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Dead LCD display on a C7042 power base

3071 Views 35 Replies 11 Participants Last post by  JazzMaverick
I bought a used digital 6 car set. It all seems to work fine except for the LCD Display that shows no sign of life. Nothing on the screen and no sounds. Does anyone have any tips for troubleshooting, please? I am fairly technical and I have a multimeter if there are any testing I can do on my own.

I am considering buying the RJ11/USB cable, but if the issue is on the power base itself there might be no point....
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That is pretty unusual, so it could be a port problem

easy check would be to see if the port is being recognised.

When you plug in the display and power up the C7042 do the red and green LEDs light up on the powerbase?
Where are you by the way?
I have tried with the LCD plugged in when booting and plugging it in after. Same result. One green and one red light on the Powerbase at all times.

I am in Singapore, so if there is anyone on the forums living around here, and have a C7042 for me to test my equipment with it would be brilliant. :)

Sorry for the late reply, was incapasitated by a bout of food poisoning.
OK, so its not recognising the display at all. I think there is a reasonable chance that the port is dead. If the lights had not been there then at least the C7042 would have recognised there was a display there. So even buying a cable would be risky :(
Thanks for your help!
Perhaps one thing worth checking...

If the display is totally dead it might be the internal 5V regulator has failed. If thats the case the port itself could be fine i.e. ready to function with instead the cable and pc/rms apps attached.

Since you have a multimeter you could check voltages on the regulator... 0V, V(in) of 12-13.8V and V(out) of 5V. Its a L7805 so the pin out is available on line. Word of caution... any shorting of the three pins would destroy the L7805 for sure so utmost care required.

Are the voltages present?

Small print: Only attempt this test if you feel competently trained to do so.

c

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I just checked... with a perfectly functioning system if I disconnect one of the RS485 RX/TX lines... so that the tower takes power but does not communicate via RS485... the following happens when I turn on:

1/ the tower green LED briefly lights and all the LCD digits turn black briefly.

2/ the tower green LED and the LCD display then go blank.

3/ next the powerbase six-LEDs-in-a-row start to flash in sequence. At this point the system knows there is a display connected as that is detected by current flow on the 12V accessory line - but there is no comms taking place. The red and green lights on the powerbase are both off.

Do you observe any of the above... ? if not... probably its a case of no power getting to the PIC circuitry on the tower... again the regulator voltage check would make sense as a first next step.

c

(edited: to correct lighting descriptions)
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Yes, as it is looking like the base is just showing the same as if it were not connected to the display then I think its fairly safe to say that the base is not recognising the current draw. That could be a fault in the display which means its not pulling any current, or that the drive in the base has failed. I think the latter is more probable.
When it comes to understanding component failures of the APB C7043 I am certainly a true novice... only one failure detected to date... when the old-style internal ribbon cable broke - and that was all self-inflicted... I had removed the cover far too many times :)

c
Thanks for the comments and feedback folks!

Christopher at HPM Hobbies here in Singapore was kind enough to lend me an LCD display from one of their sets. And confirmed, the display in my set is dead. My Powerbase works fine with the display I am borrowing from HPM.

No point in trying to dig into why it fails, I guess?

Christopher was kind enough to let me try out one of your cables as well, Riko, so I will be upgrading the firmware and trying out some RCM software this weekend! Time to do some research on what possibilities have opened up!
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You'll completely forget about the display in a very short amount of time. ;-)
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I discarded the Tower years ago in preference to the PC based RMS systems and thought I would never have a need for it again.

I'm glad I kept it though as a few months ago I had issues with missed laps and I finally found the issue was the minimum lap time I set in the APB C7042 years ago was too high and was overidding the minimum lap time set in the RMS.

I resolved it by resetting the minimum lap time in the C7042 powerbase and needed the Tower to do this, I was so glad I still had the Tower in a box under the track table.

https://www.slotforum.com/forums/index.php?showtopic=195591&p=2355451
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Without the tower there is not way of resetting this?
Nope. The tower "mode" has settings, including min lap time, and analog car direction, that apparently stick through all modes.
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Nope. The tower "mode" has settings, including min lap time, and analog car direction, that apparently stick through all modes.
Hmmm, this makes me think I should try to get a spare LCD screen, just in case I run into any issues. Anyone have a spare LCD screen unit to sell, please? I tried e-bay, nothing found here in Singapore.
I would suggest before you get to deep. find an rj11 connector and replace that on the cable that comes out of the LCD display. I had a display fail and I simply cut off the old end and crimped on a new connector. After that the display worked fine. It may be possible the dealer you work with has a connector and crimper if they have a service bench. I'd replace the cable end on the LCD as a first step to seeing if you can get your display to work again.

As a sidebar: I had considered selling my c7042 and controllers. Then I was on World Wide Slot Car Chat and found the controllers and powerbases were becoming difficult to acquire. I'll keep them even thought I've moved on to the Arc Pro now. If I ever get to a point where I can have a second track setup I'll probably do so with the c7042 on a small layout. this will allow me a test track using one of the 3 c7042 Windows based race management systems I have licenses for.
I would suggest before you get to deep. find an rj11 connector and replace that on the cable that comes out of the LCD display. I had a display fail and I simply cut off the old end and crimped on a new connector. After that the display worked fine. It may be possible the dealer you work with has a connector and crimper if they have a service bench. I'd replace the cable end on the LCD as a first step to seeing if you can get your display to work again.
Yeah, I will do so first. An excuse to increase my tool collection is always welcome, since I do not have a crimping tool.

So looking at the plug it seems there are 4 wires in the tower RJ plug which would make it 6P4C? Is that a RJ11 plug? From wikipedia it sounds like the plug is an RJ14 (6P4C). RJ11 is 6P2C, which would mean only 2 wires in the plug?

Please educate me, this is the first time venturing into anything that is not ethernet. :)
Pretty sure it's an RJ11 as I have a 0.5m RJ11 extension cable for my APB Tower so I can unplug it when taking the boards apart for storage it works fine...
Heh, maybe Wikipedia has some wrong info? Not sure, but according to this page RJ11 is 6P4C, which is what is what the plug looks like. Well, that's funny. Thanks for your help!
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