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Adding an IDE Header and Resistor Pack to a WD286-WDM20 Motherboard.

ibmapc

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I want to attempt to install the parts needed to get the "Optional" on-board IDE Interface working on this motherboard which I bought a few days ago. Specs can be found Here. Looking at the attatched photo, the place for the missing IDE header is visible as well as the place for an SMT Resistor Pack (the silk screen RP5 is hidden by the shadow of the ISA connector). Also, traces can be seen connecting some of the pins of the IDE header to RP5.
WD_Motherboard.jpg
My Question is, what value of Resistor should be used here? Would 1K Ohm do the trick? Or should I use a higher or lower resistance? Also, would a Resistor Pack with Isolated resistors would be appropriate?
 
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Chuck(G)

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Have you ever seen one of these with the IDE option installed and operating?

Could be that WD/Faraday couldn't get the IDE interface to work right, so they left it off.
 

GiGaBiTe

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Only thing I could suggest is see if the other yellow resistor packs had the same value and try one of those.
 

SpidersWeb

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I haven't looked in to it, nor do I have any idea, but I poked around a few IDE cards I had laying around looking for a batch of same value resistors next to the IDE connector, on the ones nearby I found values in the range of 430 ohm to 2200 ohm. I pulled out an el cheapo super basic one - and it used 1K 1/4 watt resistors. Seems a bit odd to me that a single resistor network and pin headers is all that's needed for IDE though - if the additional cost was that minimal it kinda of seems more advantageous to sell it as an IDE board or use a cheaper chip-set?
 

ibmapc

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Have you ever seen one of these with the IDE option installed and operating?

Could be that WD/Faraday couldn't get the IDE interface to work right, so they left it off.

I've looked quite a bit and all of the ones I can find clear pictures of are missing the IDE header and resistor package. So, I guess you are sayin' don't bother because it probably won't work.

I haven't looked in to it, nor do I have any idea, but I poked around a few IDE cards I had laying around looking for a batch of same value resistors next to the IDE connector, on the ones nearby I found values in the range of 430 ohm to 2200 ohm. I pulled out an el cheapo super basic one - and it used 1K 1/4 watt resistors. Seems a bit odd to me that a single resistor network and pin headers is all that's needed for IDE though - if the additional cost was that minimal it kinda of seems more advantageous to sell it as an IDE board or use a cheaper chip-set?

Both TH99 and Stason.org info show the IDE as an option. Maybe the option never really worked out and none were sold with it. On the other hand, maybe they didn't take the time to program the bios routines for IDE. If that is true, maybe if the header and resistor package were installed, XUB could be burned to an EPROM and plugged into a NIC.

Anyway, thanks for the replies. I have a working motherboard right now. Maybe the thing to do is just buy a 16 bit IDE card. I just thought it would be nice to save the expansion slot since there are only three 16 bit slots and one 8 bit slot.
 

ibmapc

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Only thing I could suggest is see if the other yellow resistor packs had the same value and try one of those.

I'll look at the others on the board and see if I can read the writing on them. I may just leave it alone though since I can't find any evidence that the "Option" ever really existed. I'm not very good at soldering those tiny SMT parts anyway.
 

Stone

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Have you ever seen one of these with the IDE option installed and operating?

Could be that WD/Faraday couldn't get the IDE interface to work right, so they left it off.

I've looked quite a bit and all of the ones I can find clear pictures of are missing the IDE header and resistor package. So, I guess you are sayin' don't bother because it probably won't work.


Both TH99 and Stason.org info show the IDE as an option. Maybe the option never really worked out and none were sold with it.
Mine doesn't have it.

The manual surely shows and describes it.

I have a full page ad from a July, 1989 Computer Shopper with a picture of this board and it shows the IDE header.
 

ibmapc

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Mine doesn't have it.

The manual surely shows and describes it.

I have a full page ad from a July, 1989 Computer Shopper with a picture of this board and it shows the IDE header.

OK Stone,

You had to know i'd ask. Any way I can see that Ad? Is the Resistor Package visible? Can you read any numbers on it?

Thanks

Greg
 

KC9UDX

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If I were you, I'd see what size resistor network is used on other IDE buses and see what happens. It'll either work, sort of work, or not work at all.

Given the price of parts your biggest loss will only be time. You stand to gain some soldering experience.

I added IDE to a SCSI card once by adding a header and resistor network. But a hard drive controller is a little different than a motherboard and that was an actual cost option. I'm probably not the only one here to add a floppy bus to a hard drive controller the same way. The only difference in these cases is that there are working references.
 

GiGaBiTe

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I got lucky with a PC-CHIPS Socket 462 board once, it had pads on the board for an ISA slot. I didn't think of anything it at first until I noticed it had a PCI to ISA bridge and the buffer chips. I got the last box of 50 NOS ISA slots on ebay and used one and it worked surprisingly.

It's the fastest board I have with a fully functional ISA slot, I think the CPU was 1400 MHz with the ability to go a bit higher.
 

vintageklench

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IBMAPC,
don't know the value of the resistor, but I have included a picture of my wmd-20 board. perhaps you'll be able to determine what you need.
 

ibmapc

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Nope. I beeped things out and tried make some sense of things but it's WAY beyond my level of expertise. So, I gave up. No longer using that board anyway.
 
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