----- Original Message -----From: David SotnickSent: Monday, February 17, 2014 8:39 PMSubject: Re: [emax] Diagnosing non-functional Emax;
I will check those voltages when I get home this evening. Here's a theory:I replaced the LCD with an OLED about 6 months ago. I never removed the inverter from the CPU board. Is there a chance that the inverter fried itself by not having a load (EL backlight) to drive?I will try removing the inverter as it's obviously not necessary with an OLED display.-Dave
On Mon, Feb 17, 2014 at 11:30 AM, jammie <jammie.emma@....uk> wrote:
check the 5v at the floppy power connectorand the invertor inputSent: Monday, February 17, 2014 4:48 PMSubject: Re: [emax] Diagnosing non-functional EmaxHi Jammie,Thanks for the suggestion, however I think the PSU is fine. I read 5.04v on yellow, 12.3v on orange and -11.89v on violet coming off the PSU harness at the CPU PCB.
-Davesounds like you have lost the 5v connectionthe lcd uses 5v the cf card reader uses 5v and the floppy uses 5vi would check the 5v rail on the psu----- Original Message -----From: David SotnickSent: Monday, February 17, 2014 4:25 PMSubject: [emax] Diagnosing non-functional EmaxHi all,
Now it's my turnÂ… I'm sad to report that my beloved Emax SE Rack which I upgraded to SCSI and slim floppy is no longer booting.
Symptoms are: PSU voltages look good at the drive power connector. All LEDs on the front panel come on at power-on except load and enter. No LCD display and no floppy or CF reader activity. :-(
I have re-seated all cables but have not yet removed and re-seated any socketed ICs. It has just been sitting in a rack, so nothing has been jostled.
Any suggestions on where to start?
-Dave
p.s. even more frustrating: I missed out on a $60 working Emax SE on a local Craig's list ad which posted the day before I discovered my Emax was dead. :-(No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7098 - Release Date: 02/16/14No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4335 / Virus Database: 3705/7100 - Release Date: 02/17/14
Message
Re: [emax] Diagnosing non-functional Emax
2014-02-17 by jammie
no its just a tswitching transistor and a step up
transformer
the transistor switches like a square wave 0-5
volts theres some smothing caps that makes it a small sin signal this signal
then is turned into a high voltage ac with very low current via a step up
transformar because the signal is a magnitised through the coils via inductance
the windings pick up this ac sin signal then transforms it to a biger
signal
the reason for whinning when the efoil dies is
bigger resistance and the transformers windings can become lose
but when no efoil is connected it has no load so is
an open circuit
you can do away with it as it serves no perpose i
always remove them when fitting an oled
also on racks i also remove the angle circuits
as the capaciters are being charged but not
discharged as they are open circuit no load