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Hi
That board is one of the older unmodified boards. The two low ohmage resistors have been replaced by two 10 watt resistors that are now attached to the side of the scope (see the fitting sheets that are in the reference I posted) and snubber diodes fitted to the U11 74LS14 data lines to the handbox. At the same time the matching 74LS14 in the handbox also had snubber diodes fitted. The same mod made some changes to the supply of U15 but I ignore that one as it is too difficult to remove the pin from the board.
The circuit diagrams are readily available from mapug but I can send them if you email me PM.
Barry
PS if you have trouble down loading the pdf from that site I can email that also if you can take a 9MB attachment.
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