TT030 hardware st ram upgrade to 8 or 12mb GUIDE'S

[Guest]

there is a better way for sure!!!

[Guest]

ok stage 3 of the ST RAM to 8MB onboard upgrade

so what i did this time was to strip off an 8MB simm and solder the ic's onto the carriers
and test all as you go...
the next step is to wire all the pin 5's on the underside of the TT motherboard together
then from one at the top add a mad 9 connections via a 74ALS244 buffer and a 47R resistor
like .............line buffer resistor ... pin 5's group {PIN A9}
---pin34 mcu MAD9...|>--\/\/\/\.....PIN5's

so bit tired and eye strain so ill let it alone till tomorrow

tomorrow night ill post the result

the ic's i used are 1Mbx4bits X16 ics

you can access the data bus at the expansion sockets for the ram riser card {ill do this with 1Mb chips after i check the 8MB STRAM is working }
for continuity of all signals
the address bus is available at the resistor packs
few pages back i doc;s the connection

[Guest]

final stage
perform full cold tests of all lines etc {three times}
then apply power first sign of trouble switch off
i cant sleep tonight
so i carried on and guess what ??

this mod to the main pcb is tricky for sure
i used a 74ACT245 as i did not have a 244 handy
ill tidy it up with some spots of glue and some heat shrink on the resistor etc tomorrow
gonny try again and get some kip
tomorrow ill rip all the 256Kb x4bit dram from the riser 2MB card i have
and attack another simm for chips

i think 3 ics?? were not working when transplanted
what i did too find them was to place the 256Kb back except 1 and narrow down any fails this way
you need to tie the resistor of A9 to high to turn off the extra above 256 of the chip your adding
i made a full 2MB machine from 1Mb chips then finally connected back mad9 to A9

hence the rather squint looking chip
i have tried to find dil ram 1Mbx4 before old simms seem the only source
and most are SOJ

we just need better risers soj boards
with some small post holes drilled some way through the boards but not out the other side
as this would muck up the soj pads on them
this way its easier to attach pin strips etc

big thanks to cose for the board's

[Guest]

TOMORROWS PROJECT IS TO REPLACE THE 256Kb X 4bit DRAM WITH 1Mb X4 x16 ICS

the good thing about this type of riser is it uses SOJ footprints
and !!! all the address 9 work with the buffer is there
you just need to change the ram
and move the jumpers

[Guest]

if you cant be bothered to get a hot air chip remover

then what i did in the past when they cost like £££££ and not £ was to use a black and decor!!! paint stripper gun

place a 3AMP diode {1N5407 or similar high piv} inline with the LIVE inside the plug

L ---->|------heat gun
neutral ......
earth.........
then its around 350 deg instead over over 500 and slower air
the ones you get these days im sure will have a diode inline with there heater element to reduce its output
if not you can add one as needed to heater motor or both
wave it around a board ram area to warm the area up use some tweezers to take the ics off or heat and bang them off
youll find you can mod the nozzles for the task
once cool place them on conductive foam
i would wind out a sheet of tin foil and earth it
to bang them on to this will increase there life and dissipate the heat still in them quite fast but not too fast

[Guest]

ok tonight's project is the riser

im going to remove all the ram ic's from it
they are 256Kx4 ics and its 2MB type CA401059-001 rev B
{look for this code from ebay sellers before buying or you need to use DIL to SOJ converters
and until there is a slightly improved design i dont recommend them for users with less experience in soldering and checking with no power and a lcd multimeter}
it has two jumpers W1 and W2

2/8 MB Board (CA401059-xxx)
The board contains the following jumpers to select the 2MB or 8MB memory configuration:
jumper....2MB...8MB
W1.........1-2....2-3
W2........open...2-3

i am interested to see what the ST RAM will count too
with 16MB available will it be 12 as people say its the max addressable or perhaps 16???

[Guest]

get set

solder!!!!!

[Guest]

so here is how it ended up
with 8MB on-board tested and works
i added the 8MB converted card and tested it
and it still said 10240K so it ignores the other 6MB

so i removed all the riser chips and replaced back the onboard 2MB
so its now a 10MB STRAM machine 32MB TTRAM {ill add to this soon as i get the pair i ordered {see magnum topic for links }}

alls well that ends well

back to the red screen
while playing around i pressed the board down a little while i was booting from the cart
and as if by magic the wait state MCU bit 7 error disappears so i assume one of the thru holes is open circuit
so its gona be a job to solder all of them
ive isolated it to an area about 10cm square so ill do them and see if it clears the only issue left

at least its progress

i am also going to change out the funnel sockets as i cracked one
think the trick here is to buy new ones as new stock new old stock the plastics may go brittle

[frank.lukas]

TT030 hardware st ram upgrade to 8 or 12mb GUIDE'S



regards

Frank

[Guest]

http://www.conrad-uk.com/ce/en/product/ ... Detail=005

quality black flat tab {not pin tab} smd sockets

ive removed these TT boards bad sockets pin tab and replaced with tab

i had issues with the brown sockets
too low profile

ive managed to get frank aboves board to show accepts seems i need to desolder the ram now

i think all TT owners need to watch out for there boards resin dipped caps

[Guest]

point taken frank
well ive replace 100 or so stupid dipped caps with 10nf ceramics
i had so far to replace the ram and 1 funnel ic twice
and im taking no more chances with these little yellow resin dipped caps
if i remember the type used in TT machines and TT alone is the yellow ones
glass coated resin dipped
if at some point the glass outer cracks then moisture gets in
and then they start to sing to the power input of the ram chip etc
then they go brown
then BANG and goodbye to the associated chip
i want to keep my TT working so its been 5 hrs of work well spent
and i am waiting for yet more ic's from good old USA

fek!

good thing about the cart and rs232 is it tells you witch one. is gone

[bid]

I have an ST RAM board for the TT that has an intermittent fault.

I suspect that its the connectors, and I was thinking of just reheating the joints to the connectors.

Is this a good idea?

Many thanks,
Bid

[Guest]

meter it out john on LCD meter set to diode range
this is what i do first to every upgrade
each ic in the two banks has common pins
so pins on ic 1 carry through check at the top of the address pins along the rows
then ras cas to buffers and WE etc then buffer to mcu

check the two interface sockets gold pins are all correct
most often its prob gona be one pin on the mcu on it
or a ram pin
so out with the mag glass and look for anything suspect
like shards of solder between pins etc
give it a good brush with a sable brush check again for lifted pins with a needle {observe static rules with grounding the board and you}
if you find a pin or two lifted
use some flux pen on it
let it dry then solder it with a pencil tip iron and push it down with the needle for a sec or two as you solder to hold it to the pad
oh ye
and watch out for a loose jumper
the jumper maybe is intermittent can end up driving you mad
if its a 2MB it will just have 1 jumper 8 mb uses two as pic above
also does it work from cold then fail
or fail when it feels like it wait till it fails turn off spray the chip turn on ? working
try a few times to confirm the ic mark ok on top with a pencil
and use the spray sparingly as you can damage ic;'s with it also
if its a cold hot issue try some freezer spray on the mcu or buffer ics ram as a cyclic test
to see if one is heat sensitive
if it turns out to be the ram then i can help and replace it if you need it
and upgrade it too 8mb

also
more and more as i pointed out in this topic back a page or two
the yellow bipass caps in just TT's are going wrong
i think they fracture with age and material stresses and this lets in moisture
then they 'sing' for a while with spurious rubbish rf to the ic they are supposed to protect
and then one day when they decide go bang

sound like i would replace the bypass caps first think they are 100nf resin dipped {not sure the rest prob tant looking at the yellow colour}
and check for shorts etc
then retest and freezer if then needed

ps what does the TT do when the fault occurs ? ignore the 2MB??

i can lend you a test cart it will show the exact address of the faulty chip and then you know the exact one to change out or check

[Guest]

i am bringing this topic up again
because this is the last place i left my TT030
it had suffered from a blown cap on the memory power rails
each chip has a bi pass cap
in the TT they are resin dipped glass so can crack and moisture gets in
ive replaced most of the resin dipped around the memory stress areas
and now ill populate the ram again
after the last blast off
so anyway
read the whole topic
ive replaced and pin to pin and pad to pad checked the funnel ic's
even found a place in HK that will give me 10 off for 20$ of these funnels {pm me if you need}
so ill double check my pin to pin lists
and maybe my white screened TT will work
if someone can make a rev d-k picture
and a colour chart and pin to pin list as dots on the pins of the chips with a label system perhaps
16 bit 65535 colours if you choose a dot and hover over the page you can locate the same colour quick an overseer routine with 65535 to 65535 dot change colour to white locate
a blind dog can find this ...

inbetween chips is whats needed not the ports etc ..well some... as an extended need and thats your own beef

why do people in eda not think of this
?? even assign a windows sound colour standard scheme 1v per ovtave etc easy
one reg key

ill extend my pin to pin lists this can be mapped in 3 d also
as the format i used within the TT scsi here
Problem with SCSI on TT
pin to pin checks if you need to replace the ic.s

a pin chart and link would be good

but i will note that some pads are thrus and inbetween
ie the inner track goes to one ic
it links to the outer of the pad that goes somewhere else
the pad is in the middle
and easily fractured
so you need to check 3 way sometimes

[dibasber]

hi there
is it posible to upgrade the st ram on the mainboard?
i have 16 socket chips total 2mb

[Arne]

is it posible to upgrade the st ram on the mainboard?

Yes.

[dibasber]

how and what will it cost??

i allredy have a board whit 2mb extra
i ment on the mainboard itself

[Arne]

how

http://dev-docs.atariforge.org/files/stramupg.zip

and what will it cost??

probably money

[bid]

[quote="Guest"sound like i would replace the bypass caps first think they are 100nf resin dipped {not sure the rest prob tant looking at the yellow colour} and check for shorts etc then retest and freezer if then needed

ps what does the TT do when the fault occurs ? ignore the 2MB??

i can lend you a test cart it will show the exact address of the faulty chip and then you know the exact one to change out or check[/quote]

Right, yesterday, several years later, I have grabbed a digital soldering station from work, and I am going to try replacing the capacitors 1st.

2017-01-13%2008_54_18-Monolithic%20Multilayer%20Ceramic%20Capacitors%20-%2010%20Pack%20-%20Choose%20PF,NF,UF%20-%20Free%20P&am.png

There are 3x 47uf capacitors on my ST-RAM board, and it looks like mine might have been re-worked (like 20 odd years ago, lol), as there are flipping wires everywhere, and the 9013 IC has had all but 5 of its legs clipped, and is wired directly to memory chip U2.

My TT reports 8MB, but then after a restart, or randomly its gone. In addition, sometimes I just get graphics glitches when its fitted. So I have nothing to lose.

It might be, that the upgrade can me copied from my board, and I am happy to do some close ups. ... That is, if my board was originally 2MB?

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