25-04-2017, 11:34 AM
3V is good for one of these: http://biz.maxell.com/en/primary_batteries/cr_coin.html - 3.3V is impressive!
A PC will boot and run with no CMOS battery (obviously you'll have to visit Setup before the OS tried to boot). It's a red herring.
The only way to test the hardware is by substitution. Sorry to state the obvious, but if you don't have a spare PSU, you need to find one. And if that leads nowhere, then you'll have to try a new motherboard, new RAM, new graphics card, etc. The order is dictated by what else you already have or can borrow, and cost of what you don't. It's a PITA, but what else can you do? It's not like you can do component-level diagnostics and maintenance on any of it (apart from the PSU, perhaps).
That's why it's nice to have more than one identical machine - easy in the workplace, not so easy at home (though I've largely achieved it).
Most of the time, it's power supplies IME. And also IME, the PSUs that come with "bit-boxes" like this tend to be pretty crappy unless the customer specified a decent upgrade at the time of ordering. Whenever I upgrade such power supplies, I see it as an opportunity to get a quieter model.
I had very similar symptoms to this on a P4 PC many years back after I upgraded the CPU. The PSU was OK in terms of basic condition, it just wasn't man enough to power the new CPU reliably. Prior to that, I'd be irritated by the unreliability of the optical drive, so had replaced it with another. But as an experiment, once I'd upgraded the PSU, I put the original drive back in and it was 100% reliable - turns out it was more power-hungry that its replacement, and was tipping things over the edge. I didn't put 2 and 2 together because I used the drive so infrequently. Obviously, P4s were very power-hungry. It was a massive step change from the PIII, and the industry sometimes struggled because people were asking for power supplies to actually provide what they claimed they could deliver...
What's interesting is that the PMR has grown a lot since the P3. The average power drawn by a PC used to be fairly constant, hardly changing with CPU activity, but the peak power drawn by a P4 system was much greater than the average idle power. Since the P4, things have got generally more efficient, so the average has gradually fallen, but the peaks caused by CPU activity are now greater compared to the average. All of which places greater demands on the power supply (both the thing in the box, and the power supplies sprinkled all over the motherboard).
What's also interesting is how the PC power supply is consolidating. Look inside Dave's HP machines - from memory, there is only a single 12V rail emerging from the PSU (ignoring the standby supply - also 12V IIRC, but it's been a couple of years). All the conversion is done on the motherboard, including the 5V for the drives. Obviously the HPs are proprietary so not the same as generic ATX machines, but the ATX12V standard is evolving all the time, and I can envisage a time when generic motherboards are powered from a single 12V (or higher) rail (plus standby).
Anyway, it might not be the PSU, but you have to start somewhere...
A PC will boot and run with no CMOS battery (obviously you'll have to visit Setup before the OS tried to boot). It's a red herring.
The only way to test the hardware is by substitution. Sorry to state the obvious, but if you don't have a spare PSU, you need to find one. And if that leads nowhere, then you'll have to try a new motherboard, new RAM, new graphics card, etc. The order is dictated by what else you already have or can borrow, and cost of what you don't. It's a PITA, but what else can you do? It's not like you can do component-level diagnostics and maintenance on any of it (apart from the PSU, perhaps).
That's why it's nice to have more than one identical machine - easy in the workplace, not so easy at home (though I've largely achieved it).
Most of the time, it's power supplies IME. And also IME, the PSUs that come with "bit-boxes" like this tend to be pretty crappy unless the customer specified a decent upgrade at the time of ordering. Whenever I upgrade such power supplies, I see it as an opportunity to get a quieter model.
I had very similar symptoms to this on a P4 PC many years back after I upgraded the CPU. The PSU was OK in terms of basic condition, it just wasn't man enough to power the new CPU reliably. Prior to that, I'd be irritated by the unreliability of the optical drive, so had replaced it with another. But as an experiment, once I'd upgraded the PSU, I put the original drive back in and it was 100% reliable - turns out it was more power-hungry that its replacement, and was tipping things over the edge. I didn't put 2 and 2 together because I used the drive so infrequently. Obviously, P4s were very power-hungry. It was a massive step change from the PIII, and the industry sometimes struggled because people were asking for power supplies to actually provide what they claimed they could deliver...
What's interesting is that the PMR has grown a lot since the P3. The average power drawn by a PC used to be fairly constant, hardly changing with CPU activity, but the peak power drawn by a P4 system was much greater than the average idle power. Since the P4, things have got generally more efficient, so the average has gradually fallen, but the peaks caused by CPU activity are now greater compared to the average. All of which places greater demands on the power supply (both the thing in the box, and the power supplies sprinkled all over the motherboard).
What's also interesting is how the PC power supply is consolidating. Look inside Dave's HP machines - from memory, there is only a single 12V rail emerging from the PSU (ignoring the standby supply - also 12V IIRC, but it's been a couple of years). All the conversion is done on the motherboard, including the 5V for the drives. Obviously the HPs are proprietary so not the same as generic ATX machines, but the ATX12V standard is evolving all the time, and I can envisage a time when generic motherboards are powered from a single 12V (or higher) rail (plus standby).
Anyway, it might not be the PSU, but you have to start somewhere...
