This is my very first multimeter. I bought it in 1990 when I was 14 years old. Back then it cost DM50,- (Deutsche Mark in West Germany). It still works, though I don’t really use it anymore. Its best feature is its instant continuity buzzer.
Today I use a Fluke 177 and the EEVblog multimeter.
I don’t suppose you’ve still got the instructions? My Dad gave me his DT-3800 before he died but I’m not sure it’s working. WEhen I set it to continuity test it displays 655 and the number keeps changing.
I’m really sorry, but I don’t have the manual. Maybe try cleaning all the connectors and see if the resistance of the banana plugs was the cause of your problem?