Flickering Dapol class121 bubble car

[morairamike]

Hi, as title says, my Dapol class 121 bubble car suffers from flickering internal lights and also stutters.

I bought it new, it's fitted with a Marks Train soundscape decoder.

It does this on my layout but other locos and EMUs don't. The track is clean. The wheels on the 121 are clean. Both bogies are driven.

I have a rolling road which I cleaned up and connected with soldered connection to the track power. I put the 121 on the rolling road and run it. Now it was good no flickering so what's wrong. Then I decided to move the 121 sideways on its axles while running. This simulates the 121 negotiating a bend or points. Result the lights flicker.

Examination of the bogies shows that the pick ups are not leaf springs rubbing on the rear of the wheels but it has small brass wheels that are interference fit on the axles. The small wheels have a groove around their circumference into which a stiff wire is located. The stiff wire is attached to the bogie. These are the pickups. I think that there may be intermittent contact between the small wheels and the axles. The axles move through the small brass wheels to allow lateral movement. How do you clean them.

Failing that I may have to add leaf springs to some of the wheel's.

[Going Spare]

There has been much discussion on the rmweb forum (46 pages, not all of it about running issues) which might be worth having a look through.

[morairamike]

Thanks for that. Looks like a dismantle job and rework the pickups..

[96RAF]

Dapol spares handled here now Mike, but no evidence of pickups, just complete motor bogie.

https://www.dccsupplies.com/product-category/dapol-spares/oo-gauge-spares/oo-gauge-diesel-spares/class-121-122-oo-gauge/page/2/

[morairamike]

Thanks I looked at that and at £30 each and no guarantee it will fix the problem I have today dismantled the beast. I have luckily a pair of leaf pickups in my spares which I have been able to modify to fit one of the bogies. So far I have continuity between the wheels and the supply wire to the PCB. Now to put it back together and try it.

[morairamike]

Put it back together much improved have now decided to add stay alive capacitor to it.

[morairamike]

Fitted new decoder and stay alive. Gaugemaster units. Instantaneous fix.

Non sound this one. That will go in the Bachmann 121 I am receiving Monday.

[morairamike]

Well the Bachmann class 121 arrived but when I opened it to install my sound decoder 21 pin found it has a 22 pin Plux22 socket. So ordered a new decoder for the Bachmann.

So what to do with the sound decoder 21 pin. Well I opened up the Dapol 121 and removed it's 21 pin decoder. Then as I had changed the pickups on one end decided to do the other. But this time I did not remove the originals. I again used a pair of Hornby 8962M pickups which I modified and fitted using the same mounting screw as the original. So the bogie at the guards compartment end now has 8 wipers, 4 originals that rest on a brass groove collet which the axles rotates inside and the 4 new wipers on rear of the wheels. Reassembled and run. Not a flicker or a judder noted. Great outcome.

[96RAF]

Good result Mike

[morairamike]

Cheers 96 that blacksmithing, tin-smithing phase at Halton came in handy.

Once I had worked out a plan the new pickups were taped down to a piece of wood so they were flat. Measured and then they were shortened. Once the pressure pad ends had been cut off they were overlapped onto the remaining centre section. The overlap was then trimmed down to leave 5mm. Then the two ends were soldered onto the centre section. Once checked, the centre of the centre section was drilled to allow the original screw to pass through the new pickup and the original one into the bogie housing. The new pickups were tuned to endure they contact the rear of the wheels at the max in and max out positions. Class 121 reassembled tested and signed off.

[96RAF]

There has been much discussion on the 1 S of TT FB site Mike about did anyone ever use those odd trade skills in service. The only ref I can find is repairing radiators and coolers in early days. Welding as you know had to be done by a specialist ‘coded for aircraft’ tradesman in Station Workshops.

I topped up my welding skills by taking a resettlement course in the trade before I left in ‘84. Not much use for it in OO and the 5-pint brazing lamp and Mox fuelled iron is a bit overkill for loco soldering as well.

[morairamike]

Yes I saw those posts. I went for a job when I left the R.A.F. and my Halton certificate was in my CV package. The interviewer said after looking at it that I might be a bit bored as they didn't blacksmithing, tin-smithing etc. I got offered the job but went elsewhere.