Help with corroded Naomi parts! ::Image Heavy::

OldFoo · Post by **OldFoo** » Tue Mar 11, 2008 12:47 am

Hey guys,

I have some parts I picked up from a long past auction. The capcom I/O, gd-rom, and dimm have sustained rust and corrosion. The scsi ports on the gd-rom and dimm look kinda bad, but are still solid.

The I/O is in pretty bad shape. All of the connections have got it, too.

The bridge rectifier shows signs as well.

This is the worst part. The jamma edge has been completely eaten away!

A 56 pin card edge connector and a jamma finger board should make this a simple fix.

Also, does anyone know what is surface mounted on X1? It looked like a quartz crystal, but it was so far gone I couldn't tell. When I touched it, it crumbled and fell off.

So, here's what I need to know:

1. What is the best way to clean the corroded connections?

2. Will my jamma idea work?

3. What's mounted on X1?

Thanks!

warmeister

OldFoo · Post by **OldFoo** » Thu Mar 13, 2008 3:55 pm

Just some quick ideas to get you going.

1. Kinda depends on what has corroded the contacts away. Ive heard tell of people using white vinegar to remove battery residue as it's supposed to neutralise the alkali in the battery gunk.

A better solution might be to obtain a commercial cleaning product such as Electrolubes Safewash P (SWAP). Its designed specifically for cleaning PCB's and contains a corrosion inhibitor too.

2. The jamma idea sounds fine. You are lucky in that the PCB you have pictured pins out the entire fingerboard to the doubled row of solder pads. Manually attatch a fingerboard to the wrecked edge and pin out each connector , remembering to use decent gauge for the power supply.

3. That definately looks like a SMD xtal , a HC49U package by the looks. Seeing as its running one of the H8/300 family which has a max speed of 5 Mhz i would hazard a guess that's its running at a typical 4 Mhz.

I don't have one of the PCB's to double check but there is little risk in throwing a spare on and seeing if it works.

MrS

OldFoo · Post by **OldFoo** » Mon Mar 17, 2008 11:15 pm

Thanks for the reply. I really appreciate the info. I've cleaned up the board and connections pretty well. Can someone check and see what's stamped on the capcom i/o's crystal? I need the values, so I can order a replacement.

Thanks!

OldFoo · Post by **OldFoo** » Thu Mar 27, 2008 11:34 pm

Can someone that owns a capcom i/o take off the top of the cage and check the crystal for me? I really need the #'s off of it. I know some of you might be hesitant to open it up, but it's as simple as removing a few screws and lifting off the metal lid. This is the last thing I need for repair. I'd appreciate any help you guys can offer.

OldFoo · Post by **OldFoo** » Fri Mar 28, 2008 1:15 am

Sure thing. It reads: D147L9

OldFoo · Post by **OldFoo** » Fri Mar 28, 2008 8:52 pm

Josh, you rock! Thanks a million!

OldFoo · Post by **OldFoo** » Thu Apr 17, 2008 2:19 am

Josh, are you sure that is what's printed on the crystal? I've posted in a electronics forum and the general consensus is that it's printed on the crystal itself. I've scoured boards, search engines, etc and still haven't found a replacement for the number you gave me. This is driving my nuts! I finally fixed the jamma edge and I'm chompin' a the bit to get this thing fired up to test. I just can't seem to win! :smt013

OldFoo · Post by **OldFoo** » Thu Apr 17, 2008 3:38 am

I'm 100% positive. Here is the proof:

OldFoo · Post by **OldFoo** » Fri Apr 18, 2008 9:42 pm

Sure enough! Man, why can't xtals have a universal code like resistors? The electronics forum my thread is in has turned into back and forth argument between other posting members. No one on there seems to know the real value of it. It's kinda funny, but frustrating! :smt017