Pine Technology 486 Board CMOS Issues / Chip Identification - Page 1
Forum section: electronics / general

author: SilverTailJay
author_rank: Newbie
timestamp: April 24, 2020, 12:16:42 pm
content: Hello!Been working on getting an old 486 Board working - a Pine Technology PT-430. Not only did it experience some battery leakage, but it also experienced some rough times during storage and had probably several years of... "mouse exposure", I'll call it. It rusted a screw out so bad I had to break a screwhole on the board to get it out.There were also some busted traces I had to fix for the keyboard, but that should be all good now.Final challenge I'm running into is getting CMOS settings to stick. I wired in a CR-2032 holder and threw a battery in to no avail! The voltage on the board goes to a few different places but I believe I've isolated where it goes to most importantly. I've included a pic of where the voltage roughly goes to, I haven't traced it 100% because it definitely goes through some internal layers.It ends up at that UM9515-01 chip, can't find a datasheet for that thing ANYWHERE, so I have no idea what it is or how it's supposed to act. That is primarily where I need help at the moment. I measured all the pins on this chip with voltage going into it, and you can see that attached. (voltages.png). If anyone with a little more experience in diagnosing these sorts of issues can lend me a hand in identifying what kind of chip this might be, an equivalent chip possibly (one that has a datasheet available, for reference purposes) I would be grateful. My only thoughts as to why this chip could be non-working at the moment are either that it is dead, or that my Battery voltage is too low. In researching I did read that the voltage from the original battery would have been 3.5V, whereas the CR2032 currently in there is only 3.3 ish volts. Wondering if maybe that's too little.Thanks!Actually, here are all the images as imgur links because the 5000KB filesize limit is well, limiting.(Board section overview)(Rough idea of where voltage goes)(Voltages on the UM9515-01)

author: Rasz
author_rank: Super Contributor
timestamp: April 27, 2020, 09:24:47 pm
content: Quote from: SilverTailJay on April 24, 2020, 12:16:42 pmunlikelyQuote from: SilverTailJay on April 24, 2020, 12:16:42 pmits a bus clock generator, might be pin compatible with MX8315. Has nothing to do with battery and cmos.https://www.datasheetarchive.com/pdf/download.php?id=d479c435a6b0af3dbd0516dc5580cf9351af90&type=O&term=MX8315this chip is working fine, otherwise your board wouldnt startcmos data/clock is integrated somewhere inside UM8498F / UM8496F chipset combo, most likely the bigger one judging by pictures of other motherboards locating 32KHz rtc crystal next to it like herehttps://www.recycledgoods.com/umc-um8498f-socket-3-system-board/on your board 32KHz crystal might be running thru HCF4069UBE CMOS hex inverter firstthe way it usually works is like here 82C206http://www.bitsavers.org/components/opti/dataSheets/82C206.pdfworst case you could source another UM8498F / UM8496F motherboard and compare signals pin by pin on the

author: dexters_lab
author_rank: Unknown
timestamp: April 28, 2020, 01:08:53 pm
content: Quote from: SilverTailJay on April 24, 2020, 12:16:42 pmtracing JP1 (CMOS Clear) should lead you to the culprit

author: Rasz
author_rank: Super Contributor
timestamp: April 29, 2020, 08:50:10 pm
content: oh, and pr0 tipQuote from: SilverTailJay on April 24, 2020, 12:16:42 pmnever post pictures in png, this isnt your lung xray/tomography, we dont need lossless pixel perfect png/tiff/dicomnot to mention source file from camera/phone was jpeg anyway