decoder wires breaking

[northolland]

Has anyone had this problem? I have been installing a Zimo 645R sound decoder and the wires keep breaking. First it was just the speaker wires. Soldered them back on to the decoder. Now I have all wires detached from the decoder. They do not like any handling at all. A bit of manoeuvring and the wires snap at the point where they are soldered to the decoder. Any suggestions about what to do now?

[RFS]

I have a Zimo MX600R where 5 of its wires had become detached from its 8-pin plug.  I'm not sure how this happened but I expect it was a manufacturing issue. Fortunately I needed to hard-wire a decoder so was able to re-use it today. I have another MX600R decoder where one wire has come off but that will be easy to refit. 

 

The problem with Zimo decoders is that the wires are soldered directly onto the pins. With Lenz Standard+ decoders, the wires are fed through slots on the side of the plug, which provides some protection from being pulled off, or simply falling off.  Zimo could learn from that method. 

Edited March 17, 2018 by RFS

[richard.h]

I have used Zimo sound decoders on all my recent sound installations and have never had any problems with them (touch wood)

Have you considered contacting your supplier about a replacement as it would be easy to do some damage and invalidate the guarantee.

[Paul-H]

I have about 20 Zimo Sound Decoders installed on both N & 00 gauge and never had any wires fall off, unlike the Hornby decoders from about 10 years ago which shed wires in the packet.

[RFS]

Have they fallen off at the decoder end though? You have to be much more careful soldering those back on because too much heat will damage the decoder and you have to be really careful not to accidentally join any of the pads on the decoder together cos that will almost definitely break it

 

 

All the wires have come off the 8-pin plug end. The other end is very much better protected due to the plastic cover protecting all the wires. 

[charliepetty]

Richard could solder them back on for you!!!  Ask him.   Charlie

[SRman]

I have had the problem with some ESU decoders. I put it down to the newer lead-free solders being more brittle than the old stuff.

[newbryford]

I have had the problem with some ESU decoders. I put it down to the newer lead-free solders being more brittle than the old stuff.

 

Some of the decoder manufacturers started using a simple strain relief by passing the wires through a hole on the end of the 8-pin plug.

 

Cheers,

Mick

[northolland]

I am happy to say that the wires are back on and everything is still working. I had to invest in a Rolson Helping Hand With Magnifier to get it done though.

 

After my message that started this thread and all your friendly advise I tried to remove the bits of wire that had remained on the soldering patch with just the aid of reading glasses and using a soldering iron with a very fine tip. The wires had broken off at the point were the solder stopped and the bare copper and isolation started, leaving a few mm of tinned wire behind on the soldering patch. However the solder on the patch would not readily melt. First I counted to 10 to then release the soldering iron, as I was fearful of destroying components with excessive heat. Nothing happened. I counted to 20, 30, and 60 and then a few came off but others remained. Looking at what was left behind I feared I had soldered some patches together. It even looked like I had made shorts with some adjacent components, but was not sure. With my failing eyesight and reading glasses on I could not really see. By now I was not too optimistic the decoder would still be in working order after all this heat having been applied to it. With a decoder that I did not know whether it was dead or alive, I decided against sending it to a specialist like Richard Croft above and was close to resigning to having destroyed £100 plus worth of decoder.

 

A few days later I came up with the idea of investing in one of those helping hand things with a magnifying glass to at least get a better look at the soldering patches, so I bought one from Amazon. When it arrived I had another look and it did not look to promising. Nevertheless - what could I do to make it worse - I took my soldering iron with the fine tip to see if I could get it cleaned up, now that I could better see what I was doing. Again the solder did not want to melt. Out of desperation I took my iron with the 2mm tip and see whether that would work better. I did improvise a heat sink by clamping a M6 metal washer to the decoder. The bigger iron did melt the solder by touching the pads for just a few seconds. The melting action cleared all patches bar one that seemed to have become connected to an adjacent component. Some scraping with a very fine screwdriver seemed to remove the excess solder and measuring with a multi-meter confirmed that the short had disappeared. So I soldered the wires back on with the 2mm tipped iron. A quick touch was enough to make the joint; trying not to shake and desolder the adjacent wires. Eventually all wires that I need were reconnected. Just tested it and lo and behold, the decoder is still alive and well. Pffjew!!

[LimboBrit]

I was attempting to fit a Zimo 8-pin sound decoder to my Hornby Class 31. The decoder was delivered with two of the pins bent. They both broke off when trying to straighten them. I am not impressed with the design/quality of these connectors. The pins just stick through a small piece of pcb board and rely on a bit of solder making the connection to the wire for next to no mechanical strength.

[charliepetty]

Send a Stamped Addressed Jiffy bag with a Large 1st or 2nd Class stamp on and we will send you a new plug.

 

DCKits-Legomanbiffo, 111 Norwood Crescent, Leeds LS286NG

 

Charlie

[LimboBrit]

6 hours ago, Richard Croft said:

That must have taken a fair bit of force? I usually use tweezers to straighten pins on decoders if I need to, I've done it many times and never snapped one off.

 

Richard

I was using tweezers. I think the solder joint was already weakened when they got bent in the first place. 

[LimboBrit]

11 hours ago, charliepetty said:

Send a Stamped Addressed Jiffy bag with a Large 1st or 2nd Class stamp on and we will send you a new plug.

 

DCKits-Legomanbiffo, 111 Norwood Crescent, Leeds LS286NG

 

Charlie

Hello Charlie, thanks for your kind offer but I'm in the Netherlands and can't get hold of British stamps over here. It's rather fiddly but I'll be trying to resolder the pins. Regards, David

[charliepetty]

On 27/07/2021 at 20:51, charliepetty said:

Send a Stamped Addressed Jiffy bag with a Large 1st or 2nd Class stamp on and we will send you a new plug.

 

DCKits-Legomanbiffo, 111 Norwood Crescent, Leeds LS286NG

 

Charlie

When I have fiddly installations with Zimo decoders, I drop a bit of white PVA on the wires on the back of the plug to save them individually moving about as its dead easy for them to drop off when bent two or three times.

 

Charlie

[bluestag]

I have four Zimo 645 decoders.   (I have four locos!)  I'm in 7mm, and on two of the locos the decoder is taped to the motor.    This reduces the stresses on the wires a bit.

 

But I have locos that require that the chip be pushed into the boiler as the chassis is attached to the body.

 

One of my decoders lost several connections.   The orange wire to the motor was first, and failed twice.    I extended it so that it is not stressed while pushing it into the boiler.    Both wires for the keep alive came loose from the decoder as well, happily not at the same time (it is polarized, you must not switch them around).    I had to cut back the heat shrink from the chip, which was not easy.   I wrapped the chip in electrical tape to protect the connections.

 

I did not have any trouble melting the solder, using a pencil point tip.

 

I think that whoever assembled this particular chip just got rough removing the insulation on the wires.    The wires are made up of very fine threads.   If they get nicked at all they will fail.    I use my finger nails to strip the insulation.    And I tin the wires before attempting to connect them to anything.

 

Hope some of that helps.