MTH PS-2 Upgrade problem

There is no practical way to bypass the speed sensor, it's a basic part of the system.

I'd work on the original engine that has the flywheel.  If it has speed control issues, the spacing of the sensor is pretty critical, and the flywheel tape should be clean and securely attached.

Hi Gunrunnerjohn,

I tried all those angles when the boards were installed in the MTH subway, I tried different tape, a different sensor...........I just gave up on the "practical" ways and was hoping for a better solution! Thanks for the input!!! I'll keep thinking, and eventually, toss it!!!

Best,

Joe

Toss it my way when you toss it.

Did you check the sensor gap? I have found that the sensor in the upgrade kit normally does not have the proper spacer for most installations, so I keep a stock of the middle of the 3 sizes available.

I'll join GRJ at the garter/bouquet toss

Your poor running subway has to be something simple.  The subway is a pretty simple conversion. Give it another try.

Is the goal install the PS2 board-set in the original subway and get to the bottom of the speed sensor issue...or to put this in your Lionel GP-38 and operate without a speed sensor?

This is conventional mode control right?

You can toggle speed control on/off using a Z4K by pressing Horn-Bell-Bell and getting the double-toot acknowledgement.  When speed control is OFF, the speed sensor is not used for speed control.  In effect, the track voltage is simply converted to DC and is directly applied to the motor.  You should be able to run you engine the old-fashioned way with all the nuisances of slowing down around curves and up grades, etc..  But this will tell you if the erratic speed is because of the PS2 speed control system of which the speed sensor, tape, flywheel stripes are one part.

You can achieve a similar effect by temporarily blocking the gap between the sensor board and the flywheel stripes which will insure the sensor can not read the stripes.  This will cause the engine to "take off" applying max available voltage to the motor in the futile attempt to get more stripe readings.  Again you should get old-fashioned speed control which should not be erratic.

Also, do you recall (in the subway with the striped flywheel) if you ever heard the engine sound rev'ing up above the idle sound?  In addition to controlling speed, the speed sensor tells the engine how fast it's going which is used to up the rev'ing sound notch.  Whether erratic or not if the rev'ing sound increases to the next step when moving this tells you that at least some of the speed sensing is working which I think is a good sign.  But if the engine sound always stayed at the idle rev'ing sound no matter the speed, then the speed sensor is not functioning at all.

Do you have a voltmeter and have steady hands?  There are exposed points on the circuit board(s) where you can confirm that the speed sensor is working at least at a basic level.  That is the voltage will go up and down as you manually turn the flywheel and the black and white stripes pass the sensor chip.  It may take a 2nd pair of hands or whatever but you should be able to turn one flywheel revolution and the voltage will go up and down 48 times.

Wouldn't that be up 24 and down 24 times Stan?  G

Great! That's what I call a real discussion!!! Stan's input, however, appears to have the most valuable information for my issue!!! As for the question of my goal, well, now, it's to keep it in the GP-38, as the subway is running FINE with the current PS 1 boards. We all know, some people like chocoalte, and others (like myself) like vanila, and I like the PS 1 boards. I've been working with them for only about a year, but I'm able to repair most of the blown ones I've come across, and being a pinball tech., I can blast my own sound EEPROMS. I think I have enough ammunition to identify this PS 2 Upgrade problem. If not GRJ wins!

Thanks gang!!!

Best Regards,

Joe

FWIW, at the MTH session Wed nite @ York, AE mentioned that MTH is working on an upgrade kit that does not have a flywheel speed sensor, but will not have as sensitive a speed control.  This would permit upgrading locos without flywheels.

Fact that can motor is horizontal does not per se make installation of sensor not viable.  I have done one upgrade where I epoxied the sensor to the motor housing rather than use the clamp-on holder, and was able to get the proper gap.  Works great.

Although probably not relevant to this issue, if you're running DCS, having 2 feeds to the same track block is not recommended.

I've bonded a number of sensors to the motor in cases where the holder wasn't appropriate.  Several cases were where it simply wouldn't fit inside the boiler shell without hitting the top, I just move it around to a spot where there's room.

I'll believe the kit without the sensor when I see it.

Please outline how you blast your own EEPROMS.  You seem like an expert in electronics but I was wondering what you did identify on your upgrade problem before you pulled out the PS2 system and returned it to Protosounds.  I like DCS but learned early on with the Protosounds system and still like and respect the system.

Wow! As always, I'm IMPRESSED with the feedbacks!!! AND with the creativity of installing the speed sensor on a horizontal motor! Good going!!!

Well gang, like most of my issues, this one is "growing arms and legs"!!! I tried Stan's Z4000 approach of disabling the speed sensor via the horn-bell-bell. Got my 2 horn blasts, and proceeded for a test run! what I neglected to tell you, and like ALL issues, ALL the facts are IMPORTANT!!! Anyway, in this particular run, i have ONE 1122R Lionel Non-Derailing switch!!! The trip is "OK" until the loco travels over that switch!!! On another run, I have several "converted" 1122R's (converted to NON-automatc, in order to have "dead sidings", remotely controlled), and the PS-2 Upgrade runs "better" on this circuit. So let me restate ONE other IMPORTANT fact, the run that has the "factory" 1122R, shows NO ill effects on any of my other loco's in conventional mode (PS-1's, PS-3, Lionel Legacy, Lionel PW, NONE have issues on this run! Maybe after two-thirds of a century on this planet, I'm loosing it, but I don't think so, at least, not yet!!!

Best Regards to all!!!!!!!!

Joe

Marty,

I'm far from an electronics expert, but I know enough to get through a lot of board problems. Again, pretty much, self taught, from years of repairing pinball machines, and a few video games, jukeboxes, etc.. I'm a retired fire fighter, but always had a side job. The past 25 years were fixing pinballs, which continues in my retirement. As for the EEPROMS, I have a programmer that I use exclusively for pinballs

Best,

Joe

I'm a bit surprised that MTH doesn't lock the PS/1 sound files so they can't be read back.  It's simple to burn them if you can read out an old one.

Hi guys (gals),

I wanted this last comment posted to clearify the problem, with hopes, someone will see something, I don't.............. This PS-2 Upgrade ( and I assume the Upgrade is somewhat different that a "regular" PS-2 (?)) runs adaquately up a 6% grade, pulling a decent load, THEN, once it crosses the 1122R Lionel Non-derailing switch, it STOPS! BUT, if i leave the transformer (Z4000) @ the voltage I intiially set it at (usually 11 V), all I need do is press the direction button, and it resumes in the SAME direction it was traveling in before the interuption. Just as though it was completely "powered down"!!! This is the ONLY loco that behaves this way!!! Doesn't this indicate a "faulty board'??? That's it, I won't bother you folks anymore with THIS issue. you guys are TOO smart for me NOT to return to the forum with future questions!!!!!!!! Thanks for ALL your input!!!!!!

Best,

Joe

That sounds like the battery isn't connected or you have a battery circuit issue. 

Question: If you just remove track power suddenly, does it go through the normal shutdown audio sequence fully?

Maybe it is a roller continuity issue and when it goes over the switch it thinks it is at a station stop.  Next direction change starts it again.

G

Right.

Does MTH make a "PS2 upgrade kit" with subway functions?  Joe, when you upgraded the subway initially, did you actually have subway functionality...or did you just get generic diesel sounds?

Good question.  Joe, when you say the engine stops on a switch, do the lights and audio cut off instantly?  Since it appears you're running conventional mode, are you able to stop and change directions (using the Direction button)?  And when you momentarily press the Direction button does the audio continue?

As for mounting a speed sensor in your GP-38, I figure if you're going through what appears to be some effort you might want to measure twice, cut once so to speak.  That is, since the motor configuration appears to be different than the MTH, can you confirm the gear-ratio is the same (number of turns of the motor to make the drive wheel turn once)?  If different, you might want to use something other than 48 total stripes to get the same speed calibration.  There are very detailed instructions somewhere on OGR that explain this.

Also, if the geometry of the engine does not allow you to aim the sensor at the edge or rim of a flywheel, you might be able to aim the sensor at the flat part of a disc with the striped patterns looking like pie wedges.

You can load the subway functions into almost anything with a 3V board.  I replaced a 5V board in one with a 3V board, much of the functionality is already in the ROM for the 3V board from what I understand.  The 5V board required the FLASH board for the subway.

GRJ,

 To answer the question about a suddenn shut down...............Yes, it fades out slowly, as expected.

I tried to meter the rollers for continuity to each other, figuring, one was "dropping the ball" when it passed over the 1122, but not so. I then inspected the wheels for good ground, and okay there as well. I like all the suggestions, and I appreciate all your time and thoughts!!!

Best,

Joe

Joe, none of the PS2 upgrades I have done run any different than a factory-built PS2.

One more tid-bit of info that i keep forgetting to mention..........This particular "board", no matter which unit I had it installed in, has a very distinct issue, you CANNOT "feather" the transformer voltage. It will either come to a dead stop, or go like the dickens!!! It has to be the speed controller???

PJ (Pinball Joe)

Yep, there is a common failure on the P/S board that kills the speed control.  The chip is easily replaced to solve that issue.  I just did one of those with that exact issue.

GREAT! I knew you'd come up with a solution!!! Which chip? Are they readily available? Now, I'm really delighted! This of course, was my fault??? (a static short?)!!!

Best Regards,

Joe

The op-amp that controls the speed is on the power board, it's U12 a LMV358M.  You can get them at Digikey.

Before you change the chip you need to validate the Tach reader.  If it is bad you will get the same symptoms.  All or nothing and no chuff.  If the gap is too large same issue.  Bad tach tape same issue.

THat is why Stan's test is important.  You can power the engine up with tach reader out of holder and look at it via a phone camera.  If you don't see the LED lite, the sensor is bad, especially if you have 5V between gray and blue wire.

If lite, the reader can be bad so do Stan's test.

If this was a new upgrade kit, it is more likely the tach reader is bad then the op amp.  G

Stan, Yes.  All 3Vs have flash programming supporting, steam, diesel, Articulated, and Station Stop.  G

OK guys, let me digest these questions, and suggestions. Recaping some of the "key points". When I had this Upgrade kit in a true MTH Subway (R21), I had played with the sensor tape, gap, etc.. I never did check for a lit LED then. OK, next, if I do the "disable" mode from the Z4K, that "should/could" eliminate the LED/tape/gap, yes, no??? THEN, depite the fact the loco stops AFTER crossing the 1122R, sound IMMEDIATELY "ramps up", as though power is JUST being applied (this occurs INSTANTLY), AND the fact that traveling on ANY stretch of track, "feathering" the speed is IMPOSSIBLE (but it will cruise at a set speed, until it reaches the 1122). More over, this does NOT happen to any other of my many MTH, Lionel locos.

I'm leaning toward GRJ's "chip" issue, as this is a consistent problem, and will occur each and everytime I run this engine.

Thanks guys!

Joe

You may have more than one issue, so first lets solve no speed control.  Turning speed control off, won't really prove much in this situation though it validates the board functions without speed control.  That would verify your engine works without speed control.

When you get to evaluating speed control issues, 5 things can cause the same symptoms, so you eliminate the easy ones first.  Bad tach tape, bad gap, bad wiring to tach sensor (since this is a diesel), bad tach reader (can be either no LED light to read tape or the LED lights but the sensor portion doesn't process) or the Power Supply boards Speed control chip (U-12).

If you read 3-5V on the gray to blue of the tach reader leads you know you have power to it.  If you read orange and blue and rotate the flywheel and see voltage pulses you know the tach reader is good.

The opamp doesn't go bad without a spike or derailment causing it.  Normally you lose the audio amp in the process.

From my (extensive experience) the tach reader is bad (assuming the gap is good and the wiring is not broken internally).  I have even had replacement readers not work.  They can be static sensitive.

That is not to say the opamp isn't bad, just not the first place to look.  If tach is bad, on rare occasions it takes out the speed amp too.

Speed control are the most complex to isolate, because 5 or more (steam) can be the cause, plus dual failure.  Most other issues a symptom only applies to one item.   G

It's a lot easier to isolate these issues if you have a test set, as you replace everything associated with the tach reader with the test set, leaving only the op-amp as the likely suspect.

You could swap the boards into another locomotive to see if the symptoms follow the boards.

Guys, I'm overwhelmed with the detail of the replies! All of you that have contributed to this question, have undoubtedly taken a great deal of your time to offer solutions. For that, I'm VERY grateful!!! I'm hoping, some day I can contribute information in the forum, that will help someone else. This being a weekend, I will not have an opportunity to try any of the latest suggestions, as weekends are a time for me to spend with my grand kids! Monday, I will be back at it!!!

Best to All,

Joe

Found some time...............I don't have 3 - 5 volts at the speed sensor (blu-gry wires)! Out of pure curiosity, I started to meter a few local components, and found "D3" to almost read a dead short, BUT, only IN circuit! Could be associated with U12? When I took it off the board (referring to D3), it read "one-way", as it should. Darned if I could get the value off it though. I just bought a few components from Mouser, as this is one of my pinball component sources. They have the "LMV 358M", as well!

Thanks guys!

Joe

The op-amps come in a bunch of different packages, you want this one.

LMV358M/NOPB-NDIC OPAMP GP 1MHZ RRO 8 SOIC

Does anyone know the chip number for the opto tach reader offhand?

Rod

I don't have a number for the chip, but the little board is $3.50 from MTH with the chip.

AG-0000041     Tach Board - w/ 2.2mm spacer between board & optical sensor
AG-0000058     Tach Board

Optical Sensor

AG-0000078

Thanks guys.

I am having the same issue with a PS-2 conversion in an RK Hiawatha.

Rod

There are 3 boards available, with different spacers.  Personally, having unsoldered and resoldered a board, I'd opt for the complete pkg w/ proper spacer.

If you want to get technical, there are more tach boards available.   If I tossed in Locosound, there's even more...

Tach Reader board (no spacer)    AG-0000033    for Mabuchi motor w/ 30mm flywheel
Tach Reader board (1.5 mm spacer)    AG-0000047    for Mabuchi motor w/ 27mm flywheel
Tach Reader board (2.2 mm spacer)    AG-0000041    for Pr Steam with 30 mm flywheel
Tach Reader board (no spacer) with hole in pcb    AG-0000058    for RK L-3 Mabuchi w/ 30mm flywheel

And, or course, the sensor itself.

Optical sensor component    AG-0000078    Omron part EE-SY124