the citcuit is to produce PRBS, but when I jointing the resistances , the ground and VCC are short. I do not the reason why.
And I find that, when I jointing the resistances one antoher, the resistance between ground and VCC is reduced from 82Ω+130Ω to 0Ω.
MC10131(DFF)MC10107(NOR)
I would expect to measure about 21 ohms. Are you sure you measured 0 ohms? If yes, then use a milli-ohm meter to locate the short (as your probes get closer to the short, the measured resistance will get closer to zero).
Or maybe your installed resistors are the wrong value.
An ECL board without a ground plane? That's scary.
Hi,
I think that your problem is due to the high number of parallel resistances and their low values. You have ten resistances of 82Ω+130Ω =212 Ω in parallel. If possible try to increse these values to 820+1k3 or 8k2 + 13k, for example.