27:05 - I was wondering what that bodge was on the Video DAC. My Amiga doesn't have that. I checked PCB explorer and was confused as it shows that trace on that pin on the DAC just going to a via that then doesn't go anywhere. Turns out that is why the bodge is there, because they forgot to install the trace on the motherboard.
Hi mate. nice video. I have some trouble with my 1200, after years dont start, i made a recap but no luck. I´ve got black screen with some times red screen with horizontal interference lines. No floppy activity and fix power led. I test with other known working roms and the same. I can reset amiga with keyboard with a 1 standard flash in shift key led. All 5v reset /halt tested and are ok. U49 POWER OK is good too. I suspect if i have random red screen all custom chips are ok? And maybe a bad contact or cutted trace from rom shocket???? Uffff, im a bit lost... I need a clue. Thanks in advance...
Red screen could be a kickstart rom issue. Do you have a DiagRom you can test with? That's a 2 rom set for the A1200. It'll run tests and send results to the screen and serial port. Also check the rom sockets & clean them if necessary. If you have a scope it's worth checking the clock, address and data lines.
Possibly the worst way of removing surface mount electrolytic caps imaginable. So if it doesn't damage the board how come a pad is missing? Do NOT do it this way. Just heat one leg and rock the cap sideways a little then go back and heat the other one and no danger of ripping a pad of the board.
Not at all. The pad was lost to the soldering iron during cleanup, as can be seen in the video, not from removing the cap. It was most likely already damaged by leaking cap juice.
I don't understand. You are talking about the removal at around 23:30? Add fresh solder then heat up that solder and the legs will move with the hot solder and without any resistance as shown........ what am I missing?
I'm not a personal fan of it but I know a lot of people swear by it - it does apply upward pressure on the legs while you're snipping it which might take a pad with it. The twist method has never failed me, neither has the 2 iron/hot tweezers method. I would *never* recommend the "heat 1 leg and rock" method on an SMD cap as this puts loads of stress on the remaining pad and tends to lever it off the board
12:40 - It's ALIVE!!
Thanks for sharing this.
Nice video Tim, You have a beautiful machine there :) and nice fix too :)
19:30 - I took the keyboard connector out when I recapped it
Yay!
The A2091 is a SCSI controller, whereas your 1200 have an IDE controller.
27:05 - I was wondering what that bodge was on the Video DAC. My Amiga doesn't have that. I checked PCB explorer and was confused as it shows that trace on that pin on the DAC just going to a via that then doesn't go anywhere. Turns out that is why the bodge is there, because they forgot to install the trace on the motherboard.
Yep, I think rev 1A is one of the early ones...
Hi mate. nice video. I have some trouble with my 1200, after years dont start, i made a recap but no luck. I´ve got black screen with some times red screen with horizontal interference lines. No floppy activity and fix power led. I test with other known working roms and the same. I can reset amiga with keyboard with a 1 standard flash in shift key led. All 5v reset /halt tested and are ok. U49 POWER OK is good too. I suspect if i have random red screen all custom chips are ok? And maybe a bad contact or cutted trace from rom shocket????
Uffff, im a bit lost... I need a clue.
Thanks in advance...
Red screen could be a kickstart rom issue. Do you have a DiagRom you can test with? That's a 2 rom set for the A1200. It'll run tests and send results to the screen and serial port. Also check the rom sockets & clean them if necessary. If you have a scope it's worth checking the clock, address and data lines.
Possibly the worst way of removing surface mount electrolytic caps imaginable. So if it doesn't damage the board how come a pad is missing? Do NOT do it this way. Just heat one leg and rock the cap sideways a little then go back and heat the other one and no danger of ripping a pad of the board.
Not at all. The pad was lost to the soldering iron during cleanup, as can be seen in the video, not from removing the cap. It was most likely already damaged by leaking cap juice.
I don't understand. You are talking about the removal at around 23:30? Add fresh solder then heat up that solder and the legs will move with the hot solder and without any resistance as shown........ what am I missing?
I'm not a personal fan of it but I know a lot of people swear by it - it does apply upward pressure on the legs while you're snipping it which might take a pad with it.
The twist method has never failed me, neither has the 2 iron/hot tweezers method. I would *never* recommend the "heat 1 leg and rock" method on an SMD cap as this puts loads of stress on the remaining pad and tends to lever it off the board