I’m having intermittent entrapment / shutdowns loss of comm between cpu and DSP also communication of Dpram losted and card 1 and 2 not matching at right time I’ve checked boards with hyperterminal all good clean boards and backplane board I’m losted

You check the power supplies? Make sure the voltage is right and AC ripple?

Hi unkind Buffalo I did check all four power supplies at boards and backplane but not sure what you mean about ripple

I mean checking the DC voltage to see how much AC ripple is on it, I wouldn’t want to see anymore than .50 mV AC on the DC side, I had an intermittent problem with a T4 because the ac ripple was to high

PS1 is the one to focus on. Measure at the DSP card, adjust to 5.2vdc and check for ripple. Also could be card edge connections. Remove the first 3 boards and clean the edges and sockets, exercise in & out.

Thanks for the response’s guys I will definitely check ps1 ac ripple on dc side on Monday it ran all day today without a hiccup now if I do see a high ripple should just replace ps1 supply right

Yeah, replace the power supply, usually high ripple is a cap going bad, also agree with indirtwetrust, pull the cards and clean the contacts on the board up with an eraser, and exercise them back and fourth into the base board