A600 Faulty

ancalu · 20 March 2007, 21:58

Hi all!

I´m new here and don´t speak english very well, so be patient ;-)

I have bought an Amiga 600 from Ebay, and the seller turn it on before send it to me and everything was ok.

Now when I turn it on (by rf or rca video), all I get it´s a blank (black) screen with the power led on, and the caps lock led also on (If I push the key, continues still on). I put a worbench disc, no action (don´t try to read it)..all black.

I have check the psu and got +13.99 ,-13.40 y 5.2. Is that correct?? I think it´s a little overload. It should be +12,-12 and 5.But the Amiga turns on!

Any idea?

Thanks in advance

Zetr0 · 20 March 2007, 23:32

Hello ancalu,

welcome to the EAB, i am sure you will like it here.

The voltages that you have mentioned are in good tollerance for your amiga (+-10%)

However with this being said I am unsure as to why it is just hanging / crashing on a black screen.

I would check the following

1. Check the 'Trap door slot'
If there is an expansion in there make sure it is fitted correctly and tightly.

2. Do you hear a clicking sound from the floppy diskdrive ?

3. Check the output switch near the RF cable ( ntsc / pal )

4. Try an RGB to SCART cable if your TV can handle that

sorry i cannot be more help...

best of luck ancalu

ancalu · 21 March 2007, 04:22

more facts:

When boot , no floppy sound,and caps lock led always turn on from the beginig. No flicking.

I have check to boot without floppy,mouse and keyboard and no lucky. Always black screen.

I have no ram expansion nor HD.

Only 1 time, if I put the power plug a little loose and move it, i could get the floppy moving (but no picture) and frist a green screen and later in another ocasion a white screen.

I use a samsung Flat tv

Hope this helps!

Thanks

s2325 · 21 March 2007, 11:20

green screen = chip ram problem(s)

lopos2000 · 21 March 2007, 11:44

Check that your kickstart is seated properly.

musashi5150 · 21 March 2007, 13:27

Yes, take the cover off and make sure every socketed chip is seated nicely. You could even remove them and give them a clean if you are feeling brave enough. IIRC not too much was socket in these machines?

These old girls tend to get upset when moved about - a guy on here a while ago had the same problem with his A4000 - but he got it working again.

alexh · 21 March 2007, 14:25

There are no socketed chips on the A600 beside the Kickstart ROM. Everything is surface mount.

ancalu · 21 March 2007, 14:43

I have taken out the rom chip, clean everything and no response. Black Screen

Also I try to pull out everything, and boot up ONLY with the PCB. Pull out floppy, hard drive bay, mouse, and keyboard and no response.Again Black Screen.

It´s like the PCB don´t recived power (but the chips gets a little hot, so I suppose the pcb have somr current. But perhaps some voltages are mising, so in one time a get a green screen and a white screen perhaps was because i pull the power jack and this currents came again to the pcb)

Anyway..hoe do I take away the pcb from the case?? For me seams very difficult. I can´t move out the pcb from the yoysticks hole!! jejeje

Thanks in advance!

Ah!! also..could you tell me any point in the pcb to check voltages??

Thanks in advance!

Smiley · 21 March 2007, 19:55

Sounds like a blown/broken kickstart chip.

alexh · 21 March 2007, 22:14

Is there such a thing?

If you have an EPROM and the window isnt covered up I guess left in sunlight it could erase.

I think it is more likely that it's just buggered

Smiley · 21 March 2007, 22:51

Well putting a KS rom in upside can blow it.

If its a black screen with no FD activity then its not loading the bootstrap/kickstart correctly

ancalu · 21 March 2007, 23:41

Hi again.

More news. After taking out the pcb and looking at it... i saaw this:

http://img338.imageshack.us/my.php?image=placa2jw3.jpg

If you look at the upper right, you could see a missing part:

http://img380.imageshack.us/my.php?image=ein1rz1.jpg

The seller says that this computer always worked perfectelly..but comparing this with a unused motherboard..the component is missing:

http://img45.imageshack.us/img45/468...15back3mc6.jpg

So..i don´t know wtah to do. Right now I´m looking for a new board, but find it is very difficult and are expensive!!!

Any idea?

Thanks in advance!

alexh · 21 March 2007, 23:54

It is a surface mount capacitor... C12A

Should be easily replaced by someone with a little soldering knowledge with a non surface mount one.

Shame we dont know what it was for, sometimes missing capacitors are ok. (Well not OK but wont stop something from working)

It has definately been removed. Other photographs of A600 motherboards have different combinations of resistors & capacitors in that area so it could be configuration stuff.

ancalu · 22 March 2007, 00:04

Hi Alex!

Thanks for your help!

Two questions:

1) Can the computer work without c12a?? (the seller says so)
2) Is there any possibility that if I put the component the computer would work again o pherhaps others parts faulty?

Ah!! and finally How Do I know the value of c12A??
Thanks in advance!

alexh · 22 March 2007, 00:10

I dont have time to check but if you find out which page has the resistors and capacitors on the schematics I'll take a look.

http://www.ianstedman.co.uk/Download...schematics.zip

Look for the R459, R202, R203, R222, R225 and C12A

The value of C12A should be on the schematics.

alexh · 22 March 2007, 00:16

Some are on videocct.png and are something to do with the delay line on the video encoder...

But I didnt not find C12A so keep looking

alexh · 22 March 2007, 01:11

C12a is on sheet decoupling.png

It is on the circuit marked VIDEO power. It is marked as 33uF

It doesnt look that important (it is just a decoupling capacitor).

ancalu · 22 March 2007, 08:19

Thanks for the info!!

So, if is not important..the computer should boot up anyway...Is that right?

So...where could be the problem?

Some say static electricity (i have bath earth isolation) and others dead CPU..any iea?

Thanks in advence!

Zetr0 · 22 March 2007, 10:17

It might be an idea to TRY a spare a kickstart rom, if you have one, or ask if someone could lend you one to test

ancalu · 28 March 2007, 17:43

Unfortunally I don´t have any spare Kickstart rom, so...right now I´m looking for somewhere to buy a new cheap Amiga 600 motherboard.

I saw some on Ebay for about 12 Euros, bot none auction at this moment.

Thanks a lot.

20 March 2007, 21:58	#1
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	A600 Faulty Hi all! I´m new here and don´t speak english very well, so be patient ;-) I have bought an Amiga 600 from Ebay, and the seller turn it on before send it to me and everything was ok. Now when I turn it on (by rf or rca video), all I get it´s a blank (black) screen with the power led on, and the caps lock led also on (If I push the key, continues still on). I put a worbench disc, no action (don´t try to read it)..all black. I have check the psu and got +13.99 ,-13.40 y 5.2. Is that correct?? I think it´s a little overload. It should be +12,-12 and 5.But the Amiga turns on! Any idea? Thanks in advance Last edited by ancalu; 20 March 2007 at 22:08.

21 March 2007, 22:14	#10
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,397	Is there such a thing? If you have an EPROM and the window isnt covered up I guess left in sunlight it could erase. I think it is more likely that it's just buggered Last edited by alexh; 21 March 2007 at 22:21.

21 March 2007, 23:54	#13
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,397	It is a surface mount capacitor... C12A Should be easily replaced by someone with a little soldering knowledge with a non surface mount one. Shame we dont know what it was for, sometimes missing capacitors are ok. (Well not OK but wont stop something from working) It has definately been removed. Other photographs of A600 motherboards have different combinations of resistors & capacitors in that area so it could be configuration stuff. Last edited by alexh; 22 March 2007 at 00:09.

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20 March 2007, 23:32	#2
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	Hello ancalu, welcome to the EAB, i am sure you will like it here. The voltages that you have mentioned are in good tollerance for your amiga (+-10%) However with this being said I am unsure as to why it is just hanging / crashing on a black screen. I would check the following 1. Check the 'Trap door slot' If there is an expansion in there make sure it is fitted correctly and tightly. 2. Do you hear a clicking sound from the floppy diskdrive ? 3. Check the output switch near the RF cable ( ntsc / pal ) 4. Try an RGB to SCART cable if your TV can handle that sorry i cannot be more help... best of luck ancalu

21 March 2007, 04:22	#3
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	more facts: When boot , no floppy sound,and caps lock led always turn on from the beginig. No flicking. I have check to boot without floppy,mouse and keyboard and no lucky. Always black screen. I have no ram expansion nor HD. Only 1 time, if I put the power plug a little loose and move it, i could get the floppy moving (but no picture) and frist a green screen and later in another ocasion a white screen. I use a samsung Flat tv Hope this helps! Thanks

21 March 2007, 11:20	#4
s2325 Zone Friend Join Date: Jun 2006 Location: Gargore Age: 43 Posts: 17,789	green screen = chip ram problem(s)

21 March 2007, 11:44	#5
lopos2000 Zone Friend Join Date: Apr 2005 Location: Cider is best In The West Posts: 1,238	Check that your kickstart is seated properly.

21 March 2007, 13:27	#6
musashi5150 move.w #$4489,$dff07e Join Date: Sep 2005 Location: Norfolk, UK Age: 42 Posts: 2,351	Yes, take the cover off and make sure every socketed chip is seated nicely. You could even remove them and give them a clean if you are feeling brave enough. IIRC not too much was socket in these machines? These old girls tend to get upset when moved about - a guy on here a while ago had the same problem with his A4000 - but he got it working again.

21 March 2007, 14:25	#7
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,397	There are no socketed chips on the A600 beside the Kickstart ROM. Everything is surface mount.

21 March 2007, 14:43	#8
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	I have taken out the rom chip, clean everything and no response. Black Screen Also I try to pull out everything, and boot up ONLY with the PCB. Pull out floppy, hard drive bay, mouse, and keyboard and no response.Again Black Screen. It´s like the PCB don´t recived power (but the chips gets a little hot, so I suppose the pcb have somr current. But perhaps some voltages are mising, so in one time a get a green screen and a white screen perhaps was because i pull the power jack and this currents came again to the pcb) Anyway..hoe do I take away the pcb from the case?? For me seams very difficult. I can´t move out the pcb from the yoysticks hole!! jejeje Thanks in advance! Ah!! also..could you tell me any point in the pcb to check voltages?? Thanks in advance!

21 March 2007, 19:55	#9
Smiley Amiga-less! Join Date: Feb 2005 Location: UK Posts: 1,350	Sounds like a blown/broken kickstart chip.

21 March 2007, 22:51	#11
Smiley Amiga-less! Join Date: Feb 2005 Location: UK Posts: 1,350	Well putting a KS rom in upside can blow it. If its a black screen with no FD activity then its not loading the bootstrap/kickstart correctly

21 March 2007, 23:41	#12
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	Hi again. More news. After taking out the pcb and looking at it... i saaw this: http://img338.imageshack.us/my.php?image=placa2jw3.jpg If you look at the upper right, you could see a missing part: http://img380.imageshack.us/my.php?image=ein1rz1.jpg The seller says that this computer always worked perfectelly..but comparing this with a unused motherboard..the component is missing: http://img45.imageshack.us/img45/468...15back3mc6.jpg So..i don´t know wtah to do. Right now I´m looking for a new board, but find it is very difficult and are expensive!!! Any idea? Thanks in advance!

22 March 2007, 00:04	#14
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	Hi Alex! Thanks for your help! Two questions: 1) Can the computer work without c12a?? (the seller says so) 2) Is there any possibility that if I put the component the computer would work again o pherhaps others parts faulty? Ah!! and finally How Do I know the value of c12A?? Thanks in advance!

22 March 2007, 00:10	#15
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,397	I dont have time to check but if you find out which page has the resistors and capacitors on the schematics I'll take a look. http://www.ianstedman.co.uk/Download...schematics.zip Look for the R459, R202, R203, R222, R225 and C12A The value of C12A should be on the schematics.

22 March 2007, 00:16	#16
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,397	Some are on videocct.png and are something to do with the delay line on the video encoder... But I didnt not find C12A so keep looking

22 March 2007, 01:11	#17
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,397	C12a is on sheet decoupling.png It is on the circuit marked VIDEO power. It is marked as 33uF It doesnt look that important (it is just a decoupling capacitor).

22 March 2007, 08:19	#18
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	Thanks for the info!! So, if is not important..the computer should boot up anyway...Is that right? So...where could be the problem? Some say static electricity (i have bath earth isolation) and others dead CPU..any iea? Thanks in advence!

22 March 2007, 10:17	#19
Zetr0 Ya' like it Retr0? Join Date: Jul 2005 Location: United Kingdom Age: 49 Posts: 9,768	It might be an idea to TRY a spare a kickstart rom, if you have one, or ask if someone could lend you one to test

28 March 2007, 17:43	#20
ancalu Registered User Join Date: Mar 2007 Location: Spain Posts: 12	Unfortunally I don´t have any spare Kickstart rom, so...right now I´m looking for somewhere to buy a new cheap Amiga 600 motherboard. I saw some on Ebay for about 12 Euros, bot none auction at this moment. Thanks a lot.

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