ColinB Posted June 6, 2020 Share Posted June 6, 2020 I have just bought a second hand loco on EBay, which surprisingly I got for a really good price. I tried it on DC and it was a bit jerky, so I opened it up to lubricate it. I was also going to work out whether it was DCC ready, it is an 0-6-0 so there is not much room. To my surprise there is already a 4 pin decoder sitting there. So I power up my Elite and nothing happens, so I wrote 8 to CV8 to reset the chip, just in case the loco was set to some large number. Still it doesn't work on DCC. I then go and read CV8 to look for the manufacturers id, but again nothing. Could it be a zero 1 chip? It looks like a DCC decoder, but the pins are round the wrong way, the socket is on the decoder and the pins are on the loco harness. If I cannot read the manufacturer Id, usually the decoder is dead but normally they don't run on DC. Any ideas? I have absolutely no knowlege of 4 pin decoders, I just assumed they were the same as 6 pin ones with the front and back light outputs not connected. I will eventually convert it to 6 pin, it gives me more options for decoders, but I would like to get this one working. Link to comment Share on other sites More sharing options...
Chrissaf Posted June 6, 2020 Share Posted June 6, 2020 It looks like a DCC decoder, but the pins are round the wrong way, the socket is on the decoder and the pins are on the loco harness..The socket on the 4 pin decoder is completely normal and standard ... see below for a random selection via Google../media/tinymce_upload/92b7786c2bd036152e7be50bb8ad3bd3.jpg. Link to comment Share on other sites More sharing options...
jane1707819582 Posted June 6, 2020 Share Posted June 6, 2020 From memory zero 1were just 3 wires Link to comment Share on other sites More sharing options...
Chrissaf Posted June 6, 2020 Share Posted June 6, 2020 I also believe if my memory serves, that Zero 1 decoders were 'hard wired' in and didn't have a factory fitted plug and socket arrangement. Link to comment Share on other sites More sharing options...
96RAF Posted June 6, 2020 Share Posted June 6, 2020 Zero 1http://www.kingstrains.co.uk/Hornby-Zero-1-Loco-Decoder-Chips-Pair Link to comment Share on other sites More sharing options...
ColinB Posted June 6, 2020 Author Share Posted June 6, 2020 Thanks for the info Chrissaf, I did look at the Hornby shop and they did sell ones exactly like the fitted. It looks like this one has failed, but still works with DC, weird. Generally when my ones die, they kill everything. I will change it to a 6 pin, and get a new decoder. It works perfectly on DC, backward, forwards. Link to comment Share on other sites More sharing options...
96RAF Posted June 6, 2020 Share Posted June 6, 2020 Maintaining your success rate with things electronic then Colin.Knitting - analogue - knitting. Link to comment Share on other sites More sharing options...
ColinB Posted June 6, 2020 Author Share Posted June 6, 2020 Yes, but I did nothing to it all I did was test it on DC as the listing never mentioned DCC. I must admit I would have been very embarrassed had it worked, what I paid for it was only slightly more than the cost of the decoder. I have a rough idea how a decoder works, but I am only guessing. I can only assume something must have happened to the processor that controls the DCC, and if this happens it reverts to only working on DC, but as I say that is only a guess, we used to do a similar thing on one of our modules. The loco was worth more than I paid for it so I am happy, I never expected a decoder so nothing lost. I will rewire it to take a 6 pin decoder rather than the four, they are are a lot easier to source, I am just intrigued as to how it got damaged, without taking out the rest of the circuitry. I mean it has to use the motor driver circuit whether running in DC or DCC. Link to comment Share on other sites More sharing options...
Howbi Posted June 6, 2020 Share Posted June 6, 2020 @ColinB, don't forget that the 6 pin decoder does not have the Blue wire attached to enable lights to work on the yellow & white wires.......might as well use the standard 8 pin decoder, same size and cheaper to buy.........HB Link to comment Share on other sites More sharing options...
Fishmanoz Posted June 7, 2020 Share Posted June 7, 2020 Hard to source the 4-pin? Hattons has it for a start. Link to comment Share on other sites More sharing options...
ColinB Posted June 7, 2020 Author Share Posted June 7, 2020 Ok, I was only repeating what gets mentioned on this site that 4 pin decoders are hard to source. There are substantually more 6 pin decoders out there than 4, and yes if there was the room I would put an 8 pin in. It is like function decoders there is no advantage in using 4 pin, the socket is about the same size as 4 and they are not any cheaper. I will probably use a Zimo 6 pin with their" stay alive" as it is a 0-6-0 tank and if I want to use the blue wire it comes on a flying lead with this decoder, or is on a PCB pad.. Link to comment Share on other sites More sharing options...
96RAF Posted June 7, 2020 Share Posted June 7, 2020 Ok, I was only repeating what gets mentioned on this site that 4 pin decoders are hard to source. There are substantually more 6 pin decoders out there than 4, and yes if there was the room I would put an 8 pin in. It is like function decoders there is no advantage in using 4 pin, the socket is about the same size as 4 and they are not any cheaper. I will probably use a Zimo 6 pin with their" stay alive" as it is a 0-6-0 tank and if I want to use the blue wire it comes on a flying lead with this decoder, or is on a PCB pad.. 6-pin gets its positive from the track Colin. The two wires additional to the 4-pin are the directional lights switching. There shouldn’t be a blue wire. https://images.app.goo.gl/zDi79zGGPC6VnVsj8 Link to comment Share on other sites More sharing options...
Lord Boot Sale Posted June 7, 2020 Share Posted June 7, 2020 I brought a Hornby Jinty at a Model Railway Exhibition a couple of years ago, it was fitted with a 4pin DCC decoder, like yours it less than the cost of a decoder, it ran perfectly on DC, I set up a DCC controller to read the decoder, the decoder was not recognised and I was unable to reprogram it, later I tried the decoder on a decoder tester/programmer it did not respond, I put in a replacement decoder and all worked OK. Link to comment Share on other sites More sharing options...
96RAF Posted June 7, 2020 Share Posted June 7, 2020 Chances are those decoders were the old factory fit R8215s, a very poor decoder which could lose their address just by being powered down and left overnight. Later 4-pin and 6-pin decoders are based on the NMRA warranted R8249. Link to comment Share on other sites More sharing options...
ColinB Posted June 7, 2020 Author Share Posted June 7, 2020 On the Zimo the blue wire is a flying lead, correct there is not a pin for it to go to, just like the extra function on 8 pin. If it doesn't have a flying lead there is a pad identified, it is the same one you wire one side of the "stay alive" to. A 6 pin in Zimo is the same as an 8 pin, it just doesn't have the extra two wires connected. On some of my locos I have 6 pin Zimos rewired to 8 pin, you cannot add "stay alive" to the Zimo 8 pin easily, but you can to the 6 pin (it appears it is a marketting decision), so I buy a 6 pin and do the rewiring.Interesting info about the decoder. Link to comment Share on other sites More sharing options...
ColinB Posted June 10, 2020 Author Share Posted June 10, 2020 I surveyed EBay and found a supplier doing the Hornby 4 pin decoder quite cheap, so I "wimped" out and replaced the faulty four pin with a new four pin decoder. I am pleased to say it now works on DCC. Weird that the old one worked on DC but not DCC, but it looks like RAF96 is right, must have just been a bad batch. Link to comment Share on other sites More sharing options...
96RAF Posted June 10, 2020 Share Posted June 10, 2020 R8215 in toto was a bad ‘batch’ Colin. It was Hornby’s original basic decoder and it was not very reliable, hence the R8249 replacement which is reliable and NMRA warranted even if a bit limited in the CV stakes. Unfortunately even after the launch of R8249 many factory fit models were still getting the R8215 and they got Hornby a bad name for it. As they say you can only make one first impression and R8215 didn’t hack it. Link to comment Share on other sites More sharing options...
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