It seems this past year I've been spending about 75% of my time fixing things which has brought progress on the layout to a crawl. The gremlins have come up with another problem that needs attention. A few months ago I bought a DC Genesis F7 A/B set intending to convert them to DCC. I bought a DIGITRAX SDH166D HO DCC Sound Decoder for the A unit and a non sound DIGITRAX HO DH165K0 MOBILE DECODER CIRCUIT BOARD REPLACEMENT for the B unit. At first everything seem fine although the sound was a bit disappointing. Before long a strange problem cropped up with the A unit. When starting up, the horn would sound two longs, a short, and a long which I think is standard for a grade crossing. The set would run for a few yards and then the entire system would shut down. I traced the problem to that A unit because the B unit runs fine by itself. I also discovered that the problem doesn't occur when the loco is running in reverse, only forward. When I power the system back up, the horn goes through the grade crossing sequence. When I attempt to run the loco forward, it moves for 2 or 3 yards and then shuts everything down.
I've tried doing a factory reset and tried running it on address 0003 and also giving it the road number address. It makes no difference. The A unit will not run for long in a forward direction and I have no idea why or how to proceed to figure out what's happening.
Any ideas?
Try straight track only.
Try without the shell.
Try a lower volume.
dennis461 Try straight track only. Try without the shell. Try a lower volume.
What is that going to tell me?
It has stalled out on straight track.
The factory reset lowered the volume.
What good would it do to remove the shell?
While I can't help with a cure I can state that I had a similar problem, minus the shorting, with a Digitrax — I think it was an SDH164K1C — decoder. On powering up the track it would play the grade crossing sequence TWICE! No amount of resetting or playing with CVs ever cured it so I reassigned it to the trailing unit of a two-unit MU ed pair of F-40 PH with the horn volume set to zero. Normally F7 was supposed to trigger the horn macro.
On a Digitrax forum I did read of others with the shorting problem.
I since gave away the Kato F-40s and hope the new owner is happy with them.
Good Luck, Ed
gmpullman While I can't help with a cure I can state that I had a similar problem, minus the shorting, with a Digitrax — I think it was an SDH164K1C — decoder. On powering up the track it would play the grade crossing sequence TWICE! No amount of resetting or playing with CVs ever cured it so I reassigned it to the trailing unit of a two-unit MU ed pair of F-40 PH with the horn volume set to zero. Normally F7 was supposed to trigger the horn macro. On a Digitrax forum I did read of others with the shorting problem. I since gave away the Kato F-40s and hope the new owner is happy with them. Good Luck, Ed
That's good to know. If there isn't a solution to this problem other than to mute the loco, I can cross Digitrax off the list of companies I will do business with in the future. Putting a product on the market with a flaw this serious is inexcusable. What's the point in paying for a sound decoder if I have to turn off the sound to get it to work?
John-NYBW What is that going to tell me? It has stalled out on straight track. The factory reset lowered the volume. What good would it do to remove the shell?
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Function button F7 turns on the grade crossing horn if CV155=0. If you change CV155 to 1 or 2, F7 makes the diesel sound notch down (F6 is notch up). Apparently F10 also triggers the 'crossing gate sequence'. My guess is your decoder has the F10 button 'on' so blows the horn at startup. Maybe change CV155 and re-map F10 (and F7?) so neither has the option to start the horn sequence.
https://www.digitrax.com/static/apps/cms/media/documents/documentation/Decoder_Manual_V2-01_2014.pdf
DigitalGriffin John-NYBW What is that going to tell me? It has stalled out on straight track. The factory reset lowered the volume. What good would it do to remove the shell? Straight track will tell you if your turning trucks are shorting against something. No turn = no short, then it's likely a truck turn issue. (Could also be a coupler if it's not insulated from frame) Shell could be the show coming loose or interferring with a power feed. I once had a shell pushing a coupler down which caused the horn hook to brush a rail. It wasn't insulated and..... It's possible the decoder is also going bad and overloading. Lowering the volume would reduce power required to the decoder. I've had early loksounds (with the high impedence) fail on me this way.
The sound at full volume is pretty weak and reset to factory defaults makes it barely audible. If I have to run with volume at that level, there's no point in having a sound decoder at all. Since the problem has persisted even after resetting to factory defaults, I doubt the problem is the volume level.
The decoder is practically new so if it is going bad, it's going back to Digitrax but based on the feedback I'm getting from other posters, it sounds like this is a common problem with Digitrax sound decoders.
I'll try removing the shell but I shrink wrapped all the spliced wire connections and used Kapton tape liberally wherever wires and the metal frame came even close to each other so I doubt the shell is the issue but I'll give that a try anyway. I have to remove the couplers to get the shell off so that will check two things at once.
It was years ago, but I had a couple of Digitrax sound decoders that had almost no audio power. They were so quiet that I could only hear them if I were running those trolleys by themselves with no other trains running on the layout. I don't buy those decoders anymore.
It takes an iron man to play with a toy iron horse.
MisterBeasley It was years ago, but I had a couple of Digitrax sound decoders that had almost no audio power. They were so quiet that I could only hear them if I were running those trolleys by themselves with no other trains running on the layout. I don't buy those decoders anymore.
That's the way the sound was at the default level but there are CVs that allow you to crank up the sound. Even at max level it's not very loud but what's worse is the horn didn't sound like a horn. It sounded more like the buzzer on a quiz show when somebody gives a wrong answer. Kind of like the one on Family Feud.
I won't ever buy another Digitrax sound decoder. Their basic non-sound decoder is an inexpensive option and those have worked acceptably well for me. I was impressed with an Soundtraxx Economi decoder which I got for around $63 plus shipping and tax.
Sound is a lot more complicated than people relize and installing the speaker has a potential of a host of problems. Got a bunch of Digitrax stuff and no problems but the speaker to get right is a major pain as are all speakers but it can be done and also a better speaker can change everything sometimes.
This particular decoder came with an attached speaker and keep alive so I doubt the speaker is causing the electrical problems. I probably could improve the sound with a different speaker but the issue at hand is the electrical shorting which keeps shutting down the system. I'm starting to experience the same thing with other locos although not as frequently. I started another thread about problems I'm having with my Lenz LH100 throttle and I'm beginning to suspect that is the source of this problem and not anything inside the loco. At this point it could be either.
The SD decoders are 8 bit decoders. Sound on these were bad. Digitrax came out with the SDX 16 bit decoder. I would got with another brand sound decoder. Joe
ba&prr The SD decoders are 8 bit decoders. Sound on these were bad. Digitrax came out with the SDX 16 bit decoder. I would got with another brand sound decoder. Joe
Again. Sound quality isn't the issue here.
How old are the F7s? Specifically, do you know when they were made?
The early runs of Genesis F-units had power pickup issues that caused the power to drop out from time to time. This aggravated the problems their sound-equipped locos were already having with the MRC sound decoders they used back then. I have a pair of Genesis F3s from that era- I bought the DC models then installed a pair of (non-sound) replacement board decoders into them and experienced the power drop-out problem pretty regularly.
The problem was the fit of the axles into the pickup bars in the sideframes- the axle stubs weren't sticking out far enough to engage the pickups reliably. I replaced the wheelsets with Northwest Short Line wheels which had axle stubs that stuck out farther. Once the new ones were in place, my drop-outs ended immediately. The F3s have been excellent runners ever since.
Intermittent power pickup can make a decoder do crazy stuff. A sound decoder, even more so. I'm not saying that the decoder doesn't have a problem, but you might actually have another problem that is aggravating or contributing to anything else that is wrong with it.
Check how well the axles are engaging the pickup bars in the sideframes- if there's a pickup problem there, replacing the decoder won't fully solve your problem.
-Fritz Milhaupt, Publications Editor, Pere Marquette Historical Society, Inc.http://www.pmhistsoc.org
fmilhaupt How old are the F7s? Specifically, do you know when they were made? The early runs of Genesis F-units had power pickup issues that caused the power to drop out from time to time. This aggravated the problems their sound-equipped locos were already having with the MRC sound decoders they used back then. I have a pair of Genesis F3s from that era- I bought the DC models then installed a pair of (non-sound) replacement board decoders into them and experienced the power drop-out problem pretty regularly. The problem was the fit of the axles into the pickup bars in the sideframes- the axle stubs weren't sticking out far enough to engage the pickups reliably. I replaced the wheelsets with Northwest Short Line wheels which had axle stubs that stuck out farther. Once the new ones were in place, my drop-outs ended immediately. The F3s have been excellent runners ever since. Intermittent power pickup can make a decoder do crazy stuff. A sound decoder, even more so. I'm not saying that the decoder doesn't have a problem, but you might actually have another problem that is aggravating or contributing to anything else that is wrong with it. Check how well the axles are engaging the pickup bars in the sideframes- if there's a pickup problem there, replacing the decoder won't fully solve your problem.
I bought the set of F7s on ebay so I have no idea how old they are. They were run on an LHS layout that went out of business. One of their customers bought it and put it up for sale on ebay. I suspect it might be an early Genesis.
I'm also suspecting that the problem is not in the locos or the decoders but in my Lenz LH100 throttle which I described in another thread. This was the first set of locos that started having problems but soon I began having similar troubles with other locos. I have a new throttle scheduled to arrive on Tuesday so that should tell me where the problem lies.