Uncreative Labs

Joined: 14 Jan 2007 Posts: 15

My name is TinyTinker...
I got a hold of this site through Google when looking up help for vintage hardware.

Here's the thing...

I just recently aquired an old AMD K5 75Mhz PC (circa late 1995). It is a K-NET AT Formfactor Microtower. I'm not too familiar with systems from this period as back in 1995 the only computer I had was a 1MB Macintosh Plus system which I kept until late 1998. Then is when I purchased my first AMD K6 IBM Aptiva system, which was ATX formfactor.

Anyhow, the case has a 2 digit led display showing MHz speed the system is running. The led shows 33Mhz. However, I know this to be incorrect as I ran Everest Home edition and it is telling me the system is running at spec, which is 75Mhz. Even the AMI BIOS upon startup is telling me that the system is a 75Mhz AMD K5.

What I would like to know is how to change the LED to show the proper speed if possible. Could someone be kind enough to walk me through it or link me to a site with an explanation of this sort of thing.

Any help would be appreciated. Thanks.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

It's likely that your case was home to either a 386 or 486 running at 33MHz before being upgraded to a K5-75. The LED display recieves its power from the motherboard, but the readout is controlled by a separate PCB by some jumpers. If you want to change the readout you will have to unscrew it from the inside of the case to get at the jumpers. I've done this on two or three machines, and it seems that these LED displays are somewhat non-standard. So, each one is a little different. Sometimes you get lucky and the settings are silk screened onto the PCB. It is doubtful you will find the documentation on the internets. Though, these devices are pretty simple, so just using trial and error will generally allow you to set it the way you want. I usually set the display while the computer is running, but you could probably power it with any 5V source.

Good Luck

Joined: 19 Apr 2006 Posts: 261 Location: WisConSin

The AMD k5-"PR75's" where a strange beast they normally don't run at 75mhz actually 66mhz x 1x multiplier on my machine. I also had a few 5x86s that were labeled x5-75mhz also had a 5k86-75mhz to add to confusion (they were actually a 486DX5-133mhz)

Good Luck with the jumper on the speed LED Smile

Joined: 14 Jan 2007 Posts: 15

ryan wrote:

The AMD k5-"PR75's" where a strange beast they normally don't run at 75mhz actually 66mhz x 1x multiplier on my machine. I also had a few 5x86s that were labeled x5-75mhz also had a 5k86-75mhz to add to confusion (they were actually a 486DX5-133mhz)

Good Luck with the jumper on the speed LED Smile

After about an hour of fiddling around with the led jumpers I got to say 75.

My CPU allegedly has a clock speed of 50mhz with a 1.5x multiplier. Everest Home under Windows 95 reports that it is a 586 class processor running at 75Mhz. I can run Pentium class programs that would not normally run on a 486 just fine.

So far my config is as follows..

AMD K5 75Mhz
32MB RAM (2x 16MB FP 72PIN SIMMS)
1MB Micronix MX86200 1MB PCI Video
2.1GB ATA Hard Drive
24x CD-ROM
D-Link DE-220PCT ISA Network Adapter PnP (Ethernet 10Mbps)
US Robotics Sportser Model 0640 56K Modem
Aztech 2320 WaveRider Pro 3D PnP
3.5" 1.44MB Floppy Drive

Now all I need is advice for an operating system...

I have Windows 95b running on there. I would rather run DOS 6.22 and Win 3.11 on there but finding and configuring drivers is a pain for DOS/Win3.x. I also have Windows NT 4.0 and Windows NT 3.1 and that's about all I can run on there.

What OS would be good for a system like this?

Joined: 03 Feb 2006 Posts: 488 Location: pennsylvanai

good you have patience with the display.
evereexs had a real display that read the speed and also, reported the disk copying progress.
the clones only had a dumb display that could be set to anything.
many times a fast, over 100 mhz, board was put in an old case with a 2 digit display, the trick there was to set the display jumpers to LO and HI as 100 or 133 was not possible.

running windows 3.1 ( better wfwg 3.11) drivers are available for many of the older video cards.
I do have a collection of drivers. I think the only driver you must worry about are the video drivers, soundcard drivers should not be a problem. when you mess around with nt or wfwg , you will miss PnP. it doesn't work perfectly with 95, somewhat better with 98.

everest is the updated aida32, I still use aida (dos)
and NSSI to check hardware.

hint, to make it easier to install win 3.1 or 3.11 or better still wfwg 3.11, copy all floppies to a cd or a directory NOT CALLED
WINDOWS and run setrup from there.

ther eis a glitchy thing.. himem.sys or smartdrv installs differently in dos 6.22 and wfwg. the driver from wfwg is OLDER
and the driver from dos 6,22 should be used. otherwise
there will be 2 versions, one in config.sys
and one in autoexec.bat ( thinking about it recall it is smartdrv- not 100% sure) when BOTH are loaded, as when you install
wfwg on top of a properly working dos 6.22 install, windows is glitchy or perhaps it will not run at all!
just rem out the line in config.sys.

98 lite is another possibility. if you Can install 128megs of raM, YOU WILL BE OK.. you may find the mb chipset seriously limits the amout of rAM YOU CAN INSTALL.
another thing that irritates is that if the mb has 72pin simm and 168? pin dimm sockets all cannot be used at the same time.
the biggest 72pin simms i have seen are 32m, i hear there are 64 meg simms but have never seen one.

i gave up on dos/wfwg because too many web pages would not open. I could not upgrade netscape any more.

Joined: 14 Jan 2007 Posts: 15

wdegroot wrote:

good you have patience with the display.
evereexs had a real display that read the speed and also, reported the disk copying progress.
the clones only had a dumb display that could be set to anything.
many times a fast, over 100 mhz, board was put in an old case with a 2 digit display, the trick there was to set the display jumpers to LO and HI as 100 or 133 was not possible.

running windows 3.1 ( better wfwg 3.11) drivers are available for many of the older video cards.
I do have a collection of drivers. I think the only driver you must worry about are the video drivers, soundcard drivers should not be a problem. when you mess around with nt or wfwg , you will miss PnP. it doesn't work perfectly with 95, somewhat better with 98.

everest is the updated aida32, I still use aida (dos)
and NSSI to check hardware.

hint, to make it easier to install win 3.1 or 3.11 or better still wfwg 3.11, copy all floppies to a cd or a directory NOT CALLED
WINDOWS and run setrup from there.

ther eis a glitchy thing.. himem.sys or smartdrv installs differently in dos 6.22 and wfwg. the driver from wfwg is OLDER
and the driver from dos 6,22 should be used. otherwise
there will be 2 versions, one in config.sys
and one in autoexec.bat ( thinking about it recall it is smartdrv- not 100% sure) when BOTH are loaded, as when you install
wfwg on top of a properly working dos 6.22 install, windows is glitchy or perhaps it will not run at all!
just rem out the line in config.sys.

98 lite is another possibility. if you Can install 128megs of raM, YOU WILL BE OK.. you may find the mb chipset seriously limits the amout of rAM YOU CAN INSTALL.
another thing that irritates is that if the mb has 72pin simm and 168? pin dimm sockets all cannot be used at the same time.
the biggest 72pin simms i have seen are 32m, i hear there are 64 meg simms but have never seen one.

i gave up on dos/wfwg because too many web pages would not open. I could not upgrade netscape any more.

As for Win 3.x and the Web, I agree its hopeless for web pages. Windows 95 is becoming the same way. I use IE 5.0 (I can't seem to locate IE 5.5 anywhere) and pages display improperly all the time with that.

Anyway, thanks for the advice. It is greatly appreciated.

Joined: 20 Nov 2004 Posts: 589 Location: Shandong, China

Does your motherboard have a 1.25X multiplier available? I've seen Pentium 75 chips run at 60MHz x 1.25 before. Hell, if you motherboard has a 75MHz option, you should see if you have a 1X multiplier available.