5 v rail pulled down hard, blowing fuse

[fredcapo]

I had time to get back on this... I replaced the 5 v regulator and the problem remains. I did not replace anything else in the power supply except fuse.

The 5 vdc rail,is pulling down to 3.4 volts at 1.3 amps.

If I pull the 4 TMS4464-10nl ram chips, the 5 v rail goes normal (5.7 v at 150 ma). Installing only 1 ram chip pulls it down but not fully.

Could this be all 4 ram chips bad, a logic issue, or a deficiency with the 5 v power supply not being able to supply enough current?

I may try running with an external 5 volt supply when back in the shop. Thanks.

[g1]

That sounds like a lot of current, do all 4 ram chips get equally hot? And any 1 of the 4 still pull down the voltage?
If so, they may all be bad.