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RTC error. Can this be fixed, or is the board junk?

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Mr B

Senior Admin Emeritus
Joined
Dec 28, 2000
Location
East Bridgewater, MA
I just picked up (part of) a HP Pavilion 6830(KR) (P 2937 A), a few days ago... It was a "dumpster dive" find, that was just the case, and mobo.

It's got an Asus mATX board in it, that I can find little info on anywhere other than HP's site itself. HP shows a mobo layout jpeg of the board that "supposed" to be in it (an Asus CUW-AM), but the board I have is slightly different.

Anyways...it's (was) a Celeron700 system, that originally had 64MB SDRAM, a 20GB HDD, and a 40x CD-ROM.

I put my old C366 in it, and 128MB of PC133, and it booted! But.... The RTC (Real Time Clock) is way, WAY off... It runs at two or three times the correct speed. What I mean by that is, as you watch the clock in the BIOS, it'll tick off 60 seconds in around 20 to 30 real time seconds.

Once I got into Windows, it would display the correct time and speed, if I set it in Windows, until I reboot. I had it running for about half an hour (real time), and when I rebooted, the clock in Windows jumped ahead over an hour.

I cleared the CMOS, and flashed the BIOS, and neither fixed this. I also replaced the CMOS battery (twice) with known good ones... I'm assuming that this is why the thing got thrown out.

Is there any way to repair this, or is the mobo toast? Everything else (onboard sound, vid, etc...) works great...just the clock is royally screwed up.

TIA!!

Brian

*edited to include line about CMOS batteries*
 
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Did you check the CMOS battery? That'd be my next idea. Bust out a multimeter and see if you're getting the right voltage. I know when you think of a battery going dead in a watch the clock ticks slower, but its just as possible to wire up a clock on a motherboard that gets juice from the PS and uses the CMOS battery to slow it down. I don't know, I'm just throwing out ideas here.
 
I forgot about that....the battery was missing, and I tried two different ones in it. (both known good). No effect.

Thanks for the reply...good thought, but I already tried it (just forgot to mention it above).

B.
 
It's a really weird problem. I would tend to think that it's because some component has failed. Short of testing EVERY capacitor in the RTC, you might not be able to do much with it.
 
Ah crap! I know! Why don't you just download some software that synchronizes the computer with the National Institute of Standards and Technology? [Shameless plug for my employer ;)] NIST is responsible for all the satellite set clocks you can buy. NIST tells you what time it is. hehehe...
 
RadRacer said:
Ah crap! I know! Why don't you just download some software that synchronizes the computer with the National Institute of Standards and Technology? [Shameless plug for my employer ;)] NIST is responsible for all the satellite set clocks you can buy. NIST tells you what time it is. hehehe...

LOL...I've had a shareware proggie for that for ever. That's what I used to set the time in Windows, and when I rebooted, the clock jumped over an hour.

The one I have is called "Chronograph"...it connects to one of the atomic clocks in the US.

B.
 
It might be a bad crystal (Silver cilindrical thingie ~0.5" long) which is probably somewhere between the BIOS chip and battery, and it most likely runs at 32.768KHz.

If that isn't the problem, I think you're out of options...other than what RadRacer suggested.
 
How is the cpu speed running, I thought the real time clock was regulated by the crystal frequency generator. If the frequency is jumping around also then you'd just have to replace that.
 
Hey KillorBe...how's life been treatin' ya! :)

Yeah...that's kinda what I thought too. I'm thinking the board it gone..

I had two thoughts for it...get a cheap vid card (PCI w/ S vid out), put the DVD drive in it, and use it to play DVD's (and Fold, of course..LOL).

Or if I could "fix" it, buy a C700, put a 20GB drive in it (I have one I could use here), buy a cheap CD-ROM, and sell it locally, to help finance the PC3200 I need for my main rig.

If I can find a mATX board for it cheap enough, I still might do the latter of the two. How hard (and expensive) can a mATX intel board be to find? :p
 
Mr B said:
Hey KillorBe...how's life been treatin' ya! :)
What can I say, it depends on your POV, it could be better but then again it could be a lot worse, oh well I have my rigs to play with. (One good thing is that I drink wayyyy less than I used to, but I still have 'those' days :( )

Mr B said:
Yeah...that's kinda what I thought too. I'm thinking the board it gone..

If you need a crystal let me know, I'm sure I've got an old board with a good crystal (Don't worry about shipping and such, it's free as I'm sure it'll be put to good use....F@H:) )
 
skab said:
How is the cpu speed running, I thought the real time clock was regulated by the crystal frequency generator. If the frequency is jumping around also then you'd just have to replace that.

the CPU ran solid, no fluctuations, at 66.?MHz bus, 366(ish)Mhz speed. I say "ish", as like most boards, it doesn't run right on the 66, it's actually a touch over, and that small .xMhz of bus makes it 366+ Mhz. I just can't remember the exact .xx.

But it ran steady, and stable.

Replacing the crystal? Hmmmm... *grabs removable mobo tray from HP machine across the room*

Ok...I see two crystals on this board...one by the SDRAM slots, near what looks to be a voltage regulator and clock generator, and the other is way in the corner, next to the 3rd PCI slot (mATX board, remember, so that IS the corner of the board).

I'd assume the one by the vgen and clockgen chips is the one I'm concerned with here... On it, and printed next to it, is;

14.31818MHZ
S.K.E 18PF

On the board;

14.318MHZ_AXIAL

I'm assuming I'd have to find one on a dead mobo with identical numbers, right?

*digs out old Soyo slot 1 board*

Ok...there's one next to the first PCi slot...it reads on the crystal:

14.3D9P1

Wonder if this is good?

B.
 
Well, I did some soldering, and took that crystal off the old dead Soyo, and put it on the HP/Asus board.

While it works (boots up, correct CPU speed, etc..) it didn't fix the problem with the clock. :(

I've made a bit of a deal for an ECS K7SEM, to replace it. So I get rid of the proprietary HP ca-ca in the bargain, too. ;) (can you tell I'm heartbroken over that...LOL :p )

At least I learned a bit of a new trick with the soldering iron.... :)

B.
 
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