# Odd QSI Behavior--very odd



## lownote (Jan 3, 2008)

I have QSI/Airiwre setup in an Aristo Mikado. Recently, the Mikado started running poorly--from standby , or neutral, the light would come on, it would make a chuff, then it would quit. Give it a nudge, same thing. It would work fine for a while, then on stop would revert to this behavior. Poor power pickup, you're thinking, and so was I. I rewired it so it's getting power from all eight tender wheels and I swapped in a new Mikado drive. Now even though it's getting power from the loco and the tender at the same time (I did George's switch mod) it still does this "false start." 

I set it on a test track and hooked it to the Quantum programmer--the programmer will not recognize the loco. I even took it apart and pulled the Gwire cable, and it still won't recognize the loco. It does recognize my other QSI-equipped engines.I reset it manually, using the red switch and the power startup trick ,but still no go. 


It runs fine, once it gets started, it answers commands from Airwire, and I can progam CV values with Airwire 



My guess is that there is some kind of intermitent continuity break in the QSI card, causing it to cut out at start.

Any ideas? I'm going to call QSI tomorrow


----------



## Greg Elmassian (Jan 3, 2008)

Did you double check the power pickup, sounds like a short somewhere. Not enough of a short to nix all operation, but enough to interfere with enough current for the motor and interfere with the low power of the programmer. 

Try not powering it from the rails, feed the power from 2 wires. Something is fishy. 

Regards, Greg


----------



## lownote (Jan 3, 2008)

hanks Greg--that's what I'm thinking, although I'm not running it under DCC so it's got a full 20 volts available at all times. I'm pretty confident that power pickup is solid. I'll try metering the power at the pins in the socket, see what that reads. Is it possible that there's a briken trace that makes better contact as it gets warm? Because the engien runs well once it's underway, it's just from stop that it shows this behavior


I'm glad to know it wasn't the old Aristo Mikado drive that was at fault.


----------



## Greg Elmassian (Jan 3, 2008)

Well, it's good to eliminate all the easy stuff. Lay the loco on it's back and try to rotate each of the 8 drivers. If you find play, you have found your problem. 

Also, look at it from each side and make sure all the drivers are in phase with each other, easy way to do is look at the counterweights. 

I thought I had electrical problems with my Mallet, acted just like yours, and turns out all 8 drivers loose! 

Regards, Greg


----------



## lownote (Jan 3, 2008)

The drive is fine, wheels are good. I just tested it with the dummy plug in the aristo socket, it runs fine, both with and without the tender. But then when the QSI card is installed, the trouble starts

The only thing I did differently with this card is I cut out the polyswitch it shipped with and bridged the contacts. On visual inspection the bridge looked solid. Maybe that's weak?


----------



## Greg Elmassian (Jan 3, 2008)

Worth a check, there's some other things pretty close by. I cut the leads of the polyswitch off right next to the body, then twist the 2 leads sticking up together. This often leaves a sharp point, so make sure it does not stick into the body of the big electrolytic cap that wants to lie on top of it. 

Regards, Greg


----------

