what the hell? got little bombs on the screen

[floppydood]

and it's all crashed and ive now lost all my work

what do these bombs mean? heeelp. i tried restarting it but they've come back

[floppydood]

here, ive taken a photo of it


i dont understand, it had been working fine for about 2 months

[pterodactyl]

From a Techie Alison post...... hope this helps....

Error description GEM Error code
=========================================
OK (no error)....................0
Fundamental error................1
Drive not ready..................2
Unknown command..................3
CRC error........................4
Bad request......................5
Seek error.......................6
Unknown media....................7
Sector not found.................8
No paper.........................9
Write fault.....................10
Read fault......................11
General error...................12
Write protect...................13
Media change....................14
Unknown device..................15
Bad sectors on format...........16
Insert other disk...............17
Invalid function number.........32
File not found..................33
Path not found..................34
No handles left.................35
Access denied...................36
Invalid handle..................37
Insufficient memory.............39
Invalid memory block address....40
Invalid drive specified.........46
No more files...................49
Range error.....................64
Internal error..................65
Invalid program load format.....66

Those bombs that appear on your screen are error messages from
the 68000 micro-processor.

Number
Description of bombs
===========================================
Reset: Initial PC2...............1
Bus Error........................2
Address Error....................3
Illegal Instruction..............4
Zero Divide......................5
CHK Instruction..................6
TRAPV Instruction................7
Privilege Violation..............8
Trace............................9
Line 1010 Emulator..............10
Line 1111 Emulator..............11
[unassigned, reserved]..........12
[unassigned, reserved]..........13
Format Error....................14
Uninitialized Interrupt Vector..15
[unassigned, reserved].......16-23
Spurious Interrupt..............24
Level 1 Interrupt Autovector....25
Level 2 Interrupt Autovector....26
Level 3 Interrupt Autovector....27
Level 4 Interrupt Autovector....28
Level 5 Interrupt Autovector....29
Level 6 Interrupt Autovector....30
Level 7 Interrupt Autovector....31
Trap Instruction Vectors.....32-47
[unassigned, reserved].......48-63
User Interrupt Vectors......64-255

[simbo]

it is something or a chip that should provide an interrupt and doesnt {pin is disconnected}

this is a common problem
you can try the 1" drop fix
but i would carefully open it up
remove the floppy drive
open the top metal case after lifting out the psu

then press home all the ic's and reseat them totaly if possible

it can be caused by a build up of lead and tin crystalic oxides on the pins on the chips
or by a loose connection on one or more pins
when things are 'tinned' soldered this uses flux and other impurities in there metal make up
most metals are self cleansing and therefore throw out these impurities to there surface
lead is a few atoms more than gold so its safe to assume it cleanses more
but at the expence of more of its self as oxides as gold is more negative charge...
this causes resistances on the pins be it vcc supply or signals its all going on in there....
gold is far better but here we have copper lead tin ++

this can also be caused by the keyboard processor seating so reseat it also

[floppydood]

ok I tried the "1inch drop" fix. it seems to have actually fixed it. (well, so far anyway (been on for 5 minutes now))

[floppydood]

haha. After I posted that, guess what happened.

Ok. Looks like I'm going to have to do this the hard way. I've also got some other guy trying to help me out (I'll be honest the replies here are sometimes late and I can't wait to get my ST running ok again)

anyway after about an 1 hour tyring to figure out how to take the power suply unit out I've got thus far!



Dont know what is what I don't have the mad-skills that you guys do. are the IC's all the 16 chips at the bottom? so I just press hard on those right?

[insanity]

anyway after about an 1 hour tyring to figure out how to take the power suply unit out I've got thus far!

Just hi-jacking this thread, while you have the top off, could you take a decent photo and post it up...
It'll help the motherboard pics we have here:

http://www.atari-forum.com/wiki/index.p ... _revisions

Looks like you have an upgrade there by the way...

baz

[floppydood]

while you have the top off, could you take a decent photo and post it up...
It'll help the motherboard pics we have here:

sure bro.
betterpicof520st.JPG
2.69MB

edit: just noticed it's a bit blury on the numbers/letters, is it still okay or do it again?

[simbo]

actual problem:===================================

ok i see exactly what it is

on the right corner photo above is one of the sometimes dodge plcc flyers piggyback board
carefully take it out and put it back in tight but press the ic around under it
i think you need to add a square of card to its top to protect the connections etc...

also carefully open the 'metal can' in the center
and re-seat the connector in there also

all other ic's in sockets
press home

then carefully reassemble

it could be something shorting as these plcc riser thing was a pain in the place
years ago so was the 'metal, can bit.... i used to add a square of sponge {dont use black ic sponge as its full of carbon}
i used a stiff block of hi density packing stuff for hard disks

also
pay attention to:=================================

one of the cable headers doesnt look so healthy and may need pressed back together
the one to the right of the ok sign on the metal can

try that... im sure it will work and also protect the riser board from the case above

should be done while there:==========================

please also pay attention while your inside the machine
and service the psu there is a few topics in the guides for this task
mainly involves some resolders to the underside of its pcb
becouse the pcb is single sided its far more likely that mechanical effects will take place with it
and cause bad connections on its componenets
so needs a solder up and if you read the faq youll find some info on how to tell if any of the components that do age
look when they are bad {most often i replace quite a few capacitors here mainly } they are cheep they are like batteries that have a given output for a given initial charge
and are used to accumulate current as a resoviour ....

[floppydood]

sorry for my ignorance, what do you mean by press home?

other than that i understand all.

[simbo]

no probs sorry

press home
home is like the ic socket firm in place

so press well on the ic and it goes crunk and all the pins lock back in

i use my right hand first finger but the front middle of it and the thumb at the back and clench hand
to give an even preasure to avoid mechanical stress for dil's
for plcc i use two thumbs diaganol corners

not to hard just firm

the sockets always go cccc form the pins rrrr uuu nnn k stop at the first k

[simbo]

be very carefull with the riser its delicate!!!

use a flat screwdriver with attention and a good light...!! daylight

[floppydood]

thanks, i think i've done it all now. I'll wait another time to do PSU soldering touching up, probs next week

by the way, putting it all back together is a nightmare (well, for a beginner like me) after twisting all those metal clips back and forth i now have a new problem

basically where does this cable go???

[simbo]

hi

first thing BEFORE you put it together

your psu capacitors i added some squares too are very obviously fried

look at the picture ive reposted

you need to replace these parts NOW ..!
this WILL cause chipset damage ... also crashing etc...
so replace all 5 of them there is also i think in this psu 2 more to the right off picture you should also replace
as i said these things are like batteries and usualy contain a liquid electrolyte and this with time dries out
so you MUST replace them or very soon you wont have an atari...

the connector your holding is the floppy drive power

[floppydood]

ah thanks, ah damn! looks like i'll have to take everything off again

Ahhright, yes. I was saying earlier in a thread my ST was getting quite hot (hot enough to smell a bit of plastic in the room!) this will explain it. right well in that case I'll have to ask my dad on that bit as he knows a bit soldering stuff (he likes to fix up '30s & '40s radios) and I know for a fact he has capacitors of somesort somewhere.

thanks for that warning, don't wanna do any damage!

and Simbo can I just say your'e freakin awesome for helping me out this far man. appreciate it. Will let you know on how the PSU goes tomorow. not gonna bother turning it on tonight.

[floppydood]

I really didn't want to have to bump this thread until a few minutes ago... bascially. waaaaaah! they came back just now. all 24 of the little buggers.
Simbo, Shall I just repeat the steps in your post until it totally goes away? press home the IC's? maybe I missed one.

It was doing so well too. about a week of no 24bombings and boom.
anymore after a 2nd dose of opening it up and doing the hard way followed by another 24bomb attack then I'll have to look for another 520 on ebay.

[floppydood]

ok i've redone your post. taken out all the ics and pressed in again.

just gotta put it back together again now. the annoying thing about this problem is, you never know if you've fixed it straight away, you'll be doing something fun on the atari and it will ambush you

[floppydood]

nope, they came back

s'time to put this one in the bin

[Atarist8te74]

I have an stfm here. Maybe you could transfer everything over and get a working machine

[simbo]

did you fix the psu????
sorry i was away for a few days rest...
you do need to you know

the voltages will be all over the place
with hum on the psu rails

and silicon doesnt like hum at all !!!

i feel its the psu and most prob as i told you the unit that plugs in the front socket above the square ic {on top}
coming from the memory card dont forget to snap out and reseat the ram
give there pins a clean

take a picture of the modified unit {added bit of card etc}
also did you make sure to clean the pins with a burnish pen
here is a link in ebay to get one or go to maplin {they charge a fortune}
http://cgi.ebay.co.uk/Fibreglass-Abrasi ... 7001r24106

DONT give it
your almost there with this one

what to do is leave the metal top off for a week just put the top case back
add the 4mb board carefully somewhere.... out the way and well insulated !!!

if youve checked this all out and still have issues
replace the cable header i mentioned as its probably gubbed beyond repair
it looks half hanging appart in the above picture you posted
{one to the right and above the OK on the metal video shifter can in the middle of the pcb}
this one plugs into the memory board
and needs to be right or youll get bombs like spurious interupt from bad memory reads and writes !!
and coms to the expanssion board