Anyway, there are a couple of slight issues with the capacitor kit I ordered. First of all I'd just like to say that the values are all as they should be and that there are no issues with the quantity of capacitors in the kit I received according to the pick list included.
The first issue is that they not the same physical size. Allow me to demonstrate:
On the left is the board, pre-capacitor removal near the PCMCIA slot; on the right is the replaced capacitors from the kit:
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| Left - Original Right - New |
Or how about these two capacitors near the A1200's RAM:
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| Top - Original Bottom - New |
The more astute amongst you may have noticed that although the capacitance values are the same the cannister sizes are actually different. This is a bit disappointing (and I dropped my review of the kit to 4 stars because of it) as I would have expected all of the capacitors to be available with the correct physical size rather than just the majority. I know some of you may be thinking, "Well that bit is inside and no-one will see it!" but that's not the point. If I'm going to the effort of keeping this A1200 alive then I would much rather the board looked like it did when it came from the factory (minus the op-amp faux pas).
On the positive side, they were easier to solder in as there was lots more pad to hit with the iron...
Top tip. Have separate flux and apply liberally to the board when de-soldering or soldering stuff on. Don't forget to remove any excess with isopropyl alcohol. The reason I mention it is because I don't have any and some of the caps were an absolute **** to solder without it. Relying on the flux in the solder I have was not really very useful since it tended to burn away before I could get the iron to the pad (remember how small this stuff is!) resulting in a few suspicious looking joints. I will have to re-visit them but not before I have obtained some flux.
As I got towards the end I realised that I had two numbers on the leaflet which accompanied the caps that did not seem to be on my motherboard. Ah. The good thing was I had taken lots of pictures of the board before I removed all the caps for just such an occurrence. A quick visit to my phone to look at the pics and that was sorted.
Or was it?
In my haste I disposed of the piece of paper that accompanied the kit. This was a mistake. When I saw I had two caps left it looked liked I had two gaps to fill. The values of the caps matched the values shown on the photos I had taken of the board before I started so no problem. Except there is. The kit contained 18 capacitors. My Rev.1A motherboard has 19.
Arse.
I have a gap at C407. There is no gap at C460. The vast majority of photographs of Amiga A1200 motherboards show no component at C460 but do show one at C407.
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| C407 - Wherefore art thou? |
The first photo in this post shows clearly that I've replaced C460 with another cap. Here, though, is what most A1200 boards look like:
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| C460 missing but C407 clearly visible next to the radial cap top right. |
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| C407 Decoupling Capacitor |
The capacitor C460 is something to do with the reference voltage at the video encoder (see bottom right of the schematic extract below).
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C460 connected to Iref |
Dang nabbit. I need to try and work out whether to risk removing C460 and moving it to C407.
To be continued...
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