I'm repairing a Philips PM5544 electronic testcard for the Broadcast Engineering Museum.
https://becg.org.uk/I've fixed most of the faults but I need a SN7525 sense amplifier for the magnetic core memory. Can anyone help please. The design was done in 1969/1970, before the first 1702 EPROM was available. Later versions of the PM5544 used EPROM instead of core.
Here's the output at the moment. The cogging on the circle is due to two dead bits from the core which stores data for the circle.