I've looked round all the pins and the readings look OK. Nothing stands out as wrong.
It may just be a zapped IC, I know that's the easy option saying that and 99% of the time it is always something else so if we can it's best to prove it as far as possible.
Reading the switches on a DVM in circuit may not show leakage. On a low ohms range they would appear fine.
With a bit of solder braid its a couple of minutes work to isolate those pins and diodes (including D201... missed that one).
What I would do then is get a small diode (anything like a 1N4148) and briefly connect it across say pins 29 and 17 (the open/close function) and see if anything works. Obviously watch polarity. You have to do that "by hand" to simulate a switch press.
We measured pins 41 to 37 I think to make sure the connections were intact to the main PCB.
Scopes always help but it's not worth one just for this unless you'll get the use from it. We would use it to confirm the oscillator is running and to see if any data is present on the data and clock lines and whether or not it changes in response to key presses.
As it stands at the moment it looks like the front panel IC or the system control IC that the front panel feeds into could have a problem. Again though, the IC's are the last to condemn.
It may just be a zapped IC, I know that's the easy option saying that and 99% of the time it is always something else so if we can it's best to prove it as far as possible.
Reading the switches on a DVM in circuit may not show leakage. On a low ohms range they would appear fine.
With a bit of solder braid its a couple of minutes work to isolate those pins and diodes (including D201... missed that one).
What I would do then is get a small diode (anything like a 1N4148) and briefly connect it across say pins 29 and 17 (the open/close function) and see if anything works. Obviously watch polarity. You have to do that "by hand" to simulate a switch press.
We measured pins 41 to 37 I think to make sure the connections were intact to the main PCB.
Scopes always help but it's not worth one just for this unless you'll get the use from it. We would use it to confirm the oscillator is running and to see if any data is present on the data and clock lines and whether or not it changes in response to key presses.
As it stands at the moment it looks like the front panel IC or the system control IC that the front panel feeds into could have a problem. Again though, the IC's are the last to condemn.
Just thinking a bit more on this, the "no display" condition does perhaps point more to an IC problem.
It's always good to go over the failure mode... it was I think all working until you replaced the gear ?
So a "normal" failure hasn't occurred. The two most likely possibilities are a physical problem such as cracked print etc or that in some way the IC came into contact with something that was charged up.
I think you have to still isolate those pins etc to prove as best as possible that only the IC ('s) are left.
It's always good to go over the failure mode... it was I think all working until you replaced the gear ?
So a "normal" failure hasn't occurred. The two most likely possibilities are a physical problem such as cracked print etc or that in some way the IC came into contact with something that was charged up.
I think you have to still isolate those pins etc to prove as best as possible that only the IC ('s) are left.
Thanks to keep answering my questions even if I take so long between each test. But I promess to wrap this project up within 2012😱
Just did so. Unsoldering was easier than I would have thought - first time using solder braid. I checked that each unsoldered pin of the IC did not contact the PCB. But nothing more happened when I turned on the CDP - nothing on the display. I also tried mimicking a switch with a diode as you suggested. I tried the open/close and the play functions. But again, nothing.
But do you think there is still a chance the ceramic resonator could be the faulty one? I could probably get one locally for next to nothing. But for the microcontroller, it looks like I'll have to order from some Chineese supplier which, with shipping, would cost about 25$. Well worth it if it fixes my CDP, but in doubt I'd first spend a buck or two on a resonator. Plus it's much less work to replace.
Just did so. Unsoldering was easier than I would have thought - first time using solder braid. I checked that each unsoldered pin of the IC did not contact the PCB. But nothing more happened when I turned on the CDP - nothing on the display. I also tried mimicking a switch with a diode as you suggested. I tried the open/close and the play functions. But again, nothing.
Yes, everything was working. And when replacing the tray gear, I also messed around the display, removing the front panel to reach a push button that had fallen between the display and the front panel. So I might have zapped the IC.
But do you think there is still a chance the ceramic resonator could be the faulty one? I could probably get one locally for next to nothing. But for the microcontroller, it looks like I'll have to order from some Chineese supplier which, with shipping, would cost about 25$. Well worth it if it fixes my CDP, but in doubt I'd first spend a buck or two on a resonator. Plus it's much less work to replace.
It's 99.9999% certain the ceramic resonator won't have failed as long as it's physically OK.
When looking at processors the exact same type has to be fitted. It's common for the same processor to be used in many items, and it's the suffix code that determines the program it runs. The parts list shows "/3312" That's the important part and unique to the Rotel.
When looking at processors the exact same type has to be fitted. It's common for the same processor to be used in many items, and it's the suffix code that determines the program it runs. The parts list shows "/3312" That's the important part and unique to the Rotel.
Ok, thanks very much for all your help, really appreciated. I'll order a processor and post my results when the transplantation is done.
It's no problem... just hope you get a result after all this.
I think we have covered all bases looking at this one.
I think we have covered all bases looking at this one.
Well, after a few months, I finally took some time and replaced the display processor. It actually went faster than I thought - that soldering braid really works well.
But no luck, the display and buttons still do nothing. In a last attempt, I'll try replacing the ceramic resonator.
BTW, for anyone looking for a place to order ICs, I just picked a random chinese supplier and received, partly to my surprise, my processor 3 weeks later. The supplier was ic-agent.com (contact: Jennifer@ic-agent.com).
Thanks again for your help.
But no luck, the display and buttons still do nothing. In a last attempt, I'll try replacing the ceramic resonator.
BTW, for anyone looking for a place to order ICs, I just picked a random chinese supplier and received, partly to my surprise, my processor 3 weeks later. The supplier was ic-agent.com (contact: Jennifer@ic-agent.com).
Thanks again for your help.
Hi,
Check the display some of the display have a fuse close to power connector. Can you see the maker of the display?. Noritake have a fuse that look like a transistor. I have two display that blown the fuses and I had hard time finding it. The display will be completely blank.
Check the display some of the display have a fuse close to power connector. Can you see the maker of the display?. Noritake have a fuse that look like a transistor. I have two display that blown the fuses and I had hard time finding it. The display will be completely blank.
Thanks for the update... that's a shame it hasn't fixed it. Don't know what else to suggest to you (I know you are going to try the resonator). Keep us updated.
Thanks for the advice, tauro0221. But as per Mooly's recommendation, I have already tested the display, and it's still alive. I'll post results when I get a chance to replace the resonator...
Did you get the problem with the display finally sorted?
Curious, as I'm looking for a spare transport ...
Curious, as I'm looking for a spare transport ...
Nope, haven't tried replacing the resonator. I plan to, at some point, but the unit and a new resonator are sitting together on a shelf, as my job and remodeling projects are keeping me too busy right now. But if I ever become hopeless regarding my cdp, I'll get back to you in case you're still interested...
Just wanted to let you know... a few months ago, I tried replacing the resonator, but it did not help. So I still have no display, I can only play/stop/skip with the remote and I have to manually pull and push the drawer.
But still, I keep using it because it sounds better than my other CDPs!
Thanks again everyone for your help.
But still, I keep using it because it sounds better than my other CDPs!
Thanks again everyone for your help.
Thanks for updating the thread and a real shame nothing has worked so far. I was just reading through it all again... and I can't help feel its either something really really "simple" or a real one off (lol, obviously 😀) issue. I suspect its one of those things you need in front of you now, to get a feel and to see whats going on.
I've no fresh suggestions I'm afraid beyond rechecking absolutely everything connection and continuity wise.
I've no fresh suggestions I'm afraid beyond rechecking absolutely everything connection and continuity wise.
Hi,
You can do some checks if you have an scope. The data to display it is send by the micro processor serially thru the DIN\ and the DCK\. First I would check that at the display connector you have the -VF/+VF. Second check the reset signal RST\ that it is high. If the rst\ it is high you can reset the display by momentary grounding the RST\. That would reset the display. If you have an scope then check the DIN\ and CLK\ for pulsing signal coming from the micro processor. The clock it is used to clock the data into the display from the main microprocessor. The are also some signal but I can not read the letter like OTC, the fourth from left to right look like REM and the the third from right to left DDA. I would check all the connectors signal to make sure they are toggling. If they do then the problem it is in the display controller.
You can do some checks if you have an scope. The data to display it is send by the micro processor serially thru the DIN\ and the DCK\. First I would check that at the display connector you have the -VF/+VF. Second check the reset signal RST\ that it is high. If the rst\ it is high you can reset the display by momentary grounding the RST\. That would reset the display. If you have an scope then check the DIN\ and CLK\ for pulsing signal coming from the micro processor. The clock it is used to clock the data into the display from the main microprocessor. The are also some signal but I can not read the letter like OTC, the fourth from left to right look like REM and the the third from right to left DDA. I would check all the connectors signal to make sure they are toggling. If they do then the problem it is in the display controller.
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