I think I killed my turntable...

[wm3798]

So I was making some fine-tuning adjustments to my Walther's built up turntable, the earlier non-DCC one, and I think I may have rooned it. 

In the process of cleaning and adjusting the wipers in the pit that transfer track and motor power to the bridge, I think I created a short that lasted longer than it liked.  Now when I turn on the main power to it, the LED just blinks and blinks and blinks.  I get track power, but no movement of the table whatsoever.

Using my little LED tester, the track power leads work, as do the leads for the motor power, but when I place the bridge into the pit, completing the circuits, the power light just blinks.  I tried rebooting it, unplugging and replugging, the whole shebang.  Nothing.

Has anyone experienced this, and is there a reasonable fix?

[choochin3]

  That is all.

[John]

Try rebooting the flux capacitor - then contemplate the outcome with a Vitamin Y - if no joy, repeat procedure 3 times, then call a roofer ...

[RWCJr]

Greetings Lee!!  Ewww, hate to say this, but I did the same thing to my non-DCC walthers unit.
The good news Lee, its NOT the bridge, its the controller. I was blessed in having a spare controller from a very noisy eBay unit that I bought for parts. I didn't ohm out the controller to see what the problem was with the controller. But it may be very fixable.
BTW, this is my first post on this site, and already I've seen posts from you, Marty, Pudster, and Fifer, LOL. Good to catch up with you guys.

[Philip H]

I don't have one, but the controller dying makes sense.  Sounds like a job for an old fashioned rheostat!

[trainforfun]

Mine was doing exactly that in november 2009 , this is when I sent it to Walther's to get it fix ... I am still waiting , the guy there at first wanted to replace some parts to get it fix , after about a year of waiting for parts he offered me to upgrade it to DCC since it was coming shortly ( ! ) , the DCC one are always suppose to come but are also push back by a couple of months every 2 months ...

Before I sent it back , I tried so many times to reboot , I read the instructions many times hoping I was missing something but no luck . There is not much to learn about the TT in the few sheets that come with it .

This TT was so nice , it was a dream machine !

I am still waiting .   

[TrainCat2]

Regards
Dave

[wm3798]

Hmmm.  I wonder if I sent the controller to one of our wizards here on the 'wire if I could get it repaired faster than Walther's could do it.... or better yet,  a new simple controller that isn't as difficult to mount on the fascia.

The other less desireable option would be to just gut the electronics out of it, and just run power to the motor with a resistor and a couple of momentary contact switches.  I find that the programmable indexing never lands where you want it to anyway.

Lee

[alhoop]

Not absolutely sure but I think the small chip on the controller is a PIC and if so it is probably code protected which means no one can read it  in order to program a replacement even if the part # can be identified.
Best bet is finding a used controller from someone whose bridge has died.
Al

PS There is a new one on  that site for $500.00. Almost makes me want to rip mine out and sell it! Almost!!

[wm3798]

I saw that one.  Kind of pricey for a parts donor.  In my simple mind, the only thing between me and an operating turntable is the chip that does the indexing, which I never used anyway (or much...)  The question marks are, is the motor operated by AC or DC, and at what voltage?  The power going in is AC-12V, but all those chippy things in there obviously do something.  If it's DC, then I bypass the indexing, and add a simple DPDT to change directions and a momentary contact button to apply the juice.

Any thoughts?
Lee

[alhoop]

Lee:
Looking at  pictures of both sides of the controller board it looks like the bridge rectifier on the front feeds a voltage regulator and filter capacitor on the back. If the regulator doesn't have proprietary markings you can read the part # and get the voltage used to control the motor(possibly),
ie if the marking is something like 7805 then  it is 5 volts, 7812 is 12 volts etc.

[wm3798]

What are the odds of the motor being anything but simple DC?  I'm thinking if I can find the contacts, I can simply rig up a low voltage power source, like a wall wart, and just add voltage until it moves at the rate it did with the controller.  (Or until smoke comes out of it, whichever comes first)

I'm also thinking that the reverser on the track power appears to be integral to the bridge, and purely by a simple mechanical gap in the contacts.  Since the DCC decoder will point in the right direction regardless of track polarity, I should be able to bypass any electronics in the bridge as well.

Lee

[alhoop]

Lee:
When I researched the Walthers N 130' turntable for my article in N-Scale Magazine Nov/Dec  2010  I seem to remember that there is a serial type communications between the control board and the bridge - which is why I think there is a PIC on the control board.
The motor driver will probably look something like this:

The IXDN is capable of up to 4 amps which is much more than needed for the bridge motor and is controlled by a PicAxe microcontroller but I would guess the PIC on the controller board controls something like this on the bridge which will make tying into the control lines difficult if not impossible.

If you just want DC control of the bridge motor use a circuit like this (ignore the diodes and switches around the motor)-and isolate the motor leads in the bridge and bring them out to the slip rings. The IDXN404PI is obsolete but Mouser.com part # 579-TC4424CPA is a pin for pin and spec replacement. Not shown but + voltage goes to pin 6 of the chip. Sw1 and SW2 control motor direction.
Pushbutton switches control motor direction and when a switch is released the motor will stop immediately, not an effect you can get from just pushbutton switches controlling a voltage source.
Here is a youtube video showing that a transfer table stops immediately when driven by this circuit:
http://www.youtube.com/watch?v=BeyjJu1iwh0


BTW are you absolutely sure that all wipers are making contact with the bridge ring?

[wm3798]

Ya lost me.     Remember, I'm a Mass Comm major... I only know how to push the buttons on the outside of the shiny box...

Lee

[alhoop]

Lee:
Doncha have a technician in that operating crew of yours?
Mebbe he/they can help decipher my stuff.

Regards
Al