Hi folks, Sorry for this question: My HP-67 shows "Error" message when reads a card, after several minutes of use, seldom. My suspicion is a defective capacitor on the card reader board. Could you tell me the values and types of these capacitors to replace? Tips appreciated; picture attached. Thanks, D-D.
The caps connected to pins 6 and 10 of the IC are 22 uF, P/N 0180-2615. The cap connected to pin 16 is 6.8 uF, P/N 0180-2663.
Refer to the HP-97 Service Manual on the MoHPC flash drive and Tony Duell's schematics, now available for FREE!
http://www.hpcc.org/cdroms/schematics5.0/index.html
Dave
Thanks, Are these tantalum capacitors? Is polarity needed?
The caps aren't tantalum, but they are polarized. The marking is visible on the cap in the middle of the pic, and in the schematic. So you're looking for an axial electrolytic caps. The ones on my 67 are marked 4 volts. The third cap on the right with the red band is marked 15K and measures 15.7 uF using a handheld DMM. This is different from the schematics.
Dave