Author Topic: Head surgery  (Read 288 times)

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Offline Alex Eisenhut

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Head surgery
« on: November 30, 2019, 02:54:50 pm »
The floppy drive head kind. Got a Commodore 1541-II drive here with the D500 Mitsumi mechanism. Looks like a coil can fail open circuit in the head.

The blue wire connection is open circuit to the rest of the wires. Yes I checked to see if the wire itself is good from the PCB to the head, that connection is good.

I plan on putting in paint stripper drop by drop on the potting compound, maybe it will reveal more detail as I go along.

Anybody ever attempt something like this? The thing's a doorstop anyways.
« Last Edit: November 30, 2019, 02:57:49 pm by Alex Eisenhut »
 

Offline Alex Eisenhut

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Re: Head surgery
« Reply #1 on: November 30, 2019, 03:25:08 pm »
If anyone wonders here's the schematic
http://www.zimmers.net/anonftp/pub/cbm/schematics/drives/new/1541/1541-II.340503.gif
U12 is a LA8200M amplifier,
https://cdn.datasheetspdf.com/pdf-down/L/A/8/LA8200M_SanyoSemiconductorCorporation.pdf
and CN3 goes to the head assembly. From what I gather the read head is a center tapped winding and the write coil is another winding entirely. Looks like the read head lost a winding connection.
 

Offline Alex Eisenhut

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Re: Head surgery
« Reply #2 on: December 03, 2019, 02:18:08 am »
Meh, looks like I'm not the only one to have discovered the coil opening "feaure" of these drive heads.

https://retrohax.net/commodore-1541-floppy-drive-fixing-chaos/

Still no answer. I wonder if I can rip out the guts of a PC 360K floppy and somehow jam it in the 1541 drive. I know the 1571, the double-sided version of the 1541 can read PC floppies but that's down to the MFM controller but it shows the heads are the same for that kind of media.
 


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