here is the link to the rebuild kit for the power supply. You can contact him through ebay, tell him your problem and see what he suggests. He has amazing prices, and does really good work if its not the power supply. 89-94 CHEVY S10 S-10 BLAZER DIGITAL CLUSTER REPAIR KIT | eBay

No offense to the guy who said something about a 200$ rebuilt kit, I dont know about you, but I would rather spend about 90 less for the same job, and keep your OG miles on your truck. This guy has been doing it for quite some time.
Keep in touch with me to let me know how this goes, I have electronic knowledge so i will try my best to help you with this, Take care