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Old OS8.1 change resolution on PowerMac G3

C

cyberluke

macrumors newbie
Original poster
Oct 13, 2022
12
3
Hi, I just got PowerMac G3 and found out it is not Unix based, therefore no terminal.

It is connected to VGA CRT monitor. On Powerbook G4 I can switch to 640x480 (after checking Show unsupported resolutions)

Here in Powermac G3 with OS 8.1 there is only one resolution:
1152 x 870, 75Hz

The dropdown contains only one property: Show recommended resolutions - this cannot be unchecked and there is no other property.

I want to play original Dark Forces in full screen (640x480).
 
Ah, no dip switches on adapter. It is very old ancient MAC to VGA adapter. I just bought a very old G3 Beige desktop.

The adapter itself and the type of moulded connector looks like from pre-2000 already.

My plan is to try SwitchRes now, but I need to learn how to connect to Windows Samba netshare (the G3 is already on the network, I see it in router via DHCP).

I can also try smaller CRT. Currently this one is 19'' EIZO 160Hz. I can try 14'' or 15'' generic SVGA CRT.
 
cyberluke said:
Ah, no dip switches on adapter. It is very old ancient MAC to VGA adapter. I just bought a very old G3 Beige desktop.

The adapter itself and the type of moulded connector looks like from pre-2000 already.

My plan is to try SwitchRes now, but I need to learn how to connect to Windows Samba netshare (the G3 is already on the network, I see it in router via DHCP).

I can also try smaller CRT. Currently this one is 19'' EIZO 160Hz. I can try 14'' or 15'' generic SVGA CRT.
Click to expand...
Those multi switch adapters are cheap and easy to find, if not all that user friendly, but once you get the switches set correct for Muti-sync VGA they work good.

Tho the Rage Pro is pretty weak, more so if you don't have the VRAM upgrade SIMM, and those have become all but impossible to find.

A upgrade PCI VGA card is also nice.
 
"Those multi switch adapters are cheap and easy to find" - I already have the multi sync adapter just without DIP switches. Original owner reported it worked in 800x600 for him on projector. I guess this is some EDID related stuff on EIZO 19''.

1) What do you mean by multi switch adapters? Yes, they are easy to find in USA. But not in Europe. In Europe everyone want like 50 USD for el cheapo cable I already have.

2) I don't have the VRAM upgrade. But I am a retro gamer and have a lot of PCI, VLB, ISA, AGP cards ^_^ ...the reason why I bought this G3 is only to play Prince Of Persia, Dark Forces, Doom and Warcraft 1 in 640x480 and for that, the current setup is enough. I will be probably reinstalling OS9.1 instead of 8.1 together with SwitchRes utility and DAVE (for Samba netshare) and see if that makes a good setup.

So I'm not doing any big upgrades there, if I want something better, I can use G4 PowerPC 1.33Ghz powerbook and connect it to CRT as well.
 
cyberluke said:
I already have the multi sync adapter just without DIP switches. Original owner reported it worked in 800x600 for him on projector.
Click to expand...
This is what you need:
www.amazon.com

PTC MAC to VGA Adapter, DB15 Male to HD15 Female w/10 Dip Switches

The Mac PnP (Plug and Play) adapter brings a new level of versatility to monitor adapters. Simply attach the adapter on your monitor cable, plug the adapter into the video out of your computer and start the computer. The adapter is preset to automatically allow the computer to display all availab...
www.amazon.com
 
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
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It does not matter you find it on ebay.de - it is shipped from USA. It is same like ebay.com. There are some local old stores across Europe, I will ask on Facebook. Thank you.
 
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Got adapter from Czechia:

PremiumCord Redukce MAC na VGA monitor | KRUP

PremiumCord Redukce MAC na VGA monitor
www.krup.cz www.krup.cz

It is a classic stuff by Manhattan brand you can get in US.

Instead of 8 dip switch version from photo, I got 6 dip switch version.

UNIMAC-6D is model name.

It does not work! Yes, you can set Sync on H and Sync for V. But that will enable only 1024x768, 75hz only. Cannot change it. No 640x480. No VGA, only SVGA.

It would be good to edit monitor EDID on Windows, but then again, it is working on 386, 486, Pentium I,II,III.
 
Ok,so dip switch 5 only - mode 5 is separate sync. It shows some resolutions, mostly 85hz. For example 640x480@85hz Dip switch 2+4 (composite sync and sync on H) shows 640x480 at 67hz.

I had to randomly move them while monitor was connected.
 
Luckily I bought two beige G3 at price of one, albeit one is rusty and full of dust. Now I booted the second one and it has much more options for resolution. Same GPU onboard. The only difference is OS8.6. So I guess the limited resolution might be OS8.1 specific.
 
According to the chart, turning on switches 1, 5 and 6 gives you 640 x 480.

img.jpg
 
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