What is your concern ?

Dissolving the surface print and staining the ceramic. With some gentle wiping, I've had surface characters "wash" away before.

I see. So far acetone didnt affect any printed stuff, but your approach is safer. I guess next time I need this stuff acetone will watch from aside only.

Some printing dissolves easier than others. Since I don't know how to pre-determine this, I play it safe.

feipoa wrote on 2022-01-03, 08:07:

Chadti99, looking at my notes for the LSD board, I have: […]
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Chadti99, looking at my notes for the LSD board, I have:

R16 if replaced with:
27 K-ohm = 3.45 V
30 K-ohm = 3.68 V
31 K-ohm = 3.75 V
36 K-ohm = 4.0 V

Since 3.45 V - 4.0 V is the target range, you'd want to replace R16 with a 50 k-ohm trim pot. This one should do: https://www.digikey.ca/en/products/detail/bou … -503RLF/2535946 But be warned, there is no suitable means to secure this trim-pot. If you solder the through-hole leads onto the surface mount pads, the continued torque of turning the screw or any small bang of the trim-pot could eventually rip up the SMD pad.

With my Biostar UUD mod, although the trim pot is soldered to the SMD pads, I have used JB Weld to secure the side of the trim pot to the shroud on the SIMM socket.

In most cases, depending on the regular used, a standard LDO (0.7 V drop) would mean you could go as high as 4.2 or 4.3 V. If they used a very low drop-out regulator, (0.3 V drop) then you might get to as high as 4.7 V. I've not seen any socket 3 boards use a very low drop-out regulator though. So most likely, with a 50K or 100K trim pot, you'd have a 3-4.2 V adjustment range. If the CPU draws too much current when overclocking, the upper limit of that 4.2 V range will shrink. For example, if you push an IBM 5x86c-100HF to 133 MHz, the max voltage gets closer to 3.85 V.

Hi Feipoa, what size trim pot would you recommend to adjust between say 4-5 volts on this same location? I’ve got an AM5x86 running fairly well at 5 volts but want to see if it might work a bit lower. Just as you predicted the 50 k-ohm trim pot topped out at 4.3. At 4.3 and this particular cpu I can post at 200 but it’s just not enough to boot. Hoping 4.5-4.75 does the trick and reduces heat a bit.

There is no size trim pot which can be used with the onboard regulator to get 4.3 - 5.0 V regulation. The low drop-out voltage regulator drops a minimum of 0.7 V. You'd have to switch to an ultra low drop-out regulator, which might drop 0.3 V.

feipoa wrote on 2022-02-10, 14:15:

There is no size trim pot which can be used with the onboard regulator to get 4.3 - 5.0 V regulation. The low drop-out voltage regulator drops a minimum of 0.7 V. You'd have to switch to an ultra low drop-out regulator, which might drop 0.3 V.

Got it, the ultra low drop out reg sounds like what I need.

Have you guys tested a Promise Ultra100 TX2 on any of the LS boards? Cant seem to get it working, almost makes it to dos prompt or windows boot animation but hangs. Might not be compatible with this board.

Chadti99 wrote on 2022-02-11, 14:48:

Have you guys tested a Promise Ultra100 TX2 on any of the LS boards? Cant seem to get it working, almost makes it to dos prompt or windows boot animation but hangs. Might not be compatible with this board.

yes actually I'm using one with my LS-486e

that board is really fickle about PCI busmaters, if you have a bus-mastering NIC or VGA card installed it might be preventing the IDE card from working properly

Worked for me too, but i don't use one atm.
The on-board IDE controller handles things well and is not a bottleneck.
Win95 starts within few seconds, which is the biggest perceived delay i experience on that rig so far.

If I recall correctly, most [if not all?] PCI network cards tend to upset SiS 496 based motherboards when a Promise host interface card is being used. I want to say there was also an issue with SCSI cards in this regard, but it is a fuzzy memory. I have a system setup around a SiS 496, which has a SCSI card installed, but I noticed I used an ISA 10/100 network card. I never do this unless there's an issue with a PCI NIC.

pshipkov wrote on 2022-02-11, 19:06:

Worked for me too, but i don't use one atm.
The on-board IDE controller handles things well and is not a bottleneck.
Win95 starts within few seconds, which is the biggest perceived delay i experience on that rig so far.

Do we know for sure the on-board works well at 66MHz 1:1 FSB?

Wanted to see if I could improve stability on the 200MHz AMD build at 1:1. Realizing I’ve only tested the Promise in UMC boards like the Biostar.

Okay I think I figured it out. I had to disable “PCI Master Burst Read/Write”

And external IDE controller didn’t help, was worth a shot.

I’ve also verified pshipkov’s findings that 313 cache timings are needed for best stability at 66MHz bus operation on the LSD with cache mod.

On-board IDE is stable at 66mhz and 1:1 for sure.
It was never a problem with any of the LuckyStar boards here, afair.
Trying to think of why you are having this issue ...
Actually what exactly is the problem ? No boot or unstable after boot ?

I can double check the Promise controller if you want - but I know it was fine too. Let me know.

I confirm that at 200mhz (3x66) 313 L2 cache timings are the way to go.
Looking at some notes here - 312 works too, but cpu has to be hard frozen with 12v Peltier.
I don't have voltage regulator so Peltier gets 5v or 12v only.

BTW, the other day I ran few more tests with the ADZ chip that runs 200mhz on air cooling and 4V - it does not pass complex compute such as VC++ code compilation and 3d rendering. But with 5v Peltier on top all seems to be fine. Going to test more today-tomorrow and if all is good will show-off with a video of the upgrade to 200mhz.

At Chadti99

WARNING about running ADZ/ADW cpus at 4v or higher on air cooling.
The ADZ processor here that was working at 200mhz air cooling is dead now.
I deeply regret going for it now. This was the one that lit up at 240mhz with 12v Peltier. Damn.
🙁

pshipkov wrote on 2022-02-12, 19:41:

At Chadti99 […]
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At Chadti99

WARNING about running ADZ/ADW cpus at 4v or higher on air cooling.
The ADZ processor here that was working at 200mhz air cooling is dead now.
I deeply regret going for it now. This was the one that lit up at 240mhz with 12v Peltier. Damn.
🙁

Oh man, sorry pshipkov, I feel partly responsible. Are you certain, have you tried on another board?

Yes, tried hard to wake it up, including on Biostar UUD which is also rock solid mobo, but the poor chip is dead. Maan.
No blame whatsoever. I should know better.
It was a stark reminder that running old silicon on out of spec voltages needs to be handled carefully.
This was the only CPU i had that can run 200MHz at 4V on air or weak Peltier.
I am hard-out from the air-cooling OC action. Going forward - any out of spec voltage to CPU will be accompanied by Peltier.

If i was you i would really consider going for 5V Peltier for the stable 200MHz and not rely on air-cooling.

What are the requirements for your other Am5x86 to run stable at 200 MHz?

I did tell you not to start selling off the Am5x86 chips which run ta 180 MHz on air, and good thing you kept some.