NOS A1200 , screen flickers when accessing floppy

keropi · 13 February 2009, 20:22

Hiya!

a close friend of mine just got a NOS Commodore A1200 and uses it with a 1240 accelerator and an A500 "heavy" PSU. The screen flickers in regions when a floppy disk is accessed. We also tried without the 1240 installed, but nothing changed...
Is there a solution to this problem?

TheCorfiot · 13 February 2009, 21:47

@keropi

Have you tried a different PSU with just the stock A1200 ?

It does sound like the PSU maybe struggling to provide a stable supply

TC

prowler · 13 February 2009, 22:06

Quote:

Originally Posted by TheCorfiot

@keropi

Have you tried a different PSU with just the stock A1200 ?

It does sound like the PSU maybe struggling to provide a stable supply

TC

Hi keropi,

TC's suggestion really does sound like your best first step. I recently traced a similar display problem on my A1200 to a faulty PSU. The minor fault had been evident from new, but I only discovered the cause when I tried the Amiga with another PSU.

prowler

keropi · 14 February 2009, 13:46

thanks for the suggestions, but unfortunatelly we have tried 3 PSU's... (1 from A1200 and 2 "heavy" A500 ones)
the problem does not go away... we even tried a different monitor

TheCorfiot · 14 February 2009, 14:15

@keropi

I had a feeling you might have tried it already, You say NOS A1200, If it was purchased form Amigakit then I suggest it goes back my friend.

I would say it has "Capacitor" issues & is unable to keep the supply stable when extra load is required, ie the floppy drive motor.

TC

14 February 2009, 14:24

its my A1200 with the problem and I am Keropi's friend, so first af all hello everybody and thanks for the answers untill now. To give you a little tip so you may help me is that the A1200 is Commodore and not Amiga.inc it was brand new in its box almost never used for several years and I took off for the first time the sticker below the case. the board is ver ID.1 and we have the flickering problem my friend posted here.

you can see parallel lines going up and down every time the floppy drive reads a disk.

we have also check the A1200 plain without the 68040 and the problem remains.

The point is that I couldnt wait for long so I have allready orderd a refubished mobo from Amigakit. but if there is a way to make the board work I would appreciate it !

Thank you all !

TheCorfiot · 14 February 2009, 14:41

@marag

Welcome to EAB & thanks for the history

My ID4 Mobo has the same issues whenever I use the floppy drive, I have to get round to replacing the Cap's on the Mobo, I just keep putting it off....

I'm 99% sure that's your problem too

TC

14 February 2009, 15:07

I think you have a point there, Keropi said the same thing from the begining but was not 100% sure. now we are

rkauer · 14 February 2009, 16:50

Look for "flicker fix" on Aminet. It's a hardware motherboard fix.

TheCorfiot · 14 February 2009, 23:54

Quote:

Originally Posted by rkauer

Look for "flicker fix" on Aminet. It's a hardware motherboard fix.

Does this fix affect Rev 1D1 Mobo's too ??

TC

rkauer · 15 February 2009, 03:25

Nope, 1D3 onwards.

Anemos · 15 February 2009, 10:42

Quote:

Originally Posted by rkauer

Look for "flicker fix" on Aminet. It's a hardware motherboard fix.

This is maybe the way solution for marag-keropi (hi guys) A1200 flik-prob..
but think he use tantalum cap,and this (also the electrolyte cap) has polarized + & -, the info dont tell nothing for this!

TheCorfiot · 15 February 2009, 12:46

Quote:

Originally Posted by Anemos

This is maybe the way solution for marag-keropi (hi guys) A1200 flik-prob..
but think he use tantalum cap,and this (also the electrolyte cap) has polarized + & -, the info dont tell nothing for this!

But their Mobo is a 1D1, no fix to apply, Change those Caps !!!!!

TC

cosmicfrog · 15 February 2009, 18:21

just 1 question from me are you using the rf for TV or rgb for a monitor ?

keropi · 15 February 2009, 19:33

rgb port for monitor...

cosmicfrog · 15 February 2009, 21:03

ok thanks, as some rf units are doggie, well mine was years ago

Anemos · 15 February 2009, 22:50

today i fix one of my 2 A1200 ,with same problem.. the Mboard is 1.D4
all OK now, the flicker is no more

i use one cap 1μF - 50V (smaller of guide but stronger voltage)
Edit: oh and polarized is: (-)on the left, (+) on the right..

TheCorfiot · 15 February 2009, 22:53

@Anemos

Thanks for that my friend, a great place to start, glad it solved your problem, I think you've finally inspired me to get may caps changed

TC

keropi · 16 February 2009, 00:33

excellent anemos!

Anemos · 16 February 2009, 12:15

@keropi ,hope to solve your problem soon.. if i can help you i do in my forum,in greeks..

13 February 2009, 20:22	#1
keropi . Join Date: Oct 2004 Location: Ioannina/Greece Posts: 5,040	NOS A1200 , screen flickers when accessing floppy Hiya! a close friend of mine just got a NOS Commodore A1200 and uses it with a 1240 accelerator and an A500 "heavy" PSU. The screen flickers in regions when a floppy disk is accessed. We also tried without the 1240 installed, but nothing changed... Is there a solution to this problem?

14 February 2009, 14:24	#6
marag Posts: n/a	its my A1200 with the problem and I am Keropi's friend, so first af all hello everybody and thanks for the answers untill now. To give you a little tip so you may help me is that the A1200 is Commodore and not Amiga.inc it was brand new in its box almost never used for several years and I took off for the first time the sticker below the case. the board is ver ID.1 and we have the flickering problem my friend posted here. you can see parallel lines going up and down every time the floppy drive reads a disk. we have also check the A1200 plain without the 68040 and the problem remains. The point is that I couldnt wait for long so I have allready orderd a refubished mobo from Amigakit. but if there is a way to make the board work I would appreciate it ! Thank you all ! Last edited by marag; 14 February 2009 at 14:43.

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13 February 2009, 21:47	#2
TheCorfiot Amibay Senior Staff Join Date: Feb 2008 Location: Cardiff / Wales Posts: 1,302	@keropi Have you tried a different PSU with just the stock A1200 ? It does sound like the PSU maybe struggling to provide a stable supply TC

14 February 2009, 13:46	#4
keropi . Join Date: Oct 2004 Location: Ioannina/Greece Posts: 5,040	thanks for the suggestions, but unfortunatelly we have tried 3 PSU's... (1 from A1200 and 2 "heavy" A500 ones) the problem does not go away... we even tried a different monitor

14 February 2009, 14:15	#5
TheCorfiot Amibay Senior Staff Join Date: Feb 2008 Location: Cardiff / Wales Posts: 1,302	@keropi I had a feeling you might have tried it already, You say NOS A1200, If it was purchased form Amigakit then I suggest it goes back my friend. I would say it has "Capacitor" issues & is unable to keep the supply stable when extra load is required, ie the floppy drive motor. TC

14 February 2009, 14:41	#7
TheCorfiot Amibay Senior Staff Join Date: Feb 2008 Location: Cardiff / Wales Posts: 1,302	@marag Welcome to EAB & thanks for the history My ID4 Mobo has the same issues whenever I use the floppy drive, I have to get round to replacing the Cap's on the Mobo, I just keep putting it off.... I'm 99% sure that's your problem too TC

14 February 2009, 15:07	#8
marag Posts: n/a	I think you have a point there, Keropi said the same thing from the begining but was not 100% sure. now we are

14 February 2009, 16:50	#9
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Look for "flicker fix" on Aminet. It's a hardware motherboard fix.

15 February 2009, 03:25	#11
rkauer I hate potatos and shirts Join Date: Oct 2007 Location: Sao Leopoldo / Brazil Age: 58 Posts: 3,482	Nope, 1D3 onwards.

15 February 2009, 18:21	#14
cosmicfrog The 1 who ribbits Join Date: Apr 2006 Location: leek, Staffs, UK Age: 56 Posts: 3,557	just 1 question from me are you using the rf for TV or rgb for a monitor ?

15 February 2009, 19:33	#15
keropi . Join Date: Oct 2004 Location: Ioannina/Greece Posts: 5,040	rgb port for monitor...

15 February 2009, 21:03	#16
cosmicfrog The 1 who ribbits Join Date: Apr 2006 Location: leek, Staffs, UK Age: 56 Posts: 3,557	ok thanks, as some rf units are doggie, well mine was years ago

15 February 2009, 22:50	#17
Anemos 70X7 Join Date: Apr 2008 Location: Ἑλλάς Posts: 1,078	today i fix one of my 2 A1200 ,with same problem.. the Mboard is 1.D4 all OK now, the flicker is no more i use one cap 1μF - 50V (smaller of guide but stronger voltage) Edit: oh and polarized is: (-)on the left, (+) on the right..

15 February 2009, 22:53	#18
TheCorfiot Amibay Senior Staff Join Date: Feb 2008 Location: Cardiff / Wales Posts: 1,302	@Anemos Thanks for that my friend, a great place to start, glad it solved your problem, I think you've finally inspired me to get may caps changed TC

16 February 2009, 00:33	#19
keropi . Join Date: Oct 2004 Location: Ioannina/Greece Posts: 5,040	excellent anemos!

16 February 2009, 12:15	#20
Anemos 70X7 Join Date: Apr 2008 Location: Ἑλλάς Posts: 1,078	@keropi ,hope to solve your problem soon.. if i can help you i do in my forum,in greeks..

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