In the power supply section there should be some labled test point "GND", "Vee", "Vcc". The 'Vee' will be -5V for the LCD (and RS232) and the "Vcc" +5V for everything else. You can also check from ground to the highest numbered pin on any of the '40Cxx' chips for 5V.
Jeff Birt From: M100 <[email protected]> On Behalf Of Russell Pitman Sent: Friday, December 31, 2021 8:52 AM To: [email protected] Subject: Re: [M100] M100 Information I am not sure that the voltages are coming through either as I need to know the correct components to check, With a correct circuit diagram. I have continuity checked the switch SW3 and that is good. 6v is seen at the battery terminals. I have noticed that Brad does a VR1 kit which might be worth sourcing, if still available. Thanks Russ Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows From: Jeffrey Birt <mailto:[email protected]> Sent: 31 December 2021 13:13 To: [email protected] <mailto:[email protected]> Subject: Re: [M100] M100 Information >> I have been looking at the circuit diagrams and manuals for it but none seem to match the motherboard that is inside this model. Cap and resistor numbers are different. That would be a very odd PCB. Kyocera even carried the same component designations through to the Olivetti M-10. The M100 and T102 are different, are you referencing the correct schematic? There are two versions of the M100 PCB but the changes are minor. There are a few component differences in the reset circuit and the RS-232 output. The later model also uses a standard EPROM pin-out for the ROM. Have you checked the power supply voltages? Always start with PCR: Power, Clock, Reset. Checking these three things first will go a long way to finding the problem. Jeff Birt From: M100 <[email protected] <mailto:[email protected]> > On Behalf Of Russell Pitman Sent: Thursday, December 30, 2021 10:00 PM To: [email protected] <mailto:[email protected]> Subject: [M100] M100 Information Hi all I have recently received my first M100 but unfortunately I am unable to get any response from it. I have been looking at the circuit diagrams and manuals for it but none seem to match the motherboard that is inside this model. Cap and resistor numbers are different. Finally I have noticed that the contrast potentiometer (VR1) is no longer working and am wondering if this is why no display is seen? Does anyone know where I can source one of these? Many thanks Russ Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
