Have some ST-225's but do not know if the signal tape part be same. Will dig one out if I can remember which box in garage they are in and pull the baord 🙁

Horun wrote on 2024-11-12, 04:19:

Have some ST-225's but do not know if the signal tape part be same. Will dig one out if I can remember which box in garage they are in and pull the baord 🙁

Hi !
Thank you for your willingness, but photo of ST-225 will not help 🙁

This fleabay listing is for this model drive.

It has useful pictures.

https://www.ebay.com/itm/256654423910

This image in particular, looks most useful for your purpose.

It looks like the film ribbons are 'every other wire' staggered into otherwise completely uninteresting IDC header strips, there on the side of the interface encoder board.

ANOTHER listing for a 4038 is for a 'spare parts' shredded drive, that still has the IDC connector on the film strip leads.

https://www.ebay.com/itm/386906921120

It has this useful image.

For the SMALL film cable, this youtube video briefly shows the backside if this cable as the uploader rotates the drive.

https://m.youtube.com/watch?v=YuY53-7gBz8

For the LAST of the 3 film cables, it apparently goes on the TOP board, near the front plate area.

THIS image looks useful.

wierd_w wrote on 2024-11-12, 12:53:

THIS image looks useful.

Hi.
Exactly !
I need a good quality photo of this part of the ribbon cable and plug.

Mine ends like that 🙁

What an absolute unit, lovely specimen!
tubetimeus was recently reverse engineering PCBs of MFM drives on twitch. Here is corresponding repository https://github.com/schlae/HardDriveInfo
Question is what is this ribbon for? Hall effect sensors? It connects near two NE592 diff amps, but those are most likely used for amplifying HEAD from the wide connector.

HI, Locutus!
Here you are.

gap wrote on 2025-09-29, 14:40:

HI, Locutus!
Here you are.

Hi buddy - THANK YOU !!!
There is still hope for this drive - have to dig it out and try 😉

I must admit, I'm a bit confused - could you please check if my guess is correct ?

HI!
Your assumption is obvious.
It's hard for me to add anything useful here without destructive action.

gap wrote on 2025-09-30, 10:21:

HI!
Your assumption is obvious.
It's hard for me to add anything useful here without destructive action.

Those two pictures will do - thanks !!!

I repaired one such broken FFC, was not easy and quite frankly it's not exactly pretty now but the HDD works well, in fact even in RLL mode. So I call it a success.

I think this is a separate data path from the servo head. Only 3 signals on it (the coil in the head is most likely center-tapped) and the rest is ground to add interference shielding. 2,3 and 4 are signals, 1+5 is ground. This can be verified by studying the PCB side a little bit, I spy some video amps there so the siginals are fast but probalby only one-way (input), as the servo surface would be. If so it's more cricital to get 2,3,4 soldered with similar wire lengths and preferably with as wires with external copper/foil shield. 1 and 5 would be way less critical and could be even routed through that external shield.

Deunan wrote on 2025-09-30, 15:08:

I repaired one such broken FFC, was not easy and quite frankly it's not exactly pretty now but the HDD works well, in fact even in RLL mode. So I call it a success.

Hi.
Thanks for your replay.
Once I’m done with freshly acquired dead asus motherboard, I’ll try to solder this FFC…