Proto Sound 2 5v board repairs

@gunrunnerjohn posted:

I have to smile here, I have a whole box of dead 5V boards, and I have no desire to work on them.  Paul, you can have them for the cost of shipping!

So did the box of dead 5V boards change hands?

If sitting on a pile of dead 5V boards with goal of fixing several/many,

1) I'd want to know if you can you power up JUST the smaller power supply board and reach some confidence level that it is working?  You'd think you could at minimum confirm a few different voltages.

2) Then, I'd think some kind of test fixture or test connector/harness would be handy that can mate the two boards with more separation than the final connectors.  In other words, something where you can probe/measure voltages on both sides of BOTH boards mated and powered.  This might entail some effort to make a clamp or whatever with spring-loaded "pogo" pins or the like.

@stan2004 posted:

So did the box of dead 5V boards change hands?

They're out of my hands, Paul has them now.

I found it real interesting that MTH had a pile of the power supply boards, those are likely the ones that need replacing most often.  What a shame they pitched them.

OTOH, perhaps this means the glass is half-full.

I'd be more concerned if there was a box of dead logic boards...because those have got to be harder to repair given the combination of obsolete and/or custom digital chips that would be impossible to troubleshoot with "just" a meter and difficult to physically replace.

As per my earlier premise, MTH would be the other end of the "business" perspective.  I figure their "burdened" labor rate would be higher than you or GGG or the other usual suspects.  What would be interesting to see is the procedure/process by which those power supply boards ended up in the box.  I figure somewhere in there is a check to see if a Wincap (or whatever that cap was called) is installed...and if so replace.  For all we know, there might be another 1 minute test such as a particular diode that changing would solve some percentage of failures.  Etc..

So as a "business" proposition, there must have been a line-in-the-sand where MTH told their techs to spend no more than X minutes on a board then just toss it in the box.  We know the replacement parts cost of the diodes or capacitors is essentially negligible.  So it was all about time equals money.  From a "hobby" perspective time does not equal money.  That's what makes Paul's quest interesting.  I now step down from the soap box...

Addendum: I stumbled across this OGR thread where @tansqrx reports 20-30% success rate with PS2-5V board repair.  That's a very encouraging batting average!  He also posted a detailed troubleshooting checklist.

It will be interesting to see what he finds.  If he uncovers a common failure, it may actually be possible to bring some of these back to life.  I'm not worried about supply, I've already started restocking my dead 5V board box.

They are the PV diodes and rated at 1 amp and probably susceptible to age failure.  Make the DC for the various  other Power Supplies on the board.

Way back I saved a few with getting out the one bad diode, but a real pain and not always successful.  I also (once) separate boards and then reattached via jumper wires just to test, and it was not successful.

Under the rectifier you will find a rev code for the boards, you might want to work on the K, they were the last and best board.  G

Wanted to share with you something I learned. PS2 5volt board. Engine is programmed into DCS. Train starts and runs no problem but after some time running you cannot control it with your DCS or it moves to inactive. You then kill the power to the track and then power up again and engine is back in active again and starts and works for some time and then you have response loss again or engine is inactive in remote. I found that changinging the radio pickups seems to help. if you have an old failed board you can remove from old board and install in the board your having issues with. I was able to swap out while board is still in the engine by installing a wedge between both board which held the bottom board up so i could unsolder and remove the frequency filter and replace with others.

How many of them have you been able to revive?

I wonder if it would be easier to cut the header to separate the boards, then use a cable to reconnect them after replacing any damaged pins.

John, I was able to get 3 repaired so far. I have about 8 I haven't looked at yet. I've had some failures on some as well. It is a great learning experience.

I have three remaining PS2 5 volt board engines - two diesels and one subway (my beloved R36 Worlds fair).  All of my other PS2 5 volt trains have died and were upgraded to PS2 3 volts or PS3,  a number with flaking speakers and others for no apparent reason.  However, these three just keep on going, one is 20 years old and the other two are from 2002/2003.  I have no ability to change capacitors or anything else on the board, I just make sure to run them at under 16 volts (to not over tax them). Is there anything else you guys would do or should i just have my dealer upgrade them now before the inevitable failure? Or is that true - is it inevitable that these will fail before the ps2 3 volt boards?

@Paul Lytle posted:

John, I was able to get 3 repaired so far. I have about 8 I haven't looked at yet. I've had some failures on some as well. It is a great learning experience.

That's good, what is your average time to repair one of the boards?

@Strap Hanger posted:

I just make sure to run them at under 16 volts (to not over tax them). Is there anything else you guys would do or should i just have my dealer upgrade them now before the inevitable failure? Or is that true - is it inevitable that these will fail before the ps2 3 volt boards?

Nothing is inevitable, the 5V boards may outlive you.  While it's true that they are more prone to failure than 3V boards, there's no certainty that a specific 5V board will fail, some may last another 20 years.  I just run them until something goes wrong.  I do inspect them and replace any suspect caps that I can reach.

Thanks for the response, Gunrunner. Your perspective is good to hear.  If only these boards were as easy for a layman like myself to tinker with like the firing pin i just replaced on my Uberti replica.

@gunrunnerjohn posted:

Nothing is inevitable, the 5V boards may outlive you.  While it's true that they are more prone to failure than 3V boards, there's no certainty that a specific 5V board will fail, some may last another 20 years.  I just run them until something goes wrong.  I do inspect them and replace any suspect caps that I can reach.

The ones I've seen fail (and it's usually a blown cap) were made in 2000-2001. The 2002-2003 5V boards seem to not suffer from that as much, although it's really random chance. I've seen more RK steam and diesel failures with PS2 5V than Premier steam as well (except the Premier FEFs, which fail frequently). I can't say why.

All my stuff is either PS2 3V, PS32 boards (things I've upgraded) or PS3. The oldest PS2 3V locomotives I have are about 17 years old and are running fine.

I know this is a bit off topic, but is there a database of MTH engines that were supplied with the 5 volt vs the 3 volt PS2 boards?

@Lou1985 posted:

The ones I've seen fail (and it's usually a blown cap) were made in 2000-2001. The 2002-2003 5V boards seem to not suffer from that as much, although it's really random chance.

This makes some sense, as computer motherboards from around that time are notorious for leaking capacitors and fail at a higher rate.  The story I heard is there were some less than reliable manufacturers that dumped loads of them in the Asian markets around that time.  I’ve had two fail (years ago now) and a couple of monitors from that time frame.  Meanwhile stuff before and after work fine.  

I also have a set of high end speakers made in 2000 or 2001 that have built in subwoofers.  The subwoofer quit working in one and the other started sounding like a motorboat.  Both had bulging power supply capacitors, replaced with some Nichicon ones and they’re as good as new.

Maybe that was the Y2K bug they were talking about?

Surely most people involved in electronics heard about the Capacitor Plague of the early 2000's.  They were popping like firecrackers in computers!

@DaveGG posted:

I know this is a bit off topic, but is there a database of MTH engines that were supplied with the 5 volt vs the 3 volt PS2 boards?

If there is Id love to know too.  What I usually do is download the sound file from their website and try to load it into the DCS app.  It usually tells you.

@Paul Lytle posted:

... I found that changing the radio pickups seems to help. if you have an old failed board you can remove from old board and install in the board your having issues with. I was able to swap out while board is still in the engine by installing a wedge between both board which held the bottom board up so i could unsolder and remove the frequency filter and replace with others.

I am impressed that you discovered this "failure mode."

The two items you circled are crystals.  And if I understand what you're saying this could be a temperature phenomenon since the frequency of a crystal oscillator drifts with temperature in a somewhat defined/predictable manner.  We're talking in the parts-per-million category but it's a temperature dependency nonetheless.  That's why it might work for a while until the circuit board warms up and the frequency of the crystal drifts enough to cause a problem.  In fact, if you run across another board set that behaves as your describe, then take a can of compressed air, or can of component cooler, and give a blast right to the crystal.  If all of a sudden you restore DCS communications, then you know you're on to something.

In my career as a electronic technician I have seen older capacitors fail where the capacitor exploded and the foil unwrapped like an exploding firecracker and was about 6 inches long inside a radio or TV set. !

Alan

@Alan Mancus posted:

In my career as a electronic technician I have seen older capacitors fail where the capacitor exploded and the foil unwrapped like an exploding firecracker and was about 6 inches long inside a radio or TV set.