Replacing 5V PS2 with 3V PS2 ?

Pete,

You need  to replace 4 things, all of which will be in sn upgrade kit:

• The PS2 5 volt board with a 3 volt board that has 3 volt (HIROSE) connectors
• The 8.4 volt battery with the 2.4 volt battery
• The 16 ohm speaker with a 4 ohm speaker
• The 8.4 volt battery charging jack, if the engine has one, with the 2.4 volt charging jack.

Everything else stays in place.

Thanks Barry. I have only done PS1 to PS2 conversions up to now and just wanted to make sure.

Pete

The only issue you typically run into, depending on where the 5V board is located, is getting the 3V board oriented so you can connect the heatsink.  I've had to extend the harness leads for some steamers with the boards in the locomotive, and I frequently end up making a custom heatsink of aluminum bar stock to mount the 3V boards.

John, especially since the 5v to 3v boards cost more (and are harder to get) then a PS-2 steam upgrade kit, why not just do the complete upgrade with electronics (boards) in tender??

Ron

Actually Ron, I did opt to install the boards in the tender from the engine. It looked like it was going to be a major PITA to install the new board in the engine. 

Tender is done except for dressing up the wires. Maybe I will get the engine done tonight.

Pete

Norton, I agree with you in the pita aspect of installing a 3-volt board in the loco.  Last time it happened, I cannibalized the 5-volt board from a diesel in which I installed a 3-votl board.  FYI, if battery space is at a premium, much tinier batteries than the AA or AAA size are available from other sources, as are smaller speakers.  I used both in upgrading an ancient Lionel #624 to PS2.

Let the forum know how the job goes.

The best way to do the job of moving the board from the engine to the tender is with an upgrade kit like Ron pointed out.  If you want to use the 5v to 3v boards, they are available at MTH.  The part number is AE-0000015 for the power board and AE-0000016 for the processor board.

Marty, are these boards really available???  My local dealer's certified MTH tech has had a set of these on order for me for well over a month.  In that same time they have received for me six upgrade kits but 5v to 3v boards.

Ron

Ordering parts from MTH is a fairly slow affair.  I have a couple sets of the 3V board sets on order, it's been three weeks so far.

Interesting. I wasn't aware of a special 5v to 3v kits. I imagine it eliminates a few parts.

I have a few PS1 to PS2 kits on hand so I used one of those.

The engine is nearly done and so far checks out in conventional. 

One more question though. Since I installed the board in the tender and there is no constant voltage board in this engine, what is the best way to power the cab and firebox lamps? I was thinking of simply paralleling them with the headlamp but wasn't sure the headlamp driver could handle the extra current. I am guessing there is no way to control the cab light independently even if I had extra wires in the tether, which I don't.

Pete

I've seen factory installations with four bulbs on the headlight circuit, so that's one way.  Of course, you could replace the firebox light with some cool flickering LED's for a very cool firebox flame effect.

One of the negatives of the retrofit is the fact that you don't have enough wires to have separate control of different lights in the locomotive.

Ron, they are available.

John and/or Marty, since we are on the 5v to 3v conversion subject please verify and/or correct an understanding I have form other threads.  That is that a 3v board can be converted to take the 5v harness plugs (12,8 & 4-pin) by replacing these plug shrouds on the 3v board with shrouds from 5v board.  Now if this is true what about 5-pin motor harness, 7-pin chassis harness and 2-pin battery charging harness.  Do these plug shrouds also have to be changed?

And Marty I confirmed with local tech that the numbers you listed are the ones he has had on order for me.?

Ron

Correct, all the 3V board with the 5V connectors has is different connector shrouds, the boards are exactly the same.  That applies to all those things you mention except

You have to replace the battery harness, so you leave that connector shroud.  You also have to change the speaker to a 4 ohm unit.

Shrouds just pull off?

A little heat from a hair dryer or heat gun (gently!) will help.  The pins have a dimple to hold them in place, but I've done a few when all I had was a standard board.

OK!  John and/or Marty, let's take this one more step.  Of my 31 5v engines that concern me the most are the actual MU'd 5 ABA and AB sets.  It is also my understanding that the slave units in trailing MU'd engines are compatible with either a 5v or 3v board in lead engine.?????  If so is there anything different about the lead engine's boards?  Or is it just in the lead engine's wiring harnesses?

I am fairly sure that the PS-3  sets have their own slave unit boards that are NOT compatible with a 3v in lead engine.

Ron

The lead engines use a standard PS/2 board.  The slave boards are the same for 3V or 5V master boards.

PS/3 are a totally different animal, you are correct.  I've yet to see a slave PS/3 unit.

When a 5-volt in-steam-loco board needs to be replaced, I wonder if gutting the system and installing PS3 upgrade kit (I assume it will be a 2-board system like in current steamers) will be easier than trying to shoehorn a PS2 3V board in.

It really depends on the locomotive in question.  One thing you lose when you put in an upgrade kit is individual control of markers, cab lights, etc.  Obviously, this only affects locomotives that have those features separately controlled.

I have yet to run across a PS-2 5V engine that has the boards installed in the engine that I could not install the PS-2 3V in the engine. (Including RJR Mountain) I have installed 3V boards in all the Bantam engines, various RK and Premier engines.

In my opinion it is always better to put the board in the original location and retain all the extra features that presents.

I would not bother ordering AE-15/16 as MTH doesn't really have anymore of them.  What they do is have a tech remove the connectors on the AE-10/11 and install the 5V versions.  Just slows your order up, since you can do it with the old 5V parts.

Plus if I want bent pins on the board, I can do that myself 

As far as changing the battery 2 pin, you do need to do it if your placing the board in the engine with battery in the tender.  Since the engine 2 pin is a 5V variety.  Otherwise, you can leave it if the new harness is being used.

On a side note, I have even installed the battery or a Super capacitor in some Premier engines that required the new board.  This makes the engine independent of the tender except for sounds, and frees up a wire or 2 for additional tender features.

For some other manufacture PS-2 Upgrades, I place the board in the engine when possible.  Example the K-Line Hudson.  This allows for more feature control on the engine.  It does require different harness.   G

I agree that putting the board in the original location is always the best bet.  I've yet to have to resort to moving it, though I've had to modify wiring to make some of the connectors reach a few times.  I've had to come up with several creative heat sink designs to mount the 3V board.

I like the idea of installing the battery in the locomotive and having the extra wire for adding some lighting features to the tender, never thought of that.

How about posting pictures or sketches of your heat sink designs?

I don't routinely take a picture when I'm doing repairs, so I don't have pictures.  I just take 1/16" aluminum and cut it to shape so that I can screw it down to the available mounting points.  For locomotive mounted boards, there is rarely a place for the stock heatsink to mount.

GRJ, I expect that you're more proficient at bending than I am.

Well, I just take the aluminum cut into a 1" strip and use a vice to bend it.  No super metalworking skills here.

Remember, "Nothing is so easy as the job you imagine someone else doing."  I have trouble getting the corners square---I use a vise also.

Well, they're a little rounded, but square enough to do the job.

By square, I meant getting the bend perpendicular to the strip.  As I recall, you also don't have your heat sinks touch both sides of the rectifier.

Interestingly enough, I have some Radio Shack full-wave rectifiers that say nothing about needing a heat sink.  I wonder if a possibility isn't removing the rectifier from the 3-volt boards by clipping the 4 legs and mounting a rectifier elsewhere.

When I bend them, I just go on one side of the rectifier.  I use a large washer and nut on the bottom to help transfer heat.  I haven't gotten any back yet.

RJR, Maybe the best course here would be to post some pics of the particular engine you are working on. That way we might be able to offer specific solutions. It would be more difficult to fabricate a sink as effective as the one included that surrounds both sides of the rectifier. You should be able to either form the support to fit the space or add another piece of alluminum to allow mounting just about anywhere.

Pete

I'm not working on one right now, though there's one behind me and a new board set on my bench to go into it.  I could graft to the existing heatsink, but I have seen them with the heatsink on one side.  I doubt there's a huge difference.

Norton, I have none I'm working on right now.  Last one that failed, I took a 5-volt board from a diesel and dropped it in, and then upgraded the diesel with a 3-volt 5to3 kit.  But I have 3 such 5-volt steamers, so it's a matter of time.  It may be that a PS3 upgrade kit, if it has the 2-board system as used in new PS3 steamers, will provide an easier way out.

The heatsink that comes with a 3-volt board will not fit into a loco that carries a 5-volt board, due to a different relative location for the rectifier on the 2 boards.

I do await comments or my idea of a remote rectifier.

I never tried removing the rectifier, but there's no technical reason that wouldn't work.  Since the rectifier is the component that gets hottest under load, using a higher capacity one with a good heatsink would probably be a bonus. 

Interesting thought, and I can't see anything wrong with the idea.  Use pretty heavy wire between the rectifier and the board, probably #16 or maybe #18...

MTH has a PS board just like that RJR.  They use wire between the board and rectifier.  Used in some 1 gauge applications. 

I repurpose the original 5V heat sink all the time.  Single side works fine.   G

Thanks for the info.

If I am real lucky, I wont have to tackle such a task.  If........

You're right George, that's where I've seen it.  The 1 gauge locomotives sometimes have the a really large rectifier bolted to the chassis.  I haven't seen one recently, but I've worked on several that indeed did have that.  Memory fades quicker as you age.

Lionel also uses a "tethered bridge" on some of its Odyssey motor driver boards (DCDS).

Pete

It'll be interesting to see what's in that PS/3 upgrade kit.  I view the transition to PS/3 upgrades with a bit of trepidation as there's not much you can fix in the field on the PS/3 boards.  Usually, when they're dead, they're dead.