the little round metal housing with 3 wires on the bottom and short shaft with white small gear at the end ( Z4000)

No worries!  The part you are referring to is the potentiometer or "pot" (variable resistor) that controls the voltage output, one on each side. If the handle became really stiff to move it sounds like the pot may have seized up internally, or the lever assembly may be hanging up somehow. When you work on these  or replace a pot it is critical to mesh the larger and smaller gears such that the red and black markings on the gears are lined up. Otherwise you won't get zero output with the lever all the way towards you, or conversely you won't get full 20 volt output at max throttle. It sounds like you may need to replace the pot, and its not hard to do. The part is readily available from MTH, just call Midge in parts and tell her what you need.

Rod

Rod Stewart posted:

No worries!  The part you are referring to is the potentiometer or "pot" (variable resistor) that controls the voltage output, one on each side. If the handle became really stiff to move it sounds like the pot may have seized up internally, or the lever assembly may be hanging up somehow. When you work on these  or replace a pot it is critical to mesh the larger and smaller gears such that the red and black markings on the gears are lined up. Otherwise you won't get zero output with the lever all the way towards you, or conversely you won't get full 20 volt output at max throttle. It sounds like you may need to replace the pot, and its not hard to do. The part is readily available from MTH, just call Midge in parts and tell her what you need.

Rod

hello Rod Stewart.........

MTH will even sell a part such as that ?  How much would a pot like that cost ?  Is it possible to find the part number on it and order it online ?   I am hearing-impaired so talking on the phone is a problem so instead can l just order it online.  I hope it not a expensive part.

Tiffany

Here are some pix that might help. This one is of the left side throttle handle removed, showing the alignment pointer highlighted black.

This one shows the nut I think you are referring to. You would loosen this nut and back it right off the threaded brass sleeve to remove and replace the pot. Once it is loose you can disengage the two white gears and lift the left throttle handle completely out of the case. No big deal. When you install the new one make sure you insert the small metal tab on the case of the pot into its alignment hole in the mounting bracket. This is critical for proper pot indexing.

This pic shows proper alignment of the red and black markings on the gears. This is actually the right side, but the left side is the same idea.

Let us know how you make out.

Rod

Tiffany posted:

Rod Stewart posted:

No worries!  The part you are referring to is the potentiometer or "pot" (variable resistor) that controls the voltage output, one on each side. If the handle became really stiff to move it sounds like the pot may have seized up internally, or the lever assembly may be hanging up somehow. When you work on these  or replace a pot it is critical to mesh the larger and smaller gears such that the red and black markings on the gears are lined up. Otherwise you won't get zero output with the lever all the way towards you, or conversely you won't get full 20 volt output at max throttle. It sounds like you may need to replace the pot, and its not hard to do. The part is readily available from MTH, just call Midge in parts and tell her what you need.

Rod

hello Rod Stewart.........

MTH will even sell a part such as that ?  How much would a pot like that cost ?  Is it possible to find the part number on it and order it online ?   I am hearing-impaired so talking on the phone is a problem so instead can l just order it online.  I hope it not a expensive part.

Tiffany

Tiffany; The pots are pn BI-5100001 (both the same) and the last time I ordered some they were $6.00 each. That was a couple of years ago. I recall they come without the 3 wire harness, so you will have to remove the harness from the old one and solder it to the new one. Make sure you connect them exactly like they are connected to the old pot. You can likely order it online.

Before ordering a new pot though, you should disengage the two gears as described above, and see if the gear and shaft on the pot is binding, or if the problem is something else.

Rod

You can also email Midge. I have had great response from her the last couple of times.

Brassuer lists them for $6.00 still.    So that seems to still be valid price.

If you are near San Diego, I can get my friend Jimmy Osborne to help you.

Guys/gals, It is always a great idea to do what Rod does.  Anytime you have anything strange to you open, always take some quick pictures with your phone.  The Z-4000 is a prime one.

Rod Stewart posted:

Here are some pix that might help. This one is of the left side throttle handle removed, showing the alignment pointer highlighted black.

This one shows the nut I think you are referring to. You would loosen this nut and back it right off the threaded brass sleeve to remove and replace the pot. Once it is loose you can disengage the two white gears and lift the left throttle handle completely out of the case. No big deal. When you install the new one make sure you insert the small metal tab on the case of the pot into its alignment hole in the mounting bracket. This is critical for proper pot indexing.

This pic shows proper alignment of the red and black markings on the gears. This is actually the right side, but the left side is the same idea.

Let us know how you make out.

Rod

Hello Rod...........

On # 2 picture of the pen pointing at the nut is the one that I overtighten thus messing up something inside of the pot. So that will have to be replaced but I wish the wires were already soldered on the pot as I am not good in soldering ( might make it worse  to mess up something else) Is it possible to buy that Pot with the wires already soldered on as it would make it lot easier for me.  I am aware of the marker arrows pointed on the teeth so I am careful in this area. I just looked at the picture again # 2 photo, I see that will have to remove the small gear to slide the pot out of the metal bracket hole. So what needs to be done to do that ?

Tiffany

Marty Fitzhenry posted:

If you are near San Diego, I can get my friend Jimmy Osborne to help you.

Hello Marty............

I live 90 miles north of Sacremento , City of Chico. If I can get the replacement Pot with the wires already soldered on, I can installed it myself with pictures of course !!!!!  I am not good in soldering thus will mess up so prefer to get one with the wires on it and the white plug on the end of the wires.  I be GLAD to pay shipping too.

Tiffany

They come without the wires.  The part number is BI-5100001.  If you can hit my email martyfitz44@aol.com I can guide you a bit.

Marty

Marty, is that correct that there is a tension adjuster on the bottom?

Hi Tiffany; I checked MTH and it looks like they don't sell Z-4000 parts to end users anymore. Likely something to do with the UL certification. But Brasseurs as suggested above should be able to help. If you have a train shop anywhere nearby I imagine they would do the soldering for you at minimal cost, if any at all.

Also I kind of doubt that you could cause any damage to the pot by overtightening the little nut. I think the pot has failed inside and is sending erroneous values to the control board in the top of the case. Just my guess. It looks like the pot would be a fairly off-the-shelf 10K linear unit with a 1/4" shaft which you could likely also pick up locally from an electrical parts supply store cheap. I am afraid I don't recall how to remove the gear from the pot shaft, but it cant be difficult.

Rod

RJR posted:

Marty, is that correct that there is a tension adjuster on the bottom?

RJR, Marty will likely confirm, but the newer Z-4000's have adjustable tensioners with screws under the case. Older ones did not, but there is a kit you can get from MTH to retrofit. It consists of a spring and a wiper that you simply insert into a hole inside the case that has been included in all units from day one. The kits cost $1 a piece.

Rod

hello guys and gals..........

The only way I can see of removing the pot with the gear on is to cut a slot of the bracket (left side throttle) then loosen the nut and slide it out but the bad thing about it is the bits of metal dust from the cutting will get all over the coils with blue wrapping and possible short it out.  There has to be a way to fix it at home without spending a ton of money I don't have.  I see that DGJONES has the 270 watt walk around transformer made by MRC for 95 dollars plus shipping.  Would this MRC transformer work with older PS-1 protosound locomotive of 1999 era (Railking #30-2157-1 switcher) ?   Would this be a better way to go ?   I am building a 36 by 80 door layout and will soon need a transformer for that to run this switcher and half dozen small buildings with lights and some powered accessories.

SIGH,Tiffany

I'm pretty sure the gear just pulls off, it's a friction fit.  When you pull it off, you'll find the pot has a D shape cut from the end.  See circled example.

hello Gunrunnerjohn

That is good to know can it be pulled off with fingers ?  at least I have a chance to fix it at home ? I asked because if that can be done and that would be easy to take out the old pot and put in the new one and put the gear back on and plug in the wire harness into the board ? I can do that

Tiffany

You'll have to remove the handle, and then you should be able to slide the gear off.  At the most, you might need a screwdriver to lean on the bracket and push the hub of the gear away from the pot.

gunrunnerjohn posted:

You'll have to remove the handle, and then you should be able to slide the gear off.  At the most, you might need a screwdriver to lean on the bracket and push the hub of the gear away from the pot.

Hello Gunrunnerjohn

Is there anyone here who would have the correct pot with wired already soldered on that would sell to me ? then I will try this.

Tiffany

Hard to say, I don't have one myself.  If someone like GGG has one, I suppose he could solder wires to it.  The terminals are pretty big, it shouldn't be a big deal to solder the wires.

Worst come to worst, just ship the pot and the new one to someone to change the wires.  I also suspect there's someone local that shouldn't have any issue moving the harness to the new pot.

Tiffany,

Check if you have amateur radio/ham or TV repair place nearby.  They are handy with solder iron (avoid solder gun as these supply too much heat for terminals and small wires) as this would be a quick 5 minute job. 

hello guys and gals.......

Thank you for bringing this post back Rich. It was gone the other day as I needed this post to look at the pictures so I can try to repair my z4000. I will post pictures of the repairs in this thread so others can learn this as well. (UP-DATE 9-12-16) I will be getting the part Pot controller probably in few days.   (Another UP-DATE 9-15-16), I received the pot controller today by mail and will start taking pictures step by step with your help to install the new part in few days ok guys ?  The pictures are to help others with the same problem too. 

Tiffany

Hello guys and gals...........( UP-DATED 9-17-16) and same evening 2 hours later.

I am working on my Z4000 tonight to try to replace the pot controller with the new pot and I am now going to pull the gear off hopefully with my fingers if I can and  I hope I can put the gear back on the new pot property indexed as I not sure how to do that but will try.  I will post pictures soon........... Rich, please do not removed this post as this is for everybody to see the pictures of the repair.   (Another UP-DATE same evening 2 hours later) I figured out how to property "Indexed" the Pot shaft and the gear much to my surprised it was rather easy, pretty straight forward.  The gear was easy to pull off and push back on the shaft and I cut ONE wire at a time and tie together with wire nuts then reassembled the housing and turn power on and fast the throttle to 11 volts hooked up to the track with the caboose and left it on for 15 minutes, every thing is GOOD. I am GLAD it's fixed !!!!  I took the old Pot apart to see what's inside of it but could not find anything wrong with it except for wear and tear on it ( maybe it went bad due to age I guess but the other side is good, go figured ? ) Guys this is my FIRST time I ever repaired the fully electronic transformer in my life but it was God that helped me through this. I cannot express how HAPPY I am with the repairs.  Hope this will help others to repair (replace the pot controller of their z4000) as mine was only 5 years old so there are thousands out there that are older and may have the same problem I have.  Here are the pictures and have any questions , ask away !!!!

Tiffany

Good work Tiffany! We knew you could do it!  Often it's just a case of getting up the nerve to try something new.

Rod

Yep that pot has seen its day. The black carbon element looks pretty worn, especially if there is a "sweet spot" where you do most of the handle movement back and forth, that carbon will get worn down the most.  No fix for it except a new pot.

On different note, surprised MTH didn't do digital encoder rather than pot.  Light shines through a set of various hole placement that the processor reads and deciphers to a code that the processor then commands the transformer electronics to put out that voltage.  Same idea (I think) as the Lionel controllers with 128(?) steps.

Rod Stewart posted:

Good work Tiffany! We knew you could do it!  Often it's just a case of getting up the nerve to try something new.

Rod

Hello Rod Stewart

Thank you guys........... I felt pretty good about it too and when or if the right side goes bad then I can do the second one in heartbeat !! WITH God's help.

Tiffany

rrman posted:

Yep that pot has seen its day. The black carbon element looks pretty worn, especially if there is a "sweet spot" where you do most of the handle movement back and forth, that carbon will get worn down the most.  No fix for it except a new pot.

On different note, surprised MTH didn't do digital encoder rather than pot.  Light shines through a set of various hole placement that the processor reads and deciphers to a code that the processor then commands the transformer electronics to put out that voltage.  Same idea (I think) as the Lionel controllers with 128(?) steps.

Hello rrman...

I could not understand why the left side throttle (red light) pot controller went bad as I often use the right side throttle (green light) because I am right handed and don't use the left side that much, I don't get it ?  Electronics are strange sometimes !!!

Tiffany

Tiffany posted:

rrman posted:

Yep that pot has seen its day. The black carbon element looks pretty worn, especially if there is a "sweet spot" where you do most of the handle movement back and forth, that carbon will get worn down the most.  No fix for it except a new pot.

On different note, surprised MTH didn't do digital encoder rather than pot.  Light shines through a set of various hole placement that the processor reads and deciphers to a code that the processor then commands the transformer electronics to put out that voltage.  Same idea (I think) as the Lionel controllers with 128(?) steps.

Hello rrman...

I could not understand why the left side throttle (red light) pot controller went bad as I often use the right side throttle (green light) because I am right handed and don't use the left side that much, I don't get it ?  Electronics are strange sometimes !!!

Tiffany

 

Glad you got everything going again!  The more you get into this the easier some things become.  Scenery is my nemesis but once someone showed us how easy it was, and we built our mountain and ballasted, we wondered why we didn't do it sooner.

The second paragraph was more for techie types like Stan, or gunrunner John etc in case they happen to read this thread.

rrman posted:

On different note, surprised MTH didn't do digital encoder rather than pot.  Light shines through a set of various hole placement that the processor reads and deciphers to a code that the processor then commands the transformer electronics to put out that voltage.  Same idea (I think) as the Lionel controllers with 128(?) steps.

Same argument for the MTH remote, the mechanical switch for the thumbwheel is a PITA and the major source of failures for the remote!  Lionel controllers don't use physical contacts.

hello guys and gals........ (UP-DATE 9/20/16)

My Z4000 has be running good no troubles so far so good.  I guess that is all was wrong with it the pot controller !!! and probably the end of this thread, good time to delete this post ?

Tiffany