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Offline French_Fabrice  
#1 Posted : 17 August 2021 10:42:04(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,433
Location: Lyon, France
Hello Markliners,

Well, I'm in the process of converting a HAG-143 DC model to digital with a Lokpilot M4 21MTC, and I encounter a strange issue, i.e. an electric short I cannot explain...

Let me summarize:
1) This is a DC analog model (2nd hand) I've purchased 4 years ago. It is supposed to be in good conditions, but never run it.
2) I've already converted a HAG-198 AC analog model to digital with same decoder, and didn't have any electric issue. The only thing about the motor was I had to put a HAG permanent magnet and it went fine (see thread https://www.marklin-user...loco-to-digital--HAG-198 for the curious)
3) As the current one is a DC analog model, there is no need to put a permanent magnet as it already exists. After some search, the motor seems to be a "88" type.
4) This DC model has insulated wheels on one side for both bogies, as it is normal for a DC model.
4.1) I've modified the non-motor bogie, in order to put a marklin 7164 slider.
4.2) at the same time I've added a contact plate on the insulated side on the non-motor bogie
4.3) this non-motor bogie is now getting "0" from the 4 wheels, and "B" from the slider. The "0" touches the frame body with the original contact plate. "B" and "O" insulation have been tested with a multimeter and result is fine
4.4) I've reduced the wheel spacing from 14.3mm to 14.0mm of the non-motor bogie, with the Fohrmann press. Trying to reduce it more to 13.8mm is not possible as the wheels get stuck
4.5) I didn't do any change on the motor bogie. This bogie has still 2 insulated wheels on the non-gear side, and the wheel spacing is 14.0mm
4.6) I've removed the original capacitor of the motor bogie. I didn't open the motor (yet)...
5) I've prepared a 51968 adapter board to put the LPM4 decoder in it. This adapter board is set on the metal frame with double height double-sided adhesive tape. I've also added a thin insulating tape below the 51698 plate, in order to prevent possible contact from the vertical axis of the non-motor bogie to the 51968

Now, the first test.
a) the decoder is wired with only "B" (red, coming from the slider), "0" (black, coming from the metal frame), and both contacts to the motor (orange and gray). All other wires coming from the 51968 plate are not connected, and don't touch anything else
b) I've read the decoder with the Lokprogrammer (software 4.7.2) and loco put on the rail bench, updated the firmware, updated the address and CV's related to HAG-motor. It went perfectly fine ! BigGrin
c) Then I tried to test the speed with the Lokprogrammer (virtual driver's cab), and nothing except a strange buzz (electric short ?) when I clicked on "go"Crying ... The buzz stopped immediately when I clicked on "stop"

UserPostedImage

UserPostedImage

I did then many tests...and one was surprising.
When I remove the metal bogie cache on the motor bogie, I could run (partly) the motor successfully at speed 1 to 5 on the rail bench, and the motor went very smoothly. Conclusion 1: the motor is not broken.BigGrin
However, as the motor is not fixed by the metal bogie cache, it moves a lot, so it is only valid for a test purpose.
If I put back the metal bogie cache, then I'm getting the electric short again.

More investigations on this electric short show some sparkles on the insulated wheel side of the motor bogie (see arrow on the picture below). I'm completely in the dark ??? Why is there a short ?

UserPostedImage


I did some search on the web, but not found a lot of infos (broken links or info in german and I don't read german), except this one: http://xoomer.virgilio.i...%20pages/HAG_motors.html
Extract
ATTENTION! If you have to digitalise a HAG loco, with a "88" motor type, you MUST eliminate first a small screw, otherwise the decoder will be burned! I will post a web page, explain the digitalisation of a HAG loco.
End extract
Unfortunately, the links provided to Hag-forum are broken Crying


Does this issue sounds to someone ?
Is there anything special that should be done on the motor side ?
Do I need to unscrew the motor and remove/change some piece ?
Should I try to provide the insulated wheels of the motor bogie to "0" potential ?

All tips are warmly welcomed.
Cheers
Fabrice

Edited by user 28 August 2021 23:35:46(UTC)  | Reason: Not specified

Offline marklinist5999  
#2 Posted : 17 August 2021 14:46:17(UTC)
marklinist5999

United States   
Joined: 10/02/2021(UTC)
Posts: 1,870
Location: Michigan, Troy
Bon jour Fabrice! I'm no expert, but something is grounding a hot motor contact to the frame or bogie. Is the pantograph switch isolated completely? Check all wires to and from for where they go. You likley have already. Perhaps you need to unsolder a wire from the motor block because it is connected to something grounded, then reconnect it to the decoder or elsewhere insulated. If any lighting recepticles are grounded to the frame, that can also be shorting. I don't know what type HAG uses. I might try contacting HAG for advice.
Hopefully they are more prompt than Marklin Service. I submitted a CS3 issue question May 29th., and just got a reply this morning.
Offline French_Fabrice  
#3 Posted : 17 August 2021 15:01:53(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,433
Location: Lyon, France
Originally Posted by: marklinist5999 Go to Quoted Post
Bon jour Fabrice! I'm no expert, but something is grounding a hot motor contact to the frame or bogie. Is the pantograph switch isolated completely? Check all wires to and from for where they go. You likley have already. Perhaps you need to unsolder a wire from the motor block because it is connected to something grounded, then reconnect it to the decoder or elsewhere insulated. If any lighting recepticles are grounded to the frame, that can also be shorting. I don't know what type HAG uses. I might try contacting HAG for advice.
Hopefully they are more prompt than Marklin Service. I submitted a CS3 issue question May 29th., and just got a reply this morning.


Hello, and thanks for your reply.

My wiring is correct and there is nothing to unsolder.
I have also good news. I fixed the issue ! Cool

The thread about removing something was correct.
I went at HAG website and the answer is located here: https://www.hag.swiss/service/faq/ , 3rd item in Allgemeines section.

Translation from DeepL (answer is in boldface)
Can a DC be built from an AC locomotive? Or vice versa?

In principle, yes. However, the following points must be observed:

The axes must be insulated for DC models, otherwise a short circuit will occur.
The motor must be equipped with a permanent magnet on old AC models. Newer AC models with decoders already have these magnets built in.
To convert motors with field magnets, the red marked screw, which is located under the right sheet metal cap, must also be unscrewed and the washer underneath removed. Screw the screw back in.
The correct slider must now be mounted on the barrel bogie.

All required parts can be ordered directly from your HAG dealer. The spare parts list with prices can be found under Products - Spare parts lists.

We advise against rebuilding a GTW, because they have a more complex current pickup on the bogies. Also note that the execution of the work is your responsibility and we can not provide any warranty.

Of course, you can also send us the model for conversion. Advantage: You will again receive a two-year warranty on the work performed.


So I unmount the motor, unmount the right sheet metal cap, unscrew the red marked screw, removed the washer and screwed back all the stuff.

The test went perfectlty smooth BigGrin BigGrin BigGrin , and no more shortcut.

One more lesson learned.
Cheers
Fabrice

thanks 4 users liked this useful post by French_Fabrice
Offline Unholz  
#4 Posted : 17 August 2021 17:00:42(UTC)
Unholz

Switzerland   
Joined: 29/07/2007(UTC)
Posts: 1,349
Location: Switzerland
Ah, some quite familiar information and photos in the linked page. BigGrin

Although you have meanwhile successfully solved your problem, I will try to restore/update the broken link to the Swiss HAG forum (unfortunately, all the links became invalid a couple of years ago when we were more or less forced to update the forum software to a new version).

Regards, Stefan Unholz
thanks 2 users liked this useful post by Unholz
Offline French_Fabrice  
#5 Posted : 28 August 2021 23:44:35(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,433
Location: Lyon, France
Hello,

The loco is now converted with white & red leds... It was not very easy, but it is done BigGrin
Here are some pictures of the conversion:

UserPostedImage
The light guide is cut out

UserPostedImage
Leds are in place (1st side)

UserPostedImage
1st attempt was done with bad quality micro-connectors. I've removed them

UserPostedImage
With better quality micro-connectors...

UserPostedImage
Ready to test

UserPostedImage
3 white Leds

UserPostedImage
Additional rear white led

UserPostedImage
... replaced with one red led

UserPostedImage
...or both red leds

Many combination of lights are thus available. Cool It's only a matter of programming the decoder, which is very simple with Lokprogrammer.

Cheers
Fabrice
thanks 3 users liked this useful post by French_Fabrice
Offline 5HorizonsRR  
#6 Posted : 22 November 2022 20:57:07(UTC)
5HorizonsRR

United States   
Joined: 05/12/2004(UTC)
Posts: 3,211
Location: CA, USA
Hi Fabrice!

Thanks for referring me to this thread. I am also struggling to "tighten" my 14.3mm wheel spacings down. My wheels bind at 14.1-14.2mm, and I'm getting the slightest bit of electrical sparking still, I think as a result.

Did you try filing down the plastic insulated portions on the inside of the wheel flange to make more room? And if so, any problems?

Thanks!
FS + SBB Era 2-5 and Vintage Marklin
Offline French_Fabrice  
#7 Posted : 22 November 2022 21:10:58(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,433
Location: Lyon, France
Hi John,

No I didn't file anything, sorry. It works perfectly as is.

Are you still getting some sparkles on your side, even after removing the hidden washer under the right metal cap ???

Maybe Stefan has an idea BigGrin ?

Cheers
Fabrice
thanks 1 user liked this useful post by French_Fabrice
Offline 5HorizonsRR  
#8 Posted : 23 November 2022 19:32:30(UTC)
5HorizonsRR

United States   
Joined: 05/12/2004(UTC)
Posts: 3,211
Location: CA, USA
Hi- it is much better after the washer. The problem is no longer interference or shorting, but rather the wheel contacts since DC is 14.3 vs AC 13.8

Only very little sparks on switches etc... But of course I am hoping to eliminate these.
FS + SBB Era 2-5 and Vintage Marklin
Offline French_Fabrice  
#9 Posted : 23 November 2022 21:24:31(UTC)
French_Fabrice

France   
Joined: 16/05/2011(UTC)
Posts: 1,433
Location: Lyon, France
Hi John,

When I get some sparkles when running over switches, I generally put some heat shrink tube around (not above) the pukos which generate the short.
I always had excellent result with this method. I'm using K-Track.

Cheers
fabrice
thanks 1 user liked this useful post by French_Fabrice
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