On 29/04/2011 21:14, Julie wrote:
On 29 Apr, John Ballance<jwb@xxxxxxxxxx> wrote:Please may I make a serious suggestion - as the power supplies to the motherboard are critical in that they have little margin for error, ANY attempt to muck around with the 5v supply after it has been regulated by the powersupply will lead to grief. Basically, DONT!Agreed!Jim's suggestion - better power supply - is really the only valid answer. Oh, and BTW, the 'indicator' of the 5v power supply voltage being between 5.06 and 5.08v is just that. On the supplies originally fitted, the supply would hold this voltage reliably when working correctly. Towards the end of its life, the regulation became far less effective, and that was INDICATED by the change in the 5v rail.I have never been able to understand why the voltage is this critical. Neither does my OH. We are both electronics engineers. Back in the good old days, TTL would tolerate 4.75 - 5.25V, 7V absolute max. CMOS could run anywhere between 3V and 18V. (I know that many of the more recent ICs run at 3.3V.) Why is the Iyonix so sensitive?
simple answer.. Its NOT the actual voltage, its the fact that the PSU has ceased behaving as it should!
The drop in indicated voltage is a SYMPTOM that correlates with mis behaviour, rather than an absolute fact
John
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