
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Joined: 30/04/2013(UTC) Posts: 11 Location: Porto
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Hi Perz, the problem is you forgot to replace the four diodes installed in the Faller AMS contact shoes. It is not enough to replace only the four diodes inside the controllers (4019, 4020 and 4030) and track (4702).
Paulo Barbosa
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Joined: 30/04/2013(UTC) Posts: 11 Location: Porto
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Joined: 31/12/2010(UTC) Posts: 4,010 Location: Paremata, Wellington
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Originally Posted by: pamgb1963 Thanks Paulo but that's not really what I am talking about. That decoder is a wireless solution fully self-contained running off in-built batteries. You might as well just get Faller Car System vehicles and fit a guide-pin to run them on AMS track (I have seen people do that also). What I am talking about is using the existing AMS chassis and pickup shoes, power taken from the track as usual but would require slight modification of the chassis to enable wiring the decoder in. N-gauge DCC decoders are small and likely best suited to the task and give the greatest range of controller options. But they would still be a more expensive than the adaptation to silicon diodes as discussed  https://www.marklin-user...placement-silicon-diodes |
Cookee Wellington |
1 user liked this useful post by cookee_nz
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Joined: 30/04/2013(UTC) Posts: 11 Location: Porto
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Joined: 12/01/2002(UTC) Posts: 2,578 Location: Sweden
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Originally Posted by: pamgb1963 Hi Perz, the problem is you forgot to replace the four diodes installed in the Faller AMS contact shoes. It is not enough to replace only the four diodes inside the controllers (4019, 4020 and 4030) and track (4702).
Paulo Barbosa Do you think I was just guessing, not knowing what I was doing? You do not know me, obviously. Then, I only had one type of device. There might be other types of devices, that only had the problem with the selenium diodes themselves, not the design error. I can't judge from the pictures whether this is the same type I had or another one.
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Joined: 31/12/2010(UTC) Posts: 4,010 Location: Paremata, Wellington
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Originally Posted by: pamgb1963 Thanks Paulo, I replied on Yahoo but I'll add it here also :-) Very interesting, and at that price you can afford to do some experimenting. You would need to confirm these specs with measuring for different vehicles but in the 1968 catalogue was this bit of detailed info... Auto kits with flat-armature motor 53.. (pancake motor). "On 12 volts DC the armature, running light, rotates at 26000 rpm, drawing 150-170 mA. Under load the armature rotates at 4000-5000 rpm, drawing 200 mA, The armature itself is made of dynamo sheet metal and has a flat commutator. These are the secrets of the excellent performance characteristics of this motor" The smallest of the decoders on that site is rated at 500mA so well-within the tolerance range. I think even the more powerful zinc-chassis in a truck would not come close to drawing 500 mA. And there are function options also if you wanted to add LED headlights & tail-lights, or for the emergency vehicles, possibly even a flashing roof light.   |
Cookee Wellington |
2 users liked this useful post by cookee_nz
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Joined: 31/12/2010(UTC) Posts: 4,010 Location: Paremata, Wellington
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And I also posted about Faller using Silicon Diodes - they did use them in their 454 item "Loop & Polarizing straight" from 1976 - 1980... (just a pity they did not develop an improvement into their chassis to accommodate them)   |
Cookee Wellington |
1 user liked this useful post by cookee_nz
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Joined: 30/04/2013(UTC) Posts: 11 Location: Porto
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Hi perz, I don't have any doubt that your Faller controller was wrongly wired and you are right about the low quality of the selenium diodes. One can only blame Faller as around 1976 they were already fully aware of the low quality of their diodes, the proof is that they do not installed selenium diodes in the Faller AMS 454 (451+453) but silicon diodes!
Paulo Barbosa
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1 user liked this useful post by pamgb1963
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Joined: 31/12/2010(UTC) Posts: 4,010 Location: Paremata, Wellington
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Originally Posted by: pamgb1963 Hi perz, I don't have any doubt that your Faller controller was wrongly wired and you are right about the low quality of the selenium diodes. One can only blame Faller as around 1976 they were already fully aware of the low quality of their diodes, the proof is that they do not installed selenium diodes in the Faller AMS 454 (451+453) but silicon diodes!
Paulo Barbosa It's perhaps a little harsh to blame Faller for the quality, I think they used the most affordable technology and materials that were available at the time, given that AMS was not exactly cheap even back then.  They appeared to shy away from pushing the independent "two-cars in one lane" promotion possibly because it was not such a good performer and the relative complexity of the system with their various controller redesigns over the years. You absolutely have to use the correct devices with the correct tracks and the correct cars. It can be confusing for newbies |
Cookee Wellington |
3 users liked this useful post by cookee_nz
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