The first diagram is great, used it earlier in week as starting point. The 2nd pic is exactly on target. What Is the length of the screw? Is it possible to drill hole with the #50 bit but use self tapping 2-56 screws instead of 2-56 tap? Is any type of drill bit better for drilling the chassis? Really like the ESU LokPilot. Upon comparing the ESU continuous motor rating of .75A, to the DZ123, 126 and 126t, the DZ's have 1A with peak ratings of 2.0, 1.5A and 1.25 respectively. So was leaning to the one with the highest rating that would fit without shell or chassis mod. Thinking of the age of the Bachmann motor -- being less efficient --having the higher rating be better??? Also, due to lack of GP7 parts and resources, less inclined to spend any more on it than needed. Sure, I would be interested in taking a 126T or a 126(assuming it fits with no mod) off your hands but first want to get the rail screws and lugs installed and perform the dimple file down for easier shell removal just in case an unreplaceable part breaks in the process. Bachmann has very few GP7 parts in stock and little on ebay. Would really like to have all 3 locos running on the seasonal layout. Bachmann was in for repair the first season, Atlas SD35 in the 2nd and now the Bachmann down again before Thanksgiving.... If you like, please feel free to PM me with details regarding purchase. Thank you for the info.
The total screw length on the flat head screws are .125" and .175" for the round head. I use the flat head if clearance is a problem and they will work if it isn't. The thread length are only about .100" so don't even know if you could get a self-tapping screw that short and probably wouldn't trust it myself as it wouldn't have many full threads holding it. You can find a tap for about $7 delivered and I'd recommend going that way. The metal is soft so any bit is going to be fine. I'd use a #50 though and not try something else. Amazon has one for $3 delivered. Go slow on tapping the hole so as to not break the tap. If you feel much resistance back out 1/4-1/2 turn or all the way out to clear the chips. Don't force it. I can't imagine the ESU not having enough power. The loco shouldn't be drawing anywhere near .75 amps. If it is something is wrong. You could check what is does draw with a multimeter. I'll send you a PM for the cost of a new/unused DZ126T and 4 screws (2 of each kind) and 2 of the solder lugs and shipping. I"m assuming at this point you are giving up on the stock decoder???? Sumner
Definitely will follow your lead so will seek out tap and drill bit. My gut says most likely the ESU would work fine and quality companies like ESU would be more likely to spec conservatively. Measured last week The EX command <i> reported 576mA with light and 537mA w/o light at SS 24. Bought a TCS1031 yesterday morning for my DC VO which I had on eBay b4 the GP7 failed, Decided to keep VO and use as primary non-sound creeper instead. Should receive on Tues. Once good to go, will get this Bachmann issue resolved. Yes, have given up for a variety of reasons. Installed and removed 3x-worked all 3 times for 5-10min. Strike 3 your out. plus... Terrible hum at creep, and now that I'm an "expert" LOL at taking this loco apart, it actually seems pretty easy to work on.. All gearing inside trucks.. shell removal excluded. The first one had the same problem and dealer did advanced exchange so I know they just didn't the same one back. Plenty of bad online feedback. Decided not worth the effort looking for marginal component(s) ,ohm'ing out traces for hairline cracks or design motor - decoder mismatch. Plus why the soldered motor connections look like a redone as Bachmann only needed to replace the truck assembly. Quite honestly, back in the late 70's and in between jobs, developed a NASA soldering course for an aerospace contractor. Would fail at least 1 of those soldered motor wire to decoder joints. Unable to find decoder docs-the decoder pdf on the Bachmann site shows a totally different one. The only thing I heard is that the stock decoder was made by lenz?? Pretty much the reasons why.
