Getting ready to experiment with swapping logic boards between 128k-Plus, SE-SE/30 and Classic/Classic II and need some advice. As posted here earlier all of the signals/voltages between them are identical (or at least provision is made for them, whether they are interchangeable or not remains to be seen), EXCEPT the following:
The SE series is the only one that has a -12V connector. What if anything can expect to happen if I do not connect this to a 128k-Plus or Classic, or supply it to the SE, logic board? The Classic series has three more ground wires than the 128k-Plus and the SE has 4 more. Now, all grounds ultimately go to the same place, so what is the reason for the extra ground wires from the logic board to the analogue board? Is it to reduce resistance by providing more direct grounding paths? So what will happen if I combine the extra ground wires from the SE & Classic logic boards in order to test them on the 128k-Plus which only has 2 ground wires? The SE & Classic series each have 2 +5V wires. The 128k-Plus has only one. I would imagine these are simply to ensure adequate voltage is distributed throughout the more demanding logic boards and I can use either one for the 128k-Plus? Obviously on the 128k-Plus, splitting the +5V to the SE & Classic boards will most likely put strain on the Power Supply and should not be used if the the +5V voltage cannot be adjusted so that it does not fluctuate. The Classic only controls brightness via a signal from the logic board. Since the SE or 128k-Plus logic boards can't supply it, I expect the Classic to display a default video signal (hopefully the brightest setting). Should be interesting. The reverse should be no problem as the analogue boards control brightness manually. Additionally, The SE has no provision for sound in the power connector -- this is easily remedied by connecting the sound wires directly to the SE's separate sound connectors. Grounding should be handled via the multiple grounds present in the connector. This is the least of my concerns for testing purposes as is: Finally, the 128k-Plus has a battery return wire to power the PRAM. Obviously since this signal is not available in the later machines, the 128k-Plus logic boards will not retain settings on the other Macs. A permanent solution would be to install a battery on the logic board. -- Compact Macs is sponsored by <http://lowendmac.com/>. Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[email protected]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> --------------------------------------------------------------- iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com ---------------------------------------------------------------
