My DCC nightmare continues .......... I have a LaisDCC decoder fitted to a Con-Cor U50. I tried running it last week and it seemed to be ok for about 45 seconds. It ran then suddenly stopped , then started moving again, then stopped , then started moving again ....... then stopped. I have tried to see what is going on with it but have had no luck even identifying the loco. My PR4 gives error 308. My Sprog 2 V4 says error 301. So as best I can tell neither programmer can contact the electronics on the loco. Unfortunately I have not even got to the point of connecting a LED so I can't tell if power is even getting through. The good side is I could have not caused any electrical faults through lighting. All 3 wires for lighting are isolated with caption tape. Is it possible to have a broken wire or dry joint where the wires join the board ? Is it safe to check the wires using a multimeter ??? I'm off to buy a carton of headache tablets ........ back soon.
lais make a pretty tough decoder .... 308 is a communication error ... simple question, is the track and wheels clean ??
With the shell and the loco sitting on a piece of track (on or off the layout with no track power) I'd check continuity between the top of the frame and the left track rail. Do the same for the bottom of the frame and the right rail. You could also do this with track power on and check for voltage between the frame half's. If that is good then you know that the track pickup is OK. I removed the forward light and its wiring and such and used the two tabs it was connected to for my decoder power. Have you done the same? Above one can see where the decoder is getting power from (red/black wires). If there is power to there you should be good to go. If there is good power where the decoder wires attach then I'd suspect the decoder itself or the the motor connections from the decoder. I'm not sure about the Sprog error code but the 308 usually is saying that you are not getting power or good power. I've gotten around that as far as programming by simply cleaning the wheels and wiping the track down. I've had locos that ran but were hard to program if the connections were not near perfect (Note: DCC++EX now has some workarounds for that). Let us know what you find, Sumner P.S. U50 decoder installs ( HERE ).
Yes. and I've checked the wheel treads and axles are clean and the bogie frames are clean where the axles run. The bronze wheel wipers are intact and clean also.
My U50 is wired the same as yours , I milled out a little underneath the upper frame half to ensure clearance for the brush holder and the grey wire. Then I added Kapton tape. The track and wheels etc are very very clean. It's nearly midnight here so I won't be popping out to the workshop to get the multimeter but I will do it tomorrow. So far it's dead. With Lais decoders now costing the same as Digitrax I can't see me buying any more at this stage .......... If I persist with DCC. I get to try to run a train one day a week and generally I get one out of 6 days where my locos keep working.
I'm back ......... I used the Sprog 2 with "Programming track" selected. The Lais equipped Turbine was on the track but still can't be detected. I took the turbine off the track and successfully managed to fit a Kato EM13 to a GS4 ......... So I'm pretty certain the Sprog 2 is fully functional. I then put the turbine back on the programming track. The track is showing 11.5 volts and the connections are showing 11.5 volts. I had no trouble getting a voltage indication from those screws where the black and red decoder wires connect to the turbine chassis. I was able to drag the loco back and forth the track and the voltage did not fluctuate. I'm considering carefully cutting the heat shrink off the decoder to see if anything is burnt. Any other suggestions wold be welcome.
OK , so here's some photos of the card with the heat shrink so veeeeeeeeeeeeeeeeery carefully removed. and don't tell me it's toast.
While we're looking at these cards can anyone suggest a good method to remove the insulation before soldering to contacts .......... please.
in the lower picture, the diode on the far left -appears- to have some small bubbles on the top ... that i think is the red, power pickup from the right ..
Agree about that diode. Wondering did you check continuity between each motor cap and the frame halves? From what you have said it doesn't sound like there is a short there now but wonder if one somehow happened? Sorry I'm of no help on the heat-shrink removal or are you asking about removing insulation from the wire ends or something else? Sumner
Yeah I thought you'd say that. It's not really visible to the naked eye , the first I noticed it was in the photos.
I didn't know to check continuity at all ........... ummmmm , how do I do that ??? I know I can't connect a multi meter to the wires ends once it is all assembled. I did have lots of Kapton tape on the underside of the top half of the frame. The insulation removal was about the wires ............ and you are helping.
Since the motor wires from the decoder are attached to the motor caps put one probe on a motor cap and then put the other one on one frame half at a time and see if you have zero or very close to it resistance with the meter on ohms. The motors have low resistance thru them in the range of probably 50-100 ohms (the ones I've tested) so you need to have the meter on the lowest setting (200 on mine). A higher setting might show the resistance as zero since the scale is too large. If the meter is showing close to zero (see what it is when you touch the probes together) then you probably have a short now. If you had one at any time the decoder is probably bad. After installing a decoder before putting it on the track it would be a good idea to do the test above. I usually forget to and so far have been lucky but maybe this will jog my memory in the future. I bought ( THESE ) and love them for my decoder installs and other wiring like to frogs and such where I'm using 20 gauge or smaller wiring. They say 32 gauge as the small end but I think some of the ESU decoder wire I have is even smaller and it works on that also. I have other wire strippers that I've use for other projects but these work by far the best on small diameter wire. I liked them so much I bought a second pair so I could have at my in-house work area and the shop work area. Sumner
So more of my dumb questions ........... If I test the diode while it is still on the board will I affect any other components ? If I can (by some miracle) replace the diode will the DCC card work again ?
in circuit testing is okay ... replacing the diode -may- make the board work again, you should find out first why the diode went
I was going to ask what made the diode die because I could be wasting my own time if a need to change something Weeks earlier I had been running a 45 car train behind the turbine. All went well (so I believed) and the loco didn't seem hot or anything. The day the loco died it was running for only a few seconds with zero load on it. It did not derail at any point and no other short circuits happened on the track at the time. No other locomotives or rolling stock was on the track. The layout was showing 14.4 volts on the rails. The layout has LED indicators that stay on when there are no short circuits. The LED's stayed on. The Lais web site says a maximum of 16 volts ......... but recommends 12 volts. Do I need to limit the voltage to the DCC card ??? Is that even possible ?? The only thing I found was a small bit of fluff near the motor brushes. It was so small it wasn't visible when adding the DCC wires. I managed to coax it out but it was non metallic. So I guess I need to check the motor .......... what on earth do I do ??
I've hesitantly decided to look at the Laisdcc card ........ I took some photos of the multi meter so you can see where I have the touch probes plugged in and what I have the meter set too. I connected the probes to the card and I have drawn in where the probe touched and written the readings from the meter. I tried readings on the suspect diode and the one next to it. I tried connecting the other way around and only got a reading of "1" as per the photo. I am certain the red wire attached to the card connects to both diodes I am testing.
