so i was hooking up ps2 board i made..i pulled out all the big ics from their sockets before i started..
when i powered up after soldering on the ps2 board and replacing the ics, it wouldnt boot...
..then i noticed i put the CRTC in the socket wrong and missed by one pin :picard:
..so i put that back correctly in place and booted up...
i got the boot message ...but the sync is all off...ive tried reseating all the other chips..and even removed/desoldered the ps2 adapter board, but the sync is still off...
does this look like CRTC? ...or could i have possibly done the GA in?
:picard:
You'll have shorted several pins to ground and possibly fed 5V into some CRTC outputs, so it's most likely that you fried the CRTC.
Bryce.
thanks for the confirmation Bryce...
yeah..i shifted left by one pin.. :picard:
yay onto my 3rd CRTC!
ok so one more question for ya
@Bryce i must use the 'S' part and not the 'R' part correct (S is 3.7mhz R is 3mhz) on the HD6845 correct? or can i get away with the 3mhz max version?
You can use either (as Amstrad did).
Bryce.
thanks Bryce..
that makes it a bit easier to source
well... i got the replacement CRTC today....
and..CPC is doing exactly the same thing... :picard:
ive swapped over the ROM from the 6128 basic1.1 to the original 464...with no change...
ive swapped all the RAM chips out...same results...
ive swapped the Z80 out for another...no change..
i CANNOT run any diagnostics from the Lower Rom Board...just black screen or garbage..
USIFAC does detect at all either...
its looking like the Gate Array is toast :picard:
the logic chips shouldnt do this right?
edit: ..the 74LS153s could be causing this.... ill try swapping them out...
swapped out the 74LS153s same symptoms...
its really looking like the GA :(
so new gate arrays arrived today (from here https://www.icompplus.com/en/integrated-circuits/32243/40007-ic-dip-40-1030173) they all look brand spanking new!
but.... the issue remained the same......
turns out it was the effing GBS8200... the geometry got all screwed up... i defaulted it, and now its running fine...SMH (i dont get why lower rom board or usifac werent being detected tho...lower rom board working fine now..but usifac having power issues (i need thicker wires on CPCs power switch!))
im f..ckin hopeless!
Do you have the GBS Control mod? That's highly recommended as the GBS will only unleash it's full CPC potential with it. Many things will just not properly work without the mod.
Quote from: eto on 08:19, 10 October 22Do you have the GBS Control mod? That's highly recommended as the GBS will only unleash it's full CPC potential with it. Many things will just not properly work without the mod.
yeah i do have an esp8266 setup easy to remove....i was having issues with it on first power up tho... it wouldnt display until i logged into the web page and changed a few settings (and some settings wouldnt save)... i pulled it when soldering up the ps2 adapter to the cpc... thinking the gbs8200 would just work like normal on testing the ps2 adapter.. but it was all screwed up (ive never seen it do that before with or without the mod)
...that and the fact i didnt socket the CRTC properly made me think one of the chips failed
...i dont know why i didnt check the geometry on the gbs8200..SMH
re-soldering up the ps2 adapter board to the bottom of the cpc board tonight...