IBM PS/2 Model 70 or compatible floppy drive wanted (Or help with current one?)

Fred Cisin cisin at xenosoft.com
Sun Jun 30 20:20:41 CDT 2019


> On Sun, Jun 30, 2019, 3:42 PM Gary Sparkes via cctalk <cctalk at classiccmp.org>
> wrote:
>
>> Ah, just so we're all on the same page here.... The drive i'm looking for
>> seems to be "extra" special.... mine's got a ribbon cable connecting it to
>> the card edge connector .... same connector as these two pictured drives
>> but slightly different configuration. Apparently the drives shown are
>> compatible, however -
>>
>> https://www.classic-computers.org.nz/blog/images/2009-09-16-broken-ibm-drives.jpg
>>
>> Mine is like this one -
>>
>> https://upload.wikimedia.org/wikipedia/commons/6/65/Floppy_IBM_PS2_M70_back.JPG
On Sun, 30 Jun 2019, Bill Degnan via cctalk wrote:
> This looks like an adapter has already been installed possibly.

Yes.
Notice that that is a 40 pin card edge connector.
The "standard" (SA400, etc.) was originally a 34 pin card edge, and later, 
with 3.5" became a 34 pin dual row header.

IF I remember correctly, 34 of those 40 pins correspond to the 34 pin 
"standard" connector, with the other 6 being for power.
Unfortunately, for making adapter cables, MALE card edge connectors for 
cables are no longer readily available.  40 years ago, IDC ones with 
gold plated fingers were available, and there were very cheap 34 pin and 
40 pin entender cables (popular for TRS80 to avoid connect/reconnect 
cycles of the non-gold-plated Expansion Interface connectors)

If you look around, 30 years ago, there were readily available adapters 
with male 34 pin card edge and female 34 pin dual row header, for putting 
the "new" 3.5" drives into machines that had card edge cabling for 5.25".
One of those would work, if you can kludge a power adapter, such as 
cutting off 6 pins from a scrap card edge.

And, of course, in those days, there were commercially available 
after-market adapters for putting "standard" drives into PS/2.



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