Re: Identify motherboard Slot 1 SIS chipset

Posted on 2021-05-16, 20:00

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

while not there is direct connection for the PIN A21 A27 A33 A39 A45 (these are to each other) and the PIN A53 B25 B31 B36 B41 B43 B54 with the + 3.3V of the power supply (orange wire). Well that's odd. Those are all 3.3V pins, but half not connected. I guess the NC ones goes to whichever FET …

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Re: ECS 761GX-M754 no POST

Posted on 2021-05-16, 16:19

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looking at a photo of someone else's board, there are a couple of big FETs in the corner between the PCIe slot and the DDR slots. Could you measure the voltages on those pins and photograph them? Yes, if You click on a picture in my previous post to enlarge it, You can see the values written there …

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Re: ECS 761GX-M754 no POST

Posted on 2021-05-16, 11:38

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Thank You for Your other helpful advice and efforts to help. I measured the required values and it looks okay: Pin 4 RT8800 (DVD - divider?) and ground - 2,99 kOhm Pin 4 and near end R333 and R300 - 0 Ohm Pin 4 and R333 - 33,0 kOhm Pin 4 and R300 - 2,99 kOhm Resistor 333 - 32,8 kOhm Resistor 300 - …

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Re: ABIT BH6, is it dead?

Posted on 2021-05-15, 17:33

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by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's an inductor, from the looks of it it's used in the VCC line on one of the PS/2 ports to reduce noise. It failing would cause the PS/2 port to not work but shouldn't cause any more problems (assuming it didn't do significant damage to the PCB). I wonder why it failed before the fuse though. …

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Re: Identify motherboard Slot 1 SIS chipset

Posted on 2021-05-15, 16:45

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Before the block at post 41 and the continuous beeps, always make the long beep and the two short beeps, even with the POST CARD in the ISA slot. Video adapter error. did you by chance leave the vga card out of the computer on that attempt ? No the card is inserted in the slot, but it is as if it …

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Re: ABIT BH6, is it dead?

Posted on 2021-05-15, 13:54

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well, it looks like L1 definitely smoked, but that doesn't say anything about why it smoked. If this is fixable then I expect it's now a soldering iron job. There are a couple of other patches in the area that look to me like either dirt or corrosion, which I've marked. Konc mentioned that this …

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Re: ECS 761GX-M754 no POST

Posted on 2021-05-15, 09:29

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Looks useful. So I'm still assuming that the 8800 is holding the 9605 in shutdown mode, so all the UGATE and LGATE pins are never turning on. Looking at the 8800 then one thing that stands out is DVD should be +ve; from the reference design in the datasheet it should be around 1.2V. That it's 0V …

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Re: ABIT BH6, is it dead?

Posted on 2021-05-15, 08:36

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Sounds like some of the magic smoke got out (in case you haven't seen it https://en.wikipedia.org/wiki/Magic_smoke , see also Lucas Wiring Harness Smoke). Likely some component had too high a voltage applied because of a failure somewhere else. Can you get photos of the area? There's a chance that …

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Re: Identify motherboard Slot 1 SIS chipset

Posted on 2021-05-14, 21:09

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

It arrived yesterday, and it should be a PINE SI21, for the photos I try to photograph the mosfet areas. Aesthetically, the card is like new, there is no scratch on the tracks on the back. I tried with an ISA video card, it is visible in the picture with the PC on, the block is always there. Sorry, …

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Re: Identify motherboard Slot 1 SIS chipset

Posted on 2021-05-14, 20:53

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Now you've got the board, any chance of some photos of the board? It might help identify things. Out of interest, do the post card give the same result plugged in to one of the ISA slots (just in case there's a problem with that PCI slot)?

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Re: Identify old 5.25 FDD

Posted on 2021-05-14, 20:34

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by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Can't help with IDing the drive, but what are you using the drive with? It looks like the jumper is set to DS0, when I think the standard for PCs is DS1?

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Re: ABIT BH6, is it dead?

Posted on 2021-05-14, 19:24

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well it would fail and then reboot. The flash tool shown that a portion of the chip couldn't be updated, like the progress bar was color coded and like the first chunk would be color coded to say that a portion of the chip couldn't be written to. after the process was done it would reboot and the …

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Re: ABIT BH6, is it dead?

Posted on 2021-05-14, 18:59

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

1) Correct 2) Yeah a message did a appear on the screen, no beep codes 3) Yeah it just would reboot show the same message, the disk would boot only for the program to fail again. I failed several times before messaging the user here again and that was when I was told to reseat the chip and if that …

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Re: ABIT BH6, is it dead?

Posted on 2021-05-14, 18:39

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

If the socket is through hole, can you check the rear side of the motherboard under the PLCC socket? Or if it's surface mount, a picture with the chip removed. I'm wondering if when the socket cracked it may have damaged a via or surface mount pad. Just to recap the steps so far: 1) Was working, but …

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Re: IBM EGA Adapter Repair Advice Needed

Posted on 2021-05-13, 14:47

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I was taught that leaving inputs disconnected could lead to them floating around the switching voltage, leading to large currents flowing and overheating. That's true, and a good practice in general, but it applies mostly to FET technology (so anything MOS). TTL chips are based on bipolar …

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Re: IBM EGA Adapter Repair Advice Needed

Posted on 2021-05-13, 10:26

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

So I'm wondering what is the use case for HPOL being anything other than positive, since (as far as I know) all compatible monitors at the time worked that way? "Future proofing", just like their extremely successful feature connector and dual RCA jacks? :) Using the second XOR for HSYNC could just …

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Re: IBM EGA Adapter Repair Advice Needed

Posted on 2021-05-12, 20:29

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Meanwhile here are the scope measurements on the IBM from the DD DB9 video out. The frequencies and pulse lengths are right on spec, but voltages slightly low. Shouldn't Mode 1 Vertical be +ve going? It looks -ve in the scope trace, and the minuszerodegrees site gives only Mode 2 Vertical as -ve …

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Re: DOS CD-Rom issues

Posted on 2021-05-12, 15:15

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by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Okay, so the entires in autoexec.bat are: SET BLASTER =A220 I5 D1 H1 P330 C1E8 [path]UNISOUND.COM /V80 [path]DEVLOAD.COM [path]ATAPICD.SYS /D:CDROM [path]MSCDEX.EXE /D:CDROM And config.sys does not contain any changes. Neat. I think only having the one DMA might stop being able to record and …

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Re: DOS CD-Rom issues

Posted on 2021-05-12, 13:07

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Also, I've noticed that it works only with atapicd.sys. Both vide-cdd.sys and oakcdrom.sys crash the PC. Yay! Sort of. Wonder why that happens. Still, good enough for the moment. Could you post your config.sys and autoexec.bat so that if anyone else has a similar problem then they don't have to …

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Re: ECS 761GX-M754 no POST

Posted on 2021-05-12, 12:57

by

by snufkin

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Good work on the measurements, I think that confirms that the chips are RT8800 (AA-8b) and RT9605 (B3-7L). I think that the 2.2V you measured on the PWM signals going from the 8800 to the 9605 shows that there is a switching signal there. Those signals should be switching between 0V and 5V, but too …

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