Post war e-unit issue

Sounds like an issue with the four-leaf contact set.

Thanks will check that out in the morning

Bruce

Could be the two-leaf contact set too. Or a dirty drum

I had a broken tooth on a drum once that let it cycle through enough of the time that it appeared to be almost working - replacing the drum fixed it good, however, your issue sounds more like a finger issue.

It actually could be any combination of drum & fingers.

i would try to polish the drum copper parts with q tips and a cleaning fluid or even alcohol,the only thing you have to be careful about ,is don't use anything with mek or any cleaning fluid that will melt or harm plastic or you will be replacing the drum, then clean the four copper fingers with q tip's  and clean fluid, alcohol it probably the safest, and won't harm anything.them blow out carefully with a spray can of compressed air you can buy in any automotive store.if you notice any of the drum points are not sharp and pointed all the same then you will have to replace the drum, if all the points on the drum are not even and identical the drum will get stuck in neutral forward' or reverse and you have have to replace THE DRUM WITH a new one!be careful as these drum points are easily broken or damaged when cleaning!

Alan

The drum and finger sets are only a few bucks total.  If I have to take one apart, I normally replace them and be done with it.

Two comments: one useful, one virtually unbelievable (but true, I swear!).

1: In my experience it's likely one of more of the copper fingers is not contacting the drum. Also in my experience I'd be very careful in touching those fingers. They are preloaded against the drum and if they get bent I've found it essentially impossible to get them preloaded again without taking the e-unit apart, and even then a couple were too badly bent and I had to buy replacements at my local train shop.

2. Has this loco ever run correctly. I once bought a GP-7 that did exactly this. Of course the seller said he tested it for full operation. After much cleaning and fiddling with the e-unit (and eventual finger and drum replacement, as I'd bent the fingers too much) the dang thing still would not go forward. So, I broke out the Greenberg's and traced the wiring with a DMM, and sure enough, the engine was wired incorrectly. Makes me sound nuts but that's the honest truth. Quickly fixed the wiring and then it worked like a champ.

quote:

2. Has this loco ever run correctly. I once bought a GP-7 that did exactly this. Of course the seller said he tested it for full operation. After much cleaning and fiddling with the e-unit (and eventual finger and drum replacement, as I'd bent the fingers too much) the dang thing still would not go forward. So, I broke out the Greenberg's and traced the wiring with a DMM, and sure enough, the engine was wired incorrectly. Makes me sound nuts but that's the honest truth. Quickly fixed the wiring and then it worked like a champ.

I guess that tells us something about your seller. Too bad.
Makes it harder for the rest of us to sell our extra trains.

Well, to be fair, I contacted the seller and demanded a discount. He moaned and complained but relented.

He was just a quick turn operation not a collector. First and last such buyer I dealt with - collectors only from now on.

I agree with Gunrunner John. The couple dollars that it costs for new parts is a lot easier to take than fiddling with adjusting the fingers, then finding out that the drum is worn on the pins on the side, where it goes through the E unit frame. It is more fun than I need to disassemble the same E unit more than once.

I replace only what needs to be replaced.

I find it easy to tell which parts are bad while the e-unit is apart.