Where are all the parts?

[Th3_uN1Qu3]

Re: Where are all the parts?

How did i miss this one? Hmm... judging by the PCB style and color it looks like a Linkworld, but they use their own custom crap ICs not 494s.

Anyway, good job. Those "saturn" (CS) primary caps are quite decent, i keep those and YCs (their logo also looks somewhat like saturn). I've had good luck with YC secondary caps too (the ones with gold text), used some pulled out from old PSUs to fix a number of stuffs including my STB which had popped a Samxon GF. I've seen failed CS secondaries, but only when they were put next to those pesky minimum load resistors. CS's naming scheme is dubiously similar to Fukyoo though.

For the 12v rail i woulda kept the feedback point before the pi filter coil, putting it afterwards is asking for trouble. But since that system draws 90% of its power from the 5v rail the supply won't really care about that. Good job otherwise.

[Rulycat]

Re: Where are all the parts?

Yes, it's a shame really, because I think the overall quality of computers has improved over the years (nVidia chips and LCD monitors aside) or perhaps more users are now aware of crappy caps and bad PSUs. Regardless, I see many good computers today ruined by dumb, bloated software. Is it me, or is it that no one cares about writing efficient, resource-friendly software anymore?

I think considerations for cooling has improved - all the machines I see now are decently cooled. OEMs seem more conscious about using jap caps too. And as for the bloated software, well they need it to sell you the 4GB RAM package right?

[momaka]

Re: Where are all the parts?

Unfortunately, it continues with vista, spyware, DRM, 'desktop advertising,' etc.

Yes, it's a shame really, because I think the overall quality of computers has improved over the years (nVidia chips and LCD monitors aside) or perhaps more users are now aware of crappy caps and bad PSUs. Regardless, I see many good computers today ruined by dumb, bloated software. Is it me, or is it that no one cares about writing efficient, resource-friendly software anymore?

[kaboom]

Re: Where are all the parts?

Thanks, momaka.

Schottkys? You wish! Those two for 12 are fast recovery, so in addition to limited current capacity, you also had excessive junction drop. This would compound the heat problem.

This was from a time when there were computer 'shops' scattered about in the area. None would stay around long, mostly because of the examples here.

I replaced the CPU heatsink with one from a junked system. The one it had belonged on a 486, and there was no compound at all. At one time, 'clone builders' would assemble K6-400 and similar Super 7 systems w/o grease, too! I've even seen a K6 system with a sticker left on- between the top of the CPU and heatsink! In addition, they used Deer power supplies labeled as 'CROWN.' Some boxes even had nice Epox mobos- with those wendell caps. They are not around anymore...

What ignorant asses- ask about the grease and you'd get the whole "it works fine" bullshit. No wonder the Dell ovens are ubiquitous around here now...

This crap is what made people ASSume that the little nagging errors with their computers was 'normal.' Sure it was, if you didn't know any better. It was a shame, since odds were that your neighbor or friend's 'puter came from the clone shop, leaving you without an honest comparison.

Unfortunately, it continues with vista, spyware, DRM, 'desktop advertising,' etc.

[momaka]

Re: Where are all the parts?

230 Watts?!?! Yeah right, more like 23 Watts with those original schottky diodes and heatsinks. With PSUs like this, poor Tony probably went out of business many years ago .
You did an amazing job upgrading this thing, though.

[kaboom]

Semi-gutless wonders can sometimes be helped, but only sometimes.

This had saturn primary caps and fuhkyoos everywhere else. Automatic power supply roaster (~9V for fan) didn't help. The system was getting random errors and CDROM no longer read. Lotsa ripple getting into the servos and signal amps, ya know. Also looked like bad RAM, more on that later.

The line rectifier was rated for 2A, despite having the appearance of a KBL404 or a variant. NTC thermistor also only good for 2A, ceramic caps instead of UR Y caps, a missing Y cap from the negative side of the rectifier to EGC/GND (EMI), tiny wire on the common mode choke, #20AL for output leads (ampacity of #22CU), stupid heatsinks, too-small rectifier for +5 and diodes-on-a-bracket for +12. Anything else is blatantly obvious

+12 had no PI filter, so I added one. I also did not forget to move the feedback point to after the coil! Now, not having enough room to terminate all the +12V wires, I came out with a single #14 and spliced all the 12V wires to that. All the wires to the M/B connectors were replaced with #18CU, except the PG signal. The two main output rectifiers were replaced with SBL3040's. Even with the higher operating temps caused by their small heatsink, they are loafing along. The primary switchers never got excessively hot, thanks to the two new, good caps in their base bias ckt. The fan was hotwired. Here are the voltages after the improvements:

+5.15V/15.3A
+12.5V/6A
-5.3V/0.25A
-12.0/0.65A

In addition, two hard drives were connected along with the loads. Lookin' good!


Onward to the 'puter. The board was recapped, aw 'Jee.' Pure junk, those things. I added a few that were missing from 'cost cutting.' We're on the way, now... The front bezel's only holes were 5/32", starving the fan in the PS for makeup air. I opened them up, as they should've been.

Now since the RAM in these AT dinosaurs is powered straight from the +5V supply, all the trash from before the PS was fixed went right to the memory. Not so anymore. With 128MB from both SIMMs and a DIMM, memtest held for hours. The CDROM works again, and I just serviced it. Vacuumed out dust, fresh lithium grease, 2-26 on connectors/switches, cleaned lens, etc. The system was almost perfect at this point.

A 10GB HDD on the old BIOS required the EZDrive overlay. As usual, "32-Bit Transfer" was disabled. I just put my EZDrive floppy in and fixed that. Defrags at least twice as fast now. Gotta love lazy automatic installs, that 32 bit transfer was never enabled after all this time.

Now nearing the finish... I REM'd out some real-mode drivers in config.sys and autoexec.bat, as they are simply not needed in win98. Made sure all was well with the AWE64 and finished up.

Not wiping this one out as there's still data on it.

Hope you all enjoyed,
-Paul