HP 7475A Plotter

For more information, see this article's corresponding Wikipedia page: Device.

HP 7475A Plotter

Preliminary Information
Leak Risk	Medium
Batteries	None
Mounting Technology	Through Hole
Capacitor Types	Aluminum Electrolytic, Tantalum, Ceramic
Destructive Entry	No

HP plotter with HP-IB (GP-IB) interface. Hold 6 pens in carousel.

Known Issues

Fish Smell

Causes

• Leaking capacitor

• 

  Leaking cap visible on logic board with electrolyte seeping up the jacket

• 

  Sprague brand capacitor that has leaked and formed a powder moving up into the jacket of the capacitor.

Solutions

• Clean PCB and replace cap

Disassembly Notes

Screws in rear from top removes plastic shell.

Two screws going through plot mechanism and PCB hold both in. HP-IB port screws must also be removed to remove PCB.

Original Parts

Main logic board

07475-60102

Capacitor Specifications and Footprint Information

RefDes	Qty	Capacitance	Voltage	Mount	Diameter/Size	Height	Lead Spacing	Temp	Type	Brand	Series
C1	1	68 µF	35V	Through Hole	10mm	20mm	5mm	-55-105 °C	Aluminum Electrolytic	Nippon Chemi-Con	CERX
C2	1	2,200 µF	40V	Through Hole (3 pin)	25mm	67mm	9.5mm		Aluminum Electrolytic	Sprague	674D
C24	1	6,800 µF	25V	Through Hole (3 pin)	25mm	39mm	12mm	85°C	Aluminum Electrolytic	Nippon Chemi-Con	SM
C20, C25	2	22 µF	25V	Through Hole Axial	6mm	13mm	20mm	85°C	Aluminum Electrolytic	Nichicon	H8333 ?
C31, C32	2	47 µF	50V	Through Hole	8mm	12mm	3.5mm	85°C	Aluminum Electrolytic	Nichicon	SE (M)

Replacement Parts

Basic PCB Name

Capacitors

RefDes	Qty	Compatible Part Number	Order Links
			Digikey

If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.

Kits

• Digikey BOM: https://www.digikey.com/

Related Links

• Videos or other things that might be helpful to check out