Lexicon 480L bad HSP

[Zaldo]

Hi folks,

still any 480L specialists here? I have a bad HSP to fix. The effects work, but it has an continious digital crackle pattern repeating every 1.35 seconds (even w/o signal input). Crackle will become reverberated as well.

Sounds like a faulty DRAM, huh?

Best regards,
Zaldo

 

[radardoug]

Yes, faulty DRAM. Get yourself some sockets and a good desolderer!

 

[jensenmann]

+1
...and measure every coppertrace from the source to the DRAM you´re replacing. The reason is that over the years the board is bending downwards due to it´s weight and poor mounting. This force can create very small cracks in the copper traces which will then disconnect a leg of the DRAM from the circuit. This can - even worse - be temperature dependent. My old 480 used to have quite some dead traces. It has been used in an OB-van before, hence the increased mechanical stress on the PCBs.