NOS A1200 , screen flickers when accessing floppy

IT WORKED IN MINE ALSO !!!!!!!!!!!!!!!!!!

Thank you sooooooooooooo much my friend ANEMOS !!!!

even its 1D.1 the cap you told us to put there next to the IDE port did the job , the flickering is GONE !!!!

Best regards to you my friend !!!!

[Anemos]

good news marag! ,
one more perfect Amiga

[cosmicfrog]

good news all round i think

[TheCorfiot]

@Anemos

That is fantastic news all round my friend & on behalf of us all really thank you for sharing it with us, My A1200 is going under the Iron this PM.

One question for you though, what led you to that Capacitor as it's not present in all revisions & not on the famous list of "dried" out ones that must be replaced, though I've a feeling it will be added now

Best Wishes kai Heretismous

TC

[Anemos]

One question for you though, what led you to that Capacitor as it's not present in all revisions & not on the famous list of "dried" out ones that must be replaced, though I've a feeling it will be added now.
is

so im not guru electronic ,i take some experience of my father (old good electronic engineer)
this is electrolytic capacitor, the μF is the space, voltage is important (more is better).. i just test this cap coz is the smalles from my stock electrics materials .. so working fine.
and.. xeretismata!

[sanDae]

an alternate solution to amiga psu is to use c=128 psu :-)

[sanDae]

my floppy drive always make sound, even if i dont use it, some help?

[keropi]

Originally Posted by sanDae

my floppy drive always make sound, even if i dont use it, some help?

this is normal as it always checks if a disk is inserted... you can disable this with any "noclick" utility found on aminet

[Jope]

Originally Posted by sanDae

an alternate solution to amiga psu is to use c=128 psu :-)

NO.

It may work, it may not break anything when you try, but don't do it.

Thea C-128 PSU outputs 9V AC in the pins where the Amiga outputs 12V DC.

[illy5603]

Originally Posted by sanDae

my floppy drive always make sound, even if i dont use it, some help?

I formatted a disk and labeled it "STFU" and it hasn't left the drive in over 6 months.

[DesktopDynamite]

Hi there, am reviving this post as I am having similar problems with 1D1 and a Blizzard 1230IV by Phase 5...BUT mine does flicker also with mouse button clicking and cf drive access. Some intro scenes such as Frontier Elite game seems to flicker as well...
My question: is there an alternative cap to be done instead of the barrel type mentioned here? A tantalum one maybe??
TIA

[supaduper]

I have used Tantalum mainly on my recaps of many A1200`s and all work perfectly, you will have some people though say dont recap with tantalum but I have never had a problem, just get quality components

[Zetr0]

Originally Posted by supaduper

I have used Tantalum mainly on my recaps of many A1200`s and all work perfectly, you will have some people though say dont recap with tantalum but I have never had a problem, just get quality components

The primary reason I wouldn't recommend the use of Tantalum based capacitors is the fact that they very sensitive to ripple currents higher than specified and reverse currents as this can (and will) destroy the dielectric substrate and thus the capacitor - never use these to replace the audio filter capacitors. Usually there are special circuit design rules, specified from the manufacturers for safe operation of tantalum capacitors.

Essentially the Tantalum capacitor has a low tolerances out side its designated capacities / voltages and you should know the voltage / current spectrum variance of the circuit before you choose what tantalum based capacitor to put in.

Most tantalum based capacitors are solid state and simply cannot leak - but in the worse case scenario they can explode. So if a fellow EAB'er was thinking of changing the capacitors on their Amiga motherboard using tantalum capacitors I would suggest much higher - rated ones.

Although you could just use some nice high-quality 105c Panasonic or Rubicon with low ESR - As it is cheaper, will last a very long time (as long as its power cycled once a year) and looks great too.

[Amiga1992]

This was mentioned related to A600s, but it may apply to A1200s. Sometimes the video encoder needs a fix, namely there's a resistor between two of its pins.
Does your unit have it? Maybe it needs it.

Here's a post that details what was happening there:
http://eab.abime.net/showpost.php?p=830455&postcount=24

[DesktopDynamite]

Originally Posted by Akira

This was mentioned related to A600s, but it may apply to A1200s. Sometimes the video encoder needs a fix, namely there's a resistor between two of its pins.
Does your unit have it? Maybe it needs it.

Here's a post that details what was happening there:
http://eab.abime.net/showpost.php?p=830455&postcount=24

I have checked the post and it is more PCMCIA related...

[DesktopDynamite]

According to a former Commodore repair technician..

"I dont think D215 is the problem in this case. the 0.1uF axial cap on U12 is a mandatory fix that should be done att all motherboards under Rev 2B.
its a decouping problem.
the CXA1145 dont get enough power and therefore gives that flickering and it are far worse on composite video output but are also seen on RGB as the CXA sinks the RGB signals.

Here in sweden we got a service bulletin about this problem in 1993.. that all A1200 and A600 that went thrue our serviceshops should apply that fix on lower Revs than 2B and some Rev2B that are missing the decoulping capasitor.
the problem mostly occours with pcmcia cards inserted or with harddrive installed or something that draws more current the a clean A600/1200.

leave the D215 fix in place.
they are both usefull and should be there.

mlcc axial capacistor 100nF or 0.1uF
which should be on leg 1 and 13. http://www.demand.nu/retrotech/cca104x50v.html"

I now have bought this type of cap suggested above, and post back if it works or not...