INFORMTECH I T - A M 3 3 / 4 0 - DLC cpu speed issue \ VOGONS

INFORMTECH I T - A M 3 3 / 4 0 - DLC cpu speed issue

Topic actions

First post, by Kempj18

Posted on 2021-12-10, 14:39

Kempj18 Offline

Rank Newbie

Rank: Newbie
Posts: 10
Joined: 2021-10-31, 15:38

So here is the backstory. I have a INFORMTECH IT-AM33/40-DLC motherboard. No matter what cpu I put in it, and the settings I use for the speed of that cpu, it sets the speed to 16MHz, and test programs (i.e., Norton and CheckIT) see it as 16Mhz, but running at 7Mhz. Here is a link to the manual for this motherboard.

https://www.win3x.org/uh19/public/motherboard … anual/32122.pdf

I checked the jumpers and I'm getting 5 volts on the pins. This makes me think its the clock generator chip that might be bad.

Reply 1 of 7, by kixs

Posted on 2021-12-10, 14:52

kixs Offline

Rank l33t

Rank: l33t
Posts: 3588
Joined: 2013-01-31, 02:08
Location: Slovenia

Also check the turbo button/switch.

Visit my AmiBay items for sale (updated: 2026-03-23). I also take requests 😉
https://www.amibay.com/members/kixs.977/#sales-threads

Reply 2 of 7, by Kempj18

Posted on 2021-12-10, 17:08

Kempj18 Offline

Rank Newbie

Rank: Newbie
Posts: 10
Joined: 2021-10-31, 15:38

kixs wrote on 2021-12-10, 14:52:

Also check the turbo button/switch.

I did. I see 5 volts there also. No change to cpu performance if I put a jumper on it or not.

Reply 3 of 7, by weedeewee

Posted on 2021-12-10, 18:26

weedeewee Offline

Rank l33t

Rank: l33t
Posts: 3582
Joined: 2021-01-31, 16:09
Location: Belgium, Earth

do you get any change on the turbo led with the turbo jumpered and not jumpered ?

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 4 of 7, by Kempj18

Posted on 2021-12-10, 20:47

Kempj18 Offline

Rank Newbie

Rank: Newbie
Posts: 10
Joined: 2021-10-31, 15:38

weedeewee wrote on 2021-12-10, 18:26:

do you get any change on the turbo led with the turbo jumpered and not jumpered ?

No change. I think the MX8310-15PC Clock chip is the culprit.

Reply 5 of 7, by Anonymous Coward

Posted on 2021-12-11, 01:34

Anonymous Coward Offline

Rank l33t++

Rank: l33t++
Posts: 5055
Joined: 2008-03-20, 05:37
Location: Shandong, China

You can also check for turbo settings in the BIOS, or try CTRL-ALT-(+/-) on the keyboard.

"Will the highways on the internets become more few?" -Gee Dubya
V'Ger XT|Upgraded AT|Ultimate 386|Super VL/EISA 486|SMP VL/EISA Pentium

Reply 6 of 7, by Kempj18

Posted on 2021-12-12, 05:25

Kempj18 Offline

Rank Newbie

Rank: Newbie
Posts: 10
Joined: 2021-10-31, 15:38

Thanks for all the replies guy. It's a bad mx8310-15pc on the Clock output pin. I cut it loose and made soldered in a crystal oscillator chip. It worked. The bad news, it looks like crap (I'll need to clean it up). The good news, I have the CPU overclocked by 10MHz and its stable at 50. I've ran every test I can throw at it. Attached are some pictures of my work and benchmark.

Reply 7 of 7, by Kempj18

Posted on 2021-12-19, 03:45

Kempj18 Offline

Rank Newbie

Rank: Newbie
Posts: 10
Joined: 2021-10-31, 15:38

I'm going to see if I can build a replacement with a MX8315. The specs look nearly the same. The biggest difference seems to be that the 8315 is a surface mount. I'll post a picture once its complete.

Go to top of page Go to top of page

Back to General Old Hardware