Re: VCO issue !
So i continued on with the build, finished everything today. When powering on i get a flash of LED's, then the track 1 led lights up and stays lit. I try to put it into random mode but it doesnt seem to do anything, i can press run and it seems to be running although i get no sound and i dont see a moving pattern (like my other x0x). A couple of things ill mention, like i said in my first post i get exactly half of the required voltages from R105 and pin 3 on the selector switch, 4VDC and 3.5VDC there abouts. I backtracked again and checked my parts over and over, 1 mistake i had was K118 not being in Q29, it had the K30AY in there instead. I thought here is my lucky day, swap it out for K118 and ill be right.. nope, it didnt change a thing. So continuing on with the build and troubleshooting from forum posts i saw someone had an issue with C11, it seemed to be similar to what i was getting so i swapped out C11 (what voltage should i be getting across C11 btw?) and i actually lost the 4VDC on R105 and its now down to 1VDC. Its exactly the same cap, a 1uF electrolytic.
So after continuing each step of the build all the way to the end and powering on the machine i find that my VCO problem seems to be having repercussions on the proper operation of the CPU, i should atleast be getting random mode running shouldnt i? I remember when i built my last x0x i powered up and switched to random and voila it started playing a random pattern. Or was i mistaken and it was just playing that in the headphones without any leds moving?!
A couple more things, i went through with my multi-meter and checked a few IC pins on the digital section, i seem to be getting 5VDC from them all as well as from the CPU. I reckon im that close to finding the issue, i just need a little push over the line. MMM or anyone if your still out there please give me a minute !!!
Many thanks in advance.