Amiga 4000 crashes when Amiga 1438S monitor has not been powered on

  • Thread starter Thread starter awmosoft
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awmosoft

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The crash only occured when the Amiga 1438S monitor is connect to the Amiga 4000 while the monitor has not been turned on.
If I don't turn the monitor on then it crashes in a loop.

I thought it is only my Amiga 4000 setup, but years ago I saw another user on a Commodore Meeting has the same problem.

Does someone know why this problem occured?

If use a adapter from rgb adapter to vga adapter and then connect to VGA to RGB adapter and Monitor, then this problem will not occur.
 
Do you have another monitor to try it out (direct RGB), or even another Amiga with the same 1438S monitor?
 
If you turn on the monitor and then the Amiga is it working ok?

You may have to add some 75 Ohm termination resistors on the sync lines.
 
awmosoft said:
Other Amiga's like Amiga 500, 1200, CD32 with SX32 and 600 does not crashes.

If I turn on the monitor first then the Amiga 4000 does not crash.
Click to expand...
Old thread I realise, but...

I have 2 Microvitecs M1438s now, one is branded Microvitec (with VGA connector), the other Amiga (with DB23).

Microvitec one with VGA port, when plugged into my A4000 crashes the Amiga when the Amiga is powered on or resets. It will only boot up with the monitor disconnected, then works fine when I connect it. If it reboots I have to unplug the monitor to get it to boot again. All other Amigas I've tested with this monitor are fine (A600, A1200, A3000).

Amiga one with DB23 port works fine in the A4000. No issues at all.
Edit: wait! you're right, with the DB23 model connected to the Amiga, but not plugged into the power supply - on Amga power on crashes the Amiga 4000!

Doesn't help you, but I feel your pain.
 
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SpodSpod tested the original Microvitech monitor and the Amiga Microvitech monitor amd both have the same issue when connecting to the Amiga 4000.

Likely clones are also affected, but I haven't other monitor to test.

I have found a workaround solution for Amiga 1438S: use a Commodore VGA adapter (Female 23 pins connector to VGA adapter and 23 pins male to VGA Male adapter from Amigakit.

links:

VGA to Amiga RGB Monitor Adapter, Amiga Kit Amiga Store - the world's largest Amiga Store - we ship worldwide

AmigaKit Amiga Shop - we ship worldwide. Manufacturer and distributor of Commodore Amiga computer adapters, A500 RAM expansions, A1200 turbo cards and A600 memory upgrades. A1200 Dust covers and mouse mats. Joysticks and games.
amigakit.amiga.store amigakit.amiga.store

Amiga RGB to VGA Monitor Adapter, Amiga Kit Amiga Store - the world's largest Amiga Store - we ship worldwide

Amiga RGB to VGA Monitor Adapter to connect a SVGA or Multiscan monitor to the Amiga 23-pin RGB port.
amigakit.amiga.store amigakit.amiga.store
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I recall having a similar issue with my A4000 with a different monitor (it was many years ago and in another country, can't remember). What fixed it was NOT using the original Commodore db23-vga15 adapter! There's something in the logic inside the silver Commodore adapter (pictured above) that caused it not to work. It worked with any other simple DB23-vga15 adapter.
 
amigean said:
I recall having a similar issue with my A4000 with a different monitor (it was many years ago and in another country, can't remember). What fixed it was NOT using the original Commodore db23-vga15 adapter! There's something in the logic inside the silver Commodore adapter (pictured above) that caused it not to work. It worked with any other simple DB23-vga15 adapter.
Click to expand...
The commodore adapter has a simple 74LS08 IC. The black one, if it is not buffered, it has wires only.
 
amigean said:
I recall having a similar issue with my A4000 with a different monitor (it was many years ago and in another country, can't remember). What fixed it was NOT using the original Commodore db23-vga15 adapter! There's something in the logic inside the silver Commodore adapter (pictured above) that caused it not to work. It worked with any other simple DB23-vga15 adapter.
Click to expand...
That is interesting, my DB23 to VGA15 is wires only, and it crashes the machine (unless I plug in the monitor to the adaptor after boot up)
 
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