PC Engine CD-Rom2 - The Trilogy is Complete
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29-03-2023 4:47pm#1
Following on from my previous threads on this system, the PC Engine Repair/Recap and the Interface Unit RGB Mod, I had noticed one more repair was necessary. The CD-Rom2 unit wasn't powering on for an extended time, and once it did, it worked fine (ish, more on that later.) A classic sign of failing capacitors really, and hardly unsurprising given the age of the system (1988!). I noticed that Mark over at Digital Delights listed a cap kit for the unit, and being a repeat customer of Mark's, I went ahead and bought the kit. Today was the day to warm up the soldering iron, and finally finish this project up!
^^ I'd bought this console from Japan, sold as Junk. It didn't power on (now we know why), and the laser unit assembly was freely sliding along the rails. A tweak to the rail clamp resolved the sliding cd assembly, though I would like to investigate a more permanent repair. Anyway, this is the unit, it's in quite nice condition aside from the small touch of yellowing.
^^ x4 screws on the rear is all that's needed to open it up.
^^ Another screw then secures the mainboard to the case/shell.
^^ It's vitally important that the two ribbons aren't pulled apart with the case, they will break, and good luck fixing those.
^^ Tabs released, and only now is it safe to remove the ribbon connects and fully open up the system.
^^ Annoyingly it's still held together by internal wiring. I'm not going to the trouble of desoldering all of the connectors (there's x2 of them that don't open and are soldered in), but I will detach x3 small plug connectors to ease any stress on the system/wires while it's open like this and being shuffled around.
^^ The pink/blue connector, purple/black, and orange/yellow are all easily removable plug connectors. W402 and another one elsewhere appear soldered to the mainboard, so I've left those in place.
^^ Cap kit from Digital Delights. The cap-map makes things much easier, just ticking off as you go.
^^ A funky factory fit cap. I'm not entirely sure why they routed it like this, it appears to fit within the marking on the silkscreen and doesn't interfere with the power connector. Maybe it was just precautionary?
^^ Begun, the decapping has...
^^ If I didn't know better, I'd say this cap, being finally free of its plastic prison, is trying to run away...
^^ Board fully de-capped. Kinda, I spotted C102 later on (there's always one!) There's no sign of leakage or anything from these old caps thankfully, I'd say some of the power circuit ones have just dried up with heat/age over the decades.
^^ An on with the installing of the new caps. The sizings are a little different compared to the original ones, so I'm not going to snip the legs off of them all until the very end, incase I need to adjust their positioning if they're a little bigger etc (spoiler - I did have to do this.)
^^ Standard stuff.
^^ There's two Bi-Polar caps contained within the kit, to replace like for like on the board.
^^ Job done. You'll notice the positioning of the two bi-pole capacitors. I noticed later on doing a test fit, that the new ones are too tall so they need to be folded over in order to fit.
^^ A test fit did indeed indicate problems with two or three caps from the new kit. They're slightly bigger than the originals (par the course these days with caps, sometimes they're much smaller than the originals, sometimes they're bigger.) Leaving the legs on the caps allowed me to bring the caps higher on the pcb, and bend them to reduce height.
^^ Once the test fit was fine, I could then snip off all of the legs/ends. I also cleaned the board down with IPA to remove any flux left behind. I do use no-clean flux, but I like to know the board is clean after working on it.
^^ A final check of the cap map to ensure they're all done
^^ Ok, time to test. All my fully owned and legal games for the system are in storage, so I had this disc back from when I originally tested the unit.
^^ Ok, it powers up, cd-rom2 unit powers up. Time to test.
AAAAANNNNNNDDDDD......nothing. No spin of the drive. Balls.
Remember my lecture about the ribbon cables above? Well, yeah, you kinda need to plug them back in when you're finished! Another senior moment - I'm having a few of those lately. Maybe I should stop listening to podcasts when I'm working!
^^ Ribbon cables plugged IN this time!
^^ Ok, time to test again...
^^ Boom. It spins up and reads the disc as it should. Nice, it's always a relief to see.
I did however mention at the start of the thread, it worked fine-ish. The ish part relates to the sound of the cd spinning. It was very noisy, not normal noise, a rubbing/scraping noise. To finish this off I had to spend time investigating this, and boy did this take more than a minute. I disassembled the whole unit again to ensure all the wiring was routed correctly and wasn't putting any upward pressure on the cd assembly, which it wasn't. I dissembled the cd assembly itself to ensure everything was fit/screwed together correctly, which it was. I tried adjusting the spindle height thinking maybe the previous owner had given it a hard time, and the cd-rom was sitting too low (it did appear to be sitting low), but that didn't work either. I tried removing the spindle, and ensuring it was lubricated properly, no change....still a grinding/scraping noise when the cd was spinning. Then I noticed what it was....the damn cd-lens assembly cover, the one you see when you open the cd-tray/door, that wasn't as straight as it should be. It was sitting higher towards the rear than it was at the front, somebody had obviously pried it up/bent it out of shape in the past.
Fixing such thin and intricately folded metal wasn't going to happen, certainly not where precision was required. I tried gentle twists and bends in it, and the noise was changing (so I knew this was the culprit), but never went away. It felt like I'd spent longer on this cover than the actual cap kit at this point, so I needed to make a decision. I decided then it had to be removed unfortunately. It does leave a noticeable gap around the cd assembly when you open the door, but when I tested it with the cover removed and it was virtually silent, the compromise was a no brainer.
^^ It's this white metallic cover that's bent out of shape. I'll keep an eye for another junk unit maybe if I'm really at a loose end to replace it with, but it's functionally perfect now, and as said, silent. Given that, and the fact this unit is closed 99.9% of the time, I'm not concerned about dust getting in. I'll keep the cover and its two screws safely stored away incase I decide to go back to it in the future also.
But yeah, that's it - job done, the unit powered up first time with the new caps, it reads and plays discs silently too now also, so I can safely put this back on display for another 30 years!
Post edited by Inviere on5
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