common Rf issues with nemesis + many chipset accelorators

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simbo

common Rf issues with nemesis + many chipset accelorators

Post by simbo »

Hi all the falcon and TT machines with dma and other strange problems

please read the attached archive i made
for a member further down the topics list
{better to make a new post as it affects many people}


esp REV A,B machines
the problem with dma is a simple one

there is two 74LS244 buffers {low speed 10normal -20mhz max} used to switch the banking on the simm {memory} if you use fast ram {14mb etc simm} and use any type of accelorator {even dont use one }
this flaw will cause dma problems

you need to cut them off and replace them with 74HC244 {30mhz or more } or 74HCT244{40mhz bandwidth} the later is best if you can get it

if you use the buffer board for clock
there are some mods i recommed to this section
to improve it

see how i did the nemesis upgrade to my REV C machine
and fixed my rev B 030 to use the memory with no dma breakup {as per chip mod above

and gain a few tips what else to change
in older revisions to stabilise things fully

dont forget older revisions of the falcon have a faulty scsi chip
U7 L53C80JC2
and also you may need to actualy have a termination block on both ends of the cable {even one at the atari end}

you need a later version of tos to work around this if i remember....

anyway read the texts and
please feel free to add comments
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Last edited by simbo on Wed Mar 05, 2008 3:48 am, edited 3 times in total.
simbo

Post by simbo »

i updated the above archive to add more text and hints

general tips i found usefull here to reduce noise on the pcb etc


tip1
----

if you have a sluggish machine poor dma or dsp access
and slow scsi

if you open your machine up and remove the metal
use some de-flux {pcb flux remover} spray
spray it onto all the bigger ic packages
that have flux deposits round there pins
now let it steep there and dab it off with some kitchen roll
repeat this if needed to remove it all

at the time of manufacture this left over flux isnt a big problem
but as time goes on it dries up and starts to conduct
removing it can cure some machines completely
i personaly remove every spec of flux resins from the pcb

tip 2
-----
wrap it up in normal tape then
tapeing the memory upgrade boards {4/14mb}
with copper tape and ground it to the pcb rim
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Post by saulot »

The article is quite interesting, because I have a lot of trouble with my falcon and scsi (ct60, 20mhz bus, a lot of disc crashes, drive locking etc). It was sent to R.Czuba, but he didn't help much at all. I will try all of this when I will have some spare time left.

How about writing some kind of tutorial to revive the f030 machines to proper working state (with accelerated, and non accelerated buses, IC replacements.. etc)?
I'm not really into hardware and it would be very interesting to read for me (and I would really like to force my falcon to work flawlessly).
simbo

Post by simbo »

what is useful is to know is the revision details
located on the lower left of the main pcb
i never use scsi and instead just a big ide drive
and internal cdrom i added from a laptop lots of problems stem from the psu
it can supply a maximum of 7 amp +5v and only 250ma +12v
{this is a big problem if you use internal ide 3.5" drives}

so i use an atx supply and a soft power on switcher board
{i posted details in another topic further down}

but i think you need to help the scsi termination

a trick i learned a long time ago with scsi and the falcon

inside at the rear of the scsi socket is two diodes 1n4001 they have a band on them at there cathode like +5v----anode >| cathode --->fuse>---supplies scsi drive far end with active termination power supply +5v buffer reference

1} if this fuse is gone you will get disk errors
if it has active termination enabled this setting on the hard disks
{only far end drive needs termination or active termination enabled usually a jumper on it}

.....it appears not to do anything and the disk behaves as it did before {usually this setting affects the system} {not to be confused with drive termination active termination relies on power from the machine to balance the cable nulling between different grounds sometimes you get an earth loop in houses

chances are this fuse is gone its easy to beep test with a multi meter or check for low R below 1ohm

2} also do this mod while your there
see the drawing below but you'll get the drift

the two 100nf caps are ceramic type or resin dipped
the electrolytic's are 470uF @10V and 100uF @10v {use 10v types not 16v types}
if you look at the termination and active termination supply's they aren't decoupled so what happens is you get
a standing wave that builds up on the termination power resistor packs
and the cableing and drive termination
{depends how well its decoupled also}

because the rf has nowhere to go except thru the diode as -voltage eeek
leaving + half wave rectified rf behind to oscillate further

i also added to mine a diode that's cathode connects to the fuse /diode and ground} to act as a rectifier and switch away this negative voltage
if you have a negative voltage on a + rail you get less voltage as a result
each time the disk accesses so on long read writes {esp long writes}
its like a feedback in a PA system feeds back audio and this wave builds with time

incidentally the adaptec 2940 also has this design error so .... hahahahaha
other cards don't .... i always had problems with mine using the external socket till i added this tweak

always used screened scsi2 cables !!! and keep the primary cable short

i would use for several drives a two way and drive plug in card {has two female and one male on its pcb}
and use properly screened cables in between
if you use 8 bit drives
you can plug a 7 way cable into one of these pcbs also
provided the first drive isnt terminated and the last one of the 7 way cable is

3} a bad dma ic can cause this fault because its not supplied with ample clean voltage below 4.8 usually causes this problem

to cure this there are several ferrite filters marked

L80{right hand pin }
L60{bottom pin}
L64 {left hand pin}
L77 {right hand pin}
L98{right hand pin}
L72{bottom pin}
L56{bottom pin}
L60{top pin}
L76 {bottom pin}
use some 1mm red single core multi strand hook up wire
{must be multi stranded type}
connect all the above points to one +5v source
a good place is the large capacitors +pole C147
remember not all of the ferrite bead filters on the main pcb
are used for voltage supplies

these little filters above come
from the main VCC power
{layer two/three {in the middle of the pcb}}

so it suffers from voltage differences across the board
anyway
as standard esp model 001 002 rev a,b

because the fine interconnection ring of thru plate to the vcc rail
can with time start to become resistive or are week
anyway due to pcb quality {light green is bad dark green is good}
especially if the chip draws current
or more current

{ie an added accelerator or a hot chip {some chips draw more than others anyway}}
if you heatsink hot chips they draw slightly less current believe it or not..}

this causes voltage drops
but usually only after these beads
so its the vcc connection pin end to them that is usually better
to use for the wires
look in the schematics you'll find these vcc filter beads dotted around
and they have two default loops with vcc at each end

you'll see where i mean
the way to tell the right end
{to keep the filter there also and not the chip side}
is to use a low ohm range {20ohm fsd on a digital multimeter}
and connect the negative probe to the + pole of the big electrolytic cap
then the pos probe held tight to each end of the filter
there will be a minute resistance difference {maybe .002 R} or so
if it has less on one end this is nearer the vcc so is the right end


the grounding itself isn't so bad in falcons except rev a
where some wires needed added to the grounding also only occasionally where all else fails

a way to tell is to use a oscilloscope
properly grounded
and in probe X10 mode set to 10mv per graticule vertical shift
move the trace to the bottom line
set it to dc input mode and a slow 100ms sweep rate
if there is more than 150mv on the ground pins of the ic
and this pin connects to ground
direct then add a wire especialy if its any more than 20mv of noise {mush}

is the rule


now you have done these mod's
look at the added audio screening post in the topics list
do this and make the board fit over the scsi section

you can add some twist together ground wires so you don't need to unsolder them just untwist them to remove the plate


oh and some tos versions are more stable than others
experiment using a big file and several versions of tos 4
switched using a software tos changer at boot
a tip here is to use a pc scsi card and an image to reprep it if you get a catastrophic fail


remember to use one filtered socket bar for the computers
and hardware

one for monitors ON ANOTHER filtered socket bar
then the crap on the mains from the monitor is double filtered

you should use yet another filtered plug bar
to supply both from one socket point
{a good idea in practice}
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Post by saulot »

simbo: Thanks :). I have also question what equipement best to use to do this mods (soldering iron, wires etc) to receive best results.
If it comes about soldering I am rather not expert (I've done everything with rather simple equipment).

If it comes about revision of my board it's rev. J and I have tos 4.04 on board second thing is tos from ct60 flash rom (which is patched 4.04), atx power supply ESP-300ATXSP4 (manufacturer: FEEL).
I think it's wold be nice to gather all of these tips in one place, because I haven't seen similar thing anywhere on the web.

What kind of errors can be with wrong termination? Data corruption, drive lock ups? (I have something like this when the bus is not boosted or when I work in higher video modes like 800x608x256 cols). It's pretty annoying.

If it comes about my scsi cable I have scsi 2 cable(around 1m) which in turn is connected to normal 50 pin cable(I have two devices atm). Recently I've believe that by playing around with termination directly on devices I've killed my 9.1gb barracuda V (I've used 50 to 68 pin connector) :( .

How termination should be set up correctly, as far I know termination should be at the beginning of scsi chain (first and last device).
From the post you wrote I assume that there is termination from the falcon board already, so I don't need the termination from the first device counting from f030 board, is it true?

What i don't fully understand is the difference between active and normal termination, in what cases i should enable them and how. I've seen various terminators taht can be enabled on devices, can be connected to cables etc, but I haven't the rough idea (from good source) what is good and what is wrong when doing proper working scsi (and how I can tell when everything is working ok).

If it comes abou the scsi fuse I will check it in minute or two and post results... I will also try to post some pics of my board.

the bad thing about ide that I cannot use those drives, I've bought connector(2,5" to 3,5") But during boot i receive garbage on the end of device names and I cannot do anything with them. Additionaly when I scan for devices and nothing is connected to ide i recieve something like this ________________ on ide 0 and 1 (it's a random thing, ide scan lock ups for a short while, sometimes it occurs sometimes not). It's pretty weird.
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if you have accelorators & or dma dsp scsi issues

Post by samf »

Simbo,

This only applies to those who have a nemesis and are using scsi drives, correct?

Thanks
Atari Computer Nut
Virginia U.S.A.
C-Lab/CT060 Falcon,
256mb TT Ram, 14mb ST Ram,
4Gig hdd, IDE DVD Drive
simbo

Re: if you have accelorators & or dma dsp scsi issues

Post by simbo »

samf wrote:Simbo,

This only applies to those who have a nemesis and are using scsi drives, correct?

Thanks

first thanks for the relevent question you asked

ok so
the scsi problem exists in all falcons TT 030
and the root cause is the lack of termination decoupling
these modification to the scsi falcon end termination supplies
should be carried out on ALL falcon machines
{hehe and adaptec scsi pc pci cards}
its very important acceloration used or not

to do these above mods anyway
as for the wiring up the beads to +vcc this is also a very important fix
if you have a scope or an lcd digital voltage or multimeter {cheep but get a good 3dp version so it reads like 5.000v three decimal places}
and set it to mv range when testing ground to ground and 10 or 20volt
range for the +5vrail measurements
{very accurate metering and notes taken and used}
have a look around the chipsets + and - pin connection
take a note of what chip pins {ground and vcc}
have a voltage error or exactly what the voltage on the pins is
even a ground pin at more than
200 mv causes 200mv less voltage or more 4.8 instead of 5
if also the vcc rail is resistive then as much at .8 volts or more
can be missing from the supply to that ic

this is important as gates switch to ground and vdd levels to transfer data
if a register only switches down to .8v relative to the real ground {becouse the ground pin of the ic is higher than ground
this transistion isnt a clean 1 or 0 level {0 or +5v}
and can... cause data packet loss
{ crash of a disk loss of data to the chipset/dma/ dsp{clicks and pops}}

once you have this list publish it
together with the pcb revision details

and add to your posted list the outcome of adding the fix wire links
once remeasured
{would only take 1/2 hr each time to measure all the pins that connect to ground and vcc power planes {pcb layer 2 and 3}}



this step will help others for sure....

its good practice to supply the right voltages to digital ic's
if you supply even .4 v less not only will the ic's draw more current
but will run a little warmer as a result of less voltage and also
with added gate glitch {a kind of time paradox in data transfer}
so... its up to people who have a scsi device and problems
to do it or not {if you can be bothered and need scsi }
it helped my setup {fixed it fully}
using the old 8gb scsi drive i had till last year
i had no further problems
appart from the obvious lack of termination power and translateral transfers without RF coupling and re-resanance
caused by this standing wave build up
the 1n4001 in series with the +5v supply rail to this stage
will actuly drop .6 volts anyway...
so the terminations is only really supplied with 4.4v max...
pretty stupid and an obvious oversight by the guys at atari facing the sack
i personaly think if problems still exist to remove D5 andD^ and replace with a shorting wire link adding the mod
this way there is still a diode rectifier
and the right voltage here 5v instead of 4.4v
you can clamp this voltage by instead of using
the added diodes in4001

you use 500mw{milli watt} 5.1v zener avalanch diodes


do not approch this mod head on take notes and work to a plan
based on do the scsi mods first then the chipset details then decide what needs patches with wire links to the relevent power plane
... :)
Last edited by simbo on Wed Mar 05, 2008 4:02 am, edited 1 time in total.
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Post by saulot »

I'm little confused about my motherboard version. On the top i have something like this: CA401332-003 REV-J, but at the bottom I read (on pcb itself) C303006-001 REV. A.

Do I have REV.A or REV. J motherboard :?:

I've also checked F1 fuse, it's even alive ! :)

I have also question about w10 jumper on f030 board? Anyone knows what's for?
simbo

Post by simbo »

saulot wrote:I'm little confused about my motherboard version. On the top i have something like this: CA401332-003 REV-J, but at the bottom I read (on pcb itself) C303006-001 REV. A.
Do I have REV.A or REV. J motherboard :?:
I've also checked F1 fuse, it's even alive ! :)
I have also question about w10 jumper on f030 board? Anyone knows what's for?
CA401332-003 Atari Falcon PCB. F-RFMOD,

thats the part number for the modulator

the number is the A revision one


not sure maybe someone knows

so.. W10 is used to change the mc1377 sync type

back to the scsi trouble

so can you take a picture with a phone or something of the back of the drive and the cable arrangment
it just sounds like a jumper problem to me or something mundain
Last edited by simbo on Tue Feb 27, 2007 12:37 am, edited 1 time in total.
simbo

Post by simbo »

with data errors involving termination

youll get missing data or lockups

you need to set a drive to
1} autopark
2} termination on if its the last device in the chain
3} active termination its best to use this if you can

you see a drive in the chain can have its onboard termination powered by the computer to balance the cables better to get less packet loss
4} first device in the chain {not the cable }
should be drive 0 or 1 as a bootable disk
youll get strange resuslts from drivers if you boot a id 2 or above drive
so id0 or 1 only as the boot disk

the cable the last physical device is the terminated one
the rest have there termination and active termination disabled

a good tip is mechanical devices are like cars
you need to let them warm up get angry grumble a bit
then get on with there job
so always power the external drive for a few minutes
before a session be kind to grampa drive
never take a cold drive from the garage or cellar
and power it straight away
let it warm to room tempreture
same goes for any appliance

if you get wierd power problems on drives

i found this one was a bad capacitor on the drives board
its a yellow or blue block and my one was 470 nano farads
had a brown hole in it
+12v rail
when it powered it sizzled inside was bad for months
houcked it off and replaced it and the drive was fine ...still is

i feel you must see if the cable is faulty using independantly
try to use a known good cable for testing{call a pal}
with ct60 there was many issues in some modes mostly becouse of unstable oscillators or poorly fitted cables not screened as most of the falcon is badly screened anyway
look for older software and some retrofits to the older ct's
it maybe just needs a tidy up

to repair your 9.5g
you need to plug it into a pc setup right
and remove any roge partitions to confirm its ok

ok with the ide
the cable is VERY sensative to noise
you must use a sheilded cable for connection to 2.5" 3.5"
use the little cable and keep it away from the chips on the board
by bending it up and away
if you used a longer 2.5 this needs changed back or foil screened {prob better}
http://www.casecooler.com/ideata66roun.html
use this kind of ide cables

your problem with certain modes is more likely a bad clock signal somewhere or bad dma from ide
or... chipset problems caused by the ide cable too close to the chips

i used copper foil and got a dual cable from ebay the other day... {05/03/08}
made a foiled cable and groudned both ends adding {still waiting for }
cf dual card slots
already cut i can simply power on a cdrom also on ide and it seems to see it
and at the same time the cdrom not powered makes no effect to two ide devices set master /slave
so all three cdrom {ide slave } ide>> cf dual card with hard card{always ide master }
and cfcard with sd/mmc converter{when no cd its the slave}
i hope will run fine together

i hope the cd will overule the second ide on cf {it does im sure}

anyway you can use tin foil to shield the 40 pin dual cable
i used copper foil especialy for this and grounded it
find it on ebay
type ' copper foil tape ' and solder it all together!!!
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Re: if you have accelorators & or dma dsp scsi issues

Post by viking272 »

Hi Simbo,

Some great gems of information there.
I've just resurrected my old Falcon that had Nemesis installed and sadly it seems to be very flakey.
I've looked at the original ZIP file which is great for me as I no longer have the disks, but the main item I'm after is the original install documents for Nemesis.
Basically I'm hoping to order a CT63 which I think will work with Nemesis but I'm worried that the random locks will mean it will be unstable with the CT63.

Alternatively if someone has the instructions they could scan and upload that would be very useful.

Cheers
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Re: if you have accelorators & or dma dsp scsi issues

Post by [ProToS] »

you can download it here
SeeU
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Re: if you have accelorators & or dma dsp scsi issues

Post by viking272 »

[ProToS] wrote:you can download it here
Hi ProTos,

Thank you so much!!

It looks like you'd scanned in the document lastnight - so thank you for doing that.

It looks quite a lengthy installation and I recall it taking me several days! I'll start with testing the software to see if Nemesis is on or off at bootup.
Any DSP software seems to lock quite quickly also. Maybe a weekend job. :cry:
Thanks again ProTos.
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Re: if you have accelorators & or dma dsp scsi issues

Post by [ProToS] »

they aren't my scans, I just convert/compress/rotate the img to made it more "readable"
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simbo

Re: if you have accelorators & or dma dsp scsi issues

Post by simbo »

FINALY

after nearly a year of twiddling my thumbs i got around to fitting
the nemesis back into my old falcon

the falcon has a 32mhz fpu chip added
and one of djbase's 16MB simm boards the key component by far as well as a cheep simm sources
i recently found although i cant find a decent diecast box to the spec i needed
so foil tape however adhear to coax all around to avoid many common problems with non balanced feeders
on what is a vhf signal and prone to leekage
why this wasnt made up
im not sure well i am

and its becouse peter green and i know he is a good sole
is a digital guy
im an rf engineer by trade this means i can work on ship to shore and radar and sign the dotted line
as working ,,, and thats it
bits of wire are no replacement for balanced feeders like coax as an unbalanced till given both ends ratios
makes
as a tube for rf
so also has capacity so needs only a simple buffer and a 32,000 clock
or you can use the older colour clock but these day why??? for falcon as a unit as this post
is only for the falcon and nemisis and other bus cpu/fpu clock accelorators
all of them crap in rf terms

maybe ill find the right diecast metal box and add the bits i wanted to
however my solution is fine
below the nemesis i fitted is card and on its under side a foil layer
soldered to the ground points from the old fan {crap anyway}
and the copper foils make dam good screening

so fit this addin to your nemesis

i recon cost to replace all the bits about £20

if some people need 4meters of solid silver mini coax ask
its £ 2 per meter + post to you ill give you good instructions how to cut it and where and using
just a simple craft knife

as you can see
ive used miniture coax for all rf except the 500khz clock

i also !!! removed the need for the colour clock
by reusing the dsp 32mhz oscillator can
and piping it down to the nemesis to be used as the 32mhz clock
i dont need a tv or rgb output from my falcon vga is more than enough

ive still to carefully dot super glue down all the cable to finish the job
and add a layer of tape or other insulator to the top of the nemisis board
then a layer of copper foil tape and solder it all down
this will entomb it all except a small flap that can be lifted to change the ttl 48mhz oscillator can on the nemesis board
if needed
i think 48mhz is enough

youll also notice i removed the 150pf cap at the clock input to the dma chip
there is no need as the coax will supply a little capacitance of its own
and is 50Ohm impedance solid silver coax

the bench mark figures are showing the nemesis running @ 48mhz
so the bus is 24 mhz im sure??

i still need to add a few more grounding points to some ic's as i have noticed in the past
slight ground discrepancies i was planning to attend to when i got around to fitting this back in
when i got the machine it was the usual dogs breakfast and really unstable
using bits of wire to carry 32mhz rather daft even more than the pcb
at least it has some ground planes

and the best thing is the guy peter green
every time he mentions a wire its "keep it as short as possible" or "try to keep the wire as short as possible and away from ram and chips etc"
so you use coax
its a real no brainer and anyone with one of these cards needs to do this
{if you look in the archive above i added too its info}

i used a 74HCT04 for the buffer ic
this way i get at least 2.5v p-p at each chip of a pure 32mhz 40 or 48mhz carrier only!!!
and no sprogies or other rfi {scope says 4.7vp-p rf @32mhz at the dma {nice level}48mhz clock give the same level}
i have a radio ham licence and i like using 10meter band this time of year
even 9meters{32mhz} is quite popular in some zones
its nice to be able to have the machine and the radio on at the same time!!!
peter green!!!

enjoy viewing the snaps

not to tidy yet
but it will look better once all the cable's are secured and final tweak's made
and ive still to apply a bonded heatsink to the 68030 {custom thing with hidden opcodes !!! where other dont }
{as its the only chip that really gets hot above 30c}

i just got sick of waiting for a ct60/63
and i felt like a camera man on a wildlife hunt
waiting to see a glimpse of 'it'
but always next week or year or season

150% is better than nothing

i also added rudolphs tweak to the scsi system to fix its read / writes stability
and it seems fine
after 5 copies of 200mb between drives and between scsi and ide

djbase's ram board works better that the type with the simm mounted below
and is stable with 'normal' non tab ram and 48mhz @ture colour highest res with videlity

ill plug in the 55mhz can tomorrow and do more tests as i know what it was like before
chalk# and cheese*

but im sure it will be 200% when i do fit the 55mhz block

ill wait till i have some cooling in place first

and this ram board fits the case better and makes way for a flash tos ... unit
you need to add a slip of .2mm card to its top to avoid shorts with the top case {obvious}


im maybe more happy now to stick to the original atari case and psu
adding a cf card or two and scsi hdd when needed
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Re: common Rf issues with nemesis + many chipset accelorators

Post by simbo »

and now its encased in copper foil adding sutible insultation
i used a cut section of old bycycle inner tubing as the insulative layer for the foil to sit on

tag it all down and solder all copper tapes together

beleve me this is the finishing touches to a a very stable machine
even at 55mhz
i just need 48 clock im happy
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Re: common Rf issues with nemesis + many chipset accelorators

Post by EvilFranky »

Benchies @ 55 Mhz would be nice! :D
simbo

Re: common Rf issues with nemesis + many chipset accelorators

Post by simbo »

im going to remove the GAL PAL sockets first

as they are cheep crap low frequency rubbish not fit to run above 10 mhz never mind at even 32
why they are there who knows

never seen a tweek to them so time i beded them down

after i do this ill post some benchmarks again for you @ 55mhz
ive still to cut the small flap to allow a change and lift out the 48mhz TTL oscillator
change for a 55mhz
but getting rid of these sockets is a must for a stable machine i feel

these pal/gals most of them reuse the 32mhz clock in one for or another
and lost of there i/o's run above 10mhz
and i think any falcon would benifit if they were removed and the chips hard soldered carefully
or atleast changed for turned pin type socket's
although in rf terms they are not much better.....
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Re: common Rf issues with nemesis + many chipset accelorators

Post by EvilFranky »

Sounds good!

How much further in your opinion could the Falcon BUS be pushed? At the moment 25 MHZ seems the limit, do you think with the replacement of some components for higher quality versions, that the 25 MHZ limit could be broken?
simbo

Re: common Rf issues with nemesis + many chipset accelorators

Post by simbo »

i think its a matter of cohesion with slower stuff that was the issue
reading between the lines of what pgreen and nemesis docs mutter on about

something to do with lower level clocked modules interfearing

perhaps opening the 32bit bus is a better idea its 25mhz for the bus we have to play with
here and adding this way past adding a ct63 or better
there is little solution to this.... limit

i use 55mhz clock with no issues
you can use a 65 mhz clock im sure

my advice is to use a ddc or pll to provide a faster clock
to the main clock in any speed up thing like the nemesis or powerup or phantom {i need to talk to the maker again}

after adding cooling and more current more caps better vcc and grounding
in that add a 1000uf cap to the vcc feed for the mpu 68030 and add to its ground a thicker wire then mount the caps in this new added vcc feed
this will balance the mpu more
as the ground on it can rise to above .2v relative
so its worth trimming this off then transactions cost less current over a bus and there is less glitch

a 3.3R 5watt resistor and a 5V stud zener is a good idea
to regulate the whole board before testing then its easy to see where more current is being drawn
and balance this out first ~!!!!

and tighten it up like this a fan on all ic's that benifit from a faster clock is one idea
if you use good cooling maybe 100mhz is possible with a good combel videl memory combo
with enough current to actual make the combel get warm {with me its cold all the time so its hardly taxed}
so its all down to the clock you use and the mpu heating and the mpu is the week point becouse its not able to disapate properly i feel

there is a solution
using a copper heatsink from a video card ... best stick to copper ones with this die
something not avalible in years gone bye

i recomend 4.0v p-p clock level {dont use more drive the more the less here}

remove all flux and add wire thru links to the thru plating
the rest is the exact frequency you use
it must be exact multiples or halfs of multiples + - quarters
im sure youll get ~75mhz cpu / 2 as the bus with little ill efect {but dont quote me}
fit the best heatsink's and fans to the mpu 68030fg combel video dma memory ic's
and support ic's that get hot like ide and other controllers
the mpu the best cooler is placed here for sure!!!!
add cooling under the board also
there is two places near the mpu you can drill straight through the pcb to add
compression mounted heatsinks
top and bottom

all birds are different in different shape...!!!

and i am mounting mine in wood and stepping it off the wood
adding a fariday cage to the inside of the wood
using 1mm copper tape
im making the box slowly ...
and gathering the right heatsinks
i dont plan to clock it all the way to death
but i want 72mhz clock so ill need to build a ddc
i will use a 4059 http://www.3-mtr.info/shareware/FRM%20- ... CD4059%29/
or similar... cd4059 design {as i have a few here}
simbo

Re: common Rf issues with nemesis + many chipset accelorator

Post by simbo »

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

i got this and ill add the falcon pcb to this unit

then use the case as i planned to make a 'retro but pc inside'

ill need to add a MEGA / TT keyboard so ill keep looking for one

if someone has a spare one ill take it {paypal}
Shredder11
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Re: common Rf issues with nemesis + many chipset accelorator

Post by Shredder11 »

I was going to bid on that case! :lol: On the day I forgot about it and it had sold when I returned to check, however I am not totally sure now that I want a 2U case. Also it has two floppy sized front cutouts, whereas I would want a floppy, CD writer and a CF/SD flash slot. So in reality I would need to make my own custom case to get all of that.
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Frank B
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Re: common Rf issues with nemesis + many chipset accelorator

Post by Frank B »

simbo wrote:http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

i got this and ill add the falcon pcb to this unit

then use the case as i planned to make a 'retro but pc inside'

ill need to add a MEGA / TT keyboard so ill keep looking for one

if someone has a spare one ill take it {paypal}
I have a spare mega ste keyboard you can have. It has a dodgy broken ctrl key but I suspect you can sort that. I'm not sure when I'll be back from France tho.
simbo

Re: common Rf issues with nemesis + many chipset accelorator

Post by simbo »

Shredder11 wrote:I was going to bid on that case! :lol: On the day I forgot about it and it had sold when I returned to check, however I am not totally sure now that I want a 2U case. Also it has two floppy sized front cutouts, whereas I would want a floppy, CD writer and a CF/SD flash slot. So in reality I would need to make my own custom case to get all of that.

ye ha... [smilie=greencolorz4_pdt_14.gif] thats a right bummer in it
the cd drive ill bolt ontop beside cubase stuff {steinberg digital i/o}
and also the sdcard and cf can go inside
i wont need to change them too much once they are all loaded up with stuff
lid off for a few weeks while i add a few heatsinks and a fan etc

quite looking foward to getting the bird mounted inside and finaly i can get the case for a retro pc number

the only thing i see you need it doesnt have is a slot for a cdwriter
try to find a scsi 2 type there is plenty around
as its not a thing i assume you would use everyday
i got an old box had a cdreader in it
just change the drive for a dvd writer or cdwriter
and that just plugs into the rear {this is my plan i have an old drive i got some time ago from the
british heart charity shop for a 5er...}
i think the termination pack on it was worth more even had a rotory id selector and its own psu
simbo

Re: common Rf issues with nemesis + many chipset accelorator

Post by simbo »

Frank B wrote:
simbo wrote:http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

i got this and ill add the falcon pcb to this unit

then use the case as i planned to make a 'retro but pc inside'

ill need to add a MEGA / TT keyboard so ill keep looking for one

if someone has a spare one ill take it {paypal}
I have a spare mega ste keyboard you can have. It has a dodgy broken ctrl key but I suspect you can sort that. I'm not sure when I'll be back from France tho.

sounds like a good deal to me ....!!!! out with the silver conductive paint and the scalple
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