Help needed A2000 R6.2

lazIsMe · 30 May 2023, 22:15

Hello amiga lovers,

I need some advices. I am currently restoring an A2000 R6.2 with kickstart 3.1.
It have a problem on video output, both on 23 pin and composite, bottom half of the screen have sync problem but when I start it with both mouse buttons clicked (boot menu) no problem !

Any advices ?

thebajaguy · 31 May 2023, 02:58

Making an assumption that you have a PAL (Agnus) machine in a PAL / 50Hz environment and a PAL monitor, but that could be wrong.

Make sure you didn't end up with an NTSC-starting Agnus (like with a MegAChip board that has an 8375-series Agnus with an odd-numbered 318069-1x part number) or as a spare part (The 1MB version). The 8375-series Agnus starts in PAL or NTSC by default, but is later software-switchable in software later.

The next thing is to reseat all socketed chips. Age and storage conditions can make for bad contacts.

Was there any battery damage in the CPU/ROM/Agnus vicinity?

lazIsMe · 01 June 2023, 14:28

Thanks for your answer.
The motherboard was damaged by battery leakage but only at the bottom.
I will check agnus version later this week.

thebajaguy · 01 June 2023, 23:50

It is possible you may want to tinker with the Amiga Test Kit:

https://github.com/keirf/Amiga-Stuff/releases

The maker, Keir, is in France, IIRC.

Alternatively, a DiagROM might be a tool needed if you have to poke around outside the OS running.

lazIsMe · 04 June 2023, 00:32

Quote:

Originally Posted by thebajaguy

It is possible you may want to tinker with the Amiga Test Kit:

https://github.com/keirf/Amiga-Stuff/releases

The maker, Keir, is in France, IIRC.

Alternatively, a DiagROM might be a tool needed if you have to poke around outside the OS running.

I've test it with Amiga Test Kit, it boot and display sync is ok.
RAM test : garbage on screen.
Video Test : crash

I think that it's a RAM problem but ...

I have some experience with amiga 500, 600, 1200 when RAM failed I got a fixed color screen and no insert disk ...

What do you think ?

I have a retro tester pro so I can desolder RAM ic and test them.

MigaTech · 04 June 2023, 01:23

What's the video output like on the monochrome port? Also do you have any other boards connected?

There's a possibility it could be RAM related but check for corrosion in and around the 68K SKT.

lazIsMe · 05 June 2023, 14:49

Quote:

Originally Posted by MigaTech

What's the video output like on the monochrome port? Also do you have any other boards connected?

There's a possibility it could be RAM related but check for corrosion in and around the 68K SKT.

On monochrome video port it’s the exact same (but in monochrome).
I removed all card. The PCB was heavily corroded but repaired by the owner.
I have checked a lot of traces so far and none are broken.
I will post some pictures tomorrow.

EDIT LINK TO VIDEOS :
Vid 1
Vid 2

lazIsMe · 07 June 2023, 14:10

I did more tests with DiagRom 1.3 :
- Ram test OK
- Port test OK
- IRQ test OK
- Video test BAD nothing on screen
- Floppy test OK (with gotek)

So maybe Denise is BAD ?

Edit :

Previously I was testing with an OSSC.
Now with a 1084s monitor video tests doesn't give a blank screen but they doesn't look good.

MigaTech · 07 June 2023, 23:36

Video test bad could be Denise but there are other possibilities. Did you run test more than once? Was the results the same?

So DiagRom is passing RAM and showing Bad video test? Yet, Test Kit shows as RAM test as scrambled data on VDU. Sync test passed but Video Test cause (LOS) = Loss Of System.

Silly question: Does boot up to ROM seem slow and have you had any error colours?

Just an outside possibility: Have you checked power output from PSU? Check for correct voltages and stability etc. Probably all OK but still worth eliminating from the list.

lazIsMe · 10 June 2023, 15:25

Quote:

Originally Posted by MigaTech

Video test bad could be Denise but there are other possibilities. Did you run test more than once? Was the results the same?

So DiagRom is passing RAM and showing Bad video test? Yet, Test Kit shows as RAM test as scrambled data on VDU. Sync test passed but Video Test cause (LOS) = Loss Of System.

Silly question: Does boot up to ROM seem slow and have you had any error colours?

Just an outside possibility: Have you checked power output from PSU? Check for correct voltages and stability etc. Probably all OK but still worth eliminating from the list.

With DiagRom I've tested ram continuously for 4 hours without errors.
It boot quickly.
I've tested the PSU with a scope while testing no problem.
I've made a video with DiagRom tests and Amiga Test Kit Floppy.
[ Show youtube player ]

Thanks for your help

MigaTech · 11 June 2023, 00:30

Interesting video, there is definitely something not right with this Amiga visuals. However this definitely helps zero in on the fault/s.

The Visual Display issue might be Agnus. If it is any of the sub systems, it could be Copper rather than Blitter.

Have you made sure all IC's are seated firmly? Do you have access to A2000 schematics? There could be trace issues and/or component failures. Can you check mainly on RGB output. Can you run an HAM image? Also try interlaced output and report back. Still cannot rule out Denise just yet.

Try changing the screen resolutions and report back with results.

You can rule out CR as not the issue as it's passing all test and Agnus seems to be accessing that OK. The RGB test output looked OK, apart from the bar lines across the back. When you was attempting to run some of the other video tests, it looked like it was skipping them. Either that or it wasn't displaying correctly.

As Agnus is in control of the chipset, it would be worth trying some software test. Games, art packages even demos etc. If there are issues with the chipset or sub systems, it might not complete the tasks and either guru or LOS.

Probably a little early to state exactly, but it could be a visual sync issue in Agnus. What version/number Agnus is installed in your A2000?

lazIsMe · 13 June 2023, 00:46

Thanks for your advices @MigaTech. I work only on my spare time on this computer. I will come back to you this weekend.

DigitalKeeper · 13 June 2023, 13:29

Check the "TICK" Signal at Power Connector....come from Power Supply; this is needed for Timing (CIA) and to Generate the _VSYNC Signal.

If the Power Supply doesn't Generate the "TICK" Properly, change the Jumper J300:

From Original Position -> left+center (TICK from Power Supply) to center+right -> Tick (_VSYNC) from Agnus
-----

Often Agnus Socket are the Problems! Remove Agnus - check the contacts, clean it, and Replace Agnus.

lazIsMe · 23 June 2023, 13:38

Quote:

Originally Posted by MigaTech

Interesting video, there is definitely something not right with this Amiga visuals. However this definitely helps zero in on the fault/s.

The Visual Display issue might be Agnus. If it is any of the sub systems, it could be Copper rather than Blitter.

Have you made sure all IC's are seated firmly? Do you have access to A2000 schematics? There could be trace issues and/or component failures. Can you check mainly on RGB output. Can you run an HAM image? Also try interlaced output and report back. Still cannot rule out Denise just yet.

Try changing the screen resolutions and report back with results.

You can rule out CR as not the issue as it's passing all test and Agnus seems to be accessing that OK. The RGB test output looked OK, apart from the bar lines across the back. When you was attempting to run some of the other video tests, it looked like it was skipping them. Either that or it wasn't displaying correctly.

As Agnus is in control of the chipset, it would be worth trying some software test. Games, art packages even demos etc. If there are issues with the chipset or sub systems, it might not complete the tasks and either guru or LOS.

Probably a little early to state exactly, but it could be a visual sync issue in Agnus. What version/number Agnus is installed in your A2000?

I am back,

I removed all socketed IC an clean sockets and IC with deoxit.
I have schematics. I've tested a bunch of corroded traces none seems broken. I will remove all socketed IC again and ultrasonic clean the board and then try other tests.
Agnus version is : CSG 8372A

Regards

lazIsMe · 23 June 2023, 13:39

Quote:

Originally Posted by DigitalKeeper

Check the "TICK" Signal at Power Connector....come from Power Supply; this is needed for Timing (CIA) and to Generate the _VSYNC Signal.

If the Power Supply doesn't Generate the "TICK" Properly, change the Jumper J300:

From Original Position -> left+center (TICK from Power Supply) to center+right -> Tick (_VSYNC) from Agnus
-----

Often Agnus Socket are the Problems! Remove Agnus - check the contacts, clean it, and Replace Agnus.

Thanks for the advice but no change.

lilwshu · 23 June 2023, 13:45

I had a similar issue on an A2000 that had a RGB2HDMI adapter in the Denise socket - when removed the pins had bent out the contacts in the socket so Denise did not make proper contact and would randomly crash as above. I bent the pins out slightly on Denise and the socket which solved the issue.

lazIsMe · 23 June 2023, 14:03

Some news :
I restarted the A2000 after 2 weeks off, and no sync issue but after 30sec/1min sync issue is back !?
Bad caps ? Bad PSU ? I'm lost ...

dlfrsilver · 23 June 2023, 15:46

Quote:

Originally Posted by thebajaguy

It is possible you may want to tinker with the Amiga Test Kit:

https://github.com/keirf/Amiga-Stuff/releases

The maker, Keir, is in France, IIRC.

Alternatively, a DiagROM might be a tool needed if you have to poke around outside the OS running.

Keir is english and to my knowledge he lives in UK

lazIsMe · 23 June 2023, 18:12

I tried to run sysinfo, you can watch the result here :
[ Show youtube player ]

After 3 hours, I've tried to run some demos like boing ball... they didn't launch and I have lost some colors :
[ Show youtube player ]

I've rechecked the PSU with scope and no problem.

The motherboard is drying after ultrasonic bath now. I will try swapping some ic tomorrow.

MigaTech · 23 June 2023, 23:59

From your first video, it seems like an Agnus issue but then the second video, shows what looks like an RGB output problem.

Do you have access to another 8372A? That is the 1MB version found in A500 6A and A2000 model B up to 6.3.

Pins 79, 80, 81 on Agnus worth checking from video 1 result.

What version Denise have you installed?

8362 R8 A500 A2000 OCS.
8373 R4 A500 Plus A2000 ECS.

Pins 25, 26, 27 on Denise if version 8362 R8 worth checking from video 2 result.

30 May 2023, 22:15	#1
lazIsMe Registered User Join Date: Mar 2022 Location: France Posts: 15	Help needed A2000 R6.2 Hello amiga lovers, I need some advices. I am currently restoring an A2000 R6.2 with kickstart 3.1. It have a problem on video output, both on 23 pin and composite, bottom half of the screen have sync problem but when I start it with both mouse buttons clicked (boot menu) no problem ! Any advices ? Last edited by lazIsMe; 30 May 2023 at 22:27.

07 June 2023, 14:10	#8
lazIsMe Registered User Join Date: Mar 2022 Location: France Posts: 15	I did more tests with DiagRom 1.3 : - Ram test OK - Port test OK - IRQ test OK - Video test BAD nothing on screen - Floppy test OK (with gotek) So maybe Denise is BAD ? Edit : Previously I was testing with an OSSC. Now with a 1084s monitor video tests doesn't give a blank screen but they doesn't look good. Last edited by lazIsMe; 07 June 2023 at 14:54. Reason: More tests done

07 June 2023, 23:36	#9
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	Video test bad could be Denise but there are other possibilities. Did you run test more than once? Was the results the same? So DiagRom is passing RAM and showing Bad video test? Yet, Test Kit shows as RAM test as scrambled data on VDU. Sync test passed but Video Test cause (LOS) = Loss Of System. Silly question: Does boot up to ROM seem slow and have you had any error colours? Just an outside possibility: Have you checked power output from PSU? Check for correct voltages and stability etc. Probably all OK but still worth eliminating from the list. Last edited by MigaTech; 08 June 2023 at 02:36.

11 June 2023, 00:30	#11
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	Interesting video, there is definitely something not right with this Amiga visuals. However this definitely helps zero in on the fault/s. The Visual Display issue might be Agnus. If it is any of the sub systems, it could be Copper rather than Blitter. Have you made sure all IC's are seated firmly? Do you have access to A2000 schematics? There could be trace issues and/or component failures. Can you check mainly on RGB output. Can you run an HAM image? Also try interlaced output and report back. Still cannot rule out Denise just yet. Try changing the screen resolutions and report back with results. You can rule out CR as not the issue as it's passing all test and Agnus seems to be accessing that OK. The RGB test output looked OK, apart from the bar lines across the back. When you was attempting to run some of the other video tests, it looked like it was skipping them. Either that or it wasn't displaying correctly. As Agnus is in control of the chipset, it would be worth trying some software test. Games, art packages even demos etc. If there are issues with the chipset or sub systems, it might not complete the tasks and either guru or LOS. Probably a little early to state exactly, but it could be a visual sync issue in Agnus. What version/number Agnus is installed in your A2000? Last edited by MigaTech; 12 June 2023 at 01:35. Reason: Additional questions and updated information added.

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31 May 2023, 02:58	#2
thebajaguy Registered User Join Date: Mar 2017 Location: Rhode Island / United States Posts: 201	Making an assumption that you have a PAL (Agnus) machine in a PAL / 50Hz environment and a PAL monitor, but that could be wrong. Make sure you didn't end up with an NTSC-starting Agnus (like with a MegAChip board that has an 8375-series Agnus with an odd-numbered 318069-1x part number) or as a spare part (The 1MB version). The 8375-series Agnus starts in PAL or NTSC by default, but is later software-switchable in software later. The next thing is to reseat all socketed chips. Age and storage conditions can make for bad contacts. Was there any battery damage in the CPU/ROM/Agnus vicinity?

01 June 2023, 14:28	#3
lazIsMe Registered User Join Date: Mar 2022 Location: France Posts: 15	Thanks for your answer. The motherboard was damaged by battery leakage but only at the bottom. I will check agnus version later this week.

01 June 2023, 23:50	#4
thebajaguy Registered User Join Date: Mar 2017 Location: Rhode Island / United States Posts: 201	It is possible you may want to tinker with the Amiga Test Kit: https://github.com/keirf/Amiga-Stuff/releases The maker, Keir, is in France, IIRC. Alternatively, a DiagROM might be a tool needed if you have to poke around outside the OS running.

04 June 2023, 01:23	#6
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	What's the video output like on the monochrome port? Also do you have any other boards connected? There's a possibility it could be RAM related but check for corrosion in and around the 68K SKT.

13 June 2023, 00:46	#12
lazIsMe Registered User Join Date: Mar 2022 Location: France Posts: 15	Thanks for your advices @MigaTech. I work only on my spare time on this computer. I will come back to you this weekend.

13 June 2023, 13:29	#13
DigitalKeeper _Repair_Nerd_ Join Date: Jun 2020 Location: Germany Posts: 71	Check the "TICK" Signal at Power Connector....come from Power Supply; this is needed for Timing (CIA) and to Generate the _VSYNC Signal. If the Power Supply doesn't Generate the "TICK" Properly, change the Jumper J300: From Original Position -> left+center (TICK from Power Supply) to center+right -> Tick (_VSYNC) from Agnus ----- Often Agnus Socket are the Problems! Remove Agnus - check the contacts, clean it, and Replace Agnus.

23 June 2023, 13:45	#16
lilwshu Registered User Join Date: Mar 2020 Location: UK Posts: 230	I had a similar issue on an A2000 that had a RGB2HDMI adapter in the Denise socket - when removed the pins had bent out the contacts in the socket so Denise did not make proper contact and would randomly crash as above. I bent the pins out slightly on Denise and the socket which solved the issue.

23 June 2023, 14:03	#17
lazIsMe Registered User Join Date: Mar 2022 Location: France Posts: 15	Some news : I restarted the A2000 after 2 weeks off, and no sync issue but after 30sec/1min sync issue is back !? Bad caps ? Bad PSU ? I'm lost ...

23 June 2023, 18:12	#19
lazIsMe Registered User Join Date: Mar 2022 Location: France Posts: 15	I tried to run sysinfo, you can watch the result here : [ Show youtube player ] After 3 hours, I've tried to run some demos like boing ball... they didn't launch and I have lost some colors : [ Show youtube player ] I've rechecked the PSU with scope and no problem. The motherboard is drying after ultrasonic bath now. I will try swapping some ic tomorrow.

23 June 2023, 23:59	#20
MigaTech Only Amiga !! Join Date: Apr 2017 Location: United Kingdom Posts: 588	From your first video, it seems like an Agnus issue but then the second video, shows what looks like an RGB output problem. Do you have access to another 8372A? That is the 1MB version found in A500 6A and A2000 model B up to 6.3. Pins 79, 80, 81 on Agnus worth checking from video 1 result. What version Denise have you installed? 8362 R8 A500 A2000 OCS. 8373 R4 A500 Plus A2000 ECS. Pins 25, 26, 27 on Denise if version 8362 R8 worth checking from video 2 result.

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