PU-18 [5502] PS1 boot issue

old crew chip was definitely 5 wires, which clearly showed the PS1 logo.
However, a new connection to the mm3 gate will recognize it as a music CD.
http://chip.aeug.org/wiring/18p55xx6.html <- This did not help.
I regret it not taking a picture.

 

The connections on that page you linked are the ones I would expect for an Old Crow chip. If it's not working when connected up like that, the most obvious conclusion is that it's not running the Old Crow code but something else.

You could try connecting up the MM3 chip in 4-wire mode (pins 1, 8, 5 and 6) and see if that boots.

 

Thank you for answer. Still the same problem ... Yesterday I organized the problem pu-18 board. I am going to order the new 7502 cheaply on ebay.

 

Sorry to hear that - I'm really pretty much out of ideas now... If you have access to a scope you could try looking at the eye signal coming out of the RF amplifier chip and comparing it with the working board.

 

Sometimes it's really just a component failure, cracked solder joint on a 208 pin IC, etc. A really hard to debug issue.
I just found and fixed a no image PSX 9002 model where the fault was a dislocated resistor array for the CPU > DRAM RAS / CAS lines.
The resistor array is tiny and I only found the flaw because the connection was intermittent and reacted to pressure.
(I could make this PSX do a real "Fearful Harmony" xD)

Just saying, sometimes it's best to let it go ;p

 

Okay, I found this place through Google search, and I found that yours engineers are excellent. If there is another story, I will register again.