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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: on June 17, 2008, 01:04:33 AM
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I've been building an A4000T. In it are 4 4mb simms, an A3640, and, at the moment, nothing else. I've hooked up the disk and video daughterboards and the ports board (via straight-through 40-pin IDC ribbon cables), and installed the CPU card and ram. I'm trying to get it to come up to a kickstart screen, but no go. I get a blank screen (using an A520 to output to my tv) and no audio either, from either the speaker or the RCA outs on the video board. The A520 is getting power as far as I can tell, because it's syncing to my TV. I have tried this with the floppy drive from my a1200 as well as a few floppy drives from A2000s, and get the same, blank screen. Any suggestions?
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Hello,
I think I might of had the same problem, have you switched all the SCSI jumpers at the back to OFF position? If not the machine won't boot without SCSI drive. Hope that might help? Merv :roll:
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Thanks for that; I have switched them off, but still no video. Now I suspect there may be other jumpers I need to set! :)
Do I need to do anything with the keylock connector, or can I leave that connector open? I don't have a 4000T case, so I've got it in a regular AT case.
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@pkillo
I had a couple of 4000T's and seem to remember the floppy drives were Sony MPF920(PC) or something similar and that the floppy cable was modified (by factory) for these drives to work. If you are using the original floppy cable (from the 4000T)with a floppy drive other than the one that came with the 4000T plug it into the middle cable rather than the end cable and see if it works.
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I actually don't have the original cable for the floppy drive; I have only a straight-through IDC-34 cable (just like the a1200 cable). The floppy never does anything at all, no lights or vibration.
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Did you set the CPU sync jumpers on the motherboard? For the A3640 it needs to be set for external sync. For an 030, and I beleave the 060 as well need to be set for internal sync. Also both jumpers need to be set to the same position, they are right next to each other.
J100 Pins 1 and 2 CLK90 Clock Source is Internal
Pins 2 and 3 CLK90 Clock Source is External
J104 Pins 1 and 2 CPU Clock Source is Internal
Pins 2 and 3 CPU Clock Source is External
Information here
http://www.amiga-hardware.com/showhardware.cgi?HARDID=4
Diagram here
http://www.amiga-hardware.com/downloads/a4000tmbdiagram.gif
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Thanks, now I've got the clock jumpers set correctly. Still no video, though. No activity on the floppy either. :(
Edit: I just noticed that the keylock connector on the motherboard is actually labelled PWR/KEYLOCK. Does this mean I need to hook up a switch/jumper to get the system to power on at all? My understanding was that the keylock just locked out keyboard and mouse access, but there's 5 pins here, marked by color: brown, (blank), black, red, black. Seems like there's supposed to be two physical switches connected, and I'm guessing that maybe one or both need to be closed for the system to power up.
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Have you tried it with no floppy drive attached?
Rich
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Yes, I have tried it without the floppy drive. No video in that case.
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(bump) Anyone know which pins are which on the 4000T PWR/KEYLOCK connector? :)
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Try reseating the cpu board.
I had a similar problem when i got the cpu card back from france just the other day, i modified some screws and tightened it in, no nothing, same exact thing you describe, no floppy no nothing, but it did say hello to the monitor, ( i could tell because it doesnt fully support 15khz) so i took it out, put it back in and bam.
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Thanks, I will try reseating the board at lunchtime and see how it goes.
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OK, I reseated the board - and it seems like I'm making progress. I still get no display, but when I turn off the switch to the power supply, I'm getting a flash of gray. :)
I gave the system power for about 30 seconds, but no kickstart screen.
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pkillo wrote:
I just noticed that the keylock connector on the motherboard is actually labelled PWR/KEYLOCK. Does this mean I need to hook up a switch/jumper to get the system to power on at all? My understanding was that the keylock just locked out keyboard and mouse access, but there's 5 pins here, marked by color: brown, (blank), black, red, black. Seems like there's supposed to be two physical switches connected, and I'm guessing that maybe one or both need to be closed for the system to power up.
I believe that this is just a standard keylock, and the additional pins are for the power LED.
Regards
Rich
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Pokemon wrote:
For the A3640 it needs to be set for external sync. For an 030, and I beleave the 060 as well need to be set for internal sync.
060 processor boards also require jumpers to be set to EXT - at least the CSPPC/mk3 & mk2 do, not sure about others.
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Well, I tried jumping the 'red' pin with the 'black' pin next to it, no go there. I'm going to try connecting the 'brown' pin with the other 'black' pin next...
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I'm looking in the A4000T user's guide... here are a few things to check:
Jumper 300 (next to the ram slots) should be closed left for 16 mb ram.
Jumper 500 (just above video slots) should be closed left to disable sync on green.
It doesn't seem to have any information about the pinout of the keylock plug I'm afraid :(