Simon G Posted February 1 Share Posted February 1 My MRC has been left a couple of Tawcrafts DCC Point Controllers by a deceased member. They come with a single page of instructions, which are helpful in themselves, but do not address the issue of the base address and how to change it. I am familiar with loco decoders, but not with accessory decoders, so it is all rather new to me. I am trying to find out what is the base address (presumably in CV1) and how to change it. I have read that some accessory decoders have an on-board switch to put them into programming mode, but these dont seem to have one. The units seem well made and with 2 4700 microfarad capacitors, will presumably throw multiple points with ease. Picture of the decoder and one of the instruction file attached. I have tried the email address and mobile number shown, but both now do seem to exist! Any help gratefully received! Thanks, Simon Link to post Share on other sites More sharing options...
RMweb Gold bandmbill Posted February 1 RMweb Gold Share Posted February 1 My guess, based on older accessory decoders from a few years back, would be that you attach it to a DCC programming track and write to CV1 the base address in the same way you would change the address of a loco. Once programmed then connect to the normal DCC output of your system. If you program it to address 20 then output 1 would be on address 20, output 2 on 21, output 3 on 22 and output 4 on 23... 1 Link to post Share on other sites More sharing options...
Nigelcliffe Posted February 1 Share Posted February 1 I'm unsure on addressing. It might use "blocks of four" addresses. Thus, CV1=1, means the outputs are 1,2,3,4, but CV1=2 would be outputs 5,6,7,8, and thus CV1=20 would result in addresses 77,78,79,80. And regardless of which addressing scheme, there's "how does your DCC system maker interpret accessory addresses", so a value of 1 in CV1, might result in outputs being accessory addresses 1,2,3,4, or they might be 5,6,7,8. If applicable, the shift will always be +4. (There's an ambiguity in the DCC standards). The use of CV9 is non-standard, and with no other information to go on, its more guesswork. 1 Link to post Share on other sites More sharing options...
RMweb Gold bandmbill Posted February 1 RMweb Gold Share Posted February 1 14 minutes ago, Nigelcliffe said: I'm unsure on addressing. It might use "blocks of four" addresses. Thus, CV1=1, means the outputs are 1,2,3,4, but CV1=2 would be outputs 5,6,7,8, and thus CV1=20 would result in addresses 77,78,79,80. And regardless of which addressing scheme, there's "how does your DCC system maker interpret accessory addresses", so a value of 1 in CV1, might result in outputs being accessory addresses 1,2,3,4, or they might be 5,6,7,8. If applicable, the shift will always be +4. (There's an ambiguity in the DCC standards). The use of CV9 is non-standard, and with no other information to go on, its more guesswork. Yes - might be setting blocks….. I built 4 MERG Accessory Decoders 20 years ago - they were programmed on the programming track but I can’t remember how the addresses were set - they did work really well though…. Link to post Share on other sites More sharing options...
RMweb Gold bandmbill Posted February 1 RMweb Gold Share Posted February 1 Probably just do some tests program to an address then test with point motors attached….. Looks like you can’t adjust anything apart from address - if the units work with your point motors of choice then maybe find more modern units? 1 Link to post Share on other sites More sharing options...
John Clitsome Posted February 1 Share Posted February 1 Look v similar to Gaugemaster Dcc30 ACC Decoders. Have a look at the instruction sheet online - it might give a clue. 1 Link to post Share on other sites More sharing options...
Simon G Posted February 2 Author Share Posted February 2 Thanks for all the help and suggestions - issue now sorted! I first tried connecting one of the units to my Powercab, but couldnt read any CVs, so I then connected the required DC voltage as well and found that I could read the CVs. CV1 read as 2, but didnt work on accessory address 2, so I tried 5 as per Nigel’s suggestion that it might be a block system. That worked perfectly with a Peco solenoid point, and accessory address 6 worked with the next output etc. Sadly, the second unit hasn’t responded to being powered up, as the power LED doesnt light and I cant read the CVs, so something in the unit has failed. At least one of out of two is better than none! Thanks again for all the help. 1 Link to post Share on other sites More sharing options...
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