I've run into a strange problem with a loco that had a decoder installed at least a dozen years ago. I know older decoders often will not provide readback and this one has not done so on my MRC PA Wireless. The loco was initially "programmed" on my old Command 2000 which had a maximum of 8 or 10 programmable addresses with a system that did not tell you the actural address but rather a combination of two data entries and one control slide position.
By a process of trial and error, I discovered the address was 8 and got it working O.K. I put it on the program track and tried a new address (101) which seemed to take. However, on the layout it would not respond to that address. Back to the programming track and tried to reset to 8. Seemed to take but same no response story on the layout. Same process again trying 3. Ditto
Finally went to the programming track and reset cv8=8. Still no comprende. I have not tried to program on the main, but I'm wondering if these older decoders for some reason won't program on the program track. I clearly understand that it is time to upgrade these decoders, but I would like to understand what is going on here. I think the decoder is an MRC, but I assume that only by a somewhat criptic note in the box from the person who installed it. Might also be a Lenz.
I will appreciate any and all ideas.
A decoder that old possibly only supports a 2 digit address; i.e., 1 through 99. Trying to set it to 101 is probably too high for that decoder. And setting CV 8 to 8 is not a universal reset -- different brands use different reset values in different CVs. Unless you know the exact type of decoder you have, you're stuck with running it on address 8.
Something I read said that 2 digit addresses went to 127, although that seems strange. Problem is that after I tried to reset to 101 it won't respond to 8 either. Very curious.
mreagant Something I read said that 2 digit addresses went to 127, although that seems strange. Problem is that after I tried to reset to 101 it won't respond to 8 either. Very curious.
It depends on the system. The earliest systems only went to 99, but the 'address' variable int eh decoder is actually 7 bits which means it can go to 127.
What brand/model decoder is this? If it only can handle up to 99, trying 101 could have put an invalid value. And CV8=8 is not a universal reset, it's mainly Digitrax, and even the older Digitrax decoders didn;t support this.
Where your problem is is that on very old decoders, they had to use register mode programming, not paged. Try programming in register mode on the program track.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Well, now I'm getting an address of 50 on the programming track, but I still can't get the sucker to move on the layout. I've got replacement decoders on the way, but I'd still like to sort this baby out.
Kid comes up to his Dad.
"Dad, I want to go to the Moon."
"That's easy, son. All you need to do is build a rocket ship."
I have no clue what register mode is or how to tell my system to use it.
DCC is fun! DCC is fun! DCC is a pain in the ...! DCC is fun!
O.K. I beats the stink out of the alternative.
Grumble.grumble.
I just read the PA manual. It doesn't tell you. Maybe you neeed to haul out the old Command 2000 to program it.
Thanks Randy and David. A new decoder is in order and I ordered several (DH 163PS) yesterday. I just got frustrated because it did work for awhile ay address 8. As I said it now reads back as address 50, but will not respond on the layout. Probably better to quit messing with it and just wait 'till the new one comes.
That's a good one, David! Very sage advice.
The old M R C decoders can only be programed in the "REGISTER" programming mode, and can only use short addresses.
The registers are like CVs, and there are only eight.
here is the list of registers.
1. Address(short)
2. Start voltage
3. Acceleration
4. Deceleration
5. configeration register
6. (reserved for page register)
7. Version number (read only)
8. manufacture ID number (read only)
Hope this is helpful John Sawaska
PS ifound this info. in a old message on the NCE Yahoo group from Mark Gurries