Another Unknown Board!

That one is REALLY unknown, and I have no idea what it might be.  Of course, that's because all I see is this...

Try below, John - in the meantime, I spoke with the original owner and he said he bought the board at a train show many years ago, and the lad who sold it to him said it was "homemade", so I'm not wasting too much time looking for a schematic! It would be nice to know if someone else bought the same board and what kind of luck they have had with it - thank goodness it was pretty much a throw-in!

I did a VERY quick test and found that the board seemed to fire up in conventional with no TMCC signal present (as it should) and that reverse was ok, neutral was ok, but forward was pretty intermittent - triacs ohmed out ok, but could still be the problem I suppose.

Can you see the pics now?

George

If it runs in reverse and has an issue in forward, I'd suspect the triacs first.  The fact that they used triacs that I never saw on a Lionel product makes me think it's someone else making them.  OTOH, they have all the standard Lionel TMCC parts for the receiver and it looks quite professional as far as the PCB layout and build. It's also all thru-hole, so that leans to the home brew idea.  OTOH, it was wave soldered, not hand soldered, so whoever made them did a number of them.

I guess there's no part numbers or the like on it, right?

@gunrunnerjohn posted:

If it runs in reverse and has an issue in forward, I'd suspect the triacs first.  The fact that they used triacs that I never saw on a Lionel product makes me think it's someone else making them.  OTOH, they have all the standard Lionel TMCC parts for the receiver and it looks quite professional as far as the PCB layout and build. It's also all thru-hole, so that leans to the home brew idea.  OTOH, it was wave soldered, not hand soldered, so whoever made them did a number of them.

I guess there's no part numbers or the like on it, right?

Correct, no part numbers to be found. It's now officially on my list of things to look at later, when I get a few other things off my workbench! 

George

OK, I just can't put things down sometimes! I wired it back up to the same motor it came on, only now the motor had a fresh service. I programmed it as ENG 1. It does everything a TMCC board should do, however... the motor surges, bucks, and behaves as if there's an intermittent connection, or even voltage spikes - it makes the motor sound like the gears are catching/binding, etc., but they aren't. This occurs at mid speeds and smooths out with higher speeds. At startup speeds, the speed regulation is ridiculously bad, going from 30-60 in a heartbeat, then back down again, then up - all on it's own. I did change out the brush caps with brand new ones - no change. The same board runs the motor nice and smooth in conventional mode. "Bout done with this one , I have a 3 pos e-unit waiting in the wings. 

Glutton for punishment.

I don't believe it is Lionel. Aristo-Craft G gauge train engineer?

Chuck, it clearly has a Lionel design TMCC receiver, that's why I think it has to be TMCC.  I also don't believe it's Lionel, I've certainly never seen one before.

I've never seen any TMCC receiver with that big 90's era socketed IC chip.

Chuck, he's already stated that it responds to TMCC commands.  In the front, the tuneable can and the black filter are right off the RxLC boards.  Behind that is the MC3361 Narrow Band FM demodulator, an early version of the ML3372 used on current TMCC products.  It's pretty clearly a TMCC device in operation and components.

You're right about the large IC chip, I've never seen that before either.  I imagine that's either a large footprint PIC chip or one that was used to replace the PIC.  It would be very interesting to find out what's under that label.

@gunrunnerjohn posted:

Chuck, he's already stated that it responds to TMCC commands.  In the front, the tuneable can and the black filter are right off the RxLC boards.  Behind that is the MC3361 Narrow Band FM demodulator, an early version of the ML3372 used on current TMCC products.  It's pretty clearly a TMCC device in operation and components.

You're right about the large IC chip, I've never seen that before either.  I imagine that's either a large footprint PIC chip or one that was used to replace the PIC.  It would be very interesting to find out what's under that label.

Give that man a cheroot! Here is the data sheet for the MC68HC705P9 microcontroller.

I did hook up another motor this morning just to make sure that there wasn't any sort of compatibility issue - exactly the same result - intermittent spikes of what I'm guessing must be full 18vac

Wow,the old 68HC11 family!  I actually used to use that exact MC68HC705 chip in the UV erasable version in the 1980, that's a real antique!  What you have is the OTP plastic version.  I actually hand built the programmer I used for programming that part.  What a blast from the past!

OK, down a different path, maybe an accessory motor controller. Gantry crane controller? That looks large for a locomotive mount.

You know, you are probably right Chuck, it is pretty large to stick in a locomotive.  It would also explain why it doesn't run the locomotive motor all that well.

Well, you're certainly right about the size, the interior of the 219 was "redecorated" to accommodate this board 

John, how does that, "...explain why it won't run the locomotive motor all that well?"

@GeoPeg posted:

John, how does that, "...explain why it won't run the locomotive motor all that well?"

It may be used to drive a crane magnet or such.  I really can't say, just that accessory drivers don't necessarily need the same outputs as locomotives.

@gunrunnerjohn posted:

It may be used to drive a crane magnet or such.  I really can't say, just that accessory drivers don't necessarily need the same outputs as locomotives. Biggest e-unit I have ever seen!

Gotcha! I will be relegating it to the Conventional only mode by the end of today!