Hello there. Im repairing an old pcb for contactor switching machine for a client. For whatever reasons somebody stripped markings from all crucial components (it looks like sandpaper or screwdriver). Anyway, I identified two main ICs (somewhat). The board is from around 1997, so aforementioned ICs can be some old types of popular elements.
Some clues (as marked on photo):
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PHILIPINES (transistor ?)
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H9640 - letters are visible when wet using soldering flux (this is 100% h9640)
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this is tricky - 7 symbols - LMT8023/LM78023 - im sure of letters L and M
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KIA 5L - voltage regulator/ transistor (also scratched)
A and A`. old russian variable resistors (SP3-39NA 1kohm 10%)
B. BC177A - PNP transistor (CDIL)
C and D. 1uF 50V caps
E. 4.7uF 50V cap
F. 100uF 50V cap
G. 470uF 50V cap
All blue caps are 104 (0.1uF) and two common 1N4005 diodes.
Any ideas what 1. 2. 3. 4.s can be ? Im replacing all capacitors also. All photos are provided below.
