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HP 97 card reader - tantalum capacitors
11-12-2018, 05:18 PM
Post: #5
RE: HP 97 card reader - tantalum capacitors
After analyzing a different (guess newer) layout of the main board than shown in the service manual I draw the schematics of that layout to show which part is where. I attach to my answer here.

During the weekend I now changed C4 and C6 as the card reader didn't read. What should I say: success!
I measured the old tantalum caps after unsoldering. They still seem to have good values. 22µF nearly accurate, 47µF gives 52.5µF. Nevertheless there obviously was a problem with them.

I also added some comments to the schematics as IMHO there are some errors in the service manual. Table 4-6: see agenda in PDF file. Figure 4-10: Q2 should be named Q3 and Q3 as Q2.


Attached File(s)
.pdf  HP-97 - New mainboard layout.pdf (Size: 593.38 KB / Downloads: 132)
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RE: HP 97 card reader - tantalum capacitors - AndiGer - 11-12-2018 05:18 PM

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