This is common problem with vintage Pioneers, kinda blurry display. Its nothing easier, than take it apart and give it proper clean. (not mine picture)
My mint DT400 after proper cleaning.
European 230V version with Euro 2 pin mains sockets
Taken apart (kinda)
Perspex cleaning fluid applied on display. Its possible to purchase it on eBay, I have used it many times on various surfaces and always working. Beauty!
The main blurriness is coursed by film created inside, needs to be wiped out!
Same ritual is always applied:
– lighter fluid
– perspex cleaner on perspex
– light layer of WD-40 wiped with paper tissue in the end
Shiny like dog’s bollocks.
Different (multivoltage) version of DT-440,
Pioneer DT-400 on the top, DT-500 underneath and two DT-510’s at the bottom. The main difference between 500 and 510 is only design feature. Plastic display frame and plastic know on 510. Other models with Higher number (540, 550 etc) having green fluorescent display and black color.