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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Gwion on April 25, 2008, 09:39:06 PM

Title: Amiga 2000 video problem
Post by: Gwion on April 25, 2008, 09:39:06 PM
My Amiga 2000 will only display grays. I am using a A520 modulator and connected to a TV using A/V.
Any ideas why its doing this?
Title: Re: Amiga 2000 video problem
Post by: orange on April 25, 2008, 09:52:14 PM
maybe its set wrong as NTSC/PAL..
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 25, 2008, 10:00:02 PM
How do i change it to PAL?
Title: Re: Amiga 2000 video problem
Post by: davideo on April 25, 2008, 10:24:36 PM
Have you tried using the phono out connectors on the 520 to see if you get colour from them?

The other thing is - If I remember right - there's a little switch on the side of the 520. Sometimes this needs switching over to work with some TVs  :idea:

Dave G  8-)
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 25, 2008, 10:30:07 PM
The little switch didnt do anything.
Is the a Jumper on the motherboard?
Title: Re: Amiga 2000 video problem
Post by: davideo on April 25, 2008, 10:35:14 PM
There is on the 4000D.

Not sure about 2000. I'll have a quick gleg in my manual.

Dave G  8-)
Title: Re: Amiga 2000 video problem
Post by: Zac67 on April 25, 2008, 10:41:32 PM
Are you sure it's a PAL A520? They're not switchable, single standard only.
Try to get an RGB display anyway, composite quality sucks.
Title: Re: Amiga 2000 video problem
Post by: davideo on April 25, 2008, 10:44:05 PM
I can't see anything in my 2000 manual about NTSC/PAL jumpers. On the 4000D it's clearly labelled as such  :rtfm:

Dave G  8-)
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 25, 2008, 10:44:56 PM
Its a PAL Amiga 2000 and a PAL A520 (works with ma A600)
Title: Re: Amiga 2000 video problem
Post by: davideo on April 25, 2008, 10:50:01 PM
I know it's a pain in ass but have you tried phono leads?

Or tweaking the tuning on the TV slightly?

Dave G  8-)
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 25, 2008, 10:52:30 PM
Phono? Im not using RF im using the A/V connections on the A520
Title: Re: Amiga 2000 video problem
Post by: davideo on April 25, 2008, 11:01:52 PM
Ooops!!

Terminology and late nights don't mix :crazy:

Dave G  8-)
Title: Re: Amiga 2000 video problem
Post by: davideo on April 25, 2008, 11:09:05 PM
This could be your answer :idea:

The Hardware database has this about the 2000 jumpers  :rtfm:

Jumpers

These setting come out of the manual for an Amiga 2000 Revision 4.x and is compliant with Rev 6.x Amiga 2000 boards as well.

J101 This jumper determines the high order address bit for Fat Agnus. In it's normal position, the high-order bit is A23; in it's other position, this bit is A19. The current Fat Agnus chip requires the A23 signal for proper management of the memory at $C00000. Future Fat Agnus chips may do things differently; this keeps the current board compatible with simple enhancements.
J102 This jumper if available configures the A2000 for NTSC, or PAL operation. Agnus 8370, 8372A, 8372AB for example, support switching between NTSC and PAL. Rev 6.4 motherboards and possibly later revisions come with an 8375 Agnus by default which does not support switching. It was made in in separate versions for PAL and NTSC
J200 This jumper determines the time base used for the 50/60Hz CIA timer chip. In the normal posistion, the 50/60 TICK clock, based on AC line frequency, is used as a time base. In the alternate position, the verticle sync pulse from the video section is used. The system will not operate properly without one of these clocks.
J301 This jumper is closed to add a second internal floppy drive, open to leave the second floppy out of the main unit box. The Amiga expects an ID bit stream from each floppy drive; this lets it determine the drive type. External floppies have this ID circuitry on board, but as it's not an industry standard capability, it has to be implemented on the A2000 motherboard to save cost on internal drives. Leaving the jumper open prevents the Amiga from seeing the ID sequence.
J500 This jumper is used to enable the 512k of RAM at $C00000 and the real-time clock. It is normally closed; opening it will disable both this extra RAM and the real-time clock.

Dave G  8-)
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 26, 2008, 12:02:29 AM
Still no difference :s
Title: Re: Amiga 2000 video problem
Post by: rkauer on April 26, 2008, 04:40:11 AM
@Gwion:

 1- Are you 100% sure you're using a PAL Amiga and A520?

 2- The Amiga is set to PAL? What A2000 version you have?

 3- For 100% sure: the A/V is routed from the side RCA connector (Video out)?

 4- Are using the "tick" signal (J012 set to "external") in a 50Hz voltage system (outlet frequency)? 50Hz Amigas will experience not-so-funny behaviour other way.

 5- Did you try a game or in Workbench? Workbench screenmode is set to more than 2 colours?
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 26, 2008, 10:11:32 AM
1- Yes its a PAL A520

2- It says 6.2 but looks like a 6.4

3- Yes thats the connector im Using

4- Dont know i'll check

5- Game is exactly the same

Quote

rkauer wrote:
@Gwion:

 1- Are you 100% sure you're using a PAL Amiga and A520?

 2- The Amiga is set to PAL? What A2000 version you have?

 3- For 100% sure: the A/V is routed from the side RCA connector (Video out)?

 4- Are using the "tick" signal (J012 set to "external") in a 50Hz voltage system (outlet frequency)? 50Hz Amigas will experience not-so-funny behaviour other way.

 5- Did you try a game or in Workbench? Workbench screenmode is set to more than 2 colours?
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 26, 2008, 01:48:33 PM
I cant find J012.
Where is it?
Title: Re: Amiga 2000 video problem
Post by: Zac67 on April 26, 2008, 03:48:44 PM
J102 is right next to Agnus and the crystal.

_TICK doesn't matter here at all, it's there to provide a stable time base for the CIA counters in case you switch vertical frequency (which is used in A1000 & A500).

Why don't you use the composite out from the motherboard?
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 26, 2008, 04:39:32 PM
The composite out on the motherboard is in grays i want colour.
The J102 is there it just doesn't have the pins.
Title: Re: Amiga 2000 video problem
Post by: Zac67 on April 26, 2008, 07:03:39 PM
Open J102 is PAL, so either just leave it open or cut the trace.
Title: Re: Amiga 2000 video problem
Post by: CLS2086 on April 26, 2008, 10:58:16 PM
why don't you buy a RGB scart ?
do you want to record something ?
How is the F5 fuse ?
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 26, 2008, 11:22:47 PM
F5 fuse?
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 27, 2008, 03:14:20 PM
 :bump:
Title: Re: Amiga 2000 video problem
Post by: CLS2086 on April 27, 2008, 09:49:32 PM
Hi
CM on AMiga-Hardware (http://www.amiga-hardware.com/download_photos/a2000mb_rev64_3.jpg)

the green resistor like between the 2 connectors on top right
Title: Re: Amiga 2000 video problem
Post by: orange on April 28, 2008, 04:48:34 PM
I doubt it he would have any output on modulator if the fuse was blown, I didn't (IIRC it was the +12V fuse)
Title: Re: Amiga 2000 video problem
Post by: Gwion on April 28, 2008, 04:50:37 PM
what does the +12V power? GFX?
Title: Re: Amiga 2000 video problem
Post by: RiP on December 17, 2016, 10:12:56 PM
I have the same problem :(
Just bought an Amiga 500 with A520 which works fine, colored output.
But when I connect it to my Amiga 2000 rev6, it gives me grayscale output :(
Title: Re: Amiga 2000 video problem
Post by: RiP on December 17, 2016, 10:13:26 PM
I have the same problem :(
Just bought an Amiga 500 with A520 which works fine, colored output.
But when I connect it to my Amiga 2000 rev6, it gives me grayscale output :(
Title: Re: Amiga 2000 video problem
Post by: magnetic on December 17, 2016, 10:47:53 PM
Either your A520 is PAL and your using ntsc or vice versa. A2000s DO NOT change pal/ntsc with just jumper its the a4k that has that feature. Your problem is def PAL/NTSC
Title: Re: Amiga 2000 video problem
Post by: magnetic on December 17, 2016, 10:49:47 PM
Quote from: RiP;817828
I have the same problem :(
Just bought an Amiga 500 with A520 which works fine, colored output.
But when I connect it to my Amiga 2000 rev6, it gives me grayscale output :(


Wrong agnus version...
Title: Re: Amiga 2000 video problem
Post by: Oldsmobile_Mike on December 18, 2016, 12:02:24 AM
+1 for PAL/NTSC issue.
Title: Re: Amiga 2000 video problem
Post by: magnetic on December 18, 2016, 12:11:04 AM
if you have an ntsc a2000 get an ntsc a520 dont hack the motherboard..
Title: Re: Amiga 2000 video problem
Post by: RiP on December 18, 2016, 05:29:26 AM
I believe they're both pal. My A2000 is pal.
How can I check Amiga 500 pal/ntsc version?
Title: Re: Amiga 2000 video problem
Post by: spaceman88 on December 18, 2016, 12:54:36 PM
Quote from: RiP;817848
I believe they're both pal. My A2000 is pal.
How can I check Amiga 500 pal/ntsc version?


What does Sysinfo say?
Title: Re: Amiga 2000 video problem
Post by: RiP on December 18, 2016, 06:34:07 PM
SysInfo reports it's PAL ECS, so what's the problem?

EDIT: Anyone heard about it?
http://eab.abime.net/showthread.php?t=37217
Title: Re: Amiga 2000 video problem
Post by: spaceman88 on December 18, 2016, 08:34:35 PM
Quote from: RiP;817872
SysInfo reports it's PAL ECS, so what's the problem?

EDIT: Anyone heard about it?
http://eab.abime.net/showthread.php?t=37217


Well the fuse fixed his problem. Did you get a chance to check the 12v line on your A2000 yet?
Title: Re: Amiga 2000 video problem
Post by: RiP on December 18, 2016, 08:57:04 PM
What fuse? and which 12v line?
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 18, 2016, 09:19:32 PM
Quote from: RiP;817877
What fuse? and which 12v line?


Read post #20 in above linked thread...
Title: Re: Amiga 2000 video problem
Post by: RiP on December 19, 2016, 06:21:16 AM
Quote from: QuikSanz;817878
Read post #20 in above linked thread...

"You know the A520 is good cause you have tested it.
To gain confidence regarding the A2000, simply but carefully measure the voltage while the A2000 is running on both sides of F5, should be +12V on the PSU side & 0V on Pin 22 side."

So I should connect positive connector of multimeter to the fuse and negative connector to the RGB's Pin 22, right?
Or positive connector to PSU 12V and negative connector to the fuse/Pin 22?
The fuse was fine since I remember :confused:
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 19, 2016, 06:34:05 AM
Quote from: RiP;817885
"You know the A520 is good cause you have tested it.
To gain confidence regarding the A2000, simply but carefully measure the voltage while the A2000 is running on both sides of F5, should be +12V on the PSU side & 0V on Pin 22 side."

So I should connect positive connector of multimeter to the fuse and negative connector to the RGB's Pin 22, right?
Or positive connector to PSU 12V and negative connector to the fuse/Pin 22?
The fuse was fine since I remember :confused:


Easy way. Set meter for 12VDC and measure across the fuse, A fuse should be a short, 0 Volts. If open "blown" you will see 12VDC.
Title: Re: Amiga 2000 video problem
Post by: RiP on December 19, 2016, 06:45:24 AM
Quote from: QuikSanz;817886
Easy way. Set meter for 12VDC and measure across the fuse, A fuse should be a short, 0 Volts. If open "blown" you will see 12VDC.

Thanks, I'll check it but since I remember the fuse was fine, not blown when I did a simple continuity test while it was off.
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 19, 2016, 05:50:28 PM
@Rip,

Continuity check is not reliable in circuit, your meter could just be charging a cap. Must be removed, at least 1 end from the circuit for continuity to be reliable.
Title: Re: Amiga 2000 video problem
Post by: RiP on December 20, 2016, 09:07:19 AM
Well, I measured the voltage of F5 fuse and it was 0V, so what's next?
Title: Re: Amiga 2000 video problem
Post by: spaceman88 on December 20, 2016, 03:56:56 PM
Quote from: RiP;817956
Well, I measured the voltage of F5 fuse and it was 0V, so what's next?


0V across the fuse? Do you have the 12V from a ground reference?
Title: Re: Amiga 2000 video problem
Post by: RiP on December 29, 2016, 09:29:54 AM
Quote from: spaceman88;817968
0V across the fuse? Do you have the 12V from a ground reference?


Yes, and how to check 12V from a ground reference? :confused:
I really wanna get color output from my Amiga 2000 with A520 :(
Title: Re: Amiga 2000 video problem
Post by: Pat the Cat on December 29, 2016, 02:49:00 PM
Put the black probe on part of the Amiga you know is at ground, 0V.  Then put the red probe to the fuse. While the equipment is turned on,  which is why some probes have clips, so you can turn on from a distance.

If no voltage is detected, that means the fuse is blown. Or part of the  circuit behind the fuse has blown - unlikely, nearly always the fuse is sacrificed first. If you measure the resistance across a  fuse, disconnected (unsoldered in this case) then a good fuse has 0 Ohm  resitance, or close to. A blown fuse has near infinite resistance.  

I must admit, I had no luck ever getting an A2000 to work with an A520  in the UK. I suspect there is a subtle difference between A2000 and A500  video outputs on PAL Amigas. Then again, I had no schematics to fault  find with. I was very much working in the dark.

I'll dig out the Hardware Reference Manual   and see if that has any light on the issue.

EDIT:  Only difference is that A500s don't have a -12V rail, they have a -5V  rail on video pin 21. So yes, does look like the +12V supply isn't  getting to the modulator (I presume is is needed, as other people have  reported changing that fuse has let them use PAL A2000s with PAL A520s).

The  reason the fuse is there is to protect the power supply from blowing up  when the +12 rail gets shorted out. Very easy to do when fumbling with a  big D connector round the back of an Amiga. Replacing it is no big deal  if you have the skills, if not, see if you have a local Makerspace or  Hackspace to help out.
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 29, 2016, 06:18:23 PM
The fuse for that device is good. the 12V is being interrupted else where.
Title: Re: Amiga 2000 video problem
Post by: Pat the Cat on December 29, 2016, 07:03:02 PM
Quote from: QuikSanz;818385
The fuse for that device is good. the 12V is being interrupted else where.

No. If it's showing 0V (is measuring voltage) that means that no volts are getting through the fuse.

If a fuse is showing 0 Ohms (is measuring resistance) that means the fuse is good, in that it has no resistance, and should pass current when connected into a circuit.

It is very easy to have a meter set to measure the wrong thing that you are looking for.
Title: Re: Amiga 2000 video problem
Post by: spaceman88 on December 29, 2016, 07:35:05 PM
Quote from: Pat the Cat;818387
No. If it's showing 0V (is measuring voltage) that means that no volts are getting through the fuse.

If a fuse is showing 0 Ohms (is measuring resistance) that means the fuse is good, in that it has no resistance, and should pass current when connected into a circuit.

It is very easy to have a meter set to measure the wrong thing that you are looking for.


He was measuring across the fuse. If it's good he will get 0V, assuming there is 12V getting to the fuse. That's why I suggested measuring the voltage at the fuse from a ground point. A quick check for voltage on both sides of the fuse will tell him if the 12V is present and if the fuse is good.
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 29, 2016, 07:44:10 PM
Quote from: spaceman88;818388
He was measuring across the fuse. If it's good he will get 0V, assuming there is 12V getting to the fuse. That's why I suggested measuring the voltage at the fuse from a ground point. A quick check for voltage on both sides of the fuse will tell him if the 12V is present and if the fuse is good.


Exactly. A fuse should be a short, if open 12v, if closed 0v.
Title: Re: Amiga 2000 video problem
Post by: Kernel on December 29, 2016, 09:54:46 PM
EDIT: I think I figured this out actually... would it make sense that the NTSC models have 3 and 4 as the switch positions (to equate to channel 3 and 4 in the US) and the PAL models have the L and H instead?

Dumb question... is there a way to tell if an A520 is PAL or NTSC other than hooking it up and seeing what you get?  Come to think of it, how do you tell which default an Amiga is?
Title: Re: Amiga 2000 video problem
Post by: Pat the Cat on December 29, 2016, 10:33:25 PM
Quote from: Kernel;818400
EDIT: I think I figured this out actually... would it make sense that the NTSC models have 3 and 4 as the switch positions (to equate to channel 3 and 4 in the US) and the PAL models have the L and H instead?

Dumb question... is there a way to tell if an A520 is PAL or NTSC other than hooking it up and seeing what you get?  Come to think of it, how do you tell which default an Amiga is?

The two variants are almost identical, externally and internally.

Here's an NTSC one (pretty sure it's NTSC, from Brazil). Notice lack of any German markings on the back (Germany was CBMs first choice for making PAL Amigas).

http://produto.mercadolivre.com.br/MLB-818535956-amiga-a500-a520-modulador-rgb-to-rf-ou-video-para-amiga-500-_JM

This one is more likely PAL;-

http://scacom.bplaced.net/Collection/520/520.php

So it's not easy to tell which is which without plugging it in.

As for the mode an Amiga is currently running in, you look at the screen. PAL Amigas have more horizontal lines - NTSC have fewer. So if the image looks "stretched" or "compressed", it's running in the wrong mode for that application.

Generally speaking, a lot of Amiga games prefer NTSC because they can run a little faster (on a real Amiga), wheraas a PAL desktop gives you a bigger canvas to work on. Not always true, some games insist on PAL, and some applications insist on NTSC.

If you can get a page of text displayed, an NTSC system will have 200 or 400 / 8 = 26 or 52 lines of text, A PAL system can display 256 / 512 lines of text = 32 or 64 lines of text. Assuming no overscan, just a straight window with a border on your display. The larger sizes are interlaced, and will tend to shimmer like crazy on most displays (without a flicker fixer fitted).
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 29, 2016, 11:59:07 PM
Yes, notice the second one has no FCC ID#, not a US product at all.
Title: Re: Amiga 2000 video problem
Post by: Pat the Cat on December 30, 2016, 01:55:10 PM
Quote from: QuikSanz;818405
Yes, notice the second one has no FCC ID#, not a US product at all.

Must admit, having seen plenty of Amiga kit with FCC numbers, I never noticed the lack of an FCC on on PAL A520s. Mind you, I almost never examined a real one... I guess I was spoilt for choice of genlocks and monitors at the time.

Well spotted. :)
Title: Re: Amiga 2000 video problem
Post by: RiP on December 30, 2016, 04:31:05 PM
Quote from: QuikSanz;818385
The fuse for that device is good. the 12V is being interrupted else where.

Possible to measure 12/5V on the video port?
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on December 30, 2016, 04:47:02 PM
Quote from: RiP;818432
Possible to measure 12/5V on the video port?


You probably could but, the pins are close together and you don't want to short them together since you have to test it "live". If you don't have it there you will still need to backtrack. Check between the fuse and ground first, at least you'll know if it's hot. Ground is always a big trace running around the perimeter with some traces going into the other devices. You can use battery ground.
Title: Re: Amiga 2000 video problem
Post by: RiP on September 03, 2017, 01:18:25 PM
I measured 12V from pins 21&22 and it was ~16V
Then I measured 5V from pins 21&23 and it was 0V :confused:
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on September 03, 2017, 05:36:27 PM
If the MB is not getting 5V it won't run. Start from the power supply and move thru it's path down the circuit. probably a broken solder/trace or wire somewhere.
Title: Re: Amiga 2000 video problem
Post by: RiP on September 03, 2017, 09:53:24 PM
Quote from: QuikSanz;830342
If the MB is not getting 5V it won't run. Start from the power supply and move thru it's path down the circuit. probably a broken solder/trace or wire somewhere.


How? :confused:
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on September 03, 2017, 10:39:05 PM
Interrupted between here and there, follow the path. Likely a cable or a solder gone flaky.
Title: Re: Amiga 2000 video problem
Post by: RiP on September 03, 2017, 11:26:16 PM
No schematic? I can only see +5V_USER (C215), not more things =/
Title: Re: Amiga 2000 video problem
Post by: Oldsmobile_Mike on September 04, 2017, 12:29:54 AM
Quote from: RiP;830347
No schematic? I can only see +5V_USER (C215), not more things =/


http://bfy.tw/DjEW
Title: Re: Amiga 2000 video problem
Post by: RiP on September 04, 2017, 04:21:40 AM
Quote from: Oldsmobile_Mike;830349
http://bfy.tw/DjEW


Only found this: http://i.imgur.com/807NXSH.jpg
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on September 04, 2017, 05:09:05 AM
The link Mike posted works here, Check again.
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on September 04, 2017, 06:56:10 PM
Bottom Right of the schematic you linked, "User 5V" start there and trace back or forward to find the fault.
Title: Re: Amiga 2000 video problem
Post by: RiP on September 05, 2017, 07:03:48 PM
Quote from: QuikSanz;830366
Bottom Right of the schematic you linked, "User 5V" start there and trace back or forward to find the fault.

5V_User, pin12 of PSU?

Maybe Amiga 2000 doesn't have 5V line in video port:
http://www.amiga.org/forums/showpost.php?p=198523&postcount=8
Title: Re: Amiga 2000 video problem
Post by: RiP on September 10, 2017, 07:39:31 PM
Just noticed the trace between EMI211 and pin23 was blown :hammer:
Finally got colored video out, can't believe :laughing:

(https://thumbs.imgbox.com/32/42/WJVHn37N_t.jpg) (http://imgbox.com/WJVHn37N)
Title: Re: Amiga 2000 video problem
Post by: QuikSanz on September 10, 2017, 07:52:48 PM
Persistence pays off and patience is a virtue.
Title: Re: Amiga 2000 video problem
Post by: gregthecanuck on September 11, 2017, 05:47:01 AM
Nice work!