Working on a CPU board and the board is current hungry, wanting more than 1A and only getting 3VDC out of my power supply due to current draw. Can someone tell me what the typical 5VDC load is? This board is at 200 ohms, (between 5VDC and GND) which seems very low.

Thanks!

With a 200 ohm load should only be drawing 25mA (Ohm's law), but my bench supply is current limiting...

Thanks for the info! I'll try the 5VDC fixed output of my bench supply and see if that gets it fired up, pretty sure it can supply 3A.

Can someone measure the load for System 11A 5V to GND? I want to make sure I'm close before I start feeding it more current. It may not be this simple though? I measured 200 Ohms hit was still sourcing more than 1 amp, how does the math work out on that? Are there dynamic components to the load that change over time (i.e. inrush, etc.)? Not sure how I have a 200 Ohm load and drawing so much current.

Boot up is inconsistent when installed in the pin (sometimes only 5VDC led is on and no diag or blanking, sometimes it boots up just fine), so I'm trying to get it to boot up on the bench - a controlled setting. When installed in the pin, 5V line is 4.7VDC. If I do have a short, it's not showing up on the board installed out of the game, as I'm measuring a 200 Ohm load between 5V and GND. Maybe a bypass cap has gone bad and is leaking current and presenting a quasi-short after voltage is applied to the 5V, but that sounds like a pain to locate - there are what, 20? bypass caps in the 5V section?

Will try booting with a higher current supply tomorrow. No evidence of battery corrision.

Thanks!

Board booted using the higher current 5V supply. Although it fails to boot 10% if the time. Once it kept giving 10 flash sequences on either the Blanking or Diagnostic LED (don't recall which) with a single flash on the other LED on between the 10 flash sequences.

I will investigate blanking and ROM.