PS-2 Board Repair part inquiry

51 cents at DigiKey

 

Per datasheet:

 

HT244 or HCT244?  I don't find an HC244 either, but the HCT244 is a common 8-circuit non-inverting tri-state buffer.

 

Never mind, I see it's labeled HT244, that seems contra intuitive!

Thanks Guys! I'm on it!

Best,

Joe

Thanks Guys, as I wouldn't have come close to ordering the right part from Digikey, were it not for the "data sheet", and other info! The portion of the data sheet that referred to "top side marking" is a new one to me, and would surely help me with some of the other parts I'm having trouble identifying! How does one access that in a search?

 

While I wait for my HT244, Back to the diagnosis of the top PS2 board..............Now, with the sound and lights back, any suggestions where to check for the "no motor function"??? Here's what happens, and I'm sure you've experienced this, with the "sound" running at idle, then when the "direction" button is pressed, it completely shuts down, then restarts (reboots)............. If it's that block relay, well, that's another part I can't find with a 5 volt coil. I found the exact number, BUT with a 24V coil........

You guys are VERY knowledgeable, and I only hope I can contribute by helping someone in the future, myself!

Best,

Joe

The battery circuit is not function so the processor doesn't have power when you hit the direction button in conventional and track power goes to 0V.  Your on the right trail.  G

If I need one of those relays, I steal them off a dead board.  Let me know if you want one, I'll send you the board.

 

GunrunnerJohn, you're the BEST! Yes, I'd like to tae you up on the offer for the relay. I did find some in Australia, but it was to convoluted to make a purchase. My theory for testing is, I do have a working board set, BUT with a third relay, I'd have a more conclusive result with a static test, as I would rather NOT pull the relay off of the "good board" to try on the one I'm troubleshooting..............

Many thanks!!!!!!!!!!

Joe

Shoot me an email to my profile email with your address.

 

I recommend removing the relay, then doing a bench test of it before installing it.  They're pretty robust, and I've only ever seen one bad one, but it can happen.

 

Joe,  Why are you changing the relay.  I explained why the engine doesn't move or change direction when you have a bad battery circuit.

 

You also need to be careful depending on the equipment you have for desoldering the relay.  You can do more damage to the board trying to replace a component that isn't bad in the first place.  G

You're right, I tried chasing the battery circuit, and I focused on the Fairchild D508, but again I'm in trouble crossing that part. Is it a transistor ? What's the pt. #?
Best
Joe

Did you replace U-10?  Look at R-36 on the opposite side of the board near the battery terminal but between the caps.  G

I will check when I get home, on Fri. My wife and I are currently visiting in NH . Thanks for the guidance !
Best
Joe

Just got in, and checked my notes, the U10, is OK, as I changed it, which actually got me this far. The R36 meters like the "good board". Any chance it could be either the Q8 or Q22, both are identical by pt#, AND, I'm TOTALLY unfamiliar with 8 pin "transitors", and I "assume" with the "Q" designation, they are transistors. I'm going to Google these to see what the bench test proceedure is? These are those Fairchild (F) top labled components, that I can't locate. D508......???

 

Oh, back to the "relay" issue, I may not of emphasized that the board I changed U10 on had sound with a GOOD processor board, NOT the one it was married to, when it was shorted, sooooooooo, couldn't the relay have been fried on the ORIGINAL board?

 

Thanks Guys, now I have to play catch-up around the house, after having a few days of R&R (NOT railroad....[wink!])

Joe

If you PS is REV B those are obsolete Power Trenches.  They had a unique pin out and you won't find them.  I did a last buy for a group with MTH.  MTH went to a Rev E PS that changed the trace layout to use a newer Power Trench.

 

They can go, but it is rare.   G

OK, like with the pinball circuit boards, there are now obsolete components, some of which never die anyway. My PS2 (unk rev.) does have sound WHEN coupled to a "known working bottom board", it reboots, and I'm clear on understanding that it is charging circuit related. If U10 and R36 are working (U10 has been replaced, and R36 is showing roughly 2 -3 ohms of resistance (like the working board), AND Q8 is obsolete...........am I dead in the water with this project??? It's not like I NEEd this board, it's the "thrill of the hunt", the CHALLENGE!!!

Best,

Joe

Does your 8-pin transistor have 2 lines of marking?  Some Fairchild Power Trenches use a marking of FDR....  where the 2nd line of the marking fills in the dots.  If this indeed identifies the part number albeit obsolete, then if the thrill of the hunt is the objective, I suppose you could try to cross the part using component specs (Vds, Id, etc).  Or perhaps the part was also offered in a different package. In either case, if the packaging is different you might be able to tack-in it in with some re-work handi-work as a transistor only has 3 leads.  Obviously with 8-pins these devices may depend on the board as a heat sink so that's a consideration.

 

Stan, I'm going to check as you have suggested, nonetheless, your comment has me thinking a little clearer, as to the amount of legs on a transistor. Now, I can see where there's a possiblity for redundancy, and in realitly, there probably is only what I would expect in a transistor, base, emittor, collector, but somehow grouped?Am I all wet with this assumption?

Best,

Joe

R36 is .3 ohms.  You may have a fixed PS and the processor is bad, have lost track on whether you swapped a different PS on the processor to ensure the Processor work.  G

G, thanks, I basically took 2 "pairs" of PS 2 boards, one working set, and the set I'm troubleshooting, then I mix-matched them. Before replacing U10, the bad pair did NOT work in any combination. NOW the semi-repaired "top board" partially works with the good "bottom" board. However, lacking motors, which I do see clearly to be the charging circuit, but I'm baffled for the fault.

HAPPY FATHER'S DAY to ALL!

Joe

 

hi I'm trying to repair a ps2 board taken out of my 30-4037-1 engine set , i replaced

the bad nine volt battery with a BCR , the engine ran fine, all sounds and everything work,then the 330 mf cap blue paper out of it!is it possib

le the cap i believed shorted, do you think the board might work ounce i replace the capacitor, i have not replaced the cap yet but have the needed part ready. p.s. i also had another board that was dead burt after changing the capacitor the board was still dead. the board im talking about earlier developed a short after the cap self destructed,can anyone help me with either one of these proto 2 boards.also where can i get a schematic of components locations that you all were tslking about earlier, schematic  diagram and component location!

thanks for anyone's help

Alan

'

Your talking older PS-2 5V and some versions seem to fail quickly, while other last fine.  You can try replacing cap, may get lucky, but I think that is a 1 in a 100 shot.  Normally some other component is bad, and the 5V boards are one piece and you can't get them apart with out special equipment.  Usually the heat to separate the header damages components near the header.  All those small SMD fall off  G

George, I've tried to take about 10 of them apart with my hot air rework station and a kludged nozzle for the connector.  I was successful with 1 out of 10 and I decided the work necessary to separate them was simply not worth it.  You either have to go from the top and remove a couple of components in the way or go from the bottom and remove the heatsinks from the drivers.

I agree.  Not worth it, until the year 2120 when no electronic for our trains exist

Well, in 2120 it'll be someone else's problem!  I doubt health care will be advanced enough for me to make it that far.

 

 

 

can you tell me whats involved to replace the ps 2 board with a 3 volt one, i purchased one from a mth repairman that i found new old stock and he loaded the sound file i needed for a bantam 6-8-6 steam turbine,which is the one the board cap blew out. the connectors look identical to the 5 volt board yellow and white motor connect to motor and the other connectors look the same, i just don't want to install the good board and take a Chance on blowing the board!

sincerely thanks for anyone that can help.

Alan the board says rev E

 

 

 

 

 

 

 

The connector pins and the number of pins are the same, however the connector shells are not compatible.

 

If you have a 3V PS/2 board, the first operation is to take all the connector shells off the old 5V PS/2 board.  I use a little heat to make the job easier and gently work them off.  Then do the same to the 3V PS/2 board and replace them with the ones from the 5V board.  However, do NOT replace the 2-pin battery connector on the new board set as you'll be using a 3V battery and not the 9V one from the old boards.

 

You'll need a new 4 ohm speaker, a new charging port, and of course, the new battery pack.

 

Of course, first you verify that ALL the wiring is good and there are not shorts to ground or between wires.

Your also going to have to get inventive with installing the new board inside the bantam.  You do need the black PS-2 bracket.  I have on occasion used the original 5V heat sink to mount the PS-2 3V upside down, but it varies depending on heat sink and engine.  You also may have to lengthen some wires as the 5V had a slightly different position inside the engine.  You don't necessarily need a charge port, but you do need a 2 pin molex to connect to the new 2.4V battery in place of the 9V battery terminal.  Watch polarity at the plug.  Early bantam engines did not have charge ports.  G

hi may i use the same 5 volt hookup harness and just change the 5  volt regulator LM-2937et to a 3 volt regulator and then plug the connectors back on the 3 volt board , then only have to replace the 8 ohm speaker with a 4 ohm speaker. i had the 3volt board programed with the correct sound file for the 6-8-6 turbine when i purchased it!

Thanks guys for all your help and knowledge!

the capacitor that shorted on the old board was C 29 330 mf 35 volt!

NO need for the regulator.  You remove the 5V board and regulator.  The remaining connectors from the 5V board: 7, 4, 5, 12, 2 plug into the 3V board once you change the white header connectors.  In the tender the battery plug goes to a 2 pin molex and the speaker and battery are changed.  16 ohm to 4 ohm and 8.4V to 2.4V battery.  G

That capacitor is the primary cause of about half the 30 or so boards I have in my junkbox, and it takes out some diodes between the sandwich of boards.  Since it's close to impossible to get in there, that renders the board set useless.

 

What came first the chicken or the egg?  I think there is another FET that goes.  Been hard to pin point, but I have boards that will fire up with that cap swollen or where the rubber plug will push up, and other that are toast and that cap is fine.  Even on the swollen ones the CAP doesn't present a short.

 

One thing for sure, when that cap is swollen or blown the board has issues.  G

If the cap doesn't short, I suspect the board can run, I have a couple that I saw evidence of swelling and I replaced the cap.  One failed in about a month anyway, but the other one is still going six months later.

 

I'm sure there are other causes, but I maintain my belief that the cap is a significant cause of some of the 5V board failures.  I did a check of the dead boards I had with that cap swollen, and every one have the same brand cap.  I have some other boards with a different brand cap, and none of them show evidence of failure.  Many with the swollen cap have the same diode visible between the sandwich also cooked.

 

hi gunrunnerjohn, that's for the info. This is the same exact problem on my
other engine only the is swollen and i replace the cap, but the board is
still dead no apparent short, do you have any ideas about this board that is
dead? can you put a picture on the forum or my email _amustng@aol.com_
(mailto:amustng@aol.com) and point out exactly where this diode is that you
were talking about on the first board is located .I'm hoping I can fix one
of the to boards!
a picture would help with pointers pen marks toward the diode location.

Sincerely thank for anything you can do to help!
thanks again alan

In a message dated 12/22/2014 10:45:40 A.M. Eastern Standard Time,
alerts@hoop.la writes:

Trust me in that is not the only failure mode.  I have a box full twice over and while initially it looked like that would be an easy fix turns out there are many other methods of failure.

 

Those 2 diodes are on the smaller board side in the middle. They produce PV for the circuitry.  There are PV failures, 5VDC failures, other factors.

 

I have yet to save a 5V board with just a cap, though I have read one case here on the forum, and I have saved one with the PV diode short.  The rest have been fixing audio amps and light circuit issues.  I have probably logged over 200 attempts on 5V boards. 

 

You can see the 2 diodes next to each other in the first photo.  They take AC in and half rectify for +DC Voltage.  This was a board I was able to remove the PS intact since the solder joint was so weak.  The processor side was bad.  This power Supply actually works.  YOu can also see the cap is starting to swell.  Despite that, the processor side was dead, and this top half still works.  G

I only have one 5V board save, other than the lighting and coupler circuits where the parts are readily accessible.  I managed to fix one of those internal diodes by prying the boards apart enough to get the iron in and replace it.  However, a few other attempts makes me believe it's not worth it to try to fix them.

 

There are no diagrams, even for MTH techs.  Those appear to be a closely guarded secret.