ChromaQ CQ1D scroller fault diagnosis

[Tom Baldwin]

I'm trying to repair a ChromaQ CQ1D in time for panto, and am not making much progress.

 

When powered up (from a PSU which successfully powers our other ChromaQ scrollers) nothing happens (no motor twitch, nothing) except the power light flashing continously roughly a couple of times per second a couple of seconds after power up.

 

According to the manual, this normally suggests the scroll has jammed. However, this unit is currently in pieces without a scroll fitted, and the motor doesn't even begin to try and move. I've metered the voltage across the motor at scroller start up, and see nothing.

 

The motor works fine when fed directly from a supply.

I've replaced the L298 motor driver chip to no avail.

The back EMF protection diodes around the driver seem to be fine.

Since the motor never even starts to move, I don't see that it can be the slotted opto rotation sensor.

 

And now I'm out of ideas! Has anybody had this fault before?

 

Next step is to try this controller PCB with the insides of another scroller, but I don't have easy access to the other ones at present.

 

Thanks!

 

Tom

[Paul Turner]

PM Sent

[Oovis]

PM Sent

Ooh, that's not fair :D Unless your PM was 'send it to me and I'll fix it for you' I think many people would be interested in the solution :(

[gareth]

Absolutely, Oovis. The whole point of posting questions on a public forum is that the answers are also posted publically for the benefit of any other interested parties. PM'ing the information to the OP is a bit selfish, to be honest.

[maeterlinck]

Absolutely, Oovis. The whole point of posting questions on a public forum is that the answers are also posted publically for the benefit of any other interested parties. PM'ing the information to the OP is a bit selfish, to be honest.

 

Not really. Posting on a public forum simply allows the maximium number of people to be able to see the question. It is up to the respondees as to how they choose to do so.

In this case Paul Turner decided to PM the OP. I think it's fair point to question to need to publically announce he hasn't publically annouced any suggested solution.

 

So come on Paul if you want to / can etc, tell us please do! We're all ears now!

 

Edit: To add quote

[Bryson]

If what Paul did is offer to sell Tom a replacement, then he did exactly the right thing in accordance with our advertising rules.

[Ian Ferguson]

If what Paul did is offer to sell Tom a replacement, then he did exactly the right thing in accordance with our advertising rules.

 

Non advertising rules sometimes work against you !

[Oovis]

If what Paul did is offer to sell Tom a replacement, then he did exactly the right thing in accordance with our advertising rules.

If he did offer to sell a replacement why bother telling us he'd sent a PM? It implies there's a solution which he didn't feel inclined/able to share with the rest of us.

[Tom Baldwin]

No conspiracy here.

 

The PM lead to Paul phoning me, and discussing in more detail the troubleshooting steps I'd tried. We concluded the only steps left were to try replacing the PIC, and then replace the entire board - the likelihood at that stage being an arbitrary number of passives having failed.

 

And yes, during the course of the call, he did give me a price for a replacement board - but only because I asked him to!

 

So I'm afraid there's no secret sauce, just a couple more troubleshooting steps.

 

Hope this clear things up,

 

Tom

[Nicktaylor]

I know this is an old thread but I suddenly have two with the same symtoms. I dont understand why but they failed on the same job, almost like they got spiked from the mains or something like that. I really need a handbook to take the unit further apart that just removing the motor module etc.

Or I suppose those good old boys at AC maybe able to help.