The Unofficial P64 Resource Forum

Just got two pistols one is 1977 model with triangle hammer works great the other pistol is 1967 model with round hammer and when you press decocker hammer does not fall it locks at full cock and leaves trigger disengaged. Is this normal or what is solution. PLEASE HELP!

No, that is not normal. When the safety is moved to SAFE, the hammer should fall and the trigger will be disengaged. If the hammer is staying locked back, but the trigger is disengaged, then there is an issue. Possibly the disconnector is only moving the trigger bar out of the way, but not allowing the sear to let the hammer fall. Clean the gun REAL well. Disassemble it and put it in mineral spirits over night. Use a toothbrush to get into small crevices. Blow all the parts off real well with air and then lubricate as normal. When the gun is disassembled, that is a perfect time to identify any severely worn-looking parts. There is a disconnector or two for sale on Gunbroker as of the last time I checked. Could be a culprit, but clean it and try that first before throwing parts at it.

There is also a thread about polishing the safety to make it work better.

No not normal. I'd seriously considering returning it, if possible, if a thorough cleaning doesn't resolve the problem. Returning to the seller for a refund or replacement can become problematic after a gun has been home-gunsmithed, polished, parts replaced etc.

I agree with hangfire. If a good cleaning/inspection/lube won't fix the error, then return it for a return or exchange if the seller accepts it.