these early computer based units are very sensitive to the exact voltages on the PSU. there's often a sensing procedure at startup and if the voltage is out even my millivolts the computer may not come on line properly. �if it's close enough to boot the extra draw caused by engaging the disk drive could pull the PSU out enough to crash the system. �the caps decay functionally over time so they may work for several minutes and then not once they warm up...
�
the whole piece will work better with a happy PSU.
z
NEW ALLIANCE EAST!!!!
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New Alliance East�-�Facebook
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From: hazchem88
To: emulatorII-list@yahoogroups.com
Sent: Wednesday, May 30, 2012 11:22 AM
Subject: [emulatorII-list] Re: just got another EII - this one only boots sometimes.Can any one suggest things
To: emulatorII-list@yahoogroups.com
Sent: Wednesday, May 30, 2012 11:22 AM
Subject: [emulatorII-list] Re: just got another EII - this one only boots sometimes.Can any one suggest things
�
The PSU 'appears' to work, as in it did boot up once, and nearly a couple of times. The 5V rail is all OK.
So is replacing electrolytic caps just a tip for dead PSUs, or do you think it's worth a shot in my case?
--- In emulatorII-list@yahoogroups.com, Robert Van Kuran wrote:
>
> Try replacing all of the electrolytics in the PSU.
>
> it seems to be the first thing recommended to try on several posts.
> Let us know if that does the trick.
>
> Sent from my iPhone
>
> On May 30, 2012, at 6:20 AM, "hazchem88" >
> > Just got an EII yesterday.
> > 1st few times switched on, it got to boot screen, and no further.
> > So I opened up, reseated a few memory ICs around what I think is first segment (IC13 area?) - used some deoxit and replaced.
> >
> > Then this time, it booted up and all seemed good. A Bank loaded. I then tried to load a bank from another floppy, started loading, then after a bit froze and blanks screen.
> >
> > Since then I have removed and reseated just about every IC on the digital board.
>; >
> > Generally all I get is black blocks on the top row of the LCD, nothing on second. And usually ALL of the LEDs lit.
> > about 1/10 times I might get the boot screen, but no further (doesnt try to read discs).
> >
> > So in theory most of the machine is OK since I got as far as loading 1 bank.
> >
> > Wondering if this is a bad connection somewhere.
> >
> > Maybe RAM/Scanner problem?
> >
> > Can any suggest anything I can try?
> > Which Ram ICs should I check first,
> > Any tips appreciated.
> > I am very good with electronics, however, not too familiar with EIIs (but learning fast!)
> >
> > BTW, oddly, my boot up screen is unique(?)
> >
> > **Emu 3-1 SC ***
> > Mulhouse 1-02-90
> >
> > custom? maybe just the message has been changed? (maybe Mulhouse is one of the previous owners?)
> >
> >
> >
> >
> >
> >
> >
>
The PSU 'appears' to work, as in it did boot up once, and nearly a couple of times. The 5V rail is all OK.
So is replacing electrolytic caps just a tip for dead PSUs, or do you think it's worth a shot in my case?
--- In emulatorII-list@yahoogroups.com, Robert Van Kuran wrote:
>
> Try replacing all of the electrolytics in the PSU.
>
> it seems to be the first thing recommended to try on several posts.
> Let us know if that does the trick.
>
> Sent from my iPhone
>
> On May 30, 2012, at 6:20 AM, "hazchem88" >
> > Just got an EII yesterday.
> > 1st few times switched on, it got to boot screen, and no further.
> > So I opened up, reseated a few memory ICs around what I think is first segment (IC13 area?) - used some deoxit and replaced.
> >
> > Then this time, it booted up and all seemed good. A Bank loaded. I then tried to load a bank from another floppy, started loading, then after a bit froze and blanks screen.
> >
> > Since then I have removed and reseated just about every IC on the digital board.
>; >
> > Generally all I get is black blocks on the top row of the LCD, nothing on second. And usually ALL of the LEDs lit.
> > about 1/10 times I might get the boot screen, but no further (doesnt try to read discs).
> >
> > So in theory most of the machine is OK since I got as far as loading 1 bank.
> >
> > Wondering if this is a bad connection somewhere.
> >
> > Maybe RAM/Scanner problem?
> >
> > Can any suggest anything I can try?
> > Which Ram ICs should I check first,
> > Any tips appreciated.
> > I am very good with electronics, however, not too familiar with EIIs (but learning fast!)
> >
> > BTW, oddly, my boot up screen is unique(?)
> >
> > **Emu 3-1 SC ***
> > Mulhouse 1-02-90
> >
> > custom? maybe just the message has been changed? (maybe Mulhouse is one of the previous owners?)
> >
> >
> >
> >
> >
> >
> >
>