David, We're good on the placement of the RAM. On this Earthy Processor board's silkscreen all installed IC's have pin 1 oriented towards the front panel.
Rick On Mon, Apr 20, 2020 at 3:25 PM David C. Partridge < [email protected]> wrote: > Be warned that IIRC the orientation of the ICs on the earthy CPU board > isn't > consistent - pay careful attention to the markings on the silkscreen > > Also the order in which the EPROMs are installed isn't exactly what you > might expect ... Check most carefully > > David > > -----Original Message----- > From: volt-nuts [mailto:[email protected]] On Behalf Of > Rick > Bale > Sent: 20 April 2020 19:32 > To: [email protected] > Subject: [volt-nuts] Solartron 7081 > > I's been a while since I last posted on my 7081. I needed to wait to > receive new earthy CPU and DMA chips. They are cheap and easy to swap. So > far, with Joe's help, I've replaced the earthy side PROMS. Also new is all > the RAM, DMA and microprocessor. I also went back and rechecked all the > power rails. I found a little extra noise on the +5v & +40v power rails. > I corrected this by replacing C56, C57, C58 filter caps. They all measured > about 50% or less of their original uF. The 12v filter C59 was okay. > > I have the same symptom of all LED stuck on and nothing on the screen. I > feel like I need to check the data during boot up. Probably means decoding > the logic. Maybe it's hung on a reset since all the LEDs are on. It would > seem reasonable that they would all come on during boot up or on a reset. > The problem is I don't have a logic analyzer or probe but mainly don't > really know where to start in the circuit. > > Does anyone have any suggestions on where to start. Do you think I should > move the conversation to the Solartron Group? > > Thanks, Rick > > > _______________________________________________ > volt-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/volt-nuts_lists.febo.com and follow the instructions there.
