simmo009 Posted January 25, 2019 Share Posted January 25, 2019 Hello all. I am in search of your insight. I have a new Bachmann 1f, DCC ready for a 6 pin chip. Sweet runner in both directions during running in on DC loop with the blanking plug in place. So, time for the chip, a Zimo MX617N, brand new. Onto the programming track, immediate shorting out. Back to the DC loop, same thing. Yes, I have checked and rechecked the orientation of the chip, exactly as the Bachmann & Zimo instructions tell me. Incidentally, the DCC system is Z21 Black, everything else running perfectly. Does anyone have any ideas? Link to comment Share on other sites More sharing options...
Graham Radish Posted January 25, 2019 Share Posted January 25, 2019 (edited) Not sure but i had to send back a zimo sound chip today to digitrains, its just stopped working for no reason, no burning out nothing, just wont work. Even though its been working great prior, very strange. I always Crocodile clip any dcc chip first to the controller to test its even working before installing. Edited January 25, 2019 by Graham Radish Link to comment Share on other sites More sharing options...
simmo009 Posted January 25, 2019 Author Share Posted January 25, 2019 One of the guys at the club is bringing a chip tester, but that's not till next Monday. Anything in the meantime will be much appreciated. Link to comment Share on other sites More sharing options...
Graham Radish Posted January 25, 2019 Share Posted January 25, 2019 (edited) One of the guys at the club is bringing a chip tester, but that's not till next Monday. Anything in the meantime will be much appreciated. I've got a feeling this is down to chassis isolation, the chassis itself might be causing the short once the dcc chip is installed, is it hardwired decoder or socketed? test the chip on its own outside of the engine mate, the decoders track wires connect them to the track, you will then be certain where the fault is. Edited January 25, 2019 by Graham Radish Link to comment Share on other sites More sharing options...
RMweb Gold roundhouse Posted January 25, 2019 RMweb Gold Share Posted January 25, 2019 (edited) I have had a couple of malfunctioning Zimo chips recently although they were next 18 type, but neither shorted out. The supplier found out that there had been a faulty batch but they did get 2 replacements that worked. However I have had 6 pin Bachamnn / Farish sockets that were poorly put together that caused shorts when a decoder was installed but fine on DC. Its worth checking the soldered wired connections on the back of the Bachmann socket to check that there isnt a soldered bridge across the other connections. Edited January 25, 2019 by roundhouse Link to comment Share on other sites More sharing options...
Graham Radish Posted January 25, 2019 Share Posted January 25, 2019 Zimo chips when working are amongst the best out there, but quality control seems to be slipping with them lately. Link to comment Share on other sites More sharing options...
NIK Posted January 25, 2019 Share Posted January 25, 2019 Hello all. I am in search of your insight. I have a new Bachmann 1f, DCC ready for a 6 pin chip. Sweet runner in both directions during running in on DC loop with the blanking plug in place. So, time for the chip, a Zimo MX617N, brand new. Onto the programming track, immediate shorting out. Back to the DC loop, same thing. Yes, I have checked and rechecked the orientation of the chip, exactly as the Bachmann & Zimo instructions tell me. Incidentally, the DCC system is Z21 Black, everything else running perfectly. Does anyone have any ideas? Hi, It could be the socket area - I've added DCC decoders to some Bachmann OO steam outline locos where the wiring to the socket has risked short circuits when a decoder is inserted. Regards Nick Link to comment Share on other sites More sharing options...
Pete the Elaner Posted January 25, 2019 Share Posted January 25, 2019 I cannot remember how a 6 pin chip is configured. I had 1 loco which was fine until the body was replaced & I have a 1F, although I cannot remember if it was this one which was affected. I believe the clearance was so tight that the body was pressing the chip against the chassis so the 2 made contact. Link to comment Share on other sites More sharing options...
RMweb Gold Right Away Posted January 25, 2019 RMweb Gold Share Posted January 25, 2019 I seem to recall a post mentioning the need to shorten the length of the pins slightly on a Zimo decoder when fitted to certain locomotives. Could there be contact with a protuding pin in your situation? I have a 617N waiting to go in a "P" class tank when the weather warms up a bit; having previously used the erstwhile 622, it will be interesting to compare performance and reliability with its successor. Link to comment Share on other sites More sharing options...
Art Dent Posted January 25, 2019 Share Posted January 25, 2019 Hi Simmo, I tend to agree with the previous three posts - it sounds like the pins of the chip (or the chip socket) are touching the chassis - causing the short. I'm not familiar with the 1F nor the placement of its socket but if you can get some insulation tape between the bottom of the socket and the chassis t is might sort the issue, unless the leads of the chip are too long and 'punch through' the insulation. You could try shortening the legs by a mm in addition to adding insulating tape and see how that goes. What happens if you re-insert the blanking plug, re-fit the body and run the 1F on DC? Does it work as normal? If so, that tends to confirm the above. Also, how does the length of the blanking plug pins compare to the length of the chip's pins - if shorter can you trim the chip's pins to that length? Hope this helps Art Link to comment Share on other sites More sharing options...
simmo009 Posted January 25, 2019 Author Share Posted January 25, 2019 Hi Simmo, I tend to agree with the previous three posts - it sounds like the pins of the chip (or the chip socket) are touching the chassis - causing the short. I'm not familiar with the 1F nor the placement of its socket but if you can get some insulation tape between the bottom of the socket and the chassis t is might sort the issue, unless the leads of the chip are too long and 'punch through' the insulation. You could try shortening the legs by a mm in addition to adding insulating tape and see how that goes. What happens if you re-insert the blanking plug, re-fit the body and run the 1F on DC? Does it work as normal? If so, that tends to confirm the above. Also, how does the length of the blanking plug pins compare to the length of the chip's pins - if shorter can you trim the chip's pins to that length? Hope this helps Art The pins are slightly longer on the chip than the plug. I have tried pulling the chip back to replicate the depth of the blanking plug, it makes no difference. Putting the blank back in, it works just fine. The socket on this model stands vertical from the chassis, so no possibility of contact with the pins. I will put some pictures up this evening (hopefully). Link to comment Share on other sites More sharing options...
simmo009 Posted January 25, 2019 Author Share Posted January 25, 2019 I cannot remember how a 6 pin chip is configured. I had 1 loco which was fine until the body was replaced & I have a 1F, although I cannot remember if it was this one which was affected. I believe the clearance was so tight that the body was pressing the chip against the chassis so the 2 made contact. I haven't even put the body back on. There looks to be plenty of space provided, the chip is quite small. Link to comment Share on other sites More sharing options...
Graham Radish Posted January 25, 2019 Share Posted January 25, 2019 (edited) But have you tested the chip as i said outside of the locomotive? the two middle pins are track input power for 6 pin SIP chips Edited January 25, 2019 by Graham Radish Link to comment Share on other sites More sharing options...
simmo009 Posted January 28, 2019 Author Share Posted January 28, 2019 So, the guy at the club forgot to bring his chip tester. But the consensus is that it is a chip issue. Link to comment Share on other sites More sharing options...
simmo009 Posted January 28, 2019 Author Share Posted January 28, 2019 As you can see, even though the chip pins are a tad longer, there is sufficient space for them not to protrude any further than the blanking chip. Also there is 0% chance of chassis contact. Body contact is not an issue as the problem manifests itself with the body off. We tested on the club circuit tonight with exactly the same results as I had at home. Link to comment Share on other sites More sharing options...
Graham Radish Posted February 2, 2019 Share Posted February 2, 2019 Then the loco must be wired wrong. Link to comment Share on other sites More sharing options...
RMweb Gold Right Away Posted February 2, 2019 RMweb Gold Share Posted February 2, 2019 On 1/25/2019 at 8:11 AM, Right Away said: I have a 617N waiting to go in a "P" class tank when the weather warms up a bit; having previously used the erstwhile 622, it will be interesting to compare performance and reliability with its successor. The 617N failed when installed; accepted programming but got very hot to the touch even when loco was stationary which then only just moved. A phone call to a very pleasant man at the suppliers and a replacement was dispatched forthwith on receipt of the faulty one - also refunded postage. Great customer service. The replacement decoder has now been installed and fingers crossed, is working absolutely fine. Link to comment Share on other sites More sharing options...
simmo009 Posted February 2, 2019 Author Share Posted February 2, 2019 17 hours ago, Graham Radish said: Then the loco must be wired wrong. I will have to disagree with you on that one. If that were the case, it would not run with the blanking plug either. The variable is the chip, ergo, that is the item to investigate. QED. Back to the shop we go. Link to comment Share on other sites More sharing options...
Art Dent Posted February 4, 2019 Share Posted February 4, 2019 Okay ... A thought occurs. Can you wrap the entire chip (and any exposed pins when fitted) with insulation tape. If you try that does the fault still show itself? Have you tried Graham's suggestion (posts #4 & 13)? Art Link to comment Share on other sites More sharing options...
smokebox Posted February 4, 2019 Share Posted February 4, 2019 It's quite possible that the socket is miswired in such a way that one of the track and one of the motor connections are crossed. Doesn't affect dc running with a blanking plug but shorts with a decoder installed as the current paths are slightly different 1 Link to comment Share on other sites More sharing options...
simmo009 Posted February 4, 2019 Author Share Posted February 4, 2019 Tested the chip on an ESU chip tester tonight. Faulty chip confirmed. Thanks for your comments, will keep them in mind if I get future chip issues. 1 Link to comment Share on other sites More sharing options...
Graham Radish Posted February 6, 2019 Share Posted February 6, 2019 (edited) On 04/02/2019 at 22:14, smokebox said: It's quite possible that the socket is miswired in such a way that one of the track and one of the motor connections are crossed. Doesn't affect dc running with a blanking plug but shorts with a decoder installed as the current paths are slightly different Yup, this will instantly damage the chip, and sound decoders work best when all the factory pcb's are removed Edited February 6, 2019 by Graham Radish Link to comment Share on other sites More sharing options...
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