You are going to need to examine the photos closely as these have been modified. There is an extra board inside, a ribbon cable has been attached to the backside of the main board and there is an extra round connector on the rear of card. We are told that the gain appears to be limited to 8000 channels instead of 16000. Perhaps these can be restored or used as they are.
We are selling AS IS for Parts or Repair due to these having been modified and are non-standard.
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"The Model 87 I 3, Fixed Dead Time analog-to-digital converter is designed for high resolution nuclear spectroscopy. Its fast conversion time allows it to process a full scale input pulse in less than 6 µs. Fast throughput combined with 16K Gain Range make the 8713 the best choice when speed and resolution are both critical."