Yes to both of you. You are correct. It usually is a bad solder. There are threads here on how to repair these and there are a couple of places to send them to be repaired if you don't feel comfortable with the job. Salvage yards is another place to find used units - most come with some sort of guarantee. Keep in mind that these units fail with age and use - most used units (unless recently repaired) are on their way to failure at some time. Hope this helps.