Hello!
I finally grabbed a LAPC-I card, that works, but on my pentium 166mmx system it has problems, in fact inserting the lapc makes the system unable to boot.
the card is working on 386sx system, but on the pentium no. I have it on the same settings as my scc1 card. is there incompatibillity between p5 systems and lapc-i? I also use a usb pci card, maybe that is the prob?
I don't think there would be any incompatibility with the pentium processor itself, as I use my LAPC-I in a pc with a pentium 233mmx. Your best guess would be to boot the pc before adding the LAPC and then check the device manager if there are any other cards which use the same I/O and IRQ.
If that doesn't conclude anything, it could well be that the ISA-bus on your pentium hasn't got the rarely used -5v rail implemented. The Roland LAPC-I is one of the very few cards which uses it (I think, not 100% sure), and as such some motherboard manufacturers left it out.
Hope that's of some use for you.
well, there is no irq/address conflict, because the scc-1 that works has irq2/port330 as well....
that is interesting about the -5v , the mobo is a cheap one of the era, what make model is yours? perhaps on ebay there is some I can get too....
what make model is yours? perhaps on ebay there is some I can get too....
It's an ATC-5040 from A-Trend, think the BIOS date is 1998 or something like that. Should accept your CPU as well.
-5V come from the white wire of the psu and it is missing on some psu.
Type win to loose the power of your computer !
the psu has this white wire...
I got this better mobo instead, with intel chipset, atx size, atx psu, onboard video....
http://86.4.178.186/garoag_/viewdescription.p … e62b1d0&no=3887
also it is from Packard Bell, so it must be good, not the faster but I hope it does not miss any lines! 😅
wrote:-5V come from the white wire of the psu and it is missing on some psu.
While we're at it, I'd like to confirm something: so it actually depends on PSU instead of the motherboard itself, doesn't it?
I have a Soyo 845PE motherboard (a Pentium 4 mobo, actually), and it has three ISA slots. Yes, a Pentium 4 mobo with ISA slots.
As long as I have a right PSU (the one with -5V white wire) , I can put an LAPC-I card on that mobo, can't I?
read more carefully.
my psu hs also the -5v line, but the card won't work.
try and see....
wrote:read more carefully.
my psu hs also the -5v line, but the card won't work.
try and see....
Ooops.
Makes me wonder, though. Do you overclock your mobo's FSB speed? I remember reading somewhere that overclocking FSB speed may cause some older cards refuse to work. I don't remember all the details exactly, though (or did I read it here?)
Nonetheless, it seems to be motherboard problem, am I correct? And if that's the case, how do we tell whether the mobo's ISA slots got the -5V rail implemented?
no, overclock at all....
seems to be a mobo fault, it was a cheap one...
I don't know any way to test, unless u plug a similar card and see what happens , 🤣
Measure it... Ask Google for ISA bus pinout. I wouldn't call it ISA bus though if it hasn't got the -5V.
Another thing you can try is playing with the I/O recovery time settings in BIOS (if any).
1+1=10
It seems strange that a SCC1 would work in a system where a LAPC-I doesn't. Did you look for mechanical problems as well? The LAPC could have been prevented from making good contact with the ISA slot because of physically interfering components on the mainboard or inside the case. After all, the LAPC-I is a real full length card, very easy to collide with other stuff.
wrote:Another thing you can try is playing with the I/O recovery time settings in BIOS (if any).
Good idea. And while in the BIOS setup, also make sure your ISA clock divider is set right. My LAPC-I stops working when the ISA bus clock is 12 MHz or higher.
Good idea. And while in the BIOS setup, also make sure your ISA clock divider is set right. My LAPC-I stops working when the ISA bus clock is 12 MHz or higher.
For an 8-bit card, the LAPC-I should be run at a 4.77MHz clock. However, I have had no trouble getting my LAPC-I to run in a machine with a Pentium II 450MHz.
However, keropi has an interesting problem. The LAPC works in the older computer. That computer undoubtedly has a -5v line, presumably supplying about 500mA. The LAPC-I needs 50mA. It is probably due to a crappy motherboard.
yes, it is a crappy mobo, I cannot find the model or make, I had to look pics of pentium mobos, to find a bunch oem ones that look exactly like that (except colors and minor details).... bah!
I hope the new intel made one is better....
Some modern PSUs don't provide -5V even if they have white wire
I installed a PSU FSP Blue Storm 350W on a P2B-L
It has white wire but bios report an error during post: -5 deliver nothing
With an old 145W PSU on the same mobo, I get -5V
Type win to loose the power of your computer !
