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Suchergebnisse 1-13 von insgesamt 13.
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Only 5 volt is connected to the PCB. I am guessing maybe the meter is lying to me, scope is saying around 5 volt pr div, signal just looks noisy, logic probe on the same pin just shows high, no pulsing. EDIT: Bleh scrap that, it was the powersupply i was using to power the board that was making noise, after switching to a computer powersupply board no longer can be tricked into starting using a finger on the PIA trick.
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#5 Thank you for the reply, i pulled the sockets on U41 and U42 today just to check the traces, everything looks okay, there was on broken trace, but it was repaired on the back of the PCB. #6 Ive got a scope, and a logic probe, so no problem there, testing says R/W is not pulsing, and touching pin 24/25 on the PIA's makes the board boot. (R/W does pulse when the board boots)
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Zitat von frg: „Acid damage does not look so bad but repair damage worse. Seems someone did shotgun it instead of checking what waas actually broken. 10 blinks is U27 rom failure. So I would first inspect the rom socket. The actual error might actually something else. I would first remove the U41 and U42 sockets clean up and measure continuity. Then put machine pin sockets in and make sure no old desoldered PIAs are used.. I see some discolored traced at the upper left edge of u41. usually this …
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Hi, new member. Trying to help a friend fixing a 11B from a Whirlwind, but the board is a basket case, had some alkaline damage, so somebody rebuilt the reset section and did a very bad job, it does however work. Main problem with the board is on power up, diagnostic flashes 60 times, then blanking 10, and repeat, no difference if U25 or U26 is removed, however sometimes you can make the board boot by touching an ic with a finger, and when it first runs it works perfectly. Board had all the PIA …