Does anyone know what the right tool(s) are to tighten up the heatsinks on the SP20E hash boards; I have a second hand unit with extremely loose heatsinks.
Also, is it safe to drill out the rivets that are holding the intake end plate in order to remove the hash boards --- does anyone have any experiences to share (good or bad) doing this ?
Hi.
If you are very carefull, re-building the hash boards on the SP20's is VERY easy and has amazing benefits.
I no longer own any SP20's but can still do this in my sleep.
Turn off, allow to cool down.
Remove the screws that hold the top lid in place remove top lid.
Carefully remove screws from the controller board, lift up and remove the two ribbons and the fan cable.
Store the controller PCB very carefully!
Take a photo of the routing of the ribbon cables - dont skip it will help!
Remove screws take top chassis off to expose the hash boards.
Down by the fan, pull the small metal plate up and out (might be stiff) hash boards will now slide out.
Now the fun starts.
Im my opinion the assembly of the heat sinks was very poor but you can re-build them.
You need a hacksaw blade and a screwdriver and need to be very carefull!
Unscrew the heatsinks and in most cases they will just pop off. Put to one side.
Where they dont come off VERY CAREFULLY saw with the blade downwards into the block of epoxy and release them.
Take your time and dont rush or you will bugger the hash board.
When all the heatsinks are off do the board work first.
Adjacent to each heat sink there is now a big blob of epoxy resin which stops the heat sink reaching the chips.
Unfortunately this needs to go.
I found the best way to do this was to carefully put PVC tape around the epoxy and saw it off sideways with a hacksaw blade.
There is plenty of room to do it just go nice and slowly and take your time.
Get the cut as close to the PCB as you can.
Use Isopropyl alcohol and lint free wipes and polish the chips to remove ALL the old heatsink compound.
This will be hard and brittle and will probably stick in the gaps between the ASIC and the decoupling caps on the ASIC board.
I used a small flat bladed jewellers screwdriver and scraped it out the way.
Give another clean with alcohol.
Next clean the PCB using spray PCB cleaner to remove the debris.
Spray from the top of the PCB down and clean as much off as possible.
Stand upwards and allow the dry.
Depending on how well you want to do the job I certainly recomend:-
Use the saw blade and remove the copper strips off the heat sinks.
Use alcohol and clean all the heat sinks and copper pads.
Takes a long time to do and is a real pain in the ass.
Next, get some Alloy Wheel Cleaner and throw the heat sinks and copper strips into it and leave for 1 hour.
Remove and clean up. They look brand new and all the pitted corrosion is now gone.
Wash and allow to dry thoroughly.
Now ignore everything about how thick thermal compound should be applied to a chip.
It simply wont work with an SP20 trust me.
Apply a generous amount of thermal compound to the copper plate and locate into position onto the heat sink.
Put into a vise on a work bench and close until VERY tight.
As the thermal compund oozes out the edges, wipe it off.
No oozing, not enough thermal compound so re-do it until you get the hang of it.
I used cheaper conductive compound for this stage.
Next, put a large blob of themal compound (non conductive) onto the ASIC chip, locate the heat sink and tighten up.
Repeat for ALL has boards.
Get two sections of wood and sit the hash cards onto the wood along the edges so the power MOSFET devices on the rear side of the PCB dont touch the ground.
You will understand what I mean.
Next, I sat two lengths of wood over all the ASICS and put a fairly heavy weight on top to apply pressure to the heat sinks.
Mix up some epoxy resin and apply a dab over all four corners of the heat sink to hold it in place.
Get a tiny amount under the heat sink, up the edge so it has a good bind.
Take the fan off the chassis (mine was screwed if you have the rubbers pull them with a pair of long nose plyers) and throw the whole chassis into the allow wheel cleaner along with everything except the PCBs obviously and fan.
Clean the fan using alcohol and cotton buds set to one side.
Take the chassis out, clean with water and allow to dry.
Now go to sleep for the night.
In the morning put it all back together again.
Struggling with routing the ribbon cables, take a look at the photo you took yesterday it will all make sense.
Turn the beast back on and see the cooler chip temps.
Have fun!
