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Zimo DCC info ?
I'm an electronic engineer asked to repair a number of these DCC control
boards that apparently plug into/under model train locos. I've found a few failings testing cold but would like to apply some power to them. Anyone know of "block diagram" pinning for such units or any technical info? Boards are 32x30mm with surface mount components , 2x4 way connector, 21 way conn, 5 x 2way and 1x 4w connector |
Zimo DCC info ?
On May 13, 2:12*pm, "N_Cook" wrote:
I'm an electronic engineer asked to repair a number of these DCC control boards that apparently plug into/under model train locos. I've found a few failings testing cold but would like to apply some power to them. Anyone know of "block diagram" pinning for such units or any technical info? Boards are 32x30mm with surface mount components , 2x4 way connector, 21 way conn, 5 x 2way and 1x 4w connector Send them back to Zimo, I've had free repairs in the past. If you need to replace the PIC, where are you going to get the firmware? MBQ |
Zimo DCC info ?
wrote in message
... On May 13, 2:12 pm, "N_Cook" wrote: I'm an electronic engineer asked to repair a number of these DCC control boards that apparently plug into/under model train locos. I've found a few failings testing cold but would like to apply some power to them. Anyone know of "block diagram" pinning for such units or any technical info? Boards are 32x30mm with surface mount components , 2x4 way connector, 21 way conn, 5 x 2way and 1x 4w connector Send them back to Zimo, I've had free repairs in the past. If you need to replace the PIC, where are you going to get the firmware? MBQ +++++ Marked 2395 X002 on the overlay they are some sort of interface board, no PIC, only a 555 , one transistor and a number of diodes and passives and all those connectors. So far 2 have had duff lead-free soldering |
Zimo DCC info ?
cannot find reference to these boards on zimo.at
Has the same main connectors as this Bachmann E-Z Command 8 Pin To 21 Pin Adaptor http://images.nitrosell.com/product_...umb-36-559.jpg a bit bigger board plus outlet connectors, labelled on board, for LED1, LED2, motor, R+ L- = rail pickups ?, Spk = speaker? and Aux1 which the output of the 555 via the transitor goes to 21 pinning seems to agree this http://www.bobclay.co.uk/smalldcc/dcc33.jpg |
Zimo DCC info ?
On Sat, 14 May 2011 09:09:15 +0100, "N_Cook"
wrote: cannot find reference to these boards on zimo.at Has the same main connectors as this Bachmann E-Z Command 8 Pin To 21 Pin Adaptor http://images.nitrosell.com/product_...umb-36-559.jpg a bit bigger board plus outlet connectors, labelled on board, for LED1, LED2, motor, R+ L- = rail pickups ?, Spk = speaker? and Aux1 which the output of the 555 via the transitor goes to 21 pinning seems to agree this http://www.bobclay.co.uk/smalldcc/dcc33.jpg Some connections he- http://www.bachmann.co.uk/pdfs/21pin..._diagram-1.pdf Are you certain it is a Zimo board? |
Zimo DCC info ?
Geo wrote in message
... On Sat, 14 May 2011 09:09:15 +0100, "N_Cook" wrote: cannot find reference to these boards on zimo.at Has the same main connectors as this Bachmann E-Z Command 8 Pin To 21 Pin Adaptor http://images.nitrosell.com/product_...umb-36-559.jpg a bit bigger board plus outlet connectors, labelled on board, for LED1, LED2, motor, R+ L- = rail pickups ?, Spk = speaker? and Aux1 which the output of the 555 via the transitor goes to 21 pinning seems to agree this http://www.bobclay.co.uk/smalldcc/dcc33.jpg Some connections he- http://www.bachmann.co.uk/pdfs/21pin..._diagram-1.pdf Are you certain it is a Zimo board? Thanks for that , looks like the pinning here, maybe not Zimo. The owner is out of contact at the moment. There are 6 of these duff boards. Each in a little plastic box , and one had some blurb folded and fitting inside the box, that was about Zimo sound files/codes or something in German. Badly assembled probably by hand pick and place of components but mainly bad lead-free solder of pins under the 21 pin header. |
Zimo DCC info ?
On Sat, 14 May 2011 15:43:56 +0100, "N_Cook"
wrote: Thanks for that , looks like the pinning here, maybe not Zimo. The owner is out of contact at the moment. There are 6 of these duff boards. Each in a little plastic box , and one had some blurb folded and fitting inside the box, that was about Zimo sound files/codes or something in German. Badly assembled probably by hand pick and place of components but mainly bad lead-free solder of pins under the 21 pin header. Could be something simple to operate flashing light? e.g:- http://home.cogeco.ca/~rpaisley4/FredDCC.html |
Zimo DCC info ?
On 13/05/2011 9:12 AM, N_Cook wrote:
I'm an electronic engineer asked to repair a number of these DCC control boards that apparently plug into/under model train locos. I've found a few failings testing cold but would like to apply some power to them. Anyone know of "block diagram" pinning for such units or any technical info? Boards are 32x30mm with surface mount components , 2x4 way connector, 21 way conn, 5 x 2way and 1x 4w connector I've read the thread, and my opinion is that it's hardly worth the trouble, unless of course you want the "learning opportunity". Without a model number, it's nearly impossible to say what the board is. A later post by you suggests that it's a 21-to-8 pin adapter, not a DCC control board (decoder) as such. If, as you say, some of the solder joints are cold/defective, fixing them will likely fix the board. OTOH, if it actually a decoder, then most likely the chip is defective. The DCC decoders convert rail power (14-18V, 50/60HZ) to chopped DC power (effective 0 to ca. 12V), and control other devices such as locomotive lights, sound systems, etc. The decoders include EEPROM which stores the control program, and "control variables", by means of which the board's (ie, locomotive) address can be changed, and functions such as speed control can be modified. The control is accomplished via data packages transmitted from the control station via the rails to the locomotive, at about 150KHz IIRC. Most of the control circuitry is integrated into custom-made packages ("chips", in model railway parlance). You can find more at nmra.org, search for DCC. NMRA has specified recommended wiring harness colours, ie, pinouts for the board as a whole. The internal pin assignments for any chips are the manufacturer's responsibility/choice, of course. You mention some on-board specs, I agree with your guess as to what they mean. That is, if the board is an adapter, and not a decoder. I'm not an electronics expert, the above comments are based on my knowledge of DCC. HTH Wolf K. |
Zimo DCC info ? (PS)
On 13/05/2011 9:12 AM, N_Cook wrote:
I'm an electronic engineer asked to repair a number of these DCC control boards that apparently plug into/under model train locos. I've found a few failings testing cold but would like to apply some power to them. Anyone know of "block diagram" pinning for such units or any technical info? Boards are 32x30mm with surface mount components , 2x4 way connector, 21 way conn, 5 x 2way and 1x 4w connector I went to Zimo's website: http://www.zimo.at/web2010/ There is an English version, accessible via a Union Jack in the upper left corner. In Firefox, the site displays badly (it has 14 errors according to http://validator.w3.org/), but you should be able to find your board. Good hunting! Wolf K. |
Zimo DCC info ?
On May 15, 8:34*pm, Wolf K wrote:
On 13/05/2011 9:12 AM, N_Cook wrote: I'm an electronic engineer asked to repair a number of these DCC control boards that apparently plug into/under model train locos. I've found a few failings testing cold but would like to apply some power to them. Anyone know of "block diagram" pinning for such units or any technical info? Boards are 32x30mm with surface mount components , 2x4 way connector, 21 way conn, 5 x 2way and 1x 4w connector I've read the thread, and my opinion is that it's hardly worth the trouble, unless of course you want the "learning opportunity". Without a model number, it's nearly impossible to say what the board is. A later post by you suggests that it's a 21-to-8 pin adapter, not a DCC control board (decoder) as such. If, as you say, some of the solder joints are cold/defective, fixing them will likely fix the board. OTOH, if it actually a decoder, then most likely the chip is defective. The DCC decoders convert rail power (14-18V, 50/60HZ) If you can't even the basics right about DCC, why bother posting? locomotive, at about 150KHz IIRC. Completely wrong again. I'm not an electronics expert, the above comments are based on my knowledge of DCC. Need I say more? MBQ |
Zimo DCC info ?
On May 14, 9:09*am, "N_Cook" wrote:
cannot find reference to these boards on zimo.at Has the same main connectors as this Bachmann E-Z Command 8 Pin To 21 Pin Adaptorhttp://images.nitrosell.com/product_images/11/2621/thumb-36-559.jpg a bit bigger board plus outlet connectors, labelled on board, for LED1, LED2, motor, R+ L- = rail pickups ?, Spk = speaker? and Aux1 which the output of the 555 via the transitor goes to 21 pinning seems to agree thishttp://www.bobclay.co.uk/smalldcc/dcc33.jpg A picture of the actual boards would be more help. MBQ |
Zimo DCC info ?
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Zimo DCC info ?
On May 16, 2:06 am, Wolf K wrote:
On 15/05/2011 4:16 PM, wrote: Wolf wrote: [snip] he DCC decoders convert rail power (14-18V, 50/60HZ) If you can't even the basics right about DCC, why bother posting? [snip] AIUI, DCC puts a digital signal on top of an AC propulsion current. No, the "propulsion current" and the digital signal are one and the same. The latter is rectified to sine wave DC by the decoder, The DCC track voltage is a square wave digital signal and is rectified to DC in the decoder. and is in turn chopped to provide average voltages below the maximum, thus controlling the speed of the locomotive. If this is incorrect, please elucidate. That bit is correct. The signal is delivered to the locomotive in the form of data packets, whose format is specified in NMRA Standard S-9.1. This standard also indicates that the propulsion current is AC, Vmax between 14 and 18V RMS. S-9.1 is the electrical standard. The voltage limits depend on other non-DCC scale specific standards. Basic data packets are defined in S-9.2. My recollection of the propulsion current and the signal current relationship is that the former is "ordinary" AC, ie, 50/60Hz, NO. "AC" does not mean 50 or 60Hz other than in the very limited definition of household mains. depending on country, The country is irrelevant. and the latter a high frequency, whose value I've probably got wrong, because I wrote from memory. Kindly correct and elucidate my errors. You've hinted at the NMRA specs, why not read them for yourself? The system you are describing is more akin to Hornby's Zero One, long since deprecated. MBQ |
Zimo DCC info ?
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Zimo DCC info ?
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Zimo DCC info ?
On May 18, 12:40*pm, Chris wrote:
On 16/05/2011 12:54, wrote: On May 16, 2:06 am, Wolf *wrote: On 15/05/2011 4:16 PM, wrote: Wolf wrote: [snip] he DCC decoders convert rail power (14-18V, 50/60HZ) If you can't even the basics right about DCC, why bother posting? [snip] AIUI, DCC puts a digital signal on top of an AC propulsion current. No, the "propulsion current" and the digital signal are one and the same. The latter is rectified to sine wave DC by the decoder, The DCC track voltage is a square wave digital signal and is rectified to DC in the decoder. and is in turn chopped to provide average voltages below the maximum, thus controlling the speed of the locomotive. If this is incorrect, please elucidate. That bit is correct. The signal is delivered to the locomotive in the form of data packets, whose format is specified in NMRA Standard S-9.1. This standard also indicates that the propulsion current is AC, Vmax between 14 and 18V RMS. S-9.1 is the electrical standard. The voltage limits depend on other non-DCC scale specific standards. Basic data packets are defined in S-9.2. My recollection of the propulsion current and the signal current relationship is that the former is "ordinary" AC, ie, 50/60Hz, NO. "AC" does not mean 50 or 60Hz other than in the very limited definition of household mains. depending on country, The country is irrelevant. and the latter a high frequency, whose value I've probably got wrong, because I wrote from memory. Kindly correct and elucidate my errors. You've hinted at the NMRA specs, why not read them for yourself? The system you are describing is more akin to Hornby's Zero One, long since deprecated. MBQ Its not rectified at all its transformed into PWM feed to the motor the frequency can be varied on some decoders so that they can be tuned to particular motor types. Works the same way as DC PWM controllers. sigh The DCC signal is rectified to a DC supply in the decoder. Just look at a decoder and you'll spot the 4 diodes that form the bridge rectifier. The DC supplies the microcontroller and the output H-bridge. The H- bridge is driven by the uC to generate the PWM signal. MBQ |
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