Author Topic: Pc engine duo graphics glitch on cd  (Read 149 times)

Mrwoodchuck

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Pc engine duo graphics glitch on cd
« on: July 08, 2016, 03:57:46 AM »
Hi all,

It's been awhile, that's what happens when you have kids I guess..
I'm trying to finish repairing one of my duo's, it had a dead cpu that was diagnosed by thesteve, "thank you!" and I had put it in storage and did not get back to it.

I pop in a hucard and it looks great, no issues.


When I power it on with no hucard the cdrom menu is really messed up.


Currently the cdrom drive is not working because i need to replace vr105, so testing past the menu is not possible.
I was assuming the glitch was due to me replacing ic 520, apparently before I put it in storage when diagnosing the cpu I took out the ic but never put it back in.  ](*,)

After looking at the datasheet I compared a sn74hc245 to this ic and I saw no difference, as such I used the sn74hc245 because I had some sitting on old parts boards.


I tried 2 different chips, same results on both.

I was wondering if this could be a ram issue, or I should just buy the ALS245A from ebay?

Any input would be helpfull thanks all!