TD New Guy
Join Date: Jun 2007
Location: Färingtofta, Sweden
My Ride: Audi 100, 200, 200.
Engine: Five roaring inline!
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Re: Resetting code on Pioneer DEX-77
Finally! Eight years have passed, and i now have two working units! Unlocked.
How you ask? Well, i was able to score one with working code, with no working display off ebay. Having poked around quite a bit in these units by now i was confident that it was most likely the DC-DC converter that had given up. I do have two working ones, so i took the chance. Lo and behold, after i replaced it the display came on, but i exchanged the whole front panel for one in better shape. Some buttons weren't working, should be a reasonably easy fix.
I now have four units, one will play discs but pickup needs adjustment and possibly replacement. Another will load discs but not detect nor read properly. The last two are in disrepair, one is verified to accept the code, but cannot be tested properly due to missing DC-DC converter. The last one is in pieces and as of yet untested.
I can confirm that the X24C44 is a viable replacement part for the PDH001 eeprom. In a previous post i said the 93c06 was compatible. This is not the case.
Now, the good stuff. How to reset the code.
Desolder the PDH001 and place it in your eeprom reader. I use a minipro TL866CS i got cheaply off ebay. Read it using settings for the X24C44 and change the first group to "CC86". The code is now "2205". All other groups should read zero. Replace the part and test it out. If you like, reprogram the code using the standard procedure from the manual.
I know there are people on ebay and other places who will charge you to reprogram the code and not tell you their secret. But this is my own work, and information wants to be free.