HampshireHog Posted November 26, 2023 Share Posted November 26, 2023 I have recently bought an old Hornby Terrier of unknown vintage that I expected would be analogue as it was cheap. I thought I would put in a decoder myself. However it does have a decoder in the boiler housing which has no markings on. I have tried reading the manufacturer by putting it on the programme track and reading CV8 but each time it seems to come with a different number - 140 last time 255 now. CV7 now shows 198 but has shown different numbers as well. The trouble is it wont run at all after resetting CV8 to 8 and then using 3 as the loco number and setting up a long or short address doesn't help. It reacts when I try to change basic decoder CVs like 2,3 and 4 etc when it twitches or runs for a few centimetres so it can run. Am I wasting my time with a duff decoder or is there something else I should know? Help! Link to comment Share on other sites More sharing options...
96RAF Posted November 26, 2023 Share Posted November 26, 2023 Code 140 is Desktop Station a Japanese firm according to NMRA. 255 is a bad read.Code 198 may be possible to decode if the manufacturer has a web site and documentation on line.This is all I could find https://desktopstation.net/wiki/doku.php/decodersand https://desktopstation.net/hardware.html Link to comment Share on other sites More sharing options...
HampshireHog Posted November 27, 2023 Author Share Posted November 27, 2023 Thanks 96RAF for your reply. I see from the link you provided that Desktop Station list a Hornby R8246 loco decoder which in some places it says is a Hornby Sapphire chip, possibly the mini version, but I can't find an image of it to compare. It still doesn't solve the issue of not being able to get the loco running but I will try to clean more parts to see if it has too many dirty components. Link to comment Share on other sites More sharing options...
96RAF Posted November 27, 2023 Share Posted November 27, 2023 R8245 was the Sapphire decoder, no longer made but may be sitting on a dusty shelf in a shop somewhere. It was a decent decoder either 8 or 21 pin via a detachable harness. There never was a mini version.The Terrier is a very small loco so you may have to look at other makes to get a decoder of the same pin configuration small enough to fit. Zimo market very small decoders, but you need to establish if it is 4, 6 or 8 pin required, if indeed the loco has a socket and is not just hard-wired. Link to comment Share on other sites More sharing options...
Rog RJ Posted November 27, 2023 Share Posted November 27, 2023 Post 2 or 3 pictures of your decoder - someone will probably be able to identify it. Link to comment Share on other sites More sharing options...
HampshireHog Posted November 28, 2023 Author Share Posted November 28, 2023 Hi Rog, tricky to show a picture as it is hard wired and placed in the boiler space with cables going through a small hole in the bulkhead. I will give it a go and also show the wiring of the decoder on the motor. I'm not at all familiar with the wiring so someone might be able to say if it looks OK. Cheers Link to comment Share on other sites More sharing options...
HampshireHog Posted November 28, 2023 Author Share Posted November 28, 2023 Hi again 96RAF. If you search for Sapphire mini in Google an ad comes up for on the Hattons website although without an image but with the number R8246. Presumably a very old advert. Link to comment Share on other sites More sharing options...
96RAF Posted November 28, 2023 Share Posted November 28, 2023 Hi again 96RAF. If you search for Sapphire mini in Google an ad comes up for on the Hattons website although without an image but with the number R8246. Presumably a very old advert. I tested the Sapphire when it was first developed. No such thing as a mini version ever got into test much less production, a bit like their infra red wireless controller. That was way back probably 2009. Link to comment Share on other sites More sharing options...
Rog RJ Posted November 28, 2023 Share Posted November 28, 2023 https://www.hattons.co.uk/22889/hornby_r8246_sapphire_mini_decoder_with_0_5a_continuous_current_1_a_stall/stockdetail Link to comment Share on other sites More sharing options...
96RAF Posted November 28, 2023 Share Posted November 28, 2023 https://www.hattons.co.uk/22889/hornby_r8246_sapphire_mini_decoder_with_0_5a_continuous_current_1_a_stall/stockdetail There are many such links from various retailers.Scroll down that page. It says they are expecting them in 2010, so there is hope yet. Link to comment Share on other sites More sharing options...
HampshireHog Posted November 29, 2023 Author Share Posted November 29, 2023 Hi all. Am I any further forward in knowing what I should do with this loco/decoder. Should I scrap the decoder and start again? Does the wiring look OK? I have only ever used a dirct plug in decoder. Link to comment Share on other sites More sharing options...
96RAF Posted November 29, 2023 Share Posted November 29, 2023 You can buy decoders with free wire tails in order to hard wire them yourself or you buy a simple decoder and cut off the plug.I would guess a decoder swap is the way forward. Whilst you have it in bits to take out the old decoder connect each side pickup wire to a motor brush and test on DC. Link to comment Share on other sites More sharing options...
HampshireHog Posted November 29, 2023 Author Share Posted November 29, 2023 Thanks for that. I will go down that path I think. Link to comment Share on other sites More sharing options...
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