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capacitors used for driven model-polarized or not?

 
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wolfman
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Joined: 24 Nov 2005
Posts: 13
Location: Southwest USA

PostPosted: Tue Nov 29, 2005 12:19 am    Post subject: capacitors used for driven model-polarized or not? Reply with quote

Are the capacitors used in the driven circuit polarized? Your circuit diagram does not indicate this, but other references to the Maxim232A IC do show polarized caps.

I ask because I'm having trouble getting my interface running--either that or my cmos is corrupt (IBMpass returns junk); I'd rather it was a problem with the circuit! I first built it with polarized electrolytic caps but am going to substitute plain ceramic caps this evening and see how that works.

Thanks for your help--this is a wonderful resource! I built the driven circuit on a breadboard and will post pictures here if you'd like, for those like me whose electronics courses were several decades ago and had to look up a lot of stuff.


Last edited by wolfman on Thu Dec 01, 2005 4:53 am; edited 1 time in total
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victor
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Joined: 07 Mar 2004
Posts: 2470
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PostPosted: Tue Nov 29, 2005 1:01 am    Post subject: Reply with quote

MAX232A doesn't need elcos. There are only unpolarised capacitors 0.1 uf = 100nf.
Check the circuit carefully, specially D1R2 -D2R1 area.
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wolfman
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Joined: 24 Nov 2005
Posts: 13
Location: Southwest USA

PostPosted: Tue Nov 29, 2005 1:12 am    Post subject: re: capacitors used for driven model-polarized or not? Reply with quote

Thanks!

So, if the bin file read by the simple circuit gives nonsense where the password should be, should I expect any different from the driven circuit? This happens with IBMpass lite and 2.0, original and alt scan codes formats.

I get an error that the time/date are bad before the password prompt. The cmos battery had discharged and had to be replaced. This is a T22.

If this does indicate corruption I'll send you my bin and cash and have it repaired and license the writer module.


Last edited by wolfman on Thu Dec 01, 2005 4:54 am; edited 1 time in total
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victor
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Joined: 07 Mar 2004
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PostPosted: Tue Nov 29, 2005 1:24 am    Post subject: Reply with quote

SIPROG works very well on t22. If is well built, of course.
So, SIPROG or driven-i2cprog the results have to be the same. Maybe you could send the eeprom dump to see what you have read at support-at-allservice.ro.
Also some pictures of your work would be helpful

Cheers
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wolfman
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Joined: 24 Nov 2005
Posts: 13
Location: Southwest USA

PostPosted: Fri Dec 02, 2005 5:30 am    Post subject: when to power the driven circuit? Reply with quote

thanks!

I am pretty stubborn, so I'll persist until I get the driven circuit to work. I haven't had time to get back to it, and don't have a digital camera here; will borrow one and send pics.

Question--when should the circuit be powered--before or after connecting GND, SDA, SCL to the 24RF08?

Let me echo the other comments you've received about what a great service you provide. The entire rest of the 'net seems empty of help on this topic, and I'm not about to buy a new motherboard for a four-year-old laptop--your circuit and programs are going to be my salvation!
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bob
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Joined: 07 Mar 2004
Posts: 765
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PostPosted: Sun Dec 04, 2005 1:55 am    Post subject: Reply with quote

The circuit must be powered before. So, connect the circuit to the serial port and power on. Turn on the laptop, connect the wires and read. That's it.

I saw plenty of Arizona guys around here lately. Smile Welcome to the board!
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