MTH PS-2 Upgrade problem

Get technical?  Aren't you a designated tech, which means engrossed in technicalities?

I have a few ps1 engines and I don't like them. I had a chuffing problem in which I switched the chuff on a steam engine and hated it. I fixed it though. So I won't be buying ps1 engines in the future. Hooray for Proto 2,

Nickstrains

I wasn't aware of any chuffing problems w/ PS3.  My first PS3 is either in China, on the boat, or at the bottom of the Pacific.  I'd like to hear more, especially since PS3 upgrade boards should be available before the snow flies.

Robert, I said PS1, It was with my Hiawatha. I love it, just not they ps1 system. I don't own any PS3 anyway, but that may soon change.

Excuse me.  I misread.  Sorry.

I might be worthwhile to upgrade PS1 locos that you like to PS2 or, come the fall, to PS3, but a cost analysis should be done first. 

Do you know how much the upgrade kits will be or when they will come out? It would be great to not have batteries anymore.

Robert,

My first PS3 is either in China, on the boat, or at the bottom of the Pacific

That would be the Decapod. Mines with yours so I hope they aren't "sleeping with the fishes".

The Decapod will be PS3 number 9 for me, with numbers 10 and 11 scheduled (at present) for June.

Nick": No.  Actually, I don;t find batteries to be a problem except trying to fit them in upgrades, and I may have solved that by acquiring some tiny batteries and some 1/2 AA's.

Barry:  Yes.  I guess another alternative is that it's floating in the Pacific in a container that washed overboard.

Robert,

I guess another alternative is that it's floating in the Pacific in a container that washed overboard.

Floating would be better than not floating.

Not so sure.  Think about a forum thread addressing the effect of salt air upon PS3 electronics.

Hi Guys, I'm back at it again! I changed the U12, LMV358M with one I bought from Digikey, and it appeared to run "better", but only when I disabled the speed control with the horn/bell sequence. So, I removed the entire setup from the Lionel that I had installed it into, for the main reason that I never had mounted the speed sensor onto the horizontal motor.

OK, new twist........I now have the PS-2 upgrade boards installed onto a test fixture I made. This way, I can monitor voltages in a stationary condition. So, it's as though it's running like it would in a loco. One minor drawback, The motor runs free, meaning there's no friction/weight to overcome, so regulation "speed" is easy.

OK, here's my real question: Gunrunnerjohn had mentioned previously I should be reading between 3 - 5 volts at the speed sensor, between the blue and gray terminals. I tried checking the voltage with the motor in neutral, and again running (this is the nice part of the test fixture) and either way, all I get is 1.16 volts. I would "assume" that the sensor itself is not responsible, as I had another, which I substituted, and still got the same readings. There must be another component on the board that is pulling it down? I have another working board PS-2 board pair coming, that I'm hoping will allow me to compare, but in the meantime I was really hoping someone has been down this road before, and could give me an idea as to what else is directly connected to this circuit??? Thanks Guys!

-Joe

Stan, the LMV358M is easier than the audio amp, very fine pitch on those leads.

I just checked one on my bench, 1.22 volts on a Fluke bench meter between pins 1 and 3 on the tach sensor.  That sounds about right...

OK guys, just a clarification question.

Earlier in this topic a statement was made that if the voltage read between the blue and orange fluctuates when the flywheel is turned, the detector is working.

Now Stan says its the voltage between the gray and the orange that fluctuates.

Which is it?

Rod

Guys,

Stan, your feedback is VERY helpful, THANK YOU!!! Especially the data sheet reference, as I hadn't reached the point of component architechture (don't fault my spelling please). All the replies will help me to construct a course of action. And I may well be reading 1.2, as my figure of 1.16 was a result of attempting to solve "too many" problems at once. Besides this issue, I'm still fixing pinball circuit boards (much easier, as they're BIGGER [wink!]).

Best,

Joe

Sorry G!!!, for not giving credit where credit is due (regarding the 3 - 5v)!!! Nonetheless, this is a PS-2 Upgrade I purchased directly from MTH last year. AND, there is NO smoke attached to this unit..........

Best,

Joe

I have to refine my statement.  Gray is the 5V source to the tach reader and Blue is the PCB Ground or DC negative.   With a properly operating LED the reading is about 1.2V  I read 1.16 on my test set.  The detector side has 5VDC available and orange is the return (emitter).  So measuring orange against blue with provide a positive pulse when the detector conducts.  G

OK George, I get it now!

Thanks for the clarification.

Rod

Well, if that datasheet "means" something to you, it is fairly simple to "trace out" the circuit on the tiny sensor board to identify the LED and phototransistor.  Since you are/were considering a custom sensor for a non-MTH engine, you might conclude (correctly) that you could use a slotted/interrupter-style detector rather the reflective-style detector in place of the MTH board.  I figure they might use both types in pinball machines depending on what you're trying to detect.

The differences in opinion about where to measure the detector output stems from the fixed voltage drop (1.2V or so) across the emitter LED when the sensor board is working.  In other words both the gray and blue wires are/should-be fixed voltages.  So the magnitude of the orange wire voltage fluctuations relative to either gray or blue should be the same.

Stan (and ALL), it gets better at every posting!!! Thanks!

Joe

GGG, I'll do as you suggest! The "phone" test has me puzzled, but I only assume, that the phone will cause the sensors to be  tricked into a state where I'll see a reflection of sorts??? Nonetheless, I'll retrace my steps, and report back........................

Best Regards,

Joe

The Camera can detect the wavelength of the LED, that your eye can not.  So you should see a small purple dot.  That proves the power is available and the LED is lite.  I am assuming you will see it because you read the 1.2V voltage drop.  The problem is I have seen plenty of readers that the LED was lite, but the receiver side went bad.

That is why as stated early by John and I that for a tech with a tester we plug the board in and immediately know whether speed control work or not.  If not, we replace  the opamp.  If it does, I check for continuity of the G/B/O wires and if good, with good gap I replace the tach reader and it is fixed.  Only once out of several hundred repairs did I find that a dirty paper tach tape(old style) was the real culprit.  Probably 3 or 4 times I had to replace the tach reader again as the spare was bad or damaged during install.  Never had a replaced opamp not work.   G

Ah yes GGG, I totally understand the concept now!!! I had a simple tester years ago that I got from Radio Shack, that was basically a  credit card sized, reflective material that we used on the optic senders for pinballs. I hadn't used it for ions, but I bet if I can locate it, it would do exactly what the camera does. Thank you for ALL the input!!!

Best,

Joe

GOOD news Guys!!!!!!!!!! It had to be a combination of errors! After I changed the U12. I wrote that it "appeared" to be better when I disabled the speed control via the bell/horn sequence. Well, I had NOT tested the boards with the spare sensor harness and board, since changing the LMV358M. So I DID, and low and behold...........ALL is working as it should!!!!!!!!!! The first tip off, even before I read 4.6 v between the gry/org, I ran it on my tester, and I could "hear" the diesel sound changing pitch, as I increased the voltage, which it did NOT do before!!!

Now that this board is up and running..........I want to track down the board that "I" ruined 2 years ago, when I was so nieve to using a Lionel ZW transformer with a PS-2 loco! One derailment, and you know the rest of that story!!!!!!!! Now I will compare my boards to track this down (hopefully!!!)

Many, many thanks for ALL the replies, which ultimately helped me fix my PS-2 Upgrade board!!!

Best,

Joe

Nice when a plan comes together.

So it was the harness tach reader that was bad?  G