Need to find a 34-Pin Motherboard Floppy Header

[Topcat]

Looking for some floppy headers.....searching the usual sources (digikey/mouser/etc) until my eyes bled, I couldn't seem to find such a beast. Yes, the silly 34 pin floppy header for a PC motherboard....

Why? Well, I was given a bunch of Optiplex 330's, which are useless systems these days....and despite what some have said, they do not respond well to the E5450 c0 stepping LGA771 Xeon mod, tried several, it never worked. They're in a standard BTX case, so I tossed some $5 Optiplex 380 boards in them I picked up on ebay, which will run ANY 5400-series Xeon with hard mods + firmware.....



The 330 system has a floppy drive, the 380 does not. However, the 380 has the blank for header on the motherboard and the setting in the BIOS.....SO.... I need the header!







The reasoning is obvious, I want to try installing the header....which should make the floppy drive functional.....but for the life of me I can't find the headers. Scavenging them from junk boards is not worth all the aggravation, swear words, and destruction.

[eccerr0r]

Re: Need to find a 34-Pin Motherboard Floppy Header

Would mouser's Molex 70246-3404 work? You will need to pull out/cut down one pin, however.

BTW you still need to pay the aggravation, swear words, and possibly destruction when clearing the filled-in solder holes (because they likely need to be pristine to put the new headers in due to pin thickness), but yes at least you won't need to remove one from another board intact, which is tougher...

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

Would mouser's Molex 70246-3404 work? You will need to pull out/cut down one pin, however.

BTW you still need to pay the aggravation, swear words, and possibly destruction when clearing the filled-in solder holes (because they likely need to be pristine to put the new headers in due to pin thickness), but yes at least you won't need to remove one from another board intact, which is tougher...

Clearing the holes isn't a big deal.....and thanks for the P/N...after an hour of searchign I never found it. Yea, I know a few pins would need to be removed.

[stj]

Re: Need to find a 34-Pin Motherboard Floppy Header

.1" 34pin dual box-header

usually listed under pcb interconnects

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

I have some ordered. I'll update this with the outcome...the cases have floppy drives, it'd be nice to see them work versus removing them and having to find something else to fill the bay. I thought about card readers, but by the time I bought the card reader plus the cost of an internal card to run it (no internal USB headers), I'm being cheap and not wanting to spend that much on these. These will be some interesting frankensystems, but very usable, even today.

[ratdude747]

Re: Need to find a 34-Pin Motherboard Floppy Header

Are all the passives there too? I tried this (or something similar) on something similar if memory serves to no avail.

That said, on the other hand, I added a HDA header to to the unpopulated header on an alienware X-Fi card I got for cheap (had dell's proprietary audio header populated instead)... which works great.

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

Are all the passives there too? I tried this (or something similar) on something similar if memory serves to no avail.

That's the burning question, I don't know... It *appears* they are, and the setting in the BIOS to enable floppy... It was a cheap gamble, it may be a miserable failure.

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

...it may be a miserable failure.

Yup, this flopped. Was an inexpensive gamble....but not sure why.... It doesn't seem any components were missing besides the socket itself (seat of my pants says it's a firmware issue)....but I have no clue.

FWIW, another Xeon hack, this one was easy! Intel DG45ID motherboard. CPU had to be modified of course, but no firmware hacks needed and all instruction sets are supported. I stuck this board in a small slimline case, will be a fine 'work from home' special!!

[eccerr0r]

Re: Need to find a 34-Pin Motherboard Floppy Header

did it attempt seek test at least or is the drive totally unresponsive?

[Per Hansson]

Re: Need to find a 34-Pin Motherboard Floppy Header

I see two floppy headers, one IDC and one slimline.
They are labeled DSKT & DSKT2 respectively.
Nearby are two jumpers, JP1 and JP5
Not sure if they are to select or something entirely different, there is a wiggly line so could be for a built in antenna too?
I would not give up so easily, post some really high resolution images of the front and back of the floppy area.
Possibly it is just missing some passives.

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

did it attempt seek test at least or is the drive totally unresponsive?

Completely unresponsive.

I see two floppy headers, one IDC and one slimline.
They are labeled DSKT & DSKT2 respectively.
Nearby are two jumpers, JP1 and JP5
Not sure if they are to select or something entirely different, there is a wiggly line so could be for a built in antenna too?
I would not give up so easily, post some really high resolution images of the front and back of the floppy area.
Possibly it is just missing some passives.

Attached are a couple high res pics....let me know if somewthing jumps out at you....

[eccerr0r]

Re: Need to find a 34-Pin Motherboard Floppy Header

Which drive select did you use/did you use a twist or straight cable/connector?

I had an intel board where A: used a straight cable and B: was totally useless.

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

Which drive select did you use/did you use a twist or straight cable/connector?

I had an intel board where A: used a straight cable and B: was totally useless.

It was a cable from an optiplex 330. Looking at it, it is a twisted.

[Per Hansson]

Re: Need to find a 34-Pin Motherboard Floppy Header

The missing R617 seems related to disk select from what I could trace out it is connected to IDC pin 2.
The missing R960 seems related to the step command, it seems connected to IDC pin 20.
That said it seems there are not many, if any components missing when comparing to your picture of the Optiplex 330
The idea by eccerr0r seems very well worth a try: possibly it uses a straight cable.
I also note this message in the BIOS setup you show of the Optiplex 380:
Note: The "USB Controller" setup option will affect floppy operation

How does Windows see the floppy, just fine? Floppy controller and all?

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

^
I don't remember seeing the floppy controller in Windows device manager...but if it doesn't detect the floppy, it disables it IIRC. I'll try the straight cable....certainly worth a shot....I'm sure I have a drawer full of them.

[Per Hansson]

Re: Need to find a 34-Pin Motherboard Floppy Header

^
I don't remember seeing the floppy controller in Windows device manager...but if it doesn't detect the floppy, it disables it IIRC.

The "normal" behavior in old Award BIOS'es is that you can disable floppy seek, and the floppy itself.
(Select none instead of 720KB or 1.44MB) and then third you have the ability to disable the floppy controller.
Only the last one makes the floppy controller disappear in Windows.

Dell systems are simplified, no ability to select floppy size.
But I just tried it on my ancient Precision 470: with "diskette drive" set to "Off" no floppy controller was seen in Windows, or A:\ drive obviously.
With it set to "internal" (but no hardware present) it barked during POST that no floppy was present: but within Windows both the controller and A:\ drive showed up...
It might be interesting to see if the Optiplex 330 BIOS options for "diskette drive" have "internal" as a choice as well?

EDIT: If it is a BIOS issue it could be worth to check with Dell DCCU if more options are available that way:
https://www.dell.com/support/article...n-utility-dccu

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

^
Thanks for all the info!!

If it's missing components mentioned above, I'm not sure 'trial & error' guessing would do much good....I'd need a schematic...or perhaps trace back the corresponding components on the 330....

I will take another poke at this as soon as I get some of this other junk off my bench.

[Per Hansson]

Re: Need to find a 34-Pin Motherboard Floppy Header

^^When I wrote that about the missing components I had not yet compared it to your picture of the 330.
When I did compare it was when I wrote:
"That said it seems there are not many, if any components missing when comparing to your picture of the Optiplex 330"

I think testing with a straight cable would be the first test, because the 330 does not have the slimline floppy connector from what I can see.
So possibly the 380 is wired differently.

[stj]

Re: Need to find a 34-Pin Motherboard Floppy Header

why not just follow the 17 used tracks and see if any terminate at a component-pad

[Topcat]

Re: Need to find a 34-Pin Motherboard Floppy Header

I did a quick check between repairs. Straight cable versus twisted cable had no affect.... Definitely worth a try....but no go.

This post created from the machine in question.