IBM 300GL

Retro6

Retro6

Retro6

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I have an IBM 300GL its the 200MHz version...

Does anybody know anything about this computer?

I'm having problems trying to get this computer to read a whole memory stick. The computer can take a maximum of 128MB of SD RAM PC 133 and has Two RAM slots each can take a maximum of 64MB.

So the computer will not read all of my RAM it will only read 15MB out of 64MB and that is it... the RAM is not faulty and has been tested I have tried many different RAM sticks but get the same results. I've done everything I can to clean the RAM slots with compressed air etc etc, all the pins look good there are none out of place and all the electrolytic capacitors look good on the motherboard, no bulges or leaks there all clean however that doesn't mean that there aren't any faulty capacitors.

First thing I need to rule out is whether this computer took IBM specific RAM? I know from experience that some old computers would require specific RAM this is what I need to rule out.

There were a few versions of IBM 300GL computers mine is the one with the 200MHz processor installed from around 1997.

Could anybody please help I'd really like to get this rare computer back in working order for MS-DOS and Windows 95.

If anybody has any knowledge of this IBM computer I'd be very grateful.

Thanks.
 
What graphics card is it using? I don't think there would be onboard but is it a sepeasep card ?

I ask as onboard graphics cards use up system memory. But thinking about it, it's probably not that.

Can you run a memory test stick or stress test software to check the computer is stable?
 
It's been a while since I saw one. It's not specific RAM, IBM used an off the shelf 430VX chipset. Later SDRAM was higher density, which is likely why it's showing as 16MB. You need late 90s PC66 SDRAM. Most machines back then were still on EDO SIMMs. SDRAM was less common. There's also a limit of 64MB cacheable memory on the chipset, after that performance drops off.

Graphics card will be a Cirrus Logic of some description, probably a 5446. These systems pre-date integrated graphics that share system memory by about 5 years.
 
It has onboard graphics, the graphics chip is a Cirrus CL-GD5446 I don't have a compatible video card for this computer.

I did install a new CMOS battery but there always remains a configuration error on the BIOS and only see's 15MB of RAM. I did read somewhere that the computer may only take double sided memory so I've ordered another stick of RAM double sided this time to see if it works so if that doesn't work I'll try to track down some PC66 RAM to see if that does the trick.

It would make sense it only taking PC66 RAM seeing that SD RAM was pretty new at the time in 1997.
 
So I've been doing a bit more research and it would appear my theory was correct that the RAM I was using was incompatible I was using PC133 PC100 RAM So I'm going to order some PC66 RAM and cross my fingers that its the solution to the problem.
 
Can also make a big difference if the SDRAM is single or double sided - think the ones with chips on both sides were seen as 2 dimms which not all chipsets or mobos would work properly with them.
 
The RAM 32MB PC66 arrived today but its double sided... it looked single sided on the picture when I ordered it but I installed it anyway to the computer and it saw all of 32MB I thought great :) so I put the rest of the computer back together fired it up and got a continuous long beep no post... so I opened up the computer again unplugged stuff from the motherboard like drives and and stuff then tested again and I still got the long continuous beep and no post so I thought the RAM has just died so I took it out then tried it again and it worked so I then plug the rest of hardware back in to the motherboard, Hard Drive, Floppy, CD ROM tested it again to make sure and it posted ok so I installed MS-DOS then when the computer restarted it would not post so I switched it off and back on again and got that long continuous beep again no post...

I've decided to unplug everything from the board and I took the board out of the computer to check underneath to make sure there are no hairline cracks or breaks in any of the tracks on the motherboard... all looks good. So I put it all back together again and test it one more time and it boots with no problems I switch it off and back on again and that long continuous beep is back with no post.

Edit: I've just got it going again after a short break from it, first thing I noticed is that the processor is showing as 120MHz where as before it showed as 200MHz so it could be that the dip switches on the motherboard need a good clean with some electrical cleaner that could also be contributing to the problem...

There is a possibility that the voltages on the power supply could be dropping off which is common for old power supplies and easily repaired...
 
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Standard thing in something so old, check for the usual signs of corrosion around batteries and any build up of fluff around capacitors - especially if the metal on the top is domed or split then clean and/or replace as necessary.
 
Monkeh said:
Standard thing in something so old, check for the usual signs of corrosion around batteries and any build up of fluff around capacitors - especially if the metal on the top is domed or split then clean and/or replace as necessary.
Click to expand...

Its all pretty clean inside with no corrosion and has a new CMOS battery, all the capacitors are also clean, no bulges or leaks. I'm sure the problem now lays with the PSU. I have a suitable ATX power supply for it that has the AT connector to power the PCI board but I will need an ATX to AT cable adapter for the motherboard, I can get one from China dirt cheap and I'll probably have to wait about a month for it to arrive. In the mean time I'm going to test the voltages on the old PSU and there are likely bad caps inside the PSU so providing that is the problem and I can get the correct electrolytic capacitor replacement values then I'll be able to restore the original PSU.

It does seem like the PSU is dropping out but when it does work the computer function's as it should.
 
I might just have to cut my losses with this IBM.

The computer is now powering up ok and booting I go to install Windows 95 only to get an error message saying that I only have 502784 bytes of RAM and Windows 95 requires 3000000 bytes. The computer has 32MB of RAM and shows 32MB of RAM in the BIOS and counts 32MB RAM on start up so its either a crappy disk I got sold or there is yet another RAM problem.

I don't get it because I managed to install Windows 98 SE with no problems but I want Windows 95 on this computer.
 
I just had another look in the BIOS and something is corrupted in memory resources so I need to change something in the settings but what I do not know. There is always a configuration error in the BIOS.
 
Well tried it the second time and windows 95 installed and I got video drivers and audio straight away... I went and changed it to true 24 bit color but now the display on the monitor is not supported :mad: Do I have to wipe the hard drive and start again or is there any way of getting back into Windows? I don't have a CRT display I only have LCD monitors.

I don't have the option of safe mode.

Edit: I managed to get into safe mode and change the display settings, I don't know why it wasn't working the first time.

I love the look of Windows 95 although there is still some work to do to get the computer to operate normally I'm quiet chuffed that I got Windows 95 on it...

I think the next thing to do at some point is to recap the power supply and motherboard to eliminate problems although all the caps look ok it dosen't mean that they are ok and could be out of spec causing the motherboard to behave erratically. Sometimes the computer works and sometimes it doesn't.
 
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How come you don't have the option of safe mode? Press the reset button a couple of times during the Windows 95 splash screen or press f8 during post (not sure that was a thing back then).

Perhaps your video card only does 16bit colour? If you're using an old monitor you could try plugging the pc into another one.
 
It's F8 at the "Starting Windows 95..." message to get the menu where you can select Safe Mode.

That era of machine pre-dates the cap plague issues, so the board should be fine unless there's any that are bulging/leaking.

The video card will do 24 bit colour, but only up to 800x600 with 2MB VRAM. 1024x768 needs more than the 2MB VRAM typically fitted. Display issus are likely issues with plug and play monitor support, likely it's sending an out of range signal to the monitor, given that 99.99% of people were using CRTs back in the late 90s.
 
Its needs something because it is very unstable. I tried installing office 97 and that failed. Its taken an hour so far to install Publisher 97.

The computer dosn't always turn on, sometimes it will just have a long continuous beep and switching it off and back on again it will power up normally so not the most reliable computer. The RAM has been tested as well. So if the caps are all good that just leaves the power supply.

Its been 1 hour now and its only at 67% installing Publisher. I've had enough of it for today.

I don't know why people pay so much money for these old computers. I only paid 20 quid for it back in 2015 good job really.

I'd never pay the prices people want for these old machines considering... and you just never know what problems they will have. Its like buying an old car it may run but you just don't know what gremlins it will have.
 
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That's why I prefer just building one myself and using modern tech where I can whilst still getting a (fairly) period experience. Eg modern power supply, CF card, 'modern' cheap graphics cards (as in 4 MX series usually, modern 4:3 LCD display. It takes a lot of hassle and guesswork out of retro computing.
 
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