Topic: Repasting sp20 spoondolies? (Read 2927 times)

Some scientist you are...you should know that gravity is a constant  ...want an apple to race with?

Once the 2 screws are completely tightened you're saying there isn't enough pressure on the die? Would it be possible to add a washer to each screw between it and the top of the heatsink to increase pressure?

The chip that I removed the heatsink from, on the SP20, would not reach > 0.60V until I applied epoxy glue to the glue spots and pressed it until it stuck w/o wobble.
The 2 screws do a crappy job of applying uniform pressure on the die. Air is a great thermal insulator.
 
Ever seen a heatsink bolted on to a large die GPU with just 2 diagonal screws?

Has anyone tried turning an SP20 on it's side? It would seem you could eliminate the "hanging heatsink" if you rotated the SP 20 so that the blades are horizontal and not vertical. It would look a bit odd, but I wonder how it would change the temps.

It's kind of odd too considering all the good, and not cheap, choices that Spondoolies made on the SP20. I've seen the 2-screw diagonal heatsinks on small chips on a motherboard, but never the CPU. Maybe the chips weren't level enough on the board and it need a little "give" to avoid cracking the ASIC.

My understanding is that Spondoolies didn't originally add a "glue bond" on the SP20, but did later in order to prevent the heatsink from rocking during shipment. I haven't heard that the glue bond was to actually improve thermal performance. It's too bad they didn't just originally use a 4-screw heatsink design.

so bottom line it for us here what did you use that lowered your temps AS5 then ? or MG ?

I have have a large repasting project for my Scrypt Asics , a 10-15 degree reduction in temps would be great for me as well

   
Re: Repasting sp20 spoondolies?
Today at 04:16:51 PM
   
Reply with quote  #32
My understanding is that Spondoolies didn't originally add a "glue bond" on the SP20, but did later in order to prevent the heatsink from rocking during shipment. I haven't heard that the glue bond was to actually improve thermal performance. It's too bad they didn't just originally use a 4-screw heatsink design.

AS5 is a non adhesive thermal compound, it does not have good adhesive properties.
There are 2 diagonally opposite screws to tighten the heatsink, ideally there should be 4, in order to apply adequate pressure and close the thermal gap.
if you are not using glue on the white spots where the heatsink was factory glued, your heatsink might not have good thermal contact with the chip.

I did not remove the copper plate from the heatsink.

I only put AS5 on the cores and it did well the job for them sticking to it.

Did you put some Epoxy glue to the heatsink in order to make it stick back to the glued in portion and not be wobbly?

i did not remove the thermal greese from the blates between the heatsinks and the copper, i left that, as i read on some treadh that someone had a big issue whit that.

The greese looks fine ,its alot and it keeps dripping when its hot , the boards were full of greese but didnt seem to have any bad effect, i still cleaned it, i just repasted the chip between the copper plate but nothing more than that, i put just a drip as it said that the AS5 is very think and it was really consistent , i had to press abit to get some good spreading on the chips

Glad that you found humor in this thread. Sigs are cool, and a fact on this group

I do not think I compared MG thermal stuff with AS5.
All I did was remove one heatsink, took a pic, replaced the grease with AS5, screwed it back in.
The voltage on the said chip did not rise immediately to the intended level of 0.65V because the thermal gap did not close.
 Then I applied epoxy adhesive and put pressure of the heatsink until the epoxy cured. It closed the thermal gap and the chip worked fine at 0.65V. Just like it did before the heatsink was removed. What I can say is that most likely AS5 has equal thermal conductivity compared to the OEM grease. 8X thermal conductivity does not imply that temps will be reduced by 8X.
 (Final temps also depends on the temperature differential between chip and heatsink). I think it means that AS5 will conduct 8X the amount of heat than MG paste.

For starters, you should NOT have used anything with SILVER near ASIC and I think that is half of the problem...I also noticed that you are not running it in the enclosure it came in
You should only have a very small amount of grease on the top of the chip and nothing anywhere else...I see in the data you posted that the volts are very low on 3 of the chips

Use another form of thermal compound without metal in it like MX-4.
Keep in mind that due to the half-assed grease job there may be leftover grease in places it was never meant to be...at least on my miners it was everywhere..the sides of the heatsinks, between the chips, everywhere...very messy and the dust loves to stick to that grease too...
I used MG chemicals non conductive grease as it calls for quite a bit of it if you remove the grease between the copper shim and the aluminum during the process.
I re-did a couple of machines which were throttling at .62v prior to pasting and they run a lot better now...I have pics somewhere of the process will upload when I can..the original job was horrible 

Are these the same settings you had prior to re-pasting and you were getting around 1400GH/s before this?
Also since you are undervolting there is no reason to have such a spread from .67 start to .69 max unless you are in a hot location..if that is the case just drop the max voltage to .68
In the field "restart miner if rate below" ... what do you have in that field, and why do you have 272w for the max watts on all 4 loops when the realistic value you should have for that voltage is more like 230w per loop

Why did you take the boards out of the original case BTW...there is a reason the airflow is over the boards in the way they are laid out..you may be cooling the top of the board ok but the back with all the power components needs cooling as well
You have 22 hardware errors in half an hour...u definitely did something wrong in the process...did u get rid of the glue that was holding the heatsinks down? possibly damaging something in the process?