SC-1 Repair

Can't answer that. Have 2 SC-1's with problems. I channel on each of them will throw a turnout one way but not back. Maybe the same part has failed.

I noticed that I failed to include the part number. It's the Motorola MAC97A6 that seems to be the most logical part. I'll know soon, I ordered some of them from Digikey, I'll replace the two in the first channel. If so, they're only 39 cents in quantity 10, so it'll be an inexpensive fix.

I can report that at least for mine, replacing the two Motorola MAC97A6 associated with the failing channel solved my problem, SC-1 works just as good as new now. I'll keep the rest of the spares around for when these fragile things bite the dust again.

For a single failed one in a channel, it's easy to follow the trace to the connection, so you'd only have to replace the one that seems to have failed.

Wow sounds good I'll check it out. Thank you.

John could that part # be MAC97A6G or MAC97A6,412.

The Digikey # that I actually used from the invoice is 568-3744-ND 568-3744-ND, it's the same as the Motorola part. I bought 10 of them, might as well have spares.

Alright just ordered 10. Thanks again !

Hope it works for you, I'm using that SC-1 on a pair of switches now on a test layout, figured I'd give it a "burn-in" test.

The Motorola parts did the trick on my bad SC-1. Have one more to do. Wow thank you!

That TRIAC is a .8A Triac also used on the lighting and coupler control outputs of the LCRX, LCRU 1 and 2 and R2LC. Small round can like component. It use to control smoke output also, but Lionel moved to a 2 amp TRIAC that looks like a Voltage Regulator chip or power transistor.

I need one for a LCRX repair, waiting until I have a more full component list before I order. G

quote:

Originally posted by Gweedo:
The Motorola parts did the trick on my bad SC-1. Have one more to do. Wow thank you!

Yep, when I looked at the SC-1 board, it seemed to be the only one that made sense to have failed, the other passive components are much less likely to fail.

I'm glad they use readily available components at least in some of the circuits, makes it easier to keep them running.

quote:

Originally posted by GGG:
That TRIAC is a .8A Triac also used on the lighting and coupler control outputs of the LCRX, LCRU 1 and 2 and R2LC. Small round can like component. It use to control smoke output also, but Lionel moved to a 2 amp TRIAC that looks like a Voltage Regulator chip or power transistor.

I need one for a LCRX repair, waiting until I have a more full component list before I order. G

The one we're using is in a TO-92 plastic package.

Yep, as I said they moved to a higher amperage for the R2LC channel that controls smoke. The others remained MAC97. A4 is 400 volts, and the A6 was a 600 Volt. Actually they are .6 Amp rated though I thought I saw a manufacturer that had .8 amp rated ones. Any momentary short will fry them. I have had them short closed (constantly on) and short open. All depends how long the short remains. Smoked one once testing and it was quite a show G

I figured they were pretty touchy when I saw they were directly wired to the outside world. That's why I have spares.

The SC-1's were cheap enough, and they'll be good enough to control some switches. I also have a few SC-2's that seem considerably more robust.

Dump the those cheep SC-1's and go SC-2's with true relay control and higher ampacity for better power management. You are fighting yourselves trying to maintain the SC-1's when a better solution exists.

quote:

Originally posted by Jim Battaglia:
Dump the those cheep SC-1's and go SC-2's with true relay control and higher ampacity for better power management. You are fighting yourselves trying to maintain the SC-1's when a better solution exists.

I have both, but I see no reason to dump the SC-1's, they work perfectly well for switches if you don't short the outputs. I bought my SC-1's on eBay for $15 or less, the SC-2 is just a bit more.

I am just reading these posts and recently purchased two sc-1's. Hind sight being 20/20, I should have invested in the sc-2. That being said and it seems I have some channels that do not work, I have ordered some of the triacs. Am I correct in "assuming" that switches in the previous posts are Fastrack remotes?

It appears that the leakage currents through the SC-1's affect Fastrack switches and make them chatter. I've used the SC-1's for 022 switches and 1022 switches with no problems.

quote:

Originally posted by gunrunnerjohn:
It appears that the leakage currents through the SC-1's affect Fastrack switches and make them chatter. I've used the SC-1's for 022 switches and 1022 switches with no problems.

Thanks for the explanation. I did not know what caused the chatter, but my Fastrack switches chattered terribly. I changed to SC-2s and all is good. Remember on SC-2s to skip the first position or cut the trace. I just skipped for now.

quote:

Originally posted by gunrunnerjohn:
It appears that the leakage currents through the SC-1's affect Fastrack switches and make them chatter. I've used the SC-1's for 022 switches and 1022 switches with no problems.

I never opened mine up, but I wonder if there is a way to put a cap or some kind of gate to stop the leakage on the circuits.....

I haven't played with the SC-1, but the first thing that comes to my mind is a resistor connected across the terminals to provide a good drain for any leakage or current through capacitors - just like adding a light bulb to a CW-80 output.

You aren't trying to use Channel 1 and running into that problem, are you?

I was considering digging out an SC-1 and connecting it to a Fastrack switch to see what is happening. I'm not sure more leakage current is the answer, I'm guessing the Fastrack switches don't take much current to trigger, since you're just switching a gate on the logic board. I'm thinking maybe a resistor in series to lower the current, but that's just a SWAG without any real input.

I wasn't clear. I was thinking of adding resistors from the SC-1 outputs to ground (switch Common) so that the SC-1 would need to provide a bit more current, and there would be a shunt path at the switch terminals to drain off any leakage current.

Good idea Dale, that may be an even better idea. I think the current just needs a place to go.

Gunrunnerjoh

I know this is a old post. I should have researched SC-1 before hand but, didn't. I'm getting ready to take down my medium size layout and start all over. This one will be TMCC and Legacy. I was at a train show over in St. Louis this past weekend and seen 5 new SC-1's for 10.00 each so I bought all 5. In my case with a new layout would you even fool with them of just go with the SC-2. Your information is appreciated.

Larry

Well Larry you're getting 5 sc-1's for about the price of 1 sc-2. The fix as shown above works, I've done it. But the sc-2 does work a lot better, so it's really up to you and your budget!

If the SC-1 works, and you already have them in hand, why not use them.  The worst that can happen is you're not happy and you decide to upgrade to some SC-2's.

Thanks for the information guys. I have more than 20 FasTrack remotes in this old layout and probable will need a few more in the new one. I'll see how these work when I get that far. I'll compare them with a SC-2 before I trash them.

Larry

SC-1's have fairly limited current carrying capability on the individual terminals.  I think the sum of all the SC-1's terminals equals the capacity of a single channel on an SC-2 or ASC controller.  

 

If you don't push them, they work fine.  There are some connections that you can use and SC-2 or ASC for that you should never try with an SC-1 (e.g. block control).

John,

 

  I have two SC-1s I need to repair, can you tell me how you did it.

 

Thanks,

Art

Thanks John, Digikey order on way, will let you know how I make out with repair.

 

Art