bought a data east rottendog mpu. before i go to the game, i bench tested it. 5V light on, pia light goes out, but blanking light stays out.

switch matrix is active pulsing. there is a test point on the board labeled blanking. it stays low for a few seconds on boot up, then goes high, same time pia light goes out. voltage is 4.95 when high. looks to me like the board is working correctly, other than the blanking led.

using the same processor and rom in two OEM boards, the blanking light comes on, so i know its not the rom or processor chip.

i asked rottendog via email if 4.95 at the blanking test point is correct. the terse reply i got was:
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4.95V is too low!

Jim Knight

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how could it be higher, when the board only runs on 5 volts?? is it me?? i asked rottendog the same question, havent heard a reply yet.

any thoughts?

thanks