49LF020/A will not ID, erase or write

[Arakon]

I got a willem PCB 5.0 (integrated LPC/FWH socket).
Whenever I try to ID the 49LF020, I get 0x00 for both Chip and Manufacturer IDs. If I click erase, it claims to be successful, but the chip remains written. I can not overwrite (obviously). I CAN read the chip, and the data on it is correct, but it's impossible to ID or erase it. I tried with different PCs, different R/C Delay settings, using a power supply or USB power. I tried with several different chips, all have the same issue. Any ideas?

[Ezo]

Set programmer Vcc=5v, Vpp=12.7v, check.
Try with 0.97ja and programmer in pcb3b mode. Check get ID.
Check FWH/LPC socket and clean PLCC32 chip pins softly.

[Arakon]

Done all that. Turned out the manufacturer had stuck a jumper on one pin set that shouldn't be set normally. So much for "leave the jumpers as they are from factory for this".
Thanks, though, it's working now.