daver2
10k Member
What did I say...
Dave
Dave
Gary,Noteable that pin 13 appears to be high only when pin 1 is held low in the blanking phase.
To be fair, I had the same issue but they emailed me to tell me. Did they not email you?Grrrr
I decided to buy a NOP as it was only £4 and has LED's for NMI, IRQ,RST but !!!!!!!!!!!!!!!
They forgot to cut off the data pins, so while the resistors were connected, the data pins were also connected to the motherboard !!!!!!!!!!!!!!!!
Pins cut and now I have nice wave forms
Laser Business systems ROP generator more like
Gary,
That does not sound right. Pin 13 is related to to Display Enable and should be high most the 50 Hz vertical display time EXCEPT for the blanking periods.
Wait a minute, are you still running the NOP Generator? If so, the CRTC will not be initialized. You need to PETTest or your ROMs. Check for proper 50 Hz Vertical and 20 KHz Horizontal timing.
I took a quick look on my 8032 and saw the same thing as you did. I think we are being tricked because, with the welcome screen, there is only a tad of real data at the beginning of the 50/60 Hz vertical rate and I was syncing the scope at the 20 KHz display enable rate.looking at pins 1,2 & 13, they all have activity but they dont ever seem to be high at the same time at any point which means that the output on pin 12 will always be high, which it is.
I have one of them but due to a faulty socket, I had already removed and replaced the 6502 socket with a turned pin one anyway. I have still added an extra socket on top in an attempt to protect the turned pin one I soldered in because I don't fancy ever having to get it out.....
Colin.
Cheers for checking.
I will have a look at cobbling something, but PETTEST would give an initial full screen so on Tuesday (bloody work !!! four 12hr night shifts) I will give that a go.
I also might just whip out that IC and test it out of circuit just to confirm if its a dud.