Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-08-09, 02:18

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Today I measured all the motherboards. voltages are OK. and this is what the clock signals on the ISA bus and on the CPU look like. I am aware that they are dirty. the 486#2 board was very dirty and still slightly rusty, it also had a corner (the cache corner) with a slight damaged from fire (an …

---

Re: Help with a S3 Virge DX

Posted on 2023-08-06, 04:07

by

by kinetix

in Marvin \ Video

in Marvin \ Video

The Virge (and Virge/DX) chips are not dynamically clocked. The core clock is initialized by the BIOS, and keeps the same even when S3D games are started. For a Virge/DX card to show "good" 3D performance, the core clock needs to be set at around 70 to 75 MHz. Virge chips do get warm at that clock …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-08-05, 19:28

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Dorunkāku wrote on 2023-08-05, 09:49: I forgot to mention earlier, the board happily tries to charge the battery all the way up to 5 Volt. Measure the voltage on the battery when board is powered on. mmm... I get only 0.1v on the battery contacts, on both boards

---

Re: Help with a S3 Virge DX

Posted on 2023-08-05, 18:28

by

by kinetix

in Marvin \ Video

in Marvin \ Video

If it's instantly gets noticeably hot, then it's probably was zapped by static electricity or short circuit happened, i.e. chip is damaged beyond repair and is leaking energy as heat. MMM.... I just downloaded the chip manual. the bent pins were 113 (PD59, data) and 144 (Vss, digital ground, bad …

---

Help with a S3 Virge DX

Posted on 2023-08-05, 16:30

by

by kinetix

in Marvin \ Video

in Marvin \ Video

hi guys, I have a S3 Virge DX card, a PT-75 from AOpen. I don't remember where I got it from years ago, I had never test it before, until some weeks back. After cleaning and visual inspection it appeared to be mostly fine. Just a slightly bent pin (but not making contact with another) on the main …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-08-05, 05:56

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Excellent, thanks for the pictures! I'll take a look in my stash to see what parts I already have and what I need to buy. Well, I measured the clock signal on the ISA bus with a friend's oscilloscope. it delivered 7 point something Mhz (i forgot it), although with a certain "noise" (a small spike) …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-30, 17:39

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

TheMobRules wrote on 2023-07-30, 09:51: Now I'm tempted to add the 3V regulation components to my own board! I hope these pictures may help you to do that:

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-30, 15:23

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Dorunkāku wrote on 2023-07-30, 10:05: 4700 Ohm It is connected to the gate of the MOSFET. In the picture the LT1085CT does not have a heatsink, it really needs one! Yes, I removed the heatsink to take the photo, so the board could be seen better. in the photo of the complete board you can see it

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-30, 01:51

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

No, that is not going to give you correct readings. The LT1805CT needs a minimum current to actually be able to regulate its output. Measure the voltage on the capacitor TC12 with a CPU installed. Also use a Award BIOS if you like to lift the board from sub-par performance to one of the best …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-30, 01:46

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Yeah, considering that both the Intel and AMD DX4 variants support the VOLDET pin I don't understand why they would do it differently. I have another SiS471 board, the ASUS VL/I-486SV2GX4 which implements this feature in the following way: there is a jumper that allows you to connect the VOLDET pin …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-29, 18:53

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Interesting... not sure why this motherboard handles the voltage differently for AMD CPUs, but who knows? Anyways, if you get the 5x86 working with the SV8B configuration the only thing remaining would be to set the 4x multiplier for 133MHz. At least on my version of the motherboard you can do that …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-29, 00:16

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I measured Vcc for most of the 3.45v configs. off course no CPU in the socket Intel DX4 W/T: 5.1 v Intel DX4 W/B: 5.1 v AMD DX2: 3.53 v AMD DX4 V8T: 3.53 v AMD DX4-S SV8B: 3.53 v AMD DX4-S SV8T: 5.1v "Misc 5x86": 5.1v see? Anyway, I'll stay working with the configuration AMD DX4-S SV8B for the …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-28, 01:53

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

on the resistor to the left: 150 ohms on the resistor to the right: 10K I measured the voltage without the CPU in the socket. I will test every jumper config and tell you the voltage in each case I gave the regulator a close look. for the Intel dx4 on the ADJ leg of the voltage regulator there are …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-27, 20:33

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

TheMobRules wrote on 2023-07-27, 16:42: Thanks for the pictures! Give me some time while I go through the jumpers with my multimeter and I'll get back to you. you welcome. but, if you only have the 5v version, how can you measure the 3.45 settings? I asked because in your initial post you said you …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-27, 16:30

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Do you have any idea why with the configuration for the intel dx4 it is giving 5 volts? Could you share the configuration of the jumpers you are using? Can you take close photos of the components around the CPU and regulator area, including the markings on the regulator chip? I have this board, but …

---

Re: AMD 5x86 doesn't run at full speed on AOpen Vi15G

Posted on 2023-07-27, 03:28

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

hi, friend. I know this is an old thread, but it's the only place I've found to ask. I have that same Acer/AOpen VI15G motherboard (actually, I have two), the revision with a voltage regulator and support for 3.3 volts. It is part of my two old PCs, stored about 20 years ago and that nostalgia has …

---

Re: "Dexter", My freshly assembled 486 VLB based System.

Posted on 2023-07-27, 03:27

by

by kinetix

in Marvin \ System Specs

in Marvin \ System Specs

hi, friend. I know this is an old thread, but it's the only place I've found to ask. I have that same Acer/AOpen VI15G motherboard (actually, I have two), the revision with a voltage regulator and support for 3.3 volts. It is part of my two old PCs, stored about 16 years ago and that nostalgia has …

---

Re: 486 Multimedia Chassis [Built in Speakers, LED VU Meter, etc] Rebuild - Featuring an AOpen Vi15G VLB Motherboard!

Posted on 2023-07-27, 03:27

by

by kinetix

in Marvin \ System Specs

in Marvin \ System Specs

hi, friend. I know this is an old thread, but it's the only place I've found to ask. I have that same Acer/AOpen VI15G motherboard (actually, I have two), the revision with a voltage regulator and support for 3.3 volts. It is part of my two old PCs, stored about 16 years ago and that nostalgia has …

---

Re: AOpen AP53 not POSTing?

Posted on 2023-07-27, 03:02

by

by kinetix

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I've tried with 8MB SIMMs instead, and an ISA VGA card. Still nothing happens, and it doesn't complain about RAM when none is installed either. I already got my refund and the board is now in my parts box. :P Hi, I know it's an old thread. I have that same board. stored more than about 15 - 16 …

---