hey all, first post, but have been reading for many months!
I wonder if I might ask for assistance with a circuit check? I am learning how to fix early 1980s arcade boards. Lots of TTL, Z80 and 6800 processor stuff.
I have a clock circuit, with a crystal, but I think results are strange, but half the battle for me is knowing what I "should" be seeing. So I am trying to learn the foundation of electronics, so I understand..
(That's the goal!)
I'm struggling to understand why the ceramic capacitors C12 & C13 are showing LO both sides (logic probe) when powered on. Every other ceramic capacitor on the board shows HI & LO. If I check continuity in circuit (with DMM) these capacitors do not buzz, ALL other ceramic capacitors on the board DO buzz, in circuit.
I'd love to debug it, and understand what I should 'see' for this tiny circuit, and then check it and THEN I can understand what is actually happening.
Its 3 resistors (R46 isn't there, or on any other of this board type)
an LS04
2 capacitors
a crystal (12Mhz)
Apologies for the ridiculously n00bie question. I'm keen, just lacking knowledge, despite youtube! :-)