The orange 5V+ (power good) shows 1 ohm but the other red 5V+ show continuity to pin 12 on chrontel chip

Pin 5 on chrontel is grounded

pin 4 (agnd) on the pinout you sent is also grounded

What I noticed also I was just looking at resistances and some of the pins that show continuity are not fully connected.

For example JP5 pin 1 shows 0.01 resistance to pin3 on chrontel
JP5 pin 1 shoes 0.125 resistance to pin5 on chrontel

But on continuity mode in the multimeter both are low enough to show direct connection.

Makes me think the 0.125 perhaps was originally not supposed to be direct connected but partially shorted inside the chip, it would certainly explain the illogical connections

Thanks ! Yes when someone asks about 5V at the PSU they do mean the Red, and Ground is the Black.
Continuity should never be used on motherboards in my opinion. The actual Ohms are important. Some minor traces can be 2-3 ohms if long on a motherboard and is OK but if near 10 then a problem (corroded trace, cold solder joint, etc)
Many DVM report 10 ohm as Good continuity when in electronics it can mean an issue.....

added: If the 9007D is like the AV9107C-3 or -11 then there is a pin /PD that can "shut down" the clock chip which could make all control pins ground...but we do not know yet, is just a guess..
That is why we need as much info as you can collect. The odds of the whole chip being shorted is very rare. If your Ohm readings are correct there is something very wrong with how the chip is wired into the board and maybe the only way to figure it out is to remove the chip and then take readings, then solder a socket in and find a replacement IF the chip is indeed shorted....

yeah good call, I have been itching to remove it but didn't want to seem too excited about it. But now green light

Horun wrote on 2023-03-04, 00:21:

That is effing bizarre !

my reaction to the diagram post exactly 😀

treeman wrote on 2023-03-04, 00:32:

could this be a short inside the chip?

no, because you say
>pin 13 gives me 14mhz which doesn't have a direct connection to any pin
that means Chrontel chip is powered correctly and produces good buffered 14MHz clock at REFCLK pin.
but
> pin 3 4 5 9 10 12 14
would means ground 4 5 is connected to Power pin 12. Imo this is pebcak, measurement error.

> 5V+ show continuity to pin 12 on chrontel chip
>Pin 5 on chrontel is grounded

so 5 is grounded, 12 is power, but you somehow measure them connected 😀 and aty the same time Chrontel is producing good 14MHz clock.
Imo DO NOT remove the chip, watch some videos about multimeter use 😀 if pins 5 and 12 were connected your power supply wouldnt start at all, or you would see smoke from the board.

5 and 12 has resistance of 0.145 which my multimeter also gives a beep on continuity mode perhaps my mistake is using only continuity mode rather then looking at resistance to determine what is connected direct.

Too late I took the chip off, the chip pin 5 to 12 has resistance of .600 so the chip seems ok.

This is ok because now I can socket the chip and take readings with the chip on and off

treeman wrote on 2023-03-04, 08:31:

5 and 12 has resistance of 0.145

simply not possible https://www.calculator.net/ohms-law-calculato … =watt&x=28&y=13

yeah ok, your right I realised I had the psu still plugged in when I took the measurement and it was beeping the resistance with psu 5-12 is 0.045 and with psu disconnected is 1 short beep and resistance of 0.145. Yeah user error im guilty.

Anyway I took off both both jumpers jp4 and Jp5 clear, the crystal gave me some erratic readings 4.mhz 20mhz 50mhz then 0 then again some random numbers.

So correct readings are:

jp5 pin1 - > 3 9 10 12
jp5 pin 2 - > 2
jp5 pin 3 - > 4 5 14

jp4 pin1 - > 4 5 14
jp4 pin2 - > 1
jp4 pin3 - > 3 9 10 12

ok u can shoot me

rasz_pl wrote on 2023-03-04, 08:58:

treeman wrote on 2023-03-04, 08:31:

5 and 12 has resistance of 0.145

simply not possible https://www.calculator.net/ohms-law-calculato … =watt&x=28&y=13

A reading of 0.145 is very much possible, although a resistance of 0.145 is indeed not possible. Many multimeters have continuity check as secondary function in "diode check" mode, and display the voltage drop at a test current of around 1mA. 145mV diode drop between +5V and GND on a fully populated 486 board is indeed not unheard of, and the consequence of FETs without sufficient bias voltage.

treeman wrote on 2023-03-04, 09:30:

jp5 pin1 - > 3 9 10 12 jp5 pin 3 - > 4 5 14 […]
Show full quote

jp5 pin1 - > 3 9 10 12
jp5 pin 3 - > 4 5 14

jp4 pin1 - > 4 5 14
jp4 pin3 - > 3 9 10 12

hey, now we have confirmation of
> FS1/FS2 1/0 25MHz and 0/1 33MHz

you can go back to DIP pins 3 and 14 to make sure they are set to
>FSO (14)= 0 ground
>FS3 (3)= 1 +5V

frequency truth table:
3 2 1 0
I 0 0 0 8.02 MHz
I 0 I 0 25.06 MHz
I I 0 0 33.29 MHz

I added 8MHz because we can do an experiment, set jumpers so both FS1/FS2 are grounded, JP4 1-2 JP5 2-3, and measure Frequency on pin 11

ok, so far
pin 14 - > ground
pin 3 - > 5v+

I tried the combination you suggested I 0 0 0
got 8mhz on pin 11

Tried 33mhz combination = 0
Tried 25mhz combination = 25mhz... then changed to 40... 10... 2 it was not stable
Tried I 0 0 0 2 more times and got 8mhz stable

The 8mhz was also present on cpu clock pin

486 should boot fine on 8MHz, try it
edit: wait, so you even get 25MHz fine. Makes me question whole thread now 😮 😜
I have a suspicion you will need that $7 including shipping POST card ("4-Digit Card PC Analyzer Diagnostic Motherboard POST Tester Computer PC PCI ISA") after all to move forward with diagnosing real problem (if there is one)

I tried a dx2 50 cpu not booting on 8mhz, I only saw 25mhz once and it changes quickly all the other times i see 0.

Yeah I made a order for a post card since you mentioned it

Sometimes you get a worn out jumper cap that won't contact well, causes you all kinds of weirdness.

I don't think its the jumper caps, I have tried the combinations many times. The only stable combination is 8mhz 25 and 33mhz are flaky at best and non existent most time. I still believe the clock gen is problematic but like rasz said on 8mhz I should be able to boot.
I made some stupid mistakes and made the thread not look serious but I will slowly continue to investigate.

I ordered the isa diagnostic card I hope I can get a clue when I get it.

Otherwise I measured voltages to bios, keyboard controller, rtc/ram chip and all seem there. Without a scope can't verify if the data lines are active tho.

So time to have a break on this for now

so I got the diagnostic card, but it shows me nothing. All the power lines are ok, clock is there (iwas wrong) reset is there. But it doesn't advance to post

So from my understanding it doesn't progress to the bios.

I took the bios chip off and read it with my tl866 and it shows data, keyboard controller is showing voltages and no shorts, can't verify signals without a scope.

This is progress.
Can you change topic to something more descriptive? like "Octek hippo vl+ 3.02 no POST".
I dont remember, are those confirmed working cpus you tried? Now we need to determine if CPU even tries. Some way for you to monitor CPU address lines and see if it attempts fetching first byte from BIOS eprom. Obviously I dont want to tell you to buy $300 scope or $200 LA. If you can borrow one thats great, if not we got perfectly serviceable cheapskate options - https://sigrok.org/wiki/Lcsoft_Mini_Board $5 with free shipping "Board Module FX2LP" on ebay, ~$10 on amazon as "EZ-USB FX2LP CY7C68013A USB Logic Analyzer Core Board USB2.0 Development Board CY7C68013A-56 48Mhz 480Mbps EEPROM". This is how you use one https://www.instructables.com/FX2LP-CY7C68013 … Logic-Analyzer/
With LA you would first wire few probes to EPROM address lines and see if there is activity there, if not move up the chain and solder few probe wires directly to CPU socket pins (or VESA connector) on the back of pcb.

Sadly Im not aware of any chipset documentation, so fixing this board will involve tedious reverse engineering.

Edit: Reset diode on Post card blinks at the start, right?

I got an idea if you really really really wanna know it's putting out a clock... Got anything like this around? https://www.eham.net/reviews/view-product?id=3310 I just came across an old one of mine when I was looking for something, or an old RadioShack patrolman or something, analog tuning, don't matter, just see if it's putting out something in the ballpark of 33Mhz... give it a 2" stub of wire sticking up from the clock output and hold the antenna near it, tune up and down, see if it farts at you. Might also pick up high harmonics if you only have Air-Marine radio or low harmonics if you only have shortwave. Anyhoo, just an idea if you wanna mess around with it.

rasz_pl wrote on 2023-03-10, 17:44:

This is progress. Can you change topic to something more descriptive? like "Octek hippo vl+ 3.02 no POST". I dont remember, are […]
Show full quote

This is progress.
Can you change topic to something more descriptive? like "Octek hippo vl+ 3.02 no POST".
I dont remember, are those confirmed working cpus you tried? Now we need to determine if CPU even tries. Some way for you to monitor CPU address lines and see if it attempts fetching first byte from BIOS eprom. Obviously I dont want to tell you to buy $300 scope or $200 LA. If you can borrow one thats great, if not we got perfectly serviceable cheapskate options - https://sigrok.org/wiki/Lcsoft_Mini_Board $5 with free shipping "Board Module FX2LP" on ebay, ~$10 on amazon as "EZ-USB FX2LP CY7C68013A USB Logic Analyzer Core Board USB2.0 Development Board CY7C68013A-56 48Mhz 480Mbps EEPROM". This is how you use one https://www.instructables.com/FX2LP-CY7C68013 … Logic-Analyzer/
With LA you would first wire few probes to EPROM address lines and see if there is activity there, if not move up the chain and solder few probe wires directly to CPU socket pins (or VESA connector) on the back of pcb.

Sadly Im not aware of any chipset documentation, so fixing this board will involve tedious reverse engineering.

Edit: Reset diode on Post card blinks at the start, right?

Thanks for the info, the logic analyser route is definately something I am interested to be learning and the route ill be going.

Yes reset led blinks on boot, it also lights up when short the reset button pins.

I checked both the chipsets they have 5v, the northbridge gets a bit warm after a while having the board on just like the cpu. The south bridge stays cold. Not sure if this has any relevance since southbridge probably consumes less power and does less processing form what I understand.

Yes doing analysis on bios data will be my next step

treeman wrote on 2023-03-10, 10:49:

so I got the diagnostic card, but it shows me nothing. All the power lines are ok, clock is there (iwas wrong) reset is there. But it doesn't advance to post

AFAIK the clock LED on these POST cards is kinda useless. It's usually connected directly (via a resistor) to the clock line and, depending on what the other side of the LED is connected to, will be lit on either L or H state. Usually L. So it might very well be you have that line stuck at the level that turns on that LED and there is no clock after all.

Also, this is ISA clock, CPU clock is another thing and might not be present if the chip you suspect is indeed faulty. Usually if you see a voltage of around Vcc/2 (so about 2.5V on 5V logic) on CMOS clock line that would mean the clock is running, and with 50% duty cycle (which is what most circuits require and expect), but the only way to be sure is with a scope. A logic analyzer might also tell you that but you will not know if the signal is clean and has correct L/H levels.