Atlas Nscale signals: Has anyone here tried to fix one?

[drgw0579]

I really like the Atlas type "G" signals, they are perfect for a line modeled after the Reading.

But, I have 2 that for whatever reason aren't working.  One has just  a red indication.  The other has green and yellow, not red.   As far as I can tell, its not the wiring outside the pole or head.  Since these aren't exactly cheap, I am thinking of trying to open one up and if there is a bad LED, try to replace it.  Or maybe its a broken wire.  I've had these long enough that they are not under warranty.  I am pretty sure they worked when I first got them, but they've been moved around several times.  I am pretty sure the failure was caused by me.

But before I do, I have to ask, has anyone here tried this?  I am wondering if you can get the head open without damaging it.

Bill Kepner

[LarryN]

Hello,
Well, I never had to try and fix one, but I just inspected one that is not yet installed to see what i could see. With the negative terminal of my multimeter on the black signal connector wire, and the red on the other three alternately and with the meter on the low ohm scale, each of the LED'ss in turn should read between 1.7 to almost 1.9 v with the probes wired as I said. In reverse, no voltage drop, no lights. (at least with the scale setting on my meter, a Fluke 189 on the diode test setting). They also light up. So check them first at the connector. No light, could mean broke wire, solder joint or dead LED.
Next, the thin heat shrink tube on the mast to signal head can be tugged on to pull up the magnet wire from the base. If one of the wires will not pull though, it is broke in the mast.
Lastly, on the back side of the signal head is a square plastic plate that can be pried off with care. this reveals a small square PC boarded that has the LED's on it. Check it for breaks, then check to see if the LEDs light or show the voltage drop. The common lead on the PC board is the middle one on the top. The LEDS's appear to be encapsulated in a epoxy, so I do not think they can be individually removed and replaced if it comes down to that.
Good Luck!!!
Larry N

[peteski]

Hello,
Well, I never had to try and fix one, but I just inspected one that is not yet installed to see what i could see. With the negative terminal of my multimeter on the black signal connector wire, and the red on the other three alternately and with the meter on the low ohm scale, each of the LED'ss in turn should read between 1.7 to almost 1.9 v with the probes wired as I said. In reverse, no voltage drop, no lights. (at least with the scale setting on my meter, a Fluke 189 on the diode test setting). They also light up. So check them first at the connector. No light, could mean broke wire, solder joint or dead LED.

What you describe sounds correct for LED behavior, but how are you measuring voltage when the meter is on low ohm scale?
I have 4 multimeter and neither of them provides voltage high enough (on any of the ohm or diode test ranges) to light up LEDs. The Fluke 189 must use a higher voltages for those ranges.  I'm just mentioning all that in case somebody else uses meters similar to mine - they might not see the same readings you do.

EDIT: I just looked it up - Fluke 189 is a fancy (professional) multimeter. It probably shows you the voltage and resistance at the same time?  Most modelers use a low-end $20 multimeters. 

[alhoop]

What you describe sounds correct for LED behavior, but how are you measuring voltage when the meter is on low ohm scale?
I have 4 multimeter and neither of them provides voltage high enough (on any of the ohm or diode test ranges) to light up LEDs. 

Peteski:
I have an 1970's  cheap Midland multimeter (the one with a diagonal face) with a 1 1/2  volt battery in the ohms circuit and it will light some red LEDs although somewhat dimly on the Rx10 scale.
https://www.ebay.com/itm/Vintage-Midland-23-101-Portable-Multimeter-In-Original-Case-Manual/192410022958?epid=1200250686&hash=item2ccc87f42e:g:st8AAOSw8-tWZNvO
Al

[peteski]

Peteski:
I have an 1970's  cheap Midland multimeter (the one with a diagonal face) with a 1 1/2  volt battery in the ohms circuit and it will light some red LEDs although somewhat dimly on the Rx10 scale.
Al

Exactly. Some red LEDs will emit some light at 1.5V, but most yellow and green LEDs need more than 1.5V to even emit a faint glow. Then the "true green", blue and white LEDs will not light up on 1.5V. Those need more than 2.5V to start emitting light.

[LarryN]

All,
Yes I have a "fancy pants" Fluke, as well as some older meter.Remember Lafayette Electronics?! Still have my 99-50734 moving coil meter I bought new in the '70's, although it has suffered the indignities of being dropped and having one resistor burned up. I laid out $$$ for my Fluke as I actually test real railroad crossing protection system for the tourist railroad I volunteer at, and this was the meter they recommended -had to show True RMS AC+DC.
The diode test feature will put enough current through to activate the LED, but not to full brilliance. It will also display to forward voltage drop.

Larry N

[MK]

Lafayette Electronics???  Man, a walk down memory lane!  I used to walk to one when I was a kid living in lower Manhattan.  Those were the good ol' days with all the electronics stores on Canal St.  But I'm digressing... 

[LarryN]

Lafayette Electronics???  Man, a walk down memory lane!  I used to walk to one when I was a kid living in lower Manhattan.  Those were the good ol' days with all the electronics stores on Canal St.  But I'm digressing... 

Boy, I hear you! Canal st. had some cool shops. And one could find hobby electronics everywhere: Gem Electronics, Lafayette, Olson, Radio Shack and private companies. Sigh. Those days are gone. It was easy to get parts for model RR building from them too-diodes, switches wire. "Electronics stores" today just have Cat5 and USB cables.
Larry N

[MK]

Amen Larry!  My favorites were Trans Am Electornics (I know the owner) near the Holland tunnel entrance and Ramco.  There was also City Dump but their electronics were surplus so spotty at times and not main stream.

Alas, now all the stores are selling cheap Chinese knock offs and trinkets.  Sad!

[peteski]

All,
Yes I have a "fancy pants" Fluke, as well as some older meter.Remember Lafayette Electronics?! Still have my 99-50734 moving coil meter I bought new in the '70's, although it has suffered the indignities of being dropped and having one resistor burned up. I laid out $$$ for my Fluke as I actually test real railroad crossing protection system for the tourist railroad I volunteer at, and this was the meter they recommended -had to show True RMS AC+DC.
The diode test feature will put enough current through to activate the LED, but not to full brilliance. It will also display to forward voltage drop.

Larry N

That is a nice meter - I'm jealous!   
I do remember the Lafayette Electronics name, but locally I had (and still have) U-do-It Electronics store.  Back then, local Radio Shack stores also had lots of electronic parts and hobbyist-cookbooks to keep my electronics hobby going.  I also used to mail order from Jameco Electronics, Channey Electronics, All Electronics among others.

[drgw0579]

Larry N:  Thanks for reminding me about the shrink tube to the signal head.  I tugged on it, and found that one of the wires is broken. Mystery solved!   And my VOM is a HP E2372A which I've had for over 20 years.  It was a lowend model that HP sold to compete with Fluke.   It didn't sell and I picked it up when they sold them to employees at a very good price.

Bill Kepner

[LarryN]

Bill,
I hope repairing that break will solve the problem...not fun to slder such tnin wire!

Larry N

[LarryN]

That is a nice meter - I'm jealous!   
I do remember the Lafayette Electronics name, but locally I had (and still have) U-do-It Electronics store.  Back then, local Radio Shack stores also had lots of electronic parts and hobbyist-cookbooks to keep my electronics hobby going.  I also used to mail order from Jameco Electronics, Channey Electronics, All Electronics among others.

Peteski,
I've ordered from all those folks too ("Electronics Goldmine"=Chaney). If you have not checked them out M.P. Jones and Assoc. in Florida has some good stuff too. Do you remember PolyPaks? They were in the Boston area IIRC. I ordered stuff from them back in the 70's. I recently got a few old cell phone camera from Electronics Goldmine..wondering how to get them to fit into a loco...

Larry N

[peteski]

Peteski,
I've ordered from all those folks too ("Electronics Goldmine"=Chaney). If you have not checked them out M.P. Jones and Assoc. in Florida has some good stuff too. Do you remember PolyPaks? They were in the Boston area IIRC. I ordered stuff from them back in the 70's. I recently got a few old cell phone camera from Electronics Goldmine..wondering how to get them to fit into a loco...

Larry N

I sure do remember PolyPacks.  If I don't have them confused with another company, I used to visit their store (in Wakefield?).

I also got those cell phone cameras, but with what it would take to make them operational (they are just the image senor), it wouldn't be worth the trouble, especially since you can get pen-size cameras on eBay with integrated video recorder for really short money. If you want a live video feed, it is more expensive, but that system is also available (or was about 3 years ago).