PC Engine Duo Video/RAM Issue

[blueraven]

Hey Everyone,

Thanks for your dedication to keeping these consoles alive, and for this forum.

I just picked up a second PC Engine duo from a seller on eBay who claimed it was his "As-Is... backup unit"; The price was right (under $75 shipped, no peripherals or controllers), but shortly after the purchase and doing a bit of feedback research I realized that the unit was actually sold to him as a damaged/broken unit a week prior from a seller in Japan and he used the same picture from the previous seller's auction. Naturally, he forgot to mention this in his listing. 

This is how the unit looked when it powered on. Needless to day it was disappointing, but I was prepared for it.



After reading the previous posts on the CoreGrafx Video Issue here:

http://www.pcenginefx.com/forums/index.php?topic=4617.0

I double-checked the power supply (aftermarket 9v 1000ma shielded) and AV cable (official NEC) with my other system to make sure they were in working order. 

I came to the conclusion that the issue is faulty RAM, and have since ordered a few sets of replacements at Arcadecomponents.com. If I'm correct, there should be 28 solder points per chip about .75mm apart for each. I'll post the photos and follow-ups here when I get the system apart next week and actually have to do surgery. Has anybody performed this repair, and if so what were your results?

Thanks again,
blueraven

[blueraven]

The aftermarket RAM arrived today from arcadecomponents.com. Because the price was reasonable ($2.5 per chip) I ordered 4 chips in case I ran across the problem with another console. They look to be the exact same size as the current Hudson chips in the PCE. The numbers on the RAM read: Mossel MS62256L-10PC  part No. P9131A.



  I apologise for the quality of this image, my camera is a piece of crap.

[chop5]

nice,keep us posted. did you get any work ram chips?

[Platinumfungi]

Good work. I'm curious to see how this turns out. Just a thought - you might want to install a socket for the RAM just in case you have to mess with it further. Sockets are sooooooo much easier to work with.  Keep us posted.

[Bigdog302]

eek,what a issue with the video.thank God i don't have the issue with both of my turbo's.i hope the ram you found fixes it.

[channelmaniac]

Hi Blueraven,

Did you get the chips installed yet? I'm always curious as to what the chips I sell get used in.

Raymond

[blueraven]

Hi Blueraven,

Did you get the chips installed yet? I'm always curious as to what the chips I sell get used in.

Raymond

Hey channelmanic, thanks again for being the resource on this! Here's a quick update.

I have the unit apart and am working on replacing a few caps at the moment. My cell phone camera just doesn't cut it for details on the circuit board, so I will post photos later this week.

I'm guessing the previous owner could have fried out the RAM with overvoltage; He admittedly used a Genesis II power supply (I don't trust them; I think the 10V 1500mA rating is too high, and It runs too hot). I'm assuming a power surge + that AC adapter caused this problem.

EDIT: Yes I meant Genesis 1. He used an electronics store adapter to reverse the polarity, and I was 300mA off in the actual spec. 

[agt_dale_cooper]

Genesis II adapters are 10V DC, .85A, tip positive...while the power provided is in the right neighborhood, it's tip will NOT fit into Duo's orifice. :-"
I assume you meant Genesis I...
Genesis I adapters are 10V, 1.2A, tip NEGATIVE.  Duo_R has pointed this out in the past...not only is it overpowering, it's incorrectly polarized.  I don't even understand how the thing works if somebody ran it with this...I don't know, can incorrect DC polarity blow fuses?  I know shunting AC into a DC circuit can (I'm looking at YOU Nintendo adapter stuck into the back of the Sega CD base!!!  You'd be suprised at the number of times I've seen this come in), but I don't know about DC polarity...it might just not work, as opposed to blowing fuses...

In any event, I'm following your progress here...I agree with whoever said to install a socket, BTW..

[blueraven]

A bit of an update: While the chips should work in the Coregrafx system, they are incorrect for the PCE duo. 

I have scanned the motherboard and am in the process of re-ordering the correct RAM chips.

EDIT: 5/19/09 - Blackandblue, Bacteria; I did report the seller. He's no longer a registered user. Slammed with negatives shortly after our transaction (October - this is what got me to join the forum). Sadly, I was unable to reclaim my money, as the 60 days had already elapsed. Basically he was reselling stuff that was purchased broken a few weeks earlier. 

[BlackandBlue]

A bit of an update: While the chips should work in the Coregrafx system, they are incorrect for the PCE duo. 

I have scanned the motherboard and am in the process of re-ordering the correct RAM chips.

Good luck with Round 2!  Hopefully that truly is the issue and you save that poor thing.

Gotta love them Ebay sellers...

[bacteria]

It sucks when someone sells something on e-bay without being honest about its condition or what doesn't work, etc. You should consider reporting him.

[RoyVegas]

It sucks when someone sells something on e-bay without being honest about its condition or what doesn't work, etc. You should consider reporting him.

Nothing to really report him for..  The second a seller states that it is being sold "AS-IS" its buyer beware.  When I see an auction like this I usually send them an e-mail asking if it works or has any known issues.  Then ask what their return policy is if it arrives and isn't working.  If they know it doesn't work they will tell you no returns.  Never take any chances when you order things.  If there is no warranty or its stated as-is, ask questions.  At least that way if there is a problem with the item you can show Paypal the seller clearly stated it worked and you could return it.  Just make sure your covered next time.

[bacteria]

Good advice. I have bought a lot on e-bay and been lucky that everything worked, even one or two "untested" systems I took a gamble on as they were cheap.