HP 82901M 5.25in 270K FDD

HP 82901M 5.25in 270K FDD

Preliminary Information
Release Year	1980
Leak Risk	Low
Batteries	None
Mounting Technology	Through Hole
Capacitor Types	Aluminum Electrolytic, Tantalum, Ceramic
Destructive Entry	No
Hardware Specifications
Storage	5.25" DD Floppy Disks @ ~270KiB

This is a floppy drive for HP systems with an HP-IB interface to allow them to read LIF formatted 5.25" floppy floppy disks. Internally they use standard full height 5.25" internal drives like a Tandon TM100-2A.

Known Issues

Large Aged Caps

• 
  Power Supply Board with two large capacitors
• 
  Right side capacitor is 10,000uF @ 40VDC
• 
  Left side capacitor is 17,000uF @ 20VDC

Causes

• These capacitors will likely not be bad, but may have degraded from disuse. They can short if powered without caution.

Solutions

• Before powering the device, remove caps (which doesn't even require soldering) and Reform them both.

Disassembly Notes

The logic board for the entire unit is attached through the controller board for the right side drive and may have damaged plastic mounting points on the drive. They are not structurally critical to the operation of the device, but do secure the drive control board in place.

Original Parts

Power Supply

82901-60001

Capacitor Specifications and Footprint Information

RefDes	Qty	Capacitance	Voltage	Mount	Diameter/Size	Height	Lead Spacing	Temp	Type	Brand	Series
n/a	1	10000 µF	40	Screw Terminal				-40 to 85°C	Aluminum Electrolytic	Sprague	32DR COMPULYTIC
n/a	1	17000 µF	20	Screw Terminal				-40 to 85°C	Aluminum Electrolytic	Sprague	32DR COMPULYTIC

Note: Sprague PSU caps should have a Capacitor Reforming procedure attempted on them before powering or replacement. Suitable substitute parts are difficult and costly to find so unnecessary replacement is higly discouraged.

Related Links

• More general device info: https://wiki.techtangents.net/wiki/HP_82901M_5.25in_270K_FDD
• Documentation and other info: http://www.hpmuseum.net/display_item.php?hw=287