VOGONS


First post, by IgorK

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Hi all,

I have old Siemens Nixdorf PCD-5T(a)PCI-100 that I got long time ago but never tried it until today. It is dual pentium 100 MHz system.

I went to clean it and I snapped the pin 2 part of the board while trying to disconnect the drive. I think I did it, but it could be that it was like that before. Hear are the pictures:

It seems that pin 2 is very important if using various density floppy drives.

I am not sure how I would use it, but I would like to try to repair it if possible.

Thank you for the help.

Best,
Igor

Reply 1 of 6, by IgorK

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Not sure how to eddit my post.

Just to be clear. The snapped pin is on the 5,25" drive as shown it the second picture.

Reply 2 of 6, by paradigital

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I’d probably sacrifice the cable to fix this.

Scrape back some solder mask on the drive PCB until you can see copper for pin 2. Solder on a short 1-2
Inch tail, with a male single pin dupont connector or similar on the end.

Cut pin 2 wire from the cable’s plug and solder on female dupont connector.

Attach cable to drive and dupont connectors together for pin 2.

Reply 3 of 6, by Deunan

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IgorK wrote on 2025-05-26, 18:06:

Just to be clear. The snapped pin is on the 5,25" drive as shown it the second picture.

Pull the remains from the cable connector with a needle or something of the sort. Glue it back in place with superglue. It should be a clean break and hold quite well. Then use fiberglass pencil or a bit of sandpaper to unmask the copper and re-tin it. Preferably add thin wire on pin 2, everything else (odd pins and #4) can be left unconnected. That's how I would do it. And then put it in some machine and don't touch the cable again.

Just make sure the re-tinning and wire do not extend too much into the contact area or you won't be able to fit the connector on it. Just enough to restore the electrical connection.

Reply 4 of 6, by IgorK

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@paradigital @Deunan

Thank you very much for the proposed solutions. It seems that is not a big problem for someone that was already doing such a things. I will call my contact that usually does recapping for my old hardware 😀 He should be able to do this also.

Furthermore, now that I think of it, the previous owner had made a switch with 2 positions on the fdd pcb that I do not understand. Maybe it was because the pin 2 snapped while he was the owner? Please take a look if you have time.

Best,
Igor

Reply 5 of 6, by DaveDDS

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It looks like only pins 1,2,3,4 are broken off.

Pins 1&3 are ground (as are all pins on that side of the cable)
given that you have 18 connected ground pins, and you may only need
to connect Pin2 (which is not a high-frequency signal) - you probably
won't have to connect them.

Pin2 = Head Load
Not used on many drives, but IIRC TEAC drives have head load and do use it.

Pin4 = Select4 (PC uses only Select2, Selects1,3,4 are not used)

What I would try, is to connect the cable with Pins1-3 missing.
On many drives that would work, but it might not of TEAC
- If you can jumper the drive to head-load on select, that might be a way
to work around.

Otherwise I might tack (with solder) a small bit of thin flex wire to the
Pin2 connection on the broken off piece, and tack the other end of the wire
to the head-load input on the drive (you might be able to access the broken
trace which went to Pin2, otherwise trace it to a more reasonable connection
point.

Obviously you would have to be VERY careful when connecting and disconnecting
the drive from the cable - but hopefully you will only have to connect it
once.

Good luck!

PS: It's been so long since I looked into these details, I could be wrong - I have the manual for an SA400 (the
original 5.25" floppy - you can get scan of it on DavesOldComputers) - It doesn't use pins 2 or 4 (single sided,
no head loads or Select4)

So I had looked on "google" and found Pin2 called "connector clamp" - but on other locations I see it
called "Reduce write current" (which might be important for HD formats) - either way the simple fix I
suggested should work.

If you want to "sacrifice" a cable, you could cut pins 1-2 from the end, lengthen slight the Pin2
lead and use a flying single-pin connector to connect it to a suitable point on the drive (I like to
use machine screw IC socket pins).

Dave ::: https://dunfield.themindfactory.com ::: "Daves Old Computers"->Personal

Reply 6 of 6, by IgorK

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Thank you for your suggestion. I will report here once it is done.