mk s based board would both work

https://www.amazon.com/KINGPRINT-Smooth … &psc=1
the advantages are 32 bit progrming and the configuration is simply editing a text file.

although loading marlin into a regular mks is not bad.

another option if you want to fix it is offer $30 for a used tested board someone on this forum may have one laying around.

buying cheap is just that, buying cheap. If you want quality, you need to rethink your expectations.
Cheap is not going to give you quality, or reliability.

for the record, the plugs for the motors on that board are JST type, but the wiring order may be different than others (as was the case with many earlier SDs) so in the end, even if they will plug into another board, they may not work as expected.
For some reason SD tinkered with motor wiring.. and with the Press wiring being all (mostly) white, it does present its own challenges.

All of that said, yes, you could potentially make the Press into a decent printer, but it is not going to be super easy. You will have to invest a little money (new board and possibly connectors) and a lot of time and effort.

If so which replacement board is best option?

https://folgertech.com/collections/ardu … 88-drivers

https://www.amazon.com/KINGPRINT-Contro … &psc=1

That is a very good question. above are two inexpensive options you will have to figure out which on fits into you printer best.

as far as connectors ramps uses DuPont connectors and IIRC  mks uses jst connections

this site gives more board info and comparison

https://3daddict.com/mks-gen-v1-4-mainboard-controller/

First of all I personally would not purchase any printer from ali express. it is at best a gamble a crap shoot if you will.
if you want good quality purchase from a reputable dealer in the usa.

That said the creality does have a good rep.

you can buy an Ender 3 from Wal mart free shipping for $199

https://www.walmart.com/ip/Creality-3D- … 0302008005

the press you have it seems people either love or hate . some have tweaked them with excellent results. Others have been frustrated to the point of giving up on them. there were a few folks on this forum looking to buy them if you decide to give up on this unit.

As far as your board the open connectors appear to be jst type but it appears the motors are connected with something else. Possibly carl can id them . You may need to get a connector kit and set of connector to upgrade change the board.
Info here on where to get the materials.

https://3daddict.com/3d-printer-wiring/

The choice to change the board or sell the printer you have and start fresh is only one you can make.
Economically it may not make sense but if you one to not walk away from a challenge and always want to learn something new it may make sense. If you like to tinker and stay on top of the learning curve it could be the right choice.
The other thing you need to consider is this printer was made for the consumer market. It is not designed to be upgraded and tinkered with like many kits are. these are a few of the pros and cons. ultimately your dime your call.

So my view is as follows. Try to replace mobo with a board that is cheap enough and does not require days of labour intense alterations to connections etc. Is this achievable? If so which replacement board is best option?

If doing the above will the printer ever be as performant and reliable as say a $200 creality printer from aliexpress?

it appears your "SOLIDOODLE 5" is indeed a press. The press was released august through the fall of 14.
it was designed and marketed as a plug and play printer. But it was not.
This web site may help you
http://paulsaulnier.com/2015/03/16/gett … dle-press/

No the heater should not come on when plugged in . sounds like a board issue. An issue not uncommon on this model.

Since solidoodle went bankrupt and closed there doors a couple years ago a new board from the factory is not an option.

You can however install the board of your choice if the rest of the printer is in good shape.

https://www.printedsolid.com/collection … -rambo-1-1
this is board used on the Prussa mk 3

in addition
to the Rambo there is
the rumba
the ramps
the MKS( RAMPS and Smoothie versions)
and last but lot least the duet.
All these boards well documented and well supported.
as well as other variants at various quality and price points.

A duet board in this printer may be a bit of overkill kind of like putting a porche engine in a vw bug.
and you will need a screen to operate it. for max convenience.

IMHO you have come to the right place for assistance
with WardJ and carl on your case you could not be in better hands.

For more information search this site for Sollidoodle PRESS.
and of course ask questions.

I hope this helps.

I bought a solidoodle second hand quite some time ago and only now got around to starting it up. It is not getting detected though by Win 10, no com port or prompt for driver (same on multiple computers with different usb cables).

The printer mobo indicates "Solidoodle 2014 SD5 rev CA", green light comes on on mobo.

The hot bed seems to heat up on startup, the steppers dont move / initialize and none of the fans going on at start. Is this normal?

The powersupply used has output of 24V @ 7.5A.

Any assistance / guidance appreciated.

Thanks