Jon Hughes
Member
We had a 4 day holiday in the UK with the diamond jubilee and it's raining so I had some spare time. I decided to have a go at repairing some boards I bought some time back, way back and thought I'd share the findings.
I started repairing from self learning and studying various sites. I've made a mess of a few boards in my time while not having the correct equipment. You often learn from your mistakes, but I believe it pays to think things through before attacking boards with a soldering iron....
First up is a memory expansion board from Mortal Kombat 2. I think one of the previous owners got a little frustrated with it and the pictures show what happens when you lose patience - 120 bent pins on the P14 & P15 connectors. Also noticed U4 socket had been replaced with a DIL socket with a 20 pin chip installed. Removing chip U4 I found a bent leg on pin 11 (but this didn't really matter in the end).
Photo 1 the board in question.
Photo 2 & 3 the rats nest of bent pins.
Photo 4 my set up for de-soldering.
Photo 5 pin 11 straightened on chip U4.
Photo 6 nice new connectors
Photo 7 board populated
Photo 8 short pins mean the boards touch, but the originals are impossible to find.
Photo 9 RESULT!
If you can carefully look at photo 6 you may see the chip at U4 is a SN74LS244N. After investigation I found out it should match U3 & U5 and be a 74ACT0244. Luckily there is one at UD22 on a T-unit board. Desoldered UD22 from my donor board and placed it in correctly as shown in photo 7. I wonder if someone had attempted at a have a go repair at this board.
Total repair time 4 hours - would have been a lot less but the new connectors would not fit into the soldering eyes unless they were perfectly free from solder - biatch.
I started repairing from self learning and studying various sites. I've made a mess of a few boards in my time while not having the correct equipment. You often learn from your mistakes, but I believe it pays to think things through before attacking boards with a soldering iron....
First up is a memory expansion board from Mortal Kombat 2. I think one of the previous owners got a little frustrated with it and the pictures show what happens when you lose patience - 120 bent pins on the P14 & P15 connectors. Also noticed U4 socket had been replaced with a DIL socket with a 20 pin chip installed. Removing chip U4 I found a bent leg on pin 11 (but this didn't really matter in the end).
Photo 1 the board in question.
Photo 2 & 3 the rats nest of bent pins.
Photo 4 my set up for de-soldering.
Photo 5 pin 11 straightened on chip U4.
Photo 6 nice new connectors
Photo 7 board populated
Photo 8 short pins mean the boards touch, but the originals are impossible to find.
Photo 9 RESULT!
If you can carefully look at photo 6 you may see the chip at U4 is a SN74LS244N. After investigation I found out it should match U3 & U5 and be a 74ACT0244. Luckily there is one at UD22 on a T-unit board. Desoldered UD22 from my donor board and placed it in correctly as shown in photo 7. I wonder if someone had attempted at a have a go repair at this board.
Total repair time 4 hours - would have been a lot less but the new connectors would not fit into the soldering eyes unless they were perfectly free from solder - biatch.
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