A LION with a GREMLIN (not the car)

[rrebell]

I have found that if you look for the stupitest thing you could have done, that is ussually where thebproblem lies.

[maxman]

mbinsewi

I don't think Julius Cesar had a model railroad, but if he did, and an electrical problem accured, I'm sure he would resort to his "divide and conquer" approach.

Mike.

If ole Julius had a problem he’d probably just throw it to the lions.  Oh, wait a minute, that’s where all this started.

[mbinsewi]

I don't think Julius Cesar had a model railroad, but if he did, and an electrical problem accured, I'm sure he would resort to his "divide and conquer" approach.

Mike.

[Onewolf]

rrinker

 Faster way to divide and conquer, since electrons are not like wildebeests and there won't be a slow one trailing the herd to make an easy grab for the lion:

 First cut in the middle. Now you know which half of the layout has the short. Second cut, midway between the first cut and whichever end showed the short. Now you know which quarter of the layout has the short. Next one in the midpoint of that section, until you have a managable section left.

Beats starting at one end and working along. You can still switch to this - since you know everything is good up to the last point you checked, now you can check midway between the end and the last point you tested. ANd if the issue is one wire from bus A touching a wire from bus B that it shouldn't, you can keep the power off and just test with continuity mode. Paws off the third rail.

                                  --Randy

 

Ah, the old bisection method of short discovery (or root finding)....

[rrinker]

 Faster way to divide and conquer, since electrons are not like wildebeests and there won't be a slow one trailing the herd to make an easy grab for the lion:

 First cut in the middle. Now you know which half of the layout has the short. Second cut, midway between the first cut and whichever end showed the short. Now you know which quarter of the layout has the short. Next one in the midpoint of that section, until you have a managable section left.

Beats starting at one end and working along. You can still switch to this - since you know everything is good up to the last point you checked, now you can check midway between the end and the last point you tested. ANd if the issue is one wire from bus A touching a wire from bus B that it shouldn't, you can keep the power off and just test with continuity mode. Paws off the third rail.

                                  --Randy

 

[BroadwayLion]

I *knew* this but forgot about it. I kept hearing a little snick as I touched the wire, and then the currants all dribbled away. : )

[doctorwayne]

BroadwayLion

PS: Make special note to the LION: tip of soldering iron is grounded. Using it on live circuits is a good way to blow out fuses.

Did discovering this fact give you pause?  Or did it singe your paws?

Wayne

[BroadwayLion]

LION  went up to train room.

Him had to chase an electric gremlin.

There is a short between the +16v dc circuit (signals and relays) and the +~v dc Third Rail circuit (Track Power)

I have unplugged the 16v transformer and I tested between ground and the 16v bus.

Test 1 Yes voltage was present.

Test 2 20' down the bus, I cut the bus wire, 0v to the left 12v to the right, I repaired the cut

Test 3 andother 20 feet down the bus. Same result

Test 4 another 10' down the bus bus ends and is jummpped over to the second table. Table 1 = 0v; Table 2 = 12 v

At this point work stopped: it was time to go to vespers. I will need a mirror to look behing the facias to see what is there before I move to table 2 to continue my search.

 

Well at least I do not have to search wire by wire for the issue.

ROAR

PS: Make special note to the LION: tip of soldering iron is grounded. Using it on live circuits is a good way to blow out fuses.