Poor running Bachmann Class 108s 32.900 and 32.911

[Dr.Glum]

[Disclaimer: later Class 108 models may have different pickup arrangements.]

During the years of the loft layout I had not experienced good running from new with either my 2 car set (32.900 bought 2007) nor 3 car set (32.911 bought 2008). Having got them out now for the first time in some years, it was time to find out the reason. The 3 car set was worst, only intermittently picking up properly.

The photo shows the electrical arrangement of an unpowered bogie.

The power car seemed to pick up reasonably, but this unpowered end was giving nothing. The wheels/axles transmit voltage via (over-large) holes in a brass strip behind the axle boxes. The strips extend through the bogie frame giving a prong each side with a bent over end. These ends are supposed to run on slightly sprung flat plates attached to the body. I burnished everything and bent the ends of the prongs to extend slightly (as they had never touched the plates: no marks) and slightly increased the shallow angle of the plates away from the body.

This improved continuity a lot, but the outer wheel set was not making a circuit if the bogie was ever so slightly tipped by a high rail end at a joint, or a stretch of rail with a slight cant. To improve matters I swapped the non-driving bogie with the one from the other end car which was making better contact judging by the marks on the sprung plate.

All the other (non-powered) bogies seemed to have better connections between the plates and prongs, so I just burnished them. All those bearing points were given a tiny drop of RailZip. I need to run in the dark with their lights on to see if there’s still a problem.

Has anyone else had these problems and done something different?

 

[MattR]

I'm having sort of a similar problem on my Bachmann Class 105 power car, but it's with the brass prongs from the chassis plate that receive power from the front (unpowered) bogie that are supposed to make contact with the roof plate to power the interior lights/destination blind.  No matter how much I polish, clean and bend the prongs and/or plate, they just won't make contact. If I apply power and push down on the roof where the prongs are supposed to touch, the lights will flicker on, but go off immediately when pressure is removed. The unpowered car doesn't have these problems and lights up just fine. These brass prongs and plate arrangements are very suspect.

 

 

Edited March 19 by MattR

[5BarVT]

No help here, but those sound like the problems i have had, so thanks for the heads up on where to go looking.

Paul.

[08221]

On my 105s and 108s I soldered small wires from the pickups which solved the issue as it seemed that the interference fit was not reliable.

 

 

[RAF96]

My 108 2-car pair ran great on DC but since adding a decoder (old Uhlenbrok pair) running has been unreliable, stopping on bends for a moment being typical.

At some point when I am brave enough the top will come off again and a HM7K decoder will be fitted with stay alive to the motor coach. The dummy can stick with the old decoder as its only for lights at present, unless I want twin motor sounds.