Re: Cirrus Logic CL-GD5429 VLB: no picture, no sync

Posted on 2024-03-18, 16:32

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe one of the SN chips is dead? Can you trace the signal to see if H/Vsync go to one of those? H/V sync is analog signal and it goes to VGA connector almost directly (with some RC-chains) SN74F245N's are the bus transceivers (tri-state bidirectional buffers) used to isolate chip from the bus to …

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Re: Cirrus Logic CL-GD5429 VLB: no picture, no sync

Posted on 2024-03-18, 16:17

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I had a similare issue and I had a trace cut in a way I couldn't see it albeit at an angle. Does your screen issue some kind of error warning? Could you post a pic? No picture at all. Monitor doesn't detect VGA signal as it have no HSYNC/VSYNC. No error beeping at POST. PC boots as if VGA works ok …

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Re: Cirrus Logic CL-GD5429 VLB: no picture, no sync

Posted on 2024-03-18, 16:07

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

With no 75ohm load and nothing on the monitor detect pins, it might have gone into monochrome synch on green mode. If there's nothing happening on green then yeah, got a weird fault. I tested it with monitor connected and checked for sync signals with oscilloscope directly on GD5429 pins. Just in …

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Cirrus Logic CL-GD5429 VLB: no picture, no sync

Posted on 2024-03-18, 15:43

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

CL-GD5429-based VLB video card. Video BIOS is ok. POST doesn't complain 'bout missing video card. But chip produces no HSYNC (pin 69)/VSYNC (pin 68) signals. EVIDEO (pin 94) is high as expected. ESYNC (pin 95) is floating and it looks odd. Even if I pull it high to +5V no sync is present. https:// …

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Re: Are ES1869F and ES1869FC the same?

Posted on 2024-03-16, 11:28

by

by froller

in Marvin \ Sound

in Marvin \ Sound

FC is likely a slight revision of F with nothing changed feature wise. I was wondering if I can swap dead *FC with new *F. So I did and it helped me to revive the card. The only issue I noticed is brand new ES1869 can't be properly initialized with esscfg.exe only. The card needs to be plugged into …

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Re: Are ES1869F and ES1869FC the same?

Posted on 2024-03-16, 02:54

by

by froller

in Marvin \ Sound

in Marvin \ Sound

Yes they are. I've replaced ES1869FC with ES1869F and it works fine.

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2024-03-12, 13:18

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

feipoa wrote on 2024-03-12, 11:38: There may be something wrong with my AMIKEY-2 because these normally work with PS/2 mice. It certainly is. AMIKEY-2 is proven to work with PS/2 mice. And it doesn't require tying Pin26 to +5V as HT6542B does for proper start.

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Re: The World's Fastest 486

Posted on 2024-03-11, 12:58

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I made some more measurements. 90mV ripple on +5V rail (measured on decoupling caps near CPU socket) hence no recapping needed. Removing second 32MB SIMM doesn't affect FPS in Quake. Either it fits in lower 32MB or 256kB of WB cache is enough for 64MB. These SIMMs are same model and same year but …

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Re: The World's Fastest 486

Posted on 2024-03-07, 12:40

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can the amount or type of RAM affect the results? I use 2x32MB 60ns EDO. @4x40MHz I could max out all timings except one no matter which exactly. Filename VirtualBox_MS-DOS_07_03_2024_15_41_38.png File size 14.21 KiB Views 478 views File comment Memory settings

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Re: Native PS/2 mouse implementation for 386/486 boards using the keyboard controller

Posted on 2024-03-06, 17:55

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I have some news about my project. With a help of member of retro web Discord channel, I've been able to disable internal keyboard controller and enable external one. So the keyboard works great with external KBC, unfortunately once I connect PS2 mouse, the keyboard stops responding right after …

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Re: The World's Fastest 486

Posted on 2024-03-06, 15:08

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I mean performance difference between 4x40 and 3x50 is an order of magnitude greater. I can't see what you are referring to, as order of magnitude implies 1000%, a whole power of ten above, not the maximum top to bottom 25% lower 33% faster I see on the results you posted. I'm referring the …

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Re: The World's Fastest 486

Posted on 2024-03-06, 15:04

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The Serpent Rider wrote on 2024-03-06, 14:49: The difference in timings and slower CPU clock negates all benefit of higher FSB. You need to push FSB to 60-66Mhz to see performance boost. Really? 2-1-1-1 is 0.2% faster than 2-2-2-2 4x40MHz is 19.4% faster than 4x33MHz 3x50MHz is 31.3% faster than …

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Re: The World's Fastest 486

Posted on 2024-03-06, 13:14

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Somehow it is explainable I would say. If you use the exact same timing values for cache and RAM @50 and 40MHz, then cache and RAM is exactly 25% faster @ 50MHz. But the question is, why you cannot use better values at 40MHz, like cache read 2-1-1-1 and fastest for RAM. I can't use 2-1-1-1 timings …

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Re: The World's Fastest 486

Posted on 2024-03-04, 12:29

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

feipoa wrote on 2024-03-04, 11:29: Are you using identical BIOS settings for both configurations? If not, could you specify? Of course I use same settings. All memory timings set to minimal values except "RAS to MA delay" set to 3 CCLK instead of 2 and "DRAM speed" set to "Faster" instead of " …

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Re: The World's Fastest 486

Posted on 2024-03-04, 09:18

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I was experimenting with one of my AMD-X5-133ADZ's and figured out that in Doom, Quake and some other benchmarks 150MHz (50 x 3) config works approximately 4-5% faster than 160MHz (40 x 4). Even with halved PCI bus clock. Some of installed PCI cards can't stand 50MHz bus and crash while booting in …

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Are ES1869F and ES1869FC the same?

Posted on 2024-02-25, 01:49

by

by froller

in Marvin \ Sound

in Marvin \ Sound

Is there any difference between ES1869F and ES1869FC chips? I know that ES1869S is the same crystal as ES1869F but in different package. But F and FC are in the same package. I saw very similar boards with either F or FC soldered and I wonder if I can swap dead FC chip with F one? Unfortunately I …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-22, 18:06

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

In my defence I stopped using those EEPROMs once I got burned by the different pinout, I now stick to "EPROM emulator" parts, and actual EPROMs once I'm happy with the result. I stuck with EEPROMs since the time I have not yet bought TL866 and used home brewed programmer made from Arduino Mega. Now …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-22, 15:28

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

This shouldn't be needed on 28C256. In the datasheet look for "Software Data Protection". Not sure what EEPROM programmer you have but most should be capable of turning this option on/off. When it's on the /WE pin will not cause a write unless you follow a specific unlock procedure, which is …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-22, 11:27

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So the crime was solved. Particular card does support only 27-series EPROMs up to 27C256. Maximum boot ROM size is 32kB. Pin 27 (\WE) of EPROM is connected directly to A14 line in ISA slot. So addresses with A14 low makes 28-series EPROM to switch data bus for input leaving no active outputs on data …

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Re: AT/LANTIC DP83905 broken EPROM

Posted on 2024-02-17, 01:01

by

by froller

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

how about bending WE pin up? This probably should help. But I'd also tied it to Vcc just to make sure it never going to be active. It's more interesting what to do with A14 of ROM chip. I've placed 2 copies of XT_IDE at offset 0x0000 and 0x4000, bent up pin 1 (A14) and even pulled it low. It …

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