A1200 faulty chipmem

Tomse

Tomse

RISK is good
AmiBayer
Joined
Jan 30, 2010
Posts
854
Country
Denmark
Region
Copenhagen
I used http://aminet.net/package/util/moni/MemTest
to test my mem..
and yikes, my A1200 has got chipmem issues :-(

so, does any of you have a schematic for the A1200 rev 1d4 ?

and possible pcb layout ?

and any leads to where I can get some new memchips from a reliable source.

and.. any got expericen with replacing the chip mems / any pointers ?

cheers
/Tomse
 
I would test again, with another ram tester, just to be sure.
unless the reason you were testing it is because you've been having problems.
The program i use is the Microbotics ram test, available to download here:
http://amiga.resource.cx/exp/mbx1230
it's meant for testing the ram on their accelerators, but it will test any ram you have installed.
 
I actually tried downloading and extracting it, the extraction didn't go too well, so I skipped that one.

I removed my accelerator so it would only test the chipmem, which it said was faulty.

my problems are that my A1200 freezes up from time to time, mostly when I start up games, but it happens in the workbench from time to time aswell.
 
Hardly the memory chips will go bad. Did you replaced the motherboard capacitors?

Anyway, the chips are the very same as the A600 ones and can be found in old ISA video cards. Prefer the 70ns chips if you find those.
 
@juvk I know the feeling though.. I sometimes read things way faster than I should hehe.. thanks for the link, I'll take a look when I get some more time :)

@rkauer I suspect though a single chip or two since it's not the whole mem range that's the problem..

but I can see I need to make some more tests..
replacing the chips are not all that easy compared to one or more caps. :)
 
That's true. If a memory chip goes bad, then I think only Cosmo or Zetr0 are the guys to ask for help due to your location.
 
yay.. found an old PCI gfx card with similar mem chips, I checked the datasheets, and specs are the same ;-)

The gfx card is a Daytona 64v 3DX with a S3 Virge/DX 86C375 chip.
Which is in the same family as BVision and it's supported by Warp3D.
But i'm not sure if Warp3D supports the chip when on a PCI bus..
 
BVision / Cybervision - potato / potahto hehe ;-)

but thanks then I have no problems removing the mem from the virge card :)
 
There's a huge (speed)difference between BlizzardVisionPPC/CyberVisionPPC (both Permedia 2) and a CyberVision64/3D (S3 virge). So I wouldn't call it potato / potahto...
But that's offtopic anyway... :)

Anyhow... if the memory is the same as the A1200 chipmen go for it! Good luck! :)
 
don't know so much about them, other than what I heard some years ago ;-)
gfx card / gfx card hehe..
and I know only of people who used the Virge chips for 2D Windows apps.. so don't know of the performance :oops:


anyway.. yeah, I need some luck, I already have problems removing the chips from the gfx card, I'm trying with the leverage method, and it's not going too well :-(

leverage method: something to put pressure by lifting the IC, then heating the legs of the IC.
and the legs are bent inwards which makes it more difficult to access the solder mass.
hence my original thread.. any tips ??
 
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the problem is that the legs on the mem is bent inwards, so they are underneath the IC, not outwards as shown in these examples.
which makes it difficult to actually touch the area where the soldering mass and the pins connect. applying too much heat on the legs, will destroy the IC.
perhaps the chipquik can be helpful, depending on how it sticks to the legs after pulling the IC up.

These examples also more or less destroy the IC when they are removed, I need to reuse the ones I have ;-)
 
No no, they are not meant to destroy the chip. But for that type of chip I suppose the best method would be hot air with this type of nozzle:

0058736814.jpg


It directs the air nicely where it needs to be. Unfortunately they are rather expensive, so if you can't find someone to do it for you, you may need to MacGyver some kind of solution based on the same principle :)
 
It most certainly is not the right way but since the gfx card is going to be destroyed anyway, I have used a heat gun to the back of the card, when the solder melts the memory chips drop off the graphics card.

Another way, I used a small slotted screwdriver, and pushed it between each pin and the solder pad, the pin bends slightly but brakes the solder joint. This really depends on how much solder there is on each pad, so may not work.
 
good idea with the screwdriver :)

I'll try that or something similar
 
I had to go with AJK's method of low melt solder.

I bought a Chip Quik kit at their homepage (chipquick.com) but can also be bought other places, and even though it says it can remove around 8 chips, I removed 6 chips from the gfx card, and all 4 from the amiga. and I still have plenty of material to work with still (I reused some of the solder while it was still on the pcb.

I hope I didn't heat the memchips too much to kill them off.

The chips were semi easy to clean afterwards, there's alittle low melt solder left on some of the legs, but not nothing that interferes with anything.

Do any of you know of a place to get 40pin SOJ sockets ?
I haven't been lucky in my search, and definately want sockets so I can test the mem chips.
 
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