SE/30 Reloaded Board - First Test
- Thread starter Steve Rieck
- Start date
Would this work? I'm getting no PLCC results for "65C22N" on mouser or digikey. Thanks for your help.
Wait — With „harvested“, @Kai Robinson probably means bought used/second hand from unknown origin. You probably will have no issues at all with VIAs reclaimed from any Macintosh board as long as the ICs themselves are not faulty.
Yes, I'm referring to chips I removed from a stock battery bombed SE/30 board. They had little corrosion being so far from the battery. The pins are very cleaned up, tinned, have all continuity and no bridges...and they look pretty fwiw...If true, then both chips exhibiting the exact same fault seems unlikely (but not impossible) to me.
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Well, i mean both harvested from an original board AND from sources like UTSource - i'd still not rule out either VIA even if the chips were clean, they could still be faulty/totally dead. Worth testing with fresh, new ones from mouser/digikey. They're not expensive.
I will get replacement VIAs next. I'm hoping these are correct?
The thing I'm especially skeptical of is the GLU chip considering the condition it was in when I got it off the bombed board. Would any of these symptoms be consistent with a partially damaged GLU chip?
The thing I'm especially skeptical of is the GLU chip considering the condition it was in when I got it off the bombed board. Would any of these symptoms be consistent with a partially damaged GLU chip?
Nope - those are the 65C22S's - not the 65C22N's which have an open drain output, designed to replace old NMOS parts like the SE/30 uses.
I'm trying to find a W65C22N6TPLG-14 but it looks like mouser are the only stockists of WDC parts and the 'N' variant is only available in DIP not PLCC at the moment.
wdc65xx.com
I'm trying to find a W65C22N6TPLG-14 but it looks like mouser are the only stockists of WDC parts and the 'N' variant is only available in DIP not PLCC at the moment.
Where to Buy | The Western Design Center, Inc.
wdc65xx.com
How about these?Nope - those are the 65C22S's - not the 65C22N's which have an open drain output, designed to replace old NMOS parts like the SE/30 uses.
I'm trying to find a W65C22N6TPLG-14 but it looks like mouser are the only stockists of WDC parts and the 'N' variant is only available in DIP not PLCC at the moment.
Where to Buy | The Western Design Center, Inc.
W65C22N6TPLG-14 | Western Design Center | I/O Controller Interface IC | PCB Electronics Supply Chain
W65C22N6TPLG-14 offered from PCB Electronics Supply Chain shipps same day. W65C22N6TPLG-14, I/O Controller Interface IC, I/O Controller Interface IC Versatile Interface Adapter
www.pcbelectronics.com
Yeah, the problem I had (that Techknight found) was that one of my new old stock VIA chips from UTsource was defective. I had to buy some other NOS chips where they were the only source so it made sense to pick up the others from them as well. I don't think I'm at the point of calling them awful, but my opinion of UTsource has soured a bit.
if I can ask a dumb question, on the schematic redraw, what are pins connecting to "X" referring to? I assume just solder them to the pad but then there are occassional unused pins that are just not on the schematic at all so what's the difference?
More info...
With all chips in, the Rominator II and filling bank A with known good 4x16mb simms (64mb - I was previously using 4x1mb simms), the sound is no longer distorted but is a low volume HAPPY mac chime (the unique "happy" arpeggio from the Rominator II) ...still horizontal bars though (TI simasimac). Would the Rominator be making it's happy chime if it actually was sad, I don't know? Sometimes, I do that myself.
it appears the stock ROM is incompatible with the 16mb simms I'm using (OWC). That RAM only gets happy when I put the rominator II in. Tested many times.
Apologies in advance to anyone following me down this rabbit hole. Video below.
www.dropbox.com
With all chips in, the Rominator II and filling bank A with known good 4x16mb simms (64mb - I was previously using 4x1mb simms), the sound is no longer distorted but is a low volume HAPPY mac chime (the unique "happy" arpeggio from the Rominator II) ...still horizontal bars though (TI simasimac). Would the Rominator be making it's happy chime if it actually was sad, I don't know? Sometimes, I do that myself.
it appears the stock ROM is incompatible with the 16mb simms I'm using (OWC). That RAM only gets happy when I put the rominator II in. Tested many times.
Apologies in advance to anyone following me down this rabbit hole. Video below.
Dropbox
www.dropbox.com
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Same thing happened to me.
Check out your soldering on UH7.
This tiny PLCC is a pain in the neck to solder because there are so many things around it that the pads do not protrude from under the chip, which makes it incredibly difficult to solder and check its continuity.
I checked it 3 times until I discovered that 3 pins were not making contact. I resoldered said pins and Bingo. The board worked.
Goos luck
Check out your soldering on UH7.
This tiny PLCC is a pain in the neck to solder because there are so many things around it that the pads do not protrude from under the chip, which makes it incredibly difficult to solder and check its continuity.
I checked it 3 times until I discovered that 3 pins were not making contact. I resoldered said pins and Bingo. The board worked.
Goos luck
Do you mean the exact same symptoms? Thanks, will check UH7 again. Yeah just wish those pads extended a bit farther. I've been using unreasonable amounts of flux and checked everything a couple times but you're right, UH7 seems to often be the culprit as I think it sends the clock signal to the video PALs and has something to do with the RAM read/write.
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Update: I went back over UH7 under the microscope several times. Re-soldered. All pins have continuity to their respective other locations on the board. No bridges. Same results.
At this point, I'm not gonna get much done without an oscilloscope and I want to save up to get a decent one so I'm gonna put this project on the shelf for a couple weeks. Not giving up though! Never...even if I have to rebuild this thing one chip at a time.
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I just realized something maybe...
Since I get a happy chime with the Rominator II and a sad chime with the stock ROM...Why would that be?
...."Memory test is disabled for faster booting" according to the Rominator website.
This seems to me to point to the Memory test itself (which the Rominator doesn't bother with) indicating the cause of my issue or at least one of them.
Since I get a happy chime with the Rominator II and a sad chime with the stock ROM...Why would that be?
...."Memory test is disabled for faster booting" according to the Rominator website.
This seems to me to point to the Memory test itself (which the Rominator doesn't bother with) indicating the cause of my issue or at least one of them.
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Check the F258 chips and the resistor packs. This was mentioned earlier. Resistor packs being the 3 by the ram sockets. Also the F240 at the front off simm 1 and the resistor packs next to it. I would bet the F258 linked to the low part of ram is your issue.
Already checked out continuity on those which is ok. I will definitely go back over them. Need an oscilloscope to see or maybe just replace them. This is one of those 50 boards Colin ordered so I've just assumed (I know..) those factory installed chips were less likely to be the issue. But if that's where things are pointing, I get it. Thanks!
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