Radeon 8500 AGP believes two VGA monitors are attached

[s_pupp]

I have a Radeon 8500 AGP connected to a Dell monitor at 1080p 60Hz by VGA. The DVI jack is not connected to anything. The card believes in both OS9 and OSX that there is a second VGA monitor attached, but there is only one VGA port, and the DVI port does not have the four analog pins on it to allow direct connection of a second monitor via a simple DVI to VGA adapter. I have to mirror the real and imaginary monitors to avoid losing the cursor if I go off screen. This is in a dual 1.25GHz MDD G4 with a dual 1.42 Apple CPU installed.

Steps taken so far:
Zap the PRAM.
Uninstall and reinstall ATI drivers.
In OS9, trash the ATI and display prefs.
Use the ATI ROM flasher to flash the firmware from the latest version back to the earliest version.
Try another computer (a stock dual 1.25GHz MDD G4).
Replace four dented 470uF 10V capacitors on the Radeon 8500 (they were dented when I bought it used ages ago).

I recall now that this issue is what caused me to discontinue use of this card back in 2008 or thereabouts in my then stock dual 1.25GHz MDD G4. It started this behavior intermittently, then it became constant. I thought at the time that it had occurred after either a firmware or software update, but was not at all certain.

Is there anything I'm missing? Is this likely a capacitor issue from the small caps I left alone? Is this a hardware issue that will likely never be properly diagnosed?

 

[Byrd]

Is this Mac Edition card and have you tried downgrading ATI drivers? Might need a fresh install of Mac OS with each trial … reset nvram and PRAM in turn

 

[s_pupp]

Is this Mac Edition card and have you tried downgrading ATI drivers? Might need a fresh install of Mac OS with each trial … reset nvram and PRAM in turn

It is indeed a Mac edition card. I downgraded the ATI drivers and zapped the PRAM, but did not reset nvram or reinstall the OS. Good ideas - I’ll try those next.

 

[s_pupp]

I reset the nvram and performed a new installation of Tiger, with no change. It still believes there are two screens, with 32MB VRAM per screen instead of 64MB for one screen.

I then installed ATI Displays 4.5.1, then 4.5.1 update, then changed the firmware to v 220 from 126, then to 227 from 220. No change in behavior.

At this point, I’m considering either recycling it, or selling it for parts.

 

[s_pupp]

Well, one good thing came out of all this: This is my first experience with Tiger on this machine, and I like how snappy it feels compared with Leopard. I've installed the InterwebPPC browser, and am posting this from my MDD G4. I think I'll stick with Tiger on this machine.

 

[Phipli]

Well, one good thing came out of all this: This is my first experience with Tiger on this machine, and I like how snappy it feels compared with Leopard. I've installed the InterwebPPC browser, and am posting this from my MDD G4. I think I'll stick with Tiger on this machine.

Have you physically inspected the card? Perhaps there is a bent pin on a chip, or a scratch on a trace? Causing it to think there is a monitor connected to a nonexistent port.

 

[Forrest]

Have you run any graphics benchmark, ie. MacBench 4 or 5, to determine if there’s any performance hit?

I would think a true Mac edition ATI 8500 should be worth some money, even in its current condition.

 

[s_pupp]

I looked with a digital microscope. I can’t find any bent pins or damaged traces. I tried running Norton System Info gpu benchmarks, but it freezes half way through the test.