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5150 Jumper Settings

bettablue

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I finally got some time to work with my 5150 and finish the dip switch configurations. I'm a bit confused though about one item.

According to minuszerodegrees, the section labeled "Switches 5 and 6 states the following:

On Switch Block 1, the one closest to the center of the mother board... And the part that is confusing me is that according to the table below, switches 5 and 6 appear to be set to the "On" position for an EGA video card. But right after that there is a sentence that states: ON/ON setting is only applicable to the 10/27/82 dated BIOS revision.

My computer is a revision 2 5150 PC. I'm not sure which BIOS version it contains. So what do I set switches 5 and 6 to?

5=OFF, 6=OFF: MDA (monochrome)
5=OFF, 6=ON : CGA, at 40 column by 25 line mode
5=ON , 6=OFF: CGA, at 80 column by 25 line mode
5=ON , 6=ON: Cards with a BIOS expansion ROM (e.g. EGA / PGA / VGA)

ON/ON setting is only applicable to the 10/27/82 dated BIOS revision.

As always; many thanks.
 

Ole Juul

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ON/ON setting is only applicable to the 10/27/82 dated BIOS revision.

Because the earlier ones did not support the ROM on EGA/VGA cards. On his site he says:

Both BIOS revisions have two significant limitations:
* No more than 544 KB of RAM is recognised (because, by design, only the first 4 switches on switch block SW2 are used).
* The BIOS expansion ROM in cards that have one is not recognised. Examples: EGA/VGA cards, hard disk controllers.

Later, IBM made available a BIOS upgrade kit to upgrade the BIOS chip to the third revision one (dated 10/27/82, "1501476" printed on it).
Use of that kit removes the two limitations.
 

Stone

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Do you have EGA?

Does it work?

If you answered yes to both questions... enjoy the machine and don't worry about it. :)
 

SpidersWeb

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You can safely stop worrying about the BIOS.
Unless you have a 16-64KB system board in there, you'll have the third (and final) release of the BIOS.

I suspect your friend actually meant "Revision B" which is the nickname given to the 64-256KB model 5150's which came out in 1983.
 

bettablue

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Again, thanks to all of you for helping me clear that up. My Revision B mother board is labeled 64-256. The video controller is an EGA board I got for a great deal. Based on info I have, it appears the below settings should be right on the money.

From minuszerodegrees:
5=ON , 6=ON: Cards with a BIOS expansion ROM (e.g. EGA / PGA / VGA)

At least, I have all of the DIP Switches, and my configurations are done for what I have right now.

Now for the bad news... I had intended to connect the 5150 to a combination TV/monitor in my hobby room. However, my nephew had to move in with us, and he will need the TV. That means I have to wait for another deal I have in the works. If I'm able to complete that, I'll have enough to purchase a good multisynch display, and the setup will be fine the way it is. (Crossing my fingers)

If anyone has any other ideas, or advice, please feel free to send it my way. I am always open to new ideas.

Thanks again.
 

bettablue

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Again, thanks for all of the advice. I have all of the jumpers set according to what they're supposed to be, but now, I need a way to test the computer's video. I have a friend who has a Tandy EGA monitor I'm planning to pick up tomorrow to use for a few days. However, I know much of Tandy's peripherals aren't really compatible with IBM and other clone systems.

So, to keep things simple; is the Tandy monitor going to work with the EGA video controller currently installed in my 5150? If the controller and monitor are NOT compatible, I will have to wait to see if I can find an IBM 5151 or equivalent.

Again, thanks much.
 

SpidersWeb

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It should be fine, but I'd check the model number to confirm it's EGA, especially if the owner is using it on an actual Tandy.

My 1000 TL/2 runs a generic CGA monitor, but in many DOS games you'd swear it was EGA :)
(Tandy's can do 320x200 with 16 colours on a CGA display)
 

luvit

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Thomas, the first upgrade I ever did as a teen was removing our CGA card and adding an EGA card.. I kept the CGA 5153 monitor.
I understood the resolution wasn't as great, but I was thrilled with the color upgrade. Do you have a CGA monitor?
 

offensive_Jerk

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If it's an ibm ega card you can configure it for mda and cga operation too, via the dip switches on the back of the card
 

Malc

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Have you got any 16-bit VGA cards, Not all 16-bit VGA cards work in a 8-bit slot but some do so might be worth a try if you have any, And you'll be able to test out the machine if you get lucky.
 
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