Fundraising is all about personal connections and networking. Makerspaces usually consist of a majority of introverts to varying degrees. Simply posting to mailing lists and chat channels that you need to raise money is not enough, you have to directly communicate with people on the phone or in person.

Step 1:
Assemble a squad of folks with energy to push the project forward. How this works depends on what the mood of the board is, and you'll need to work with them on this of course. If they are burned out or don't have the time, you still need to get them on board with the plan and also provide a support plan to get them unburdened. If you are serious about saving your space, start by beating down the door of all current and former members who were better connected in the Makerspace community. Connect with them to build a list of other members who care about your space and get them engaged. Use the phone, email and IM is easy to ignore. You need folks who have the energy to lead the space out of the current rut, so some fresh blood is also important. Connect with anyone involved in non-profit work in general as well. If it's just a matter of the current board being lost on how to fund-raise, then connecting them with people who know how to network within your local non-profit arena is important. Networking with other non-profits in your area is important but it's a little late to start that now. Hopefully your space already has connections, even old ones that have been lost to time that could be revived (by reconnecting with members who maintained those connections in the past). But, if you can't get a team of three or more people energized to save the space then you are very unlikely to move to step 2.

Step 2:
Once you have a squad, create a plan for financial success for the current year. Assemble a plan of what needs to change with your finances to pull out of this dead-end. You'll have to work with the current treasurer and crunch some numbers to know your monthly expense total. Once you know your monthly shortfall you can attack it (plus the amount to create a cushion of savings). Create a multi-pronged approach to close the gap. Raise dues, create a list of simple workshops than can launch immediately (soldering, anything, and you need instructors ready to run them), and use any other method you've used in the past to cover overhead. Does your state allow non-profits to run raffles? Raffles can be a great way to raise money, but they can take time to setup if your space doesn't already have "raffle infrastructure" in place (in our state it takes ~100 days to process the paperwork to allow non-profits to run a raffle, plus it requires a separate bank account to hold the proceeds). Again, use ANYTHING that has worked before and run it in parallel with new stuff. It's going to be a lot of work.

Step 3:
The big ask: a member fundraiser in parallel with the above. Identify a funding number that gets your space out of immediate danger, probably three months of overhead expenses. From your squad formed in step 1, identify your most sociable and well connected member('s) and work with them to do a fund drive from members and former members. Go WAY back and find former members who might still be fond of your space even after moving away. Beat the pavement and call these folks on the phone, preferably by people who knew them when they were still active in your community. Call current members who still pay monthly but don't show up. Mainly think of folks who are more well off, be careful to not put off members who their dues represents more of a burden than others. If you can locate a whale who is willing to make a relatively large donation, make it "if we raise $xxx so-and-so will match the donation!!". Usually these folks are happy to donate even if a matching contribution is not met, but it helps drive urgency.

Step 4:
Follow through. This is the hardest part, if you pull things out of the ditch this month you can't stop. You didn't put all this energy into the space this month only to let it die the next month. Maby a periodic fundraiser for the public. Writing grants takes experience, connecting with folks who have experience is good, but it can be learned. Networking with other non-profits pays a lot of dividends though. Co-hosting workshops with other non-profits is a great way to integrate (or re-integrate) into your community. This can spark interest from other people with experience who may want to help your space with leadership and fundraising experience.

Addendum:
The way you communicate is important. Once you have a recovery plan that works on paper announce it to the members via your usual communication channels, then start reaching out via the phone. Be positive with a path forward out of closure, marketing is important. You don't want to make people feel shame, but you do need to communicate the seriousness of the situation (which is already communicated at this point). Shame in a volunteer-oriented community just drives people away. It seems strange to say these things but one never knows what the level of communication experience one is walking into when making suggestions like these.

Good luck!