Thanks for the Info, Jeff. Sorry for the dumb question, but can you point out on which two points i should measure +5V and -5V ? I think this Info can be also very usefull for other folks having power issues on NEC.
Thanks -- Kind regards / Mit freundlichen Grüßen ExPLIT IT Solutions Pawel Radomychelski -----Original Message----- From: Jeffrey Birt <bir...@soigeneris.com> Reply-To: m...@bitchin100.com To: m...@bitchin100.com Subject: Re: [M100] NEC PC-8201(A) Display issues Date: Sun, 2 May 2021 11:34:12 -0500 OK. This sounds like a power supply issue. It is odd that it comes back to normal with a power cycle though. Take it apart so that you can measure the power supply voltages. Measure the +5 and -5V when it is working properly and then when the LCD goes blank. Jeff Birt -----Original Message----- From: M100 <m100-boun...@lists.bitchin100.com> On Behalf Of ExPLIT | Pawel Radomychelski Sent: Sunday, May 2, 2021 10:53 AM To: m...@bitchin100.com Subject: Re: [M100] NEC PC-8201(A) Display issues No, this is not the case, i think. Brightness is getting higher and higher until you don't see anything. And this happens to different times: after 3, 5 or 10 minutes, sometimes after 20. On some units the lcd is flickering until it shut off. Pressing a key doesn't activate the lcd back. Only full switch off / switch on. On some units the contrast "jog dial" (doesn't know exact name of this part in English) doesnt work at all. Contrast is always locked to one position. Kind regards Pawel On Sunday, 2 May 2021, Jeffrey Birt wrote: > The unit does have an auto power off if you have not used it for 5 > minutes or so. Is this what you are experiencing? > > > > Jeff Birt > > > > From: M100 <m100-boun...@lists.bitchin100.com> On Behalf Of ExPLIT | > Pawel Radomychelski > Sent: Sunday, May 2, 2021 9:20 AM > To: m...@bitchin100.com > Subject: [M100] NEC PC-8201(A) Display issues > > > > Dear Model T / NEC collegues! > > What i noticed holding a couple of NEC PC-8201 and PC-8201A in my > hands, that many have a strange display issues: > > > > Unit working fine, after some time display is getting blank and i > can't see anything on the LCD. > > After switch off/switch on - its fine again. > > > > I noticed this problem independent prom Power Source (On AA Batteries > and 6V DC Power Supply) > > On some units this problem is getting better when replacing old NiCd > Battery with a new one or with 1F / 5,5V Capacitor. > > But still not solved completely. > > > > This is a question on our gurus: Is there a chip (Or couple of chips > and/or other components) on the mainboard which can / need to be > replaced? > > > > I am not so familiar with old electronics, nor i have an oscilograph. > > Is it possible for an avarage user with moderate soldering skills and > multimeter to solve such issues ? > > > > Thanks! > > -- > > Kind regards / > > Mit freundlichen Grüßen > > > > ExPLIT IT Solutions > > Pawel Radomychelski > > > > > > > >
