Hi,
So I'm trying to diagnose equipment, which I started by taking voltage readings. Now, these are in line with what the manual suggests but disagree with the 'PCB art'.
Is this a normal occurrence? In this case, the appliance is a 100v Japanese model and the manual is for UK/EU model.
Its powered via an external 230>100v transformer.
The problem is that a microcontoller inside works intermittently, either its damaged, a cap feeding it is, or the step down transformer puts too much (or too little) juice (if thats even a possibility)?
There is 100v AC across secondary of the step down but I think current may have a role here too.
So I'm trying to diagnose equipment, which I started by taking voltage readings. Now, these are in line with what the manual suggests but disagree with the 'PCB art'.
Is this a normal occurrence? In this case, the appliance is a 100v Japanese model and the manual is for UK/EU model.
Its powered via an external 230>100v transformer.
The problem is that a microcontoller inside works intermittently, either its damaged, a cap feeding it is, or the step down transformer puts too much (or too little) juice (if thats even a possibility)?
There is 100v AC across secondary of the step down but I think current may have a role here too.
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Theres many PCB/manual discrepancies throughout.
For instance, the line that powers a 'misbehaving' IC, the manual states -33, actual is -33.8. The pcb states -24v. Likewise somewhere else actual is 9v when it should be 5.
I'm left to assume the manual is correct and the pcb is wrong, however...
The step down transformer - can it be to blame? I've measured 100v at this transformer... I'm unsure how a transformer behaves if the VA is too low.
What I mean is, even though it measures 100v is there a chance too little or too much current is being supplied and is affecting the readings? Until I get my hands on a Japanese manual theres no way of knowing!
For instance, the line that powers a 'misbehaving' IC, the manual states -33, actual is -33.8. The pcb states -24v. Likewise somewhere else actual is 9v when it should be 5.
I'm left to assume the manual is correct and the pcb is wrong, however...
The step down transformer - can it be to blame? I've measured 100v at this transformer... I'm unsure how a transformer behaves if the VA is too low.
What I mean is, even though it measures 100v is there a chance too little or too much current is being supplied and is affecting the readings? Until I get my hands on a Japanese manual theres no way of knowing!
Manuals generally cover a specific product. Boards however, in many cases can be used for more than one product. So it is conceivable that a board used in a 40 watt circuit might be so labelled, but then also used in a 60 watt circuit (I am making the numbers up) so supply voltages won;t match the board art. Just a thought.
yes, there are more times than we'd like where manual and board art disagree. In those cases, you use your skill and experience to determine which voltage is the more reasonable to expect.
yes, there are more times than we'd like where manual and board art disagree. In those cases, you use your skill and experience to determine which voltage is the more reasonable to expect.
Fahey, I did not want to go into specifics about the problematic IC or the device as I did not think it would help but if you must really know its a dat recorder and the IC that is misbehaving (intermittently - on rare occasions it works if its been powered on long enough) is attached in datasheet.
The readings of the 100v model in my possession match those in the manual for the 230v model, but do not agree with the PCB art (which may agree with the manual for the 100v model).
I doubt the fact that the actual reading differs from that in the UK manual by 0.8v is coincidence...!
The readings of the 100v model in my possession match those in the manual for the 230v model, but do not agree with the PCB art (which may agree with the manual for the 100v model).
I doubt the fact that the actual reading differs from that in the UK manual by 0.8v is coincidence...!
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