You really should go speak with a local attorney. This is a matter of procedure and should be discussed with someone local.
Having said that, you mentioned that you were never notified of the trial. Having heard that thousands of time, generally, in civil lawsuits, there is no notice of "trial" (the exception being in small claims court). You receive a Civil Summons that tells you to file a written answer within a certain time from the date you receive the summons, typically 30 days.
If you do not file a response, the plaintiff (HOA in your case) will apply to the court for the relief sought in the complaint. This means, the plaintiff will seek an entry of default and then a default judgment because you never answered and/or denied the allegations in the complaint--that is, you owe us money. Since you did not deny that you owed the homeowner's association (HOA) money, there is no need for a trial and the court can go ahead and enter a judgment against you.
You should speak with a local attorney. Also, even if a judgment remains against you, if the judgment is satisfied quickly, it should have minimal impact on your credit. If you have a legitmate dispute and get sued, you should be able to dispute the debt, litigate and, if you lose, then pay it without suffering terribly on your credit report.
Also, you are entitled to dispute the debt to the creditor and credit reporting agency. I am unaware of many HOAs reporting to CRAs because of the expense but credit reports will pick up on public records such as judgments. Again, if the judgment is in place for a short amount of time, you should not take a big hit credit report wise.
By answering this question, general information is provided and no attorney-client relationship is established. For specific inquiries, you should consult with experienced counsel in your area.
You need to file a motion to vacate judgment, and file it before the expiration of 30 days after the judgment was entered by the court. Hand file a copy at the clerk's office, and bring a copy to get it date-stamped as filed. In the motion, state that you were never served a copy of the complaint and summons in the case; state that you received no notice of a court case or a trial date; and state that you do not owe the amounts claimed and intend to appear and defend the claim (I'm sure they must have added costs, late fees, interest and attorney's fees you can dispute as being unreasonable). I would also first go to the courthouse and request to view the file--you are entitled to do that. There will be an "affidavit of service" signed by someone, in which it will state the date, time and place where they served a copy of the complaint and court summons upon you. If those facts are false, specifically refute those facts in your motion. You should sign the motion under an affidavit yourself, giving oath that the facts stated therein are true. You will also need to sign a certificate of service, certifying that you have mailed a copy of the motion to the HOA attorney of record, and the date of mailing. As you can see, if you are unfamiliar with preparing legal pleadings, there is a lot to know and do correctly, so it may pay to get an attorney to do this for you, and have him/her settle the matter and arrange a payment schedule for you. It is even possible that the attorney could settle the case by not only agreeing for you to make payments, but in exchange have the HOA agree to CONSENT to vacate the judgment, so long as the settlement payments are made. Good luck.
The lack of service is a perfectly valid basis to move to vacate the judgment, even if there is no other defense. But if you don't settle and don't have a defense, you will be right back where you started. Get a lawyer to review this with you and file the papers, and then try to settle. Most creditors want money and don't care about whether there is a judgment on your record as long as they have been paid.