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Black Screen Amiga 2000 Rev 6.2

General hardware issues and troubleshooting etc

Moderators: terriblefire, Terriblefire Moderator

amigaricc
Posts: 15
Joined: Sat Mar 29, 2025 1:36 pm

Re: Black Screen Amiga 2000 Rev 6.2

Post by amigaricc »

OK back to the Basics, watched some Adrian's DB Videos and gave me some pointers.
On the CPU the HLT (17) is High pulled it out of the circuit and HLT is low. No Activity on D1-D4
Left HLT on CPU out of circuit and check HLT (42) Gary and it is low. That means there must be some other place that pulls HLT high?
amigaricc
Posts: 15
Joined: Sat Mar 29, 2025 1:36 pm

Re: Black Screen Amiga 2000 Rev 6.2

Post by amigaricc »

Maximilian wrote: Sun Mar 30, 2025 5:54 pm That looks like a nice board!

Thanks I was very happy to se no Battery damage. I cleaned it and washed it down with deoxit :)

Again, are you using an original A2000 PSU?
Yes I have 2 A2K PSU and both of them working fine Voltages are correct
You checked all voltages (different chips) and clocks?
Yes I have 2 A2K PSU and both of them working fine Voltages are correct
You can use an A500 repair manual for this for reference.
I'm looking at the schematics of an A2K Board
Did you check the PCB for scratches or any other damage?
Double checl board top to botom as well underside. Found a missing solder point on an Audio Cap but nothing else
You have no addons installed?
No Add Ons installed

What do the address and data pins do after reset?(check multiple times)
D1-D4 no activity
Do you have a high/low setting on your multimeter?
amigaricc
Posts: 15
Joined: Sat Mar 29, 2025 1:36 pm

Re: Black Screen Amiga 2000 Rev 6.2

Post by amigaricc »

OK Gary (30) OVL should be High but on mine low followed line to CIA U300 and when switching on it goes high but immediately goes low. Does this mean that no ROM Code gets executed?

Gary Description

" OVL (OVerLay) input causes ROM to be accessed at memory location 0.
This signal is typically driven by a port line so that ROM is mapped to
the memory 0 at RESET time. "
terriblefire
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Location: Glasgow, UK

Re: Black Screen Amiga 2000 Rev 6.2

Post by terriblefire »

amigaricc wrote: Sun Mar 30, 2025 6:33 pm OK Gary (30) OVL should be High but on mine low followed line to CIA U300 and when switching on it goes high but immediately goes low. Does this mean that no ROM Code gets executed?

Gary Description

" OVL (OVerLay) input causes ROM to be accessed at memory location 0.
This signal is typically driven by a port line so that ROM is mapped to
the memory 0 at RESET time. "
That sounds like it's executing code fine.
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
amigaricc
Posts: 15
Joined: Sat Mar 29, 2025 1:36 pm

Re: Black Screen Amiga 2000 Rev 6.2

Post by amigaricc »

Ok, took a little break and started to tone out all the pins on the CPU and Pin 64 D5 was a hairline crack right by the Battery. :x I could not believe it since the board looked pristine by the Battery. I even pulled out the Microscope to check the the line. Anyways I fixed it but now the output on serial from DiagRom is garbled. Kickstart is showing up correctly.
Any Idea on why diagrom output would be garbled?
On the Screen Output I went to check the RAM and all tested fine. The Only thing I see was int the SystemInfo showing this:
"Is 'DIAG' readable at addr $f80000 (Real ROM addr): NO"
What does this mean? On my other machine It comes back with YES
20250406_190703[1].jpg
20250406_190703[1].jpg (421.77 KiB) Viewed 62 times
terriblefire
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Location: Glasgow, UK

Re: Black Screen Amiga 2000 Rev 6.2

Post by terriblefire »

amigaricc wrote: Mon Apr 07, 2025 12:36 am Ok, took a little break and started to tone out all the pins on the CPU and Pin 64 D5 was a hairline crack right by the Battery. :x I could not believe it since the board looked pristine by the Battery. I even pulled out the Microscope to check the the line. Anyways I fixed it but now the output on serial from DiagRom is garbled. Kickstart is showing up correctly.
Any Idea on why diagrom output would be garbled?
On the Screen Output I went to check the RAM and all tested fine. The Only thing I see was int the SystemInfo showing this:
"Is 'DIAG' readable at addr $f80000 (Real ROM addr): NO"
What does this mean? On my other machine It comes back with YES
20250406_190703[1].jpg
That looks like an NTSC vs Pal thing. @chucky ?
———
"It is not necessarily a supply voltage at no load, but the amount of current it can provide when touched that
indicates how much hurting you shall receive."
chucky
Posts: 100
Joined: Sun Jan 13, 2019 8:42 pm

Re: Black Screen Amiga 2000 Rev 6.2

Post by chucky »

that is juat a DiagROM bug. will be fixed in next 2.0 release :)
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