Fleischmann 7160/61 Power Problems

Started by CarriageShed, July 25, 2018, 02:16:25 PM

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CarriageShed

A little while ago (several months) I bought a second-hand Urie S15 kit complete with a Fleischmann 7160/7161 chassis. A quick test showed that the chassis wasn't picking up power too well, but the motor did work. The loco was kangarooing down the track but it seemed that I just needed to improve the pick-up.

The loco sat on a shelf until yesterday when I finally decided to get around to doing something about it. I cleaned the axles and wheels of a fair amount of fluff and stuff, and saw that the pick-up strips were sitting over the top of the wheels so that they were only just about brushing them. It seemed more likely (to my non-engineering mind) that the pick-ups should be lowered so that they were between the wheels and the chassis block, brushing against the inside of the wheels, so that's what I did.

Then I tested the loco under power on the layout and... nothing. Not a flicker of movement. Not even a flicker on the meter to show that something was happening.

I tested the loco with two wires that were connected to the track and to points A and B in the photo below (for each side of the power/return). Nothing.


(It's a big image, so that you can zoom in for details)

I touched the same points with a meter after measuring the feed in the rails themselves. The reading was the same in the rails as it was in all those points A and B.

So that tells me (although what do I know?!) that power is coming through the wheels and the repositioned pick-ups behind them, and through the top strips, and across to the tender and those two points at the back. 'B' also applies to the motor block itself ('A' produced a spark from a brief contact and also a flicker of short-circuit on the controller, so I know that 'B' was correct!).

So what's going on? Is the motor itself fried, or missing a connection somewhere? (And how on earth does a motor fry itself without being touched for several months?) My usual loco expert seems to be away at the moment, and he's more of a Farish expert anyway, so I'm throwing this question out to all-comers. Any ideas?

Peter

ntpntpntp

#1
It's quite normal for the pickups on Fleischmann locos to rest on the tops of the wheel flanges, they're designed with a square pad for that purpose. That way the wheels can have some side-play without being interfered with by the pickups.  I'd put them back as they were to be honest.

Did you try turning the motor armature by finger, with the power on? See if it spins into life?  If it's been sitting for a while it might have a dirty commutator.   If it fires up, drop the speed right down and make sure it ticks over evenly. If it consistently stops in one position you've probably got a dead coil.

When I service my Fleischmann locos I usually remove the brushes and springs, clean out the brush holders, rub the brushes gently between fingers inside some kitchen roll, check the springs are still "springy" etc. then re-assemble and run-in at around 50% full power for a minute or so to settle the brushes before re-fitting to the chassis.
Nick.   2021 celebrating the 25th anniversary of "Königshafen" exhibition layout!
https://www.ngaugeforum.co.uk/SMFN/index.php?topic=50050.0

CarriageShed

I'll realign the pick-ups again tonight. Thanks for that tip. I'm relatively familiar with Poole Farish motors (although not to the point of taking them apart), but this is the first Fleischmann I've seen up close.

Thankfully work ended a little early today so I've just been able to test again.

Turning the motor armature by finger had no effect, but I did look again inside the motor housing to check for fluff and it seemed remarkable clean.

Then I noticed that the little bar at the very back of the motor block with the red wiring wrapped around it (you can just about see it in the photo). The wiring has what looks like a miniature coat-hanger type end on the 'A' side of the motor. This isn't touching anything at all, so I tested it by touching it to the metal connector immediately in front of it. The motor sprang into life.

That would seem to be the problem. Is this 'coat-hanger' supposed to be permanently attached to the metal connector?

Dorsetmike

I've found that the 716x motors often need to warm up a bit before they run properly, I usually put the loco on the rails then lift the tender so it can run free for a minute or two, I've been doing that with mine since 1974 and it works for me, the pick ups do need checking from time to time, I actualy had a set which started to show considerable wear, almost a groove where the wheel flange had worn it away.

That 1974 vintage motor finally started to smoke after about 40 years use, new one's ain't cheap.
Cheers MIKE
[smg id=6583]


How many roads must a man walk down ... ... ... ... ... before he knows he's lost!

ntpntpntp

Quote from: CarriageShed on July 25, 2018, 04:35:13 PM
... little bar at the very back of the motor block with the red wiring wrapped around it (you can just about see it in the photo). The wiring has what looks like a miniature coat-hanger type end on the 'A' side of the motor. This isn't touching anything at all, so I tested it by touching it to the metal connector immediately in front of it. The motor sprang into life.

Ah, that's an inductor / choke. It's part of the RF interference suppression circuitry fitted to motors to prevent upsetting nearby radio and tv.  That connection needs soldering back into position.
Nick.   2021 celebrating the 25th anniversary of "Königshafen" exhibition layout!
https://www.ngaugeforum.co.uk/SMFN/index.php?topic=50050.0

CarriageShed

Quote from: Dorsetmike on July 25, 2018, 05:26:12 PM
I usually put the loco on the rails then lift the tender so it can run free for a minute or two, I've been doing that with mine since 1974 and it works for me, the pick ups do need checking from time to time, I actualy had a set which started to show considerable wear, almost a groove where the wheel flange had worn it away.

I'll have to give that a try when I get mine working. These pick-ups have actual slots that presumably have been worn out by the wheels.

Quote from: ntpntpntp on July 25, 2018, 05:41:48 PM
Ah, that's an inductor / choke. It's part of the RF interference suppression circuitry fitted to motors to prevent upsetting nearby radio and tv.  That connection needs soldering back into position.

Oh dear. I had a feeling you were going to say that. It's a very small bit of metalwork to be soldered by my very fat soldering tip and slightly dubious soldering skills. It might be worth waiting until my electrics expert comes back from holiday and can do it with much more skill and a finer-tippped soldering iron.

CarriageShed

Actually it wasn't so hard after all. I decided to go for the soldering after all, and did it in just a few careful dabs of the iron. There's definitely more life to the loco now.

It needed quite a bit of running to iron out some of the stiffness but it's still not great. I was gradually able to reduce the speed needed to get it around the loop on my layout without stalling on two sets of points, but it's still hesitant at low speed and often stalls. Are Fleischmann locos not great at slow speed?

ntpntpntp

Quote from: CarriageShed on July 26, 2018, 09:48:56 AM
...it's still hesitant at low speed and often stalls. Are Fleischmann locos not great at slow speed?

Quite the opposite, they are fine slow runners but like any model they need to have clean and properly adjusted wheels and pickups.  Your chassis isn't really "out-of-the-box" any more though?

I presume you are running it with the loco bodyshell in place? It needs the weight over the loco wheels to ensure good pickup.
Nick.   2021 celebrating the 25th anniversary of "Königshafen" exhibition layout!
https://www.ngaugeforum.co.uk/SMFN/index.php?topic=50050.0

CarriageShed

I'm betting that my chassis is far from 'out-of-the-box'. The red that's typical of German locos has been overpainted black (with gaps) and the S15 loco body on top of it is roughly painted in an entirely inaccurate green for the SR. The body build seems to be pretty good though, and it sits well on the loco chassis.

The tender body doesn't sit quite so well on the tender chassis - some adjustment will be needed to sit it level rather than with a tilt.

I've run the loco both with the full body in place - loco and tender - and with the tender body off so that I can see the motor. My impression (with limited experience) is that the loco wheels are picking up properly. When I lift the tender off the rails and ensure that the loco chassis is still in contact, the motor can run really well. With the tender on the tracks it's a different matter.

ntpntpntp

#9
Quote from: CarriageShed on July 26, 2018, 12:40:20 PM
When I lift the tender off the rails and ensure that the loco chassis is still in contact, the motor can run really well. With the tender on the tracks it's a different matter.

So is it stopping with total loss of power, is it stalling with the motor still buzzing, or is it wheelspinning?

Have you checked the traction tyres are ok?  I think the class 38 model has at least two tyres fitted, possibly 4 (I don't actually own one of these locos but a friend used to have one)

[edit] Your photo of the chassis shows no drawbar between loco and tender - I presume you do have that?
Nick.   2021 celebrating the 25th anniversary of "Königshafen" exhibition layout!
https://www.ngaugeforum.co.uk/SMFN/index.php?topic=50050.0

CarriageShed

It's stopping with apparent total loss of power - although a quick nudge or slightly lifting the tender off the tracks gets it going again. In fact, if the tender is lifted entirely off the tracks and power comes only from the loco chassis, the motor goes pretty well.

I took a look at the traction tyres when I was cleaning the loco and they seemed okay. There were no breakages and no visible decay.

There is a drawbar. If you look again at the photo there are two black wires and a thinner bar underneath them - that's the drawbar. It's a little bent in places but it does the trick. I had the loco going round the loop for about fifteen minutes last night. It had to be started at top speed because it was regularly slowing at two areas of points, almost stalling. Travelling over these points seemed to get better in stages so that by the end the loco was at half power. Then I tested the loco at a crawl and it showed a good deal of unreliability in both directions, stalling quite easily. By that time it was well after midnight and I needed some sleep!

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