Nobody does readback in Ops Mode, without a whole lot of extra stuff and then only with specific decoders.
Readback in general is somewhat overrated - if I'm settign my sound volume to 20, do I really care if it was 10 or 40 before? If you program via computer interface and JMRI, even with no readback you will have all the CV values recorded.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
P.S. 255 was just an example - some read back with values of 164 and other random numbers above the maximum values as defined in the bocklet.
Yes we did it all in program mode. Some CV's read back others didn't.
But the main point here is that:
1. We tried all the 1636 decoders he had in stock (6 in total) - they all exhibited the same faulty characteristics.
2. We put a Digi-trax non-sound decoder in and it ran fine - no problems
So it couldn't be my frame, motor, contacts, or anthing else other than the decoder
Yes what a cop out from MRC
The NCE PowerCab, as well as all the popular DCC systems, follow NMRA standards for programming on the main. That is a huge cop-out on MRC's part.
Little_Red_Caboose I have now found the solution to the MRC DCC decoder problem. SEND IT BACK TO THE HOBBY STORE AND GET A REFUND. This is my saga with the MRC 1636 drop in decoder for Atlas engines: Back at the hobby store (who also used NCE PowerCAB on his test rig), we went through the symptoms (sound, horns, lights work, but no movement). Went into the CV's and reading back the values (as per the values set in the instruction book with the MRC decoder), almost all of them were set outside their max value (e.g. CV set to a max value of 32 had 255 in it), so my hobby store owner went through all the CV's one at a time and set them to appropriate values. Still no movement. Went back in to read them again and they were all still outside the max value, as above. It is like the new values entered were not written to the decoder. So he got another one out of the packet, exactly the same thing. Then we did another, and another. We went through all six of the 1636 decoders he had in stock and they all did exactly the same thing. This process took over two hours. Luckily for me, he's a really nice bloke and gave me my money back. So I asked him for a non-sound decoder for N Scale Atlas and he showed me a Digi-Trax one. We put it in and it worked immediately - no problems at all. WOW I didn't know that DCC could be so easy! I did get an email back from MRC before going back to the store, which was totally useless: quote: "check the connections from the decoder to the motor brush tabs, or you may have set cv # 29 to the wrong value..." Interestingly MRC did note that "the nce power cab you can not do this on the main you have to do it on a program track as the power cab does not follow nmra specs for programming on the main" Is this true? Anyone? One other qustion arises from this - Is it an issue between PowerCab and MRC incompatability? Does anyone have the 1636 decoder working with say an MRC Prodigy Cab?
I have now found the solution to the MRC DCC decoder problem. SEND IT BACK TO THE HOBBY STORE AND GET A REFUND.
This is my saga with the MRC 1636 drop in decoder for Atlas engines:
Back at the hobby store (who also used NCE PowerCAB on his test rig), we went through the symptoms (sound, horns, lights work, but no movement). Went into the CV's and reading back the values (as per the values set in the instruction book with the MRC decoder), almost all of them were set outside their max value (e.g. CV set to a max value of 32 had 255 in it), so my hobby store owner went through all the CV's one at a time and set them to appropriate values. Still no movement. Went back in to read them again and they were all still outside the max value, as above. It is like the new values entered were not written to the decoder. So he got another one out of the packet, exactly the same thing. Then we did another, and another. We went through all six of the 1636 decoders he had in stock and they all did exactly the same thing. This process took over two hours. Luckily for me, he's a really nice bloke and gave me my money back. So I asked him for a non-sound decoder for N Scale Atlas and he showed me a Digi-Trax one. We put it in and it worked immediately - no problems at all. WOW I didn't know that DCC could be so easy!
I did get an email back from MRC before going back to the store, which was totally useless:
quote: "check the connections from the decoder to the motor brush tabs, or you may have set cv # 29 to the wrong value..."
Interestingly MRC did note that "the nce power cab you can not do this on the main you have to do it on a program track as the power cab does not follow nmra specs for programming on the main"
Is this true? Anyone?
One other qustion arises from this - Is it an issue between PowerCab and MRC incompatability? Does anyone have the 1636 decoder working with say an MRC Prodigy Cab?
A value of 255 most of the time means that particular CV could not be read by the DCC system, not a value over its max as you stated. If you were trying to read the value on the main this will appen, only programming on a program track will support reading CV. I am not familiar with MRC decoders but I know some of them did not have a read back feature, are you positive decoder 1636 support readback?
When all sound and lights works usually the problem is with CV29 or poor motor contact,
Jack W.
dbutters - did you ever get a sollution for this. I have also bought a decoder from MRC (not realising the issues) and I have the same symtoms as you with a 1636 for atlas diesels. Makes all the sounds just doesn't move. Checked on DC with original board works fine. Any news? I also sent an email to MRC but have had no response yet.
I'm not one for sugar-coating things, so I'll say it. How much would you bandmouth someone who paid for a full cover ad every month?
As for Digitrax vs TCS, in HO I prefer TCS, they have better motor control. In N scale things are a little different when it comes to board repalcement decoders - there isn't a whole lot of overlap between the various manufacturers when it comes to specific board replacement decoders. Step 1 would be to see what decoders fit a specific loco. If there are more then one, then pick for the features you need. Unless you really need all the extra functions, in cases where it's either Digitrax or TCS I'd go with the TCS based on my HO experience.
Digitrax now has the SDN144PS N-scale motor-and-sound decoder. It comes with a speaker, and the MSRP is $50. That's comparable to the MRC decoder in price. These low-end sound decoders come with a small speaker. They are 8-bit sound, so don't expect the "Tsunami experience" from them. They will be more comparable to the Digitrax SoundBugs. They come with generic diesel and steam sounds, selectable by CV, and you can download different sounds using a Digitrax PR2 or PR3 programmer.
I haven't tried one myself, so I can't comment on that.
It takes an iron man to play with a toy iron horse.
You can use the light board that you removed from the loco to test the decoder for motor functions. Attach a pair of wires to the light board in the spot where it contacts the frame of the loco. Then you have to power up the MRC decoder from the rails with allegator clips. Turn the decoder over so the wider motor pads are facing up. Set the controller to mid speed. Touch the leads from the light board to the motor pads. If the LED does not light, reverse the direction with the controller. If the LED does light, adjust the speed with the control knob and the LED should vary in brightness. You should always test a decoder before you install it. With the exception of the two MRC decoders, I only use Digitrax decoders. Most of my atlas locos use the same decoder DN163AO.
Thanks everyone for your replies.
I was not trying to initiate another MRC bagging session but was wondering if anyone else has had problems similar to what I'm experiencing. It seems like the more common failure is in the sound production while the engine still continues to operate.
I have checked repeatedly to make sure there was good contact between the motor tabs nd the contact plates on the underside of the decoder and as far as I can tell there is. I have wondered if it would be worth soldering a short length of wire between the moter tabs and the decoder contacts or am I wasting my time on a decoder that is likely to break down in a short time anyway assuming that I can get it to work. I also thought that I should check that there is actually power to these contacts but without some variety of decoder tester this is going to be difficult to determine.
I will try tinkering with the MRC decoders as I already have them however I will definately not be purchasing any more.
It is disapointing that the negative sentiment towards MRC DCC decoders is not apparent anywhere in print. (Or is it?) If I had been aware of this I would not have gone down the MRC path even though they do seem to be the only feasable sound equipped decoders for N scale.
I am seriously thinking about the idea of mounting a couple of good quality HO sound decoders under my as yet small layout. Rather than giving these the same address as my locos I am thinking about giving them different addresses and simply consisting them with actual locomotives of the same engine type. This would allow me to use the same sound decoder to provide sound for a different engine without needing to reprogram. What do you think?
Also what are people's views on Digitrax vs TCS decoders. Both brands sound like they are good quality.
My investigations seem to be leading me towards Digitrax as they seem to have more functions (not that I will actually be able to use that many functons in an N scale diesel) and possibly more control over these functions. I haven't yet determined what the output voltage of the function outputs on the TCS decoders is. Are they suitable for direct conection to LEDs and 1.5A bulbs. My understanding is that Digitrax decoders are.
Good point, I should have said no sound instead of no DCC
Jeff But it's a dry heat!
For some loco's there is no other option for a drop in decoder other than MRC, rather than just coming back with the same tired old replies (they suck, they're a POS, everyone says they're crap) why not try to help the poster as the first reply did? His was the only useful post so far, is that not the point of these forums? Granted they have issues, but sometimes there's no other option, it's MRC or no DCC.
sigh---
It always happens. Someone be buyin' one of those POS's and we get another thread on how trashy these MRC things are---
Any argument carried far enough will end up in Semantics--Hartz's law of rhetoric Emerald. Leemer and Southern The route of the Sceptre Express Barry
I just started my blog site...more stuff to come...
http://modeltrainswithmusic.blogspot.ca/
Welcome to the wonderful world of MRC junk decoders. If you perform a little reading of previous messages on these forums you'll find many dissatisfied MRC decoder users.
I don't know the physical layout of the Kato loco, but with the Atlas GP 40 I have a couple. Compare the size and location of the motor tabs on the original light board to those on the decoder. make sure the decoder fits firmly where it contacts the frame. Adding a dab of solder to the tabs may be necessary to improve contact. If the motor leads do not touch the contacts on the decoder you will not get movement. I have had problems with digitrax decoders in atlas and proto locos and have had to add solder and realign the motor leads many times. I prefer Digitrax decoders and have had two MRC sound decoders in Atlas locos with very poor performance. One works sporadically and one no longer works at all.
I have been trying unsuccessfully to install and operate MRC sound decoders in a Kato F3 and an Atlas GP40. The F3 is completely unresponsive and the GP40 makes all the right sounds and responds to headlight, bell and horn commands but does not move.
I tried both locos initially on the program track but was unable to read back any info from the decoders. After checking for electrical continuity using an ohm meter and satisfying myself that the motors were definately isolated I tried them on the main with the above results.
Thinking that the decoders might be faulty I have tried fitting a U23B decoder in the GP40 and have found that I have exactly the same issue. The engine itself is not at fault because it works fine in DC with the original PC board reinstalled.
I am using an NCE power pro 5A system but have yet to run a locomotive successfully. I don't think that the system is faulty however as it is obviously sending signals to the decoder.
Any advice would be greatly appreciated and yes I have been reading all the bad press regarding MRC decoders.
I wish someone else would produce a sound equipped decoder that would actually fit in an N scale diesel!
Cheers!