Welcome to the forum   
Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Share
Options
View
Go to last post in this topic Go to first unread post in this topic
Offline gritz_1  
#1 Posted : 21 February 2020 19:53:29(UTC)
gritz_1

United States   
Joined: 11/11/2012(UTC)
Posts: 6
I am fighting a (probably losing) battle with signal lights.
I purchased, in my ignorance and excitement to stock up for a layout, many Marklin 8939s signals and others, all using incandescent lights.
I also invested in a complete Digitrax system, betting on the SE8C (signal board) to do all the signal work.
My problem - reality has now shown the Digitrax SE8C will ONLY work with LEDs.
Their LED masts are...ugly...and ungracefully mounted...and then need to be customized to look like something in a train yard...and they are not Z gauge!
Are there small (Z scale) pre-wired LEDs that I could use to try to change over a signal and replace the incandescents?
I see a lot of crying and wasted energy in my future, but at $35+ each for "new" LED signals (and I have 11 old ones), I figure I can waste a few hours trying.
I would appreciate any information as to size, specifications and buying source(s) of the LEDs anyone may have, as well as ANY experience/pictures someone may have simply repairing (or attempting to repair...) an 8939 or other signal.
Please post any pictures if you have those.
I understand this sounds like a dumb battle, but I'm looking for an oaf answer (me trying to replace bulbs) or a nerd answer, someone who says "..Just take an ABC1-KL circuit board, wire it to an Arduino this way and Bob's your uncle!"
GregConfused
Offline Poor Skeleton  
#2 Posted : 23 February 2020 17:28:02(UTC)
Poor Skeleton

United Kingdom   
Joined: 09/10/2015(UTC)
Posts: 200
Location: England, Cambridge
Originally Posted by: gritz_1 Go to Quoted Post
I purchased, in my ignorance and excitement to stock up for a layout, many Marklin 8939s signals and others, all using incandescent lights.
I also invested in a complete Digitrax system, betting on the SE8C (signal board) to do all the signal work.
My problem - reality has now shown the Digitrax SE8C will ONLY work with LEDs.

I would appreciate any information as to size, specifications and buying source(s) of the LEDs anyone may have, as well as ANY experience/pictures someone may have simply repairing (or attempting to repair...) an 8939 or other signal.
Please post any pictures if you have those.
I understand this sounds like a dumb battle, but I'm looking for an oaf answer (me trying to replace bulbs) or a nerd answer, someone who says "..Just take an ABC1-KL circuit board, wire it to an Arduino this way and Bob's your uncle!"
GregConfused


Hi Greg,

Having had a quick look at the SE8C manual, it seems that the problem is the limited output voltage from the unit. It looks like it can drive a maximum of 5V and whilst this might light up the signals a bit if you were to short out the current limiting resistors it probably won't be bright enough for your needs.

I've not been able to find a manual for the signals themselves, but I gather they use the same bulb inserts as the older locomotives, so this does open a few possibilities for you.

1) Replace the bulb inserts with modern LED replacements. Here in the UK, CKLED have a couple of options listed on ebay which would be suitable, although you'd probably have to fiddle with values etc. a bit to get everything to your liking.
2) Replace the incandescent bulbs in the inserts with LEDs. I expect normal 3mm/T1 size LEDs will fit and would be easy to solder to the insert PCB. If not, you could easily find some smaller parts that would fit. (I can make suggestions if it comes to this.)
3) The final option is to add a simple bit of circuitry to drive the incandescent bulbs. This would consist of a small transistor and a resistor, so wouldn't be overly taxing to assemble.

Hope this helps


Chris
Offline gritz_1  
#3 Posted : 23 February 2020 18:05:10(UTC)
gritz_1

United States   
Joined: 11/11/2012(UTC)
Posts: 6
Thank you Chris, great information!
I actually just received 5 LEDS for my locos from CKLED, arrived last week.
I believe changing the bulbs/rewiring to be very close to impossible; from other projects I know you need the hands the size of a 4 year old and the skill and dexterity of a brain surgeon!
The last solution you mentioned is the one I would prefer, but my very limited electronics knowledge has me stopped.
Please, if you can provide any further information on the transistor/resistor combo I would greatly appreciate it. Frankly, I did not know how to Google "boost the SE8C output via circuitry to run an incandescent mini bulb".
Another forum pointed me to enamel wired LEDs in the correct size, from China, very inexpensive - the problem is working on the light signal itself - so if i can do "magic" UNDER the board that will be fantastic.
Any sites, link or docs, again, greatly appreciated, and thank you for your input!
Greg
BigGrin
Offline Poor Skeleton  
#4 Posted : 23 February 2020 20:19:01(UTC)
Poor Skeleton

United Kingdom   
Joined: 09/10/2015(UTC)
Posts: 200
Location: England, Cambridge
Originally Posted by: gritz_1 Go to Quoted Post
Thank you Chris, great information!
I actually just received 5 LEDS for my locos from CKLED, arrived last week.
I believe changing the bulbs/rewiring to be very close to impossible; from other projects I know you need the hands the size of a 4 year old and the skill and dexterity of a brain surgeon!
The last solution you mentioned is the one I would prefer, but my very limited electronics knowledge has me stopped.
Please, if you can provide any further information on the transistor/resistor combo I would greatly appreciate it. Frankly, I did not know how to Google "boost the SE8C output via circuitry to run an incandescent mini bulb".
Another forum pointed me to enamel wired LEDs in the correct size, from China, very inexpensive - the problem is working on the light signal itself - so if i can do "magic" UNDER the board that will be fantastic.
Any sites, link or docs, again, greatly appreciated, and thank you for your input!
Greg
BigGrin


Hi Greg,

That's strange, the information I've seen suggests the 8939 bulbs are accessible and replaceable : http://www.guidetozscale.com/html/signals.html, https://www.maerklin.de/...s/details/article/8953/. Still, I don't have any of the signals myself and you have them in front of you, so I guess these articles must be misleading.

Here is a schematic for how to connect the transistors to the signal and the SE8C. I've chosen BC327 transistors which are readily available, but lots of alternatives would do the job - let me know if you need me to suggest some. You'll also need a 9V supply for the signals - a cheap plug-top (wall wart) supply will be fine, a 1A rating will be more than enough for 10 signals. You should note that the -ve of the signal supply needs to be connected to the -ve of the SE8C power supply.

The way this circuit works, the bulbs will still be fed with 4V or so when they're off. This is mostly for the sake of simplicity, but is also deliberate in that it will keep extend the life of the bulbs by preventing the surge current when they turn on. I don't think they'll be glowing visibly at this voltage, but if I'm wrong the circuit may need a small modification. I'd suggest you get one wired up and check everything is working to your satisfaction before wiring up more, If all is not good, I can describe the modification then.

IMG_2849.JPG
Hope this is enough to get you started, good luck


Chris
Offline gritz_1  
#5 Posted : 23 February 2020 20:33:04(UTC)
gritz_1

United States   
Joined: 11/11/2012(UTC)
Posts: 6
Definite help, thank you again.
It's the size issue - 67 year old fingers working on bulb that is less than 1mm. And even if I could get the bulb out, there is no 1mm LED "screw in replacement". The tube that holds the wires is about 2mm. Really way too small, for me, to comfortably work on.
More importantly, with your information I can do this all underneath the layout and do not have to change/touch the existing signals at all. This is a BIG bonus.
Having already spent more than my fair share on Z scale items, replacing 10+ signals with their newer LED counterparts would run me well over $300.
I stand a much better chance of keeping my marriage and my layout if I try the transistor route first!!!
Thank you again. I have been looking for this information for over a year.
Side note, I have been dabbling with 3D printing for my houses, accessories, etc. - I'm pretty confident I can design and make signals I could put LEDs into - but sometimes the easier solution is, well, better. Making tiny little signals, assembling, wiring, painting, etc may sound like fun, but it's not!
Offline gritz_1  
#6 Posted : 23 February 2020 20:36:19(UTC)
gritz_1

United States   
Joined: 11/11/2012(UTC)
Posts: 6
Oh, I will update you when I get a test circuit built.
Offline Poor Skeleton  
#7 Posted : 23 February 2020 21:32:26(UTC)
Poor Skeleton

United Kingdom   
Joined: 09/10/2015(UTC)
Posts: 200
Location: England, Cambridge
Originally Posted by: gritz_1 Go to Quoted Post
Oh, I will update you when I get a test circuit built.


By way of a brief follow-up, I powered up a bulb with 5V just now - it glows dimly, but I very much doubt it's bright enough to see in the signal, so I think my simple solution will be fine.

I'm only a few years behind you and do sometime wonder about the wisdom of taking up Z scale at my age! I have invested in a head-worn magnifier, which is really a godsend, and my fine tweezers have more than paid for themselves!

It's interesting to hear you've been dabbling in 3D printing, as have I. In fact many of my buildings have been made that way, as have lots of the accessories - recycling points, vending machines, tables and chairs. It's really a boon, especially now so many of the mainstream manufacturers have discontinued their Z ranges.

All the best


Chris

Offline gritz_1  
#8 Posted : 27 February 2020 21:31:00(UTC)
gritz_1

United States   
Joined: 11/11/2012(UTC)
Posts: 6
Pre-circuit update.
I did not list all of the paths I tried on this, but since I did get my CKLED lights, as I said, I decided to open a 8939 and investigate.
I knew the 8939, like others, use fiber as a "light" with the source in the base.
Again I thought I had very few solutions. I've not hooked this to test it yet, but you can see by the picture, the loco CKLED may be another answer.
Too picky in old age - $10 for a soldered wheat bulb, $10 for an LED or about $1 for the circuit you sent - still thinking on that one.
Note the CKLED is not an exact fit for the 8939 - slightly larger body, and the 8939 has small nubs (they are under the CKLED on the lefT) that hold the bulb in place. But pretty minor. Another post, and the details were a bit vague, showed a picture of a potential circuit board for the same job - but we probably just bumped it to $15 a signal.
I am going to send an email to CKLED - this may be a market for them (pfft - probably not!)
For me, it may even be possible to simply (accurately) resize the body on the CKLED for this purpose.
At a minimum I have a wonderful alternative from you and I can always replace the bulbs with LEDs as they falter. And thank you for testing!
20200227_143258.jpg20200227_143449.jpgpossible circuit.jpg
Offline Poor Skeleton  
#9 Posted : 28 February 2020 23:30:28(UTC)
Poor Skeleton

United Kingdom   
Joined: 09/10/2015(UTC)
Posts: 200
Location: England, Cambridge
That's really interesting. Can you see where the light guide is located (it's not obvious from the photo)? LEDs are much more directional than incandescent bulbs, so it's possible the LED module won't illuminate the entry to the light guide enough.

What I would say, though, is now you've got this far, replacing the bulbs with LEDs would be a doddle. You could either remove the bulbs from the PCB and replace them with LEDs or solder LEDs directly into the base of the signal (which, I think, is what I'd do). If you don't feel confident doing it yourself any electronics repair person could rattle through your collection in an hour or two.

The CK LED guys were on the stand next to my layout at last year's Zedex exhibition. Very nice guys, and great fun!

Cheers


Chris
Offline gritz_1  
#10 Posted : 29 February 2020 17:53:30(UTC)
gritz_1

United States   
Joined: 11/11/2012(UTC)
Posts: 6
CKLED cut down.jpg
Got a reply from CKLED - the LEDs are cut for the 8854 loco as well, so this should work just fine for the 8939 signal.
As I figured, the voltage is the same as the locos.
I now have 3 really good ways to approach this "problem".
Thanks again,
Greg
Users browsing this topic
OceanSpiders 2.0
Forum Jump  
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

| Powered by YAF.NET | YAF.NET © 2003-2020, Yet Another Forum.NET
This page was generated in 0.530 seconds.