Drive startup failure but it works?

[PA_Riledo]

Had a power outage today, but my SD-DVR40 (with all the add-ons!) was plugged into a surge protector and has worked beautifully for years.

Power comes on, DVR40 does not boot, fan runs. Off comes the cover. Fuse is OK. The hard drive does not spin up, but the power to the hard drive is OK.

I removed from storage the original drive (which I know works OK), plugged it into the power and data cable - does not spin up. So I try, with the old drive, the power ONLY, and the drive spins up when the DVR is energized. Plug the same drive into the power AND data cable and it does not spin up.

So I unplug the data cable just a bit, power the DVR, and then quickly plug the data cable back in as the drive is spinning up. This works - and front green power-on LED is lit (it was not lit before).

Any ideas what may have caused this or how to fix it beside the method I used.

Thanks in advance.

[PlainBill]

Had a power outage today, but my SD-DVR40 (with all the add-ons!) was plugged into a surge protector and has worked beautifully for years.

Power comes on, DVR40 does not boot, fan runs. Off comes the cover. Fuse is OK. The hard drive does not spin up, but the power to the hard drive is OK.

I removed from storage the original drive (which I know works OK), plugged it into the power and data cable - does not spin up. So I try, with the old drive, the power ONLY, and the drive spins up when the DVR is energized. Plug the same drive into the power AND data cable and it does not spin up.

So I unplug the data cable just a bit, power the DVR, and then quickly plug the data cable back in as the drive is spinning up. This works - and front green power-on LED is lit (it was not lit before).

Any ideas what may have caused this or how to fix it beside the method I used.

Thanks in advance.

First of all, let me commend you on your brass cajones. I've never been fond of plugging in the drive cable with power on.

The most likely cause is the power supply. Look at the capacitors and see if any have a bulging top.

PlainBill

[PA_Riledo]

Thanks for the suggestion, that is one of the first things I looked for. Not finding any failed capacitors, I tested the voltage to the drive, it was OK.

I will be doing some more testing today.

[PlainBill]

Looking at troubleshooting the problem from a modular approach, there are only a few possibilities; power supply, hard drive, motherboard. Your testing has eliminated the hard drive. The best approach would be to pick up another system and try swapping power supplies. Measuring voltages will only show that the supply is putting out the correct voltage; noise on the +5VDC line will cause this symptom.without affecting the output voltage.

If indeed the problem is NOT the power supply it is effectively unrepairable.

PlainBill

[PA_Riledo]

Thanks for the suggestion. It appears to be the power supply (PS). I just removed it and one of the PS leads, where the cord connects, soldered to the bottom of the PS is lose - very lose, with evidence of a bad connection with "black" burn marks around the bad solder joint. I am going to solder it back the way it should be.

Glad I found this, but can not imagine this bad PS connection not causing the HD to spin up unless the data cable was unconnected. Weird.

I found a new PS that I can buy, but less costly, is just buy a used unit on _bay. Update to follow.

[PlainBill]

Thanks for the suggestion. It appears to be the power supply (PS). I just removed it and one of the PS leads, where the cord connects, soldered to the bottom of the PS is lose - very lose, with evidence of a bad connection with "black" burn marks around the bad solder joint. I am going to solder it back the way it should be.

Glad I found this, but can not imagine this bad PS connection not causing the HD to spin up unless the data cable was unconnected. Weird.

I found a new PS that I can buy, but less costly, is just buy a used unit on _bay. Update to follow.

Note that the design of virtually any microprocessor based system will include circuitry holding the CPU in a reset state until the power supply is stable. This signal often comes from the power supply. I wouldn't be surprised if the IDE interface includes a similar provision. So with a bad solder joint on the AC connector, the power supply can't supply stable power to both the main board and hard drive long enough to generate a 'power good' signal.

Unless the connector is badly damaged, it is a trivial job to resolder the connector pins to the board.

PlainBill