I'm sure the problem is your PSU. I'm sure you do need a rail that provides -5V.

^ this is true, without a -5v signal the LAPC-I won't work

IIRC the -5v cable is the white one on the psu plug

Thanks for both of you for the quick answers!

Now I need an old PSU to test it again, in an old 486 at least.
I hope the card will work...

Btw, is it possible to "mod" an ATX PSU to provide -5V ? Are there ATX PSUs that still have a -5V rail?
Or am I bound to the old AT PSUs ?

Until very recently, Nexus sold an ATX PSU with the -5V rail. It was a 350W model. Also, you can get used ATX PSUs on ebay with the -5V rail fairly easily, and then use an ATX-to-AT PSU adapter (also available on ebay), if your mobo requires an AT PSU. Your options are not limited to just using old AT PSUs with old AT mobos. However regarding newer faster mobos, I'm not sure if the LAPC-i card is "speed sensitive". I think an old "classic" Pentium machine would be OK, and not too fast for it..

I think I found it, it is the

Nexus NX3500 120mm PSU

I am closing in for catching one in cyberspace right now...
Many thanks!

Jolaes76 wrote:

I think I found it, it is the […]
Show full quote

I think I found it, it is the

Nexus NX3500 120mm PSU

I am closing in for catching one in cyberspace right now...
Many thanks!

Yep, that's the one. I can recommend them. BTW, if you do need an adapter, here is one on ebay. I can also recommend them, having used both of these components in "new old" systems.

I meant it for an ATX mobo so I do not think I will buy the adapter.
But the NX3500 will be a rare bird, I can see 😒

-5V rail is not *that* difficult to find. I got a used Levicom Silent ATX 450W with -5V rail pretty easily. After googling a bit:
http://forums.guru3d.com/showthread.php?t=83021
I found that Antec Truepower 380W also has a -5V rail. Dont lose faith - just believe in ebay and do some research 😉

hell I just found out that my pretty damn old Levicom has more power on +12V Rail then the brand new Chieftec iArena 500W which I bought for i5 2500k rig! What a fail 😢

Thanks for the tip, I will check that out!

my goal was to find a good PSU, with the latest possible manufacture date so that it would last. I don't want to rely on any dubious 10 year old PSU when there is 350 USD under the hood...

retro games 100 wrote:

Jolaes76 wrote:

I think I found it, it is the […]
Show full quote

I think I found it, it is the

Nexus NX3500 120mm PSU

I am closing in for catching one in cyberspace right now...
Many thanks!

Yep, that's the one. I can recommend them. BTW, if you do need an adapter, here is one on ebay. I can also recommend them, having used both of these components in "new old" systems.

Is this the best high efficiency available to get to replace the older PSUS??

Because those older PSUS arent efficiency enough for me.

Is it worth to replace a old PSU like in an XT 80286, 80386, Pentium machine?
Because i want to have better quality psus.. Dont like that old AT PSU crap also..

Well, there cannot be too many options as ATX 12V ver 1.1 PSUs are the last line sure-to-have the -5V rail, in ATX 12V ver. 1.2 it is already optional (that means January 2002).

There are "exotic" medium quality brands like Codegen that produced PSUs labelelled as ATX 2.1 or ATX 2.2 P4 , but they also retain the -5V rail (afaik with 0.3A only). I have not tested the reliabilty of such a unit in an old PC but many 5-6 year old systems I met still work with these cheap PSUs, so they are much more reliable than the first generation of Codegens.

It was the PSU, alright.

I have tested it with and old ATX 1.1 PSU and the LAPC-I worked. 😀

On of the reasons I went for a CM-32L (LAPC-I is the ISA version of the CM-32L). In 5-10 years finding a -5V PSU will be even harder. That's why I'm so keen on building time machines / hybrid retro PCs using as many new parts as possible.

For example my Super Socket 7 machine has a new ATX case, new ATX PSU, new PS/2 mouse, new(ish) LCD screen, new PS/2 keyboard, new IDE DVD drive, new CF cards, new(ish) AGP card and so on.

The only real vintage bits are the ATX Super Socket 7 board, the CPU and the Ram.

With all cache disabled it's an average 386DX and a Roland MPU401AT drives whatever MIDI Module I need.

I generally follow the same principle.

I wanted to buy a CM-32L, in good condition. Import from Japan was not an alternative, I do not like ghastly glowing green boxes in the dark. Yet they still pin up insane prices on Roland modules on ebay.

Anyway, I had heard all, read all, and decided that only the CM-32L sounds "authentic" for old games. No vibrato bug either. But there was no reasonable offer for 7 months, so I bought this card instead.

You'll need at least two units anyway. Some games will only sound 100% correct on the MT-32 (Old) and some only on the CM-32L.

Good thing is that the MT-32 (Old) is relatively easy to find. The CM-32L is indeed quite rare. The CM-64 is another option. It has the CM-32L inside and another PCB. Only difference is it draws more power and slightly more noise, but hardly noticeable.

I got pretty much all my Roland stuff from Japan. After all Roland is a Japanese company.

Jolaes76 wrote:

Import from Japan was not an alternative, I do not like ghastly glowing green boxes in the dark.

Not sure if serious.

Well, I feel uneasy about keeping irradiated devices at home, that is for sure.

Mau1wurf1977,
On the long run a professional modification of an ATX 12V v2.0 or later seems to be the solution to supply the -5V rail:

adding a negative linear regulator like th MC79M05 to the -12V rail (+heatsink needed). Maybe this can still fit into the PSU box.

Still, this might be too much hassle for many retro fans...

Buying from Japan is very good, I bought a CM-64 and a BOXED like new Roland CM-500 with two MPUs (PC98 and ISA Super MPU II) from Japan, all working perfect.