HP Laserjet II stuff

Modified 01/04/08

I'm periodically asked about my posts in the SCI.ELECTRONICS.REPAIR newsgroup regarding HP Laserjet scanner chip replacement. Several thoughts...

• Check out Repair FAQ, paying attention to the suggestions about reseating the cable connectors.
• The chip was made by Hitachi, part number is HA13456AMP. Be aware that A and AMP versions are two different packages. The correct package is AMP (flatpack); the incorrect package is the A (DIP package.
  
  
• 01/04/08 - The HA13456AMP is no longer manufactured by Hitachi, but Mark 5 Ltd., based on the south coast of England, has p/n HA13456AMP in stock. There is a £10 (~$19 USD) minimum order for non-business customers, and a £25 (~$49 USD) minimum for business customers. Mark5 ships worldwide daily.
  
  
• Pin assignments of both packages of the scanned from a Japanese version of the datasheet.
• I understand from Greg Eckersley (who was kind enough to write) that these chips were commonly used as spindle motor drivers in 5-1/4 inch floppy drives. If anyone needs one in a hurry they can be found on the spindle drive board in these obsolete drives. There were different manufacturers and models of this integrated circuit with various DIP and SMD packages and pinouts...might be useful for urgent or budget-challenged repairs. Some have been successful with such replacement; others have not. A nice example of replacement with a floppy drive controller that is wired outboard is shown in the image below. It was done by Armin Elbs.
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• The correct HA13456AMP chip can be ordered from B&D Enterprises, 814-757-8300, $8 each. There is a $15 minimum order, so get two (one to use, one spare.) They will ship anywhere in the world, but I believe some folks have encountered $50 overseas FedEx shipping. I understand there are places in Germany and elsewhere that carry these chips for reasonably equivalent prices, without incurring the costly shipping from the USA.
• My own experience with replacing the chip was that it lasted only three months, even with a heatsink installed on it. (Someone suggested that it might have been because I didn't replace four caps and a 1-ohm resistor at the same time. These might be the caps connected to pins Q, R, S, and the resistor connected to pin P. Refer to the datasheet referenced above.) I believe my old-vintage scanner board may have had design defects that simply made it run hot, as evidenced by the burnt spot under the chip.
• With the above in mind, if you are thinking of replacing the chip, you might seriously consider simply buying a new scanning board, RG1-1771-030. Here in the USA at least two companies sell it for reasonable prices, and again, there are places in Germany and elsewhere that also sell it. NOTE: These are U.S. prices in 1999 and may be out of date, and overseas shipping might be astronomical. If you or a friend is travelling to the USA, pick up one while you are here.
  1. Printer Works, in California, telephone 510-887-6116, http://www.printerworks.com, $31.
  2. Laser Impact, in Texas, telephone 512-832-9151, $47.