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| Notes: |
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| 122900 | |
| 1969 (Most integrated circuits stamped with 6901-6914, ICs on board 2 a little later: 6946 latest.) | |
| 17 Dec 2004 | |
| SPARC surplus. | |
| A little grubby, some corrosion on steel sheet surfaces and on numerous screws. Several of the PCBs appear to have seen repairs by resoldering of many of the connections. Operation results are incorrect when first powered up. OK after warming up for awhile. SQRT(2) initially resulted in 1.417... |
| 17 Dec 2004 | |
| Boards reseated. Flakiness reduced. |
| 21 Dec 2004 | |
| Dismantled for cleaning. Keycaps polished to take off yellowed surface. Foam pad beneath keys had turned to tar, cleaned off. |
| 18 Jan 2005 | |
| Cleaning completed, reassembled with new screws and hardware. Foam pad for keys should be replaced so keys have a softer stop when depressed. |
| 18 Jan 2005 | |
| No response to keyboard other than clear keys. | |
| nKCM2 signal is being held active because the reed switch for the CM2 key does not release (open) after the key has been pressed. Pressing the key up from the bottom an extra fraction of an inch will release it. Apparently the reed switch was not fully inserted during manufacture, so the magnet does not travel far enough up the reed switch to release it. | |
| Reed switch unsoldered and pulled closer to the circuit board before resoldering. |
| 20 Jan 2005 | |
| Arithmetic operations produce incorrect results most of the time: anything added to itself results in 0, various single-digit operations are incorrect (3+1=2), multiplication, etc. result in values such 90909090... | |
| Single-digit errors suggest that the carry is not propagating during addition. Observation of output of CA flag shows that while the carry pulses are present, they do not go all the way to ground, but only down to about 2V. Similar behavior observed on the other outputs from the same IC (8104). Ohmmeter indicates poor connection between IC 8104 pin 7 and ground (varying from 6 ohms to open). | |
| Component-side of feed-thru for ground pin of IC 8104 resoldered. |
| 25 Jan 2005 | |
| Delay line read-head position ("R" hole on delay line) adjusted to test limits. Reset such that pulses exit delay line around positive edge of CPR, as measured at pin 8103-6, at approximately 15 deg C. |
| 26 Nov 2005 | |
| Upon power-up, numbers can be entered but operations result in display full of "9"s, also M1 and M2 will not clear. After some minutes of warm-up, all is well. |
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Canon 163
Calculators | Integrated Circuits | Displays | Simulations EEC |
bhilpert |
