Goddys 520 STfm restoration help needed

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Goddy
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Goddys 520 STfm restoration help needed

Post by Goddy »

Hello to all the ST experts out there

I have another problem after the disk drive was sorted i loaded up Speedball a awesome game that i got with my ST played it for a long time after i finished a reset my machine to try another game to see if it worked i got a few green bombs on the screen from my understanding thats a error message right ?.

So i desided to turn it off i went to have a go on it today i powered the ST up and i got this screen :cry:

Image

Whats has happened ??
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alexh
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Re: Goddys 520 STfm restoration help needed

Post by alexh »

Perhaps loose Memory chips? Or capacitors which have failed?

Ask yourself how much a working 2nd hand 520 STfm goes for on eBay before attempting a long arduous repair.
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

as usual alexh is a sour pose :(
this is half the fun with an old chap like an stfm sent here and there
and needs a repair !! terrible "just get a new one" this does not win a war :lol:


the shifter ic or mmu is loose in its socket

take the top off the floppy and psu out and the top metal case off
open the silver shifter box in the center of the board and press the ic back home
do the same with the other ics in sockets use your two thumbs and press hard

just make some time with the one you have and don't panic this is quite common

have you just got it from someone then this happens in transit if the machine is in an unmarked box
then the postal service guys dont know to place it the right way round
and the ic's fall out a bit !! and with a heat up the thermal expansion is enough to make or break a connection or two on a loose ic

what i can see is in the top right of the picture is a different pattern
chances are its just the shifter as there appears to be data flying to it from the bus

DO NOT do what some idiots recommend and drop it from 1" on a hard surface

if you got bombs before it died sounds like a loose DMA chip also
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

Yeah i got it in the post Tuesday wasnt packed to well it was lose in the box so i wasnt happy about that but no damage to the case lol i will open it up again tomorrow afternoon and have a look thanks again for your help
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

Well i opened it up and pushed down on the shifter IC and the other one's in there sockets they made a good awful crunch noise.
I assembled it back together minus the top case and powered the ST up still the same thing is happening

These are chips i pressed down there the 6 IC chips near the cart port and the shifter IC

Image

Sorry about it being all a blurr and these ones are the mmu ?

Image
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

top one is the GLUE chip
the one near to the front is the MMU

did you press them in ???

also do a test please

hold in reset turn on the psu
wait a sec or two and let go reset {just an idea?}

also take a picture of the psu and post it :contract:
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

thinking back im sure ive seen ppera with the same issue in a mega st and it turned out to be the glue chip
same pattern ,...
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

pm me an address ill send you a glue and mmu ic for testing think its something with the glue
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

Thanks i sent a PM and i did pressed the glue and mmu in i will do the reset test very soon and get a picture up of the PSU too
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

:coffe: I tryed the reset I pushed the reset button for 20 sec and let go and i got the same screen

Image

heres the picture of the psu

Image
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

i will get some jiffy envelopes and post a few things on monday :D

just putting xp back in the pc for programming and i will burn some eproms for people also
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

alexh wrote:Perhaps loose Memory chips? Or capacitors which have failed?

Ask yourself how much a working 2nd hand 520 STfm goes for on eBay before attempting a long arduous repair.

Yes true it would be easyer but the old Atari ST doesnt pop up on ebay au alot. this was the first one i seen in over a year if not more but that wont stop me getting another one day
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

when you press reset does the screen go black>??
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Re: Goddys 520 STfm restoration help needed

Post by Guest »

in the state it is the diag cart will tell you via rs232 whats wrong with the chipset
it will load and test ram etc without need to replace stuff

if the shifter is gubbed then it will output whats displayed chars to rs232

so use a pc and serial null cable in this case 25pin to 9 adapter then 9 male to 9 male null moden cable {RX < TX TX < RX and ground atari <= pc}
set hyperterminal up and it will display

i would do this before changing stuff

perhaps someone has a stF series cart that can be sent
i dont but i have the images so any diag cart will do change the roms
look for one local
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

Hi simbo2 are you posting out those chips still so i know to keep a eye out for them in the post
Last edited by Goddy on Thu Sep 13, 2012 5:49 am, edited 1 time in total.
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Goddy
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Re: Goddys 520 STfm restoration help needed

Post by Goddy »

simbo2 wrote:when you press reset does the screen go black>??
OK i set it up and just pressed the reset button the screen goes white then back to the same display as in the picture above i posted
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