HP 21 repair

[surgdog]

(06-15-2015 02:56 AM)PANAMATIK Wrote:  

(06-15-2015 01:28 AM)surgdog Wrote:  Is there anything to be done or do I just write it off? Is this repairable?

If only some traces on the main board are damaged, they can be repaired with isolated copper wire (german Kupferlackdraht). The HP-21 main board is easily accessible for repairs. If the ACT chip is damaged, you can replace it by the "new ACT". Your HP-21 is most likely repairable. Don't write it off!

Bernhard

Forgive my ignorance but what is the "new ACT"?