AmeenTrainGuy posted:Mine goes to 0.1 and can never go lowers there a solution?
I don't think this is anything to worry about unless you have problems with engines not shutting off when the handle is returned to zero.
Phranzdan posted:Just to add my two cents, the Z750 and Z1000 use thyristor control of the voltage output. The pass element is a Triac with conduction angle control in much the same manner as the trigger speed control on a drill or the dimmer used for incandescent lighting. The problem results from transient caused by the voltage across the main terminals of the Triac going from some high positive or negative value to the forward conduction drop of the Triac almost instantaneously. If you have a scope and one of these transformers handy you can watch the changing conduction angle as you vary the voltage control knob. The sudden change in voltage can cause all kinds of transients which gets into the circuitry and cause havoc. Remember, the same voltage being applied to the track is also being used to power the circuitry. There is no wave shaping just the partial sine wave applied prior to the Triac firing. When viewed on a scope, it may resemble a sawtooth especially at high conduction angles i.e. when the Triac fires early and only a small segment of the sine wave is present. In my early days in the applications development lab at RCA Solid State, we spent a lot of time mulling over how to "quiet" this type of circuit. Hope this helps in understanding the problem.
Does this mean that it would be helpful to put a TVS across the output terminals on these transformers?
H1000 posted:PRRronbh posted:Then why did MTH replace this 165VA unit with a new 180VA unit on the spot?????????
IDK, call and ask them! I didn't replace mine and it (still) works great. I can still easily find many of these first run 165va Z4000s online that obviously haven't been replaced. If you have one with problems, MTH service can be reached at (401) 381-2580.
Apparently you did not fully read and comprehend my post.
The owner of this Z4000 knows all the key people at MTH by sight and name. They all also know him by sight and name. When the problem occurred ( not able to run Premier"Protosound" GG1) engine would not leave "Reset" mode. John pulled out his index of names and personnel at MTH. He called the chief tech and handed me the phone. As I originally stated we had a great informative conversation. He knew exactly what the problem was as stated after he ask me to check out a few things.
John was told to send it in. He chose to drop it off on the way to York that Appril. He took it in asking for the tech. The tech took it asking him to wait. A few minutes late the tech returned with a new 180VA Z4000.
The reason early Z-4000's did not fully shut off is what is called 'leakage current'. It resides in the circuit until power is fully turned OFF. The way you can tell if your transformer behaves like this, or has another problem, is to look on the left rear product label. The serial number is the clue: if it starts with 0398XXXX - that Z-4000 has leakage current. It is of no concern, but if you want it corrected, Don, at MTH service can do it. Other techs might also have the two diodes needed.
bruce
turbgine posted:Some of the early Z4000 transformers would not go to 0.00 volts when you tried to cycle through a startup. I found that if you put a lighted caboose or passenger car behind the engine that would not cycle it freed up the reverse board and allowed the engine to run. Try this because it's easy to do and may solve your problem. Check the gauges on the transformer (Z4000) and see if there is any residual voltage even when the handles are at the supposed zero volt setting.
That IN FACT was/is the problem. But it was actually based upon a design assumption at the time not faulty production. And yes MTH could fix it. I the case of my fellow O-gauger friend they just exchanged it for a new 180VA Z4000.
For a "Protosound" loco to come out of "Reset" mode the voltage must drop to zero. OR appear to the loco that it did drop to zero!
By the way that lighted caboose in essences satisfied that original design assumption.
PRRronbh posted:H1000 posted:PRRronbh posted:Then why did MTH replace this 165VA unit with a new 180VA unit on the spot?????????
IDK, call and ask them! I didn't replace mine and it (still) works great. I can still easily find many of these first run 165va Z4000s online that obviously haven't been replaced. If you have one with problems, MTH service can be reached at (401) 381-2580.
Apparently you did not fully read and comprehend my post.
The owner of this Z4000 knows all the key people at MTH by sight and name. They all also know him by sight and name. When the problem occurred ( not able to run Premier"Protosound" GG1) engine would not leave "Reset" mode. John pulled out his index of names and personnel at MTH. He called the chief tech and handed me the phone. As I originally stated we had a great informative conversation. He knew exactly what the problem was as stated after he ask me to check out a few things.
John was told to send it in. He chose to drop it off on the way to York that Appril. He took it in asking for the tech. The tech took it asking him to wait. A few minutes late the tech returned with a new 180VA Z4000.
If the "owner of the Z4000 knows all the key people at MTH by sight and name", why didn't he ask them your question directly? "Then why did MTH replace this 165VA unit with a new 180VA unit on the spot?????????". You don't need this forum for a question like this if you have a resource like that at your disposal.
"He called the chief tech and handed me the phone." - Again you had the chief tech on the phone, just ask him why?!
It's not like every Z4000 ever made never had a single problem. Sometimes a warranty departments will ship you a whole new unit as it more cost effective (and faster) than repairing your old one. I don't recall MTH issuing a general recall on all of the original 165va Z4000's to be swapped out with new units - no questions asked.
bruce benzie posted:The reason early Z-4000's did not fully shut off is what is called 'leakage current'. It resides in the circuit until power is fully turned OFF. The way you can tell if your transformer behaves like this, or has another problem, is to look on the left rear product label. The serial number is the clue: if it starts with 0398XXXX - that Z-4000 has leakage current. It is of no concern, but if you want it corrected, Don, at MTH service can do it. Other techs might also have the two diodes needed.
bruce
Yep, my Z4000 has that Serial number, but my layout has enough drain per channel to drop the volts to zero. This would be an issue on a test track without a lighted lock-on. Adding anything lighted to your track fixed the problem also.
H1000 posted:bruce benzie posted:The reason early Z-4000's did not fully shut off is what is called 'leakage current'. It resides in the circuit until power is fully turned OFF. The way you can tell if your transformer behaves like this, or has another problem, is to look on the left rear product label. The serial number is the clue: if it starts with 0398XXXX - that Z-4000 has leakage current. It is of no concern, but if you want it corrected, Don, at MTH service can do it. Other techs might also have the two diodes needed.
bruce
Yep, my Z4000 has that Serial number, but my layout has enough drain per channel to drop the volts to zero. This would be an issue on a test track without a lighted lock-on. Adding anything lighted to your track fixed the problem also.
YES!!!!!!!!!!!!!!!!!!!!!!!
PRRronbh posted:H1000 posted:bruce benzie posted:The reason early Z-4000's did not fully shut off is what is called 'leakage current'. It resides in the circuit until power is fully turned OFF. The way you can tell if your transformer behaves like this, or has another problem, is to look on the left rear product label. The serial number is the clue: if it starts with 0398XXXX - that Z-4000 has leakage current. It is of no concern, but if you want it corrected, Don, at MTH service can do it. Other techs might also have the two diodes needed.
bruce
Yep, my Z4000 has that Serial number, but my layout has enough drain per channel to drop the volts to zero. This would be an issue on a test track without a lighted lock-on. Adding anything lighted to your track fixed the problem also.
YES!!!!!!!!!!!!!!!!!!!!!!!
Only in extreme circumstances - "This would be an issue on a test track without a lighted lock-on." - I don't think anyone operates this way, and those that do (on a test bench) are aware of the situation, which still doesn't warrant your comment of "What is more interesting, the first original Z4000's rated at 165VA also would not always operate "Protosound" engines."
You can buy a $350 z4000 but don't have a single piece of lighted rolling stock or lighted lock-on to solve this issue? Which now warrants you to demand MTH to replace your defective Z4000 with a newer model?
What about all of the TIUs previous to the version L that also required the light bulb trick to solve problems with low track signal, where is the mass recall for those?
We figure out these idiosyncrasies, and come up with easy and cheap work arounds to solve these minor problems. MTH is aware of these issues also and then corrects the situation in future releases of the product. I'm not about to ask MTH to replace a perfectly good Z4000 for a problem that can be solved with a 5 cent light bulb.
I guess we can say that you identified the .01% situation in which less than 5% (and decreasing) of all Z4000s ever made will not properly operate a PS1 engine..... crickets....
Please don't let this topic die! I (and perhaps a few others?) enjoy coming back every few weeks to catch up on the input.
I have found this to be a very interesting read......... crickets..... LOL!! The diversity and melting pot of our hobby has always fascinated me. I also have many PS1 engines, quite a few purchased prior to 2000, and, most (if not all) of the UP turbines. Some (F3s, PAs, DL110, Big Boy) I have converted over to ERR TMCC/RS, and some because of the 3 clanks of death. And yes, use the green battery and have the "reset" chip kit I acquired from Western Depot. As for the rest, mostly turbines, I run with no problem using my ZWC with 180 bricks and the cab1. As instructed in the TMCC manual, you can run PS1 without problems by making use of key number 9. I do not run any DCS, only TMCC/RS and conventional, and enjoy my engines from all manufacturers from 1920s to present. Yes, we all have to perform maintenance and some repairs on what we possess in our consists. The information and "tips and tricks" we find here on the Forum are invaluable.
Jesse TCA 12-68275
I thought this tread was about exhausted but I guess not. I noticed some discussion relative to "leakage current". All Solid State devices exhibit some leakage current when a bias is applied. This can be very small in the order of a few hundred Nano amps but can be as high as a few milliamps. Most devices manufactured today should be of the lower leakage variety. Prior to sale, all devices are tested to some leakage limit and those that fail are discarded. These devices are in most case functional and therefore saleable to a customer not requiring the stringent limit imposed earlier. There are companies that buy scrap barrels of rejected devices, rescreen to less stringent limits and sell the product. In an earlier post, I mentioned that the pass elements of the Z750 and Z1000 transformers were in fact Triacs. When the triac is in the blocking mode, I.E. not gated on, it will have some leakage. In most cases, this leakage is low enough to preclude problems but there may be cases where a device exhibits a higher leakage and can cause problems. I am not familiar with the circuitry of the Z4000 which I believe was one of the transformers mentioned in the "leakage" post. Suffice it to say that most modern transformers have some type of pass circuitry to allow the voltage supplied to the load to be varied. Likewise, the leakage in some cases may be high enough to cause some problems. I guess I am not certain why the reversing button could not be used to interrupt the current flow and negate the effects of the leakage current. Am I overlooking something?
Best Regards, Phranzan
So, I'm having the same problem as the original poster. My 1994 era PS Premier EMD GP-9 won't come out of neutral. I have another thread started where I'm asking for help but I noticed you guys were talking about the Z4K. I'm running one now (only a year old) and it reads .1 volts on both screens when turned on. Is this maybe a reason my engine won't come out of neutral? I've tried the reset (code 18) on my ZW but I don't get the confirmation dings and donks. If my Z4K is always reading .1, would that prohibit the train from completing the reset??? My Z4K serial starts with 1114 so I'm guessing its a newer version.
Ps.. My locomotive doesn't get the 3 dings of death when engine starts up.
I had a Z750 sitting on my repair shelf for some time which in light of the current thread, I decided to investigate. I powered it up and measured the output. With any setting of the output control, the output was 20 volts same as the input. Initially, it didn't occur to me to put a load on the output. I used a load box which consists of two 50 watt wire wound 15 ohm pots in parallel. The voltage dropped to around 2 volts at zero throttle setting. Thinking there was some leakage, I removed the Triac. There was no change in the output. As I started looking, I found there was a capacitor in series with a resistor across the Triac. This is a common technique to eliminate transients called a "snubber". This represents an impedance which is a leakage path to the output and the main reason these transformers cause some problems with PS1 engines. I had an MTH FM H-10-44 with PS1 handy and placed it on my test rack. With the throttle at zero, there was over 2 volts on the track. One way to solve the problem would be to place a load on the transformer independent of any locomotives. I tried a 68 ohm resistor which pulled the voltage down to about .8 volts but it would be over its 1/2 watt rating when the throttle was turned up. I would try one or two 14 to 18 volt bulbs in parallel to see what the result would be. I will do some experimenting to see if This will cure the problem.
Phranzdan
I'm going to use information gleaned from reading this thread to try once again to get my PS-1 Weaver to come out of neutral. I'm going to start with putting a lit caboose behind the engine.
I may have jumped the gun on my earlier post on the Z750. Although I thought the unit was O.K., it turns out that there is still an issue. I actually have three control boxes bearing the number Z750. I have been using one on my bench for some time and have not noticed a problem after many PS1 engine runs. I decide to take a look at this and one other unit both which are confirmed working and not displaying any unusual voltage in the zero throttle setting. The unit I am using on my bench appears to be a later version containing surface mount technology rather than through hole as the one I am repairing. The third unit appears to be somewhere between the other two with a resistor across the output and some other changes in the circuitry. I had to order a regulator for the one I am repairing so I won't know for a few days exactly how this compares to the two later versions. Stay tuned.
Phranzdan
