Author Topic: SN7525 wanted  (Read 620 times)

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Offline ppppenguinTopic starter

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SN7525 wanted
« on: June 11, 2024, 03:17:14 pm »
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.
Jeffrey Borinsky  www.borinsky.co.uk
 

Offline ppppenguinTopic starter

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  • Posts: 4
  • Country: gb
Re: SN7525 wanted
« Reply #1 on: June 16, 2024, 07:17:58 am »
I have now managed to find some spares. In the meantime I have done a horrible looking bodge with a LM319 dual high speed comparator and a 74LS08 quad 2 input AND gate.
Jeffrey Borinsky  www.borinsky.co.uk
 
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