68kMLA Classic Interface
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| RAM selftest failed on Apple IIe | |
| Posted by: blackswan on 2013-12-27 14:44:42 Dear members, having several problems with my Apple IIe, I finally was doing a selftest. Result: RAM: F13 F12 F11 F10 F9 F8 F7 F6My RAM looks like:  On the photo you can see, that most of the RAM chips are MT4264-20. Only the chip on column 6 is a Fujitsu MB8264-20 (in a socket). Seems like this chip has been changed already. Does anyone have an idea what's wrong here? Cheers, Blackswan | |
| Posted by: techknight on 2013-12-27 19:41:30 I just happened to browse through your photos, and noticed your IIe monitor has a horizontal line. Thats because your vertical deflection output circuitry needs attention. | |
Posted by: blackswan on 2013-12-28 13:39:25I just happened to browse through your photos, and noticed your IIe monitor has a horizontal line.Thanks for your comment on this. I already sold the broken monitor, because I was lacking tools and knowledge about the TDA1170N to repair the non-working vertical deflection of the A2M2010P. Any ideas about my RAM problem? Cheers, Blackswan | |
| Posted by: Sebastian on 2013-12-28 13:43:31 I'm not knowledgeable about IIe's, but my reasoning is that if a lot of chips seem to fail, it's probably a fault in the adress-mux, the Row adress strobe or the Column adress strobe. | |
| Posted by: techknight on 2013-12-28 15:12:51 Especially if the failure reports a pattern. Hypothetically speaking if its every 3 bytes or so, it reports a failure. If its an even-divisible error then it can be the controller/muxes. But if the failure is totally random and makes no pattern at all, its the RAM IC. | |
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