This is my first post here. I'm trying to build an Apple 1 replica (I bought the pcb from retroplace a year ago, and started collecting all the parts until I get everything to actually start building).
My electronic knowledge is far from a professional level but I love learning while doing.
So far, I soldered everything, checked the power supply section. The LM323K I had was a restamped transistor (I guess, since it was giving only 0.67V). So I changed it and now I have all the voltages correct everywhere needed.
I proceeded with populating the terminal section, powered it up, and got a nice boot screen. At least I thought, until I noticed one of the _ char was a +
I should mention I switched all the 2509v for mm1404an, because I wasn't able to find 2509v for sale.
When I clear the screen, I get the blinking @
I don't want to go into populating the computer section until I figure why there is a + where there should be a _
I tested removing D2, C3, D4a, D4b, D5a, D5b, D14a, D14b and C11b :
-> 40 x 24 fixed "█" symbols
put back the 2513:
-> 40 x 24 fixed "@" symbols
put back the 2519:
-> 40 x 24 flashing "@" symbols
put back all the mm1404an:
-> flashing "_@" symbols (and can be cleared) but with still that + sign in col 33 line 17
Any help to figure it out would be appreciated. Here is a picture of it:
PS: English isn't my first language. Please excuse any weird sentances and mistakes.