Recent content by ArjenCNX

yeah, that solidly excludes that option indeed, just considering the way it works, it would be possible that there is a soldering issue on the motherboard somewhere along the video signal as in comes in, some percussion there may show you something, as could cooling things down with some canned...

Video ram comes to mind here, check the Vram chips and make sure there is no capacitor spillage around them, and that the Vias are OK, a few gentle taps on the board can sometimes expose bad connections.

the mechanism needs to be pristinely clean and smooth, a manual eject should almost shoot the disk out, if you don't get that, there is still too much friction in the mechanism. next is the heads, clean them with alcohol, and make sure they can move freely on the rail, a bit of oil may help...

I will pause the development on this project for a while, i have here the latest files, i have got the board running, one side-note here is that i think i may have to find better diode substitutes for this project, but with the original diodes from the donor board this does run properly.

Also, i had the idea to integrate HDMI out at some point, im looking for suitable IC's for that that can take the RGB+sync signal and spit out HDMI out the back.

yeah man! so, indeed CL26 will be added, probably around 3nF, vertical image size right now is barely adjustable so ill find the cause of that as well, and then ill go over the board and optimize some more, i would like to replace some parts with SMD ones if possible, ive got some more...

GOOD NEWS! Thanks to mark_W, i found that i had the wrong value for DL1, the zener diode that protects in case of over voltage, once i placed it over from the orignal board, the unit started up and i have display now! still adjustments need to be done, geometry is not good yet, and...

Thanks very much, well i have checked the other voltages, and they are all within spec, so that is good, ii trace down C-sync as well, i assume you never did find a datasheet for the XC1186B either right?

So have 75V on the QL1, it is stable, oddly enough this is without the VGA mod in place, so it should be 60V or so. all other voltages are in check, Pin 41/42 have 5V on them, and the unit does attempt to start, this attempt doesn't last, and doesn't affect the 75V, it stays as is. i suspect...

okay now i have checked the board one more time, and i cannot see any errors there anymore, i did fix 2 connections before, now i have measured the signal on the main transistor that drives the flyback, the unit responds to the power-on command, turns on, and as it is time for the flyback to...

Yeah, i know that as well, it seems complex as i have also used some cross-reference parts for several things, such as QL2, some diodes where i replaced them with slightly faster ones, while i cannot get the XC1186 main controller IC, or the LM2418 video amp IC. currently i have soldered up...

still working on this, it seems my 60V is always too high at 80+V , the other voltages are in check, at 8 and 24V. quite strange to me. i have soldered up a new board now, but it is still not working as intended.

Now i got all the voltages dialed in, i got the +5 / +12 / +8 / +24 / +60V / -5 all stable under load, but i still have a voltage drop over the 60V line on power up, and im not sure why that is yet. i also have RL28 getting hot, and that is also un-explained as of now, its a 2R2 1/2W resistor...

Okay, i have +5 and +12 aswell now, but when powering on, and when it's time to turn on the CRT i can see from my AC power meter it's doing a hickup thing where the power goes from 25 to 35W and back to 25W again. so i may have to measure the CRT PSU under load and do some fine adjustments.

Yeah, you got that right! so the HV supply switchmode is working, the +5 +12V one isnt starting through the power on command from the keyboard, im going to find out why that is, i do have the +5V from that HV switchmode side, and that is supposed to power up and activate the main PSU.