Recent content by ryanhayward

Looks like the unit I have is configured orientated correctly. I am happy to report the red light also stays on now and goes off when I hit the reset, but unfortunately the random characters still display. I am going to work on verifying the psu first.

I am back, I was out with the human malware and the pet and my scope were left at the office. I am going to take a closer look at the voltage and the transformer so I can rule that out. Again thanks for the help guys my back ground is IT not electronics so bear with me.

I was told by several people that they were backwards, when I put the character rom in the orientation you suggest I get the checkerboard pattern when I put it in the way I had it I get the random characters.

Also I assume the brown leads from the transformer are grounds is that correct?

Hey Dave Will do, I am seeing 5ish volts off the posts of the capacitor....what are the options for replacement power supplies these days? I feel like that tech has come a long way since 1977 haha.

Oh yah I think there is something fishy about the PSU or large cap... On the post of the large blue cap I am only getting 5V.

Hey Dave I will try those things, did you happen to watch the video I posted? Also it does seem like there should be 9v coming off that capacitor, I measured at this connector the back of each pin and I was getting 4.95-5.10 on the live wires and proper ground on the grounds. Thoughts?

Hey Dave That makes sense, thanks for the pin out reference I was looking for one of those yesterday I made a video to show whats going on when I scope pin 37. Thanks Cheers, Ryan

Also I am getting 4.95-5.10 volts coming from the large capacitor to the mains on the board so I am guessing that is within normal specification?

It does indeed.

Hey Dave This is the pin I am scanning and this is the output on the screen.

Thanks Colin!

It also seems like the cpu isn't powering up at all, the light on my upgrade cpu board doesn't light up and if I remove the board completely I get no change in the display which leads me to believe its something before the CPU initialization? If I am using the correct term as was pointed out in...

On pin 41 I am getting the following activity it looks like 41 is the IRQ Reset line?

And yes you can change T-Y to X-Y