It had been some time since I’d seen a PCEngine CDROM attachment come into the shop, but these are a nightmare to work on. Lots of caps, several requiring specific heights and often VERY leaky.
This unit in particular was sent in because IMMEDIATELY on power up the drive spindle was spinning at maximum speed, preventing the drive from reading discs. Customer had purchased this unit as working on eBay but im skeptical it was tested anytime recently based on what I found inside!
Since a full service cleaning was part of the work order I started by fully tearing down the shell and all plastic bits, soaking them and giving a bath / letting dry overnight.
Then it was time for the tedious work, the recap! As soon as I started looking around the board it was evident there was severe leaking from many of the through hole capacitors, but surprisingly the SMD caps looked ok atleast from the outside.
Got all the old caps removed, 6 of them had legs snap right off due to being so rotten/corroded so then had to go back, reflow the holes and carefully extract the rotted legs with tweezers and an iron to fully clear them. I wicked all the old solder off the SMD cap pads and soaked/scrubbed the board thoroughly with 99% iso and wiped all the old fluid and grime away.
The recap is a bit slower on these as you have to pay close attention to a few clusters of caps and be sure to use low profile ones for proper clearance, luckily the Console5 kit accounts for all of this! With the new caps on, was time to move focus to the optical drive and reassembly
After getting the mainboard situation back in the now cleaned up lower shell, I fully tore down the optical drive, cleaned all the dust and hairs off all parts, deep cleaned the gears and rail and applied a fresh layer of grease throughout.
Then I reassemble and tested mechanical movement/slide to make sure everything felt right and grease was evenly distributed.
With that done, put the optical drive back in, finished reassembling the shell and gave it a quick power on test to see… unfortunately the exact same sympton pre-recap was still being exhibited, the super fast spindle movement and inability to read discs.
Took the system apart again back down to the mainboard and started checking over traces, vias, pads and any other areas of damage I might have missed. Found a few users referencing damage to traces between IC108 and 109 so removed both of those chips to check but they were ok.
After more time of probing with my multimeter and working my way back from the spindle motor connectors I found it, a tiny via under C136 had almost completely rotted out and was not showing connectivity through the board. I looked over the next hop points on both sides and ultimately decided the cleanest and best repair was a simple straight bodge wire from R132 on the underside to Pin 5 of IC108 which connected to the exact same track as the topside of the same rotted out via.
Put the system back together once more and voila… no immediate spin and it detected tray closure, spun up disc and read it like a champ!
Now knowing it was good to go, signed off on the sticker and close the shell up to let it run for a while and test out a few discs. Seemed to be reading them with no issue especially Wonder Boy III which I tested extensively.
Good call on this customer sending it in for a recap, any more time with that leaked fluid and who knows how many more traces and vias could have been lost. Either way, glad to say we could save another one of these and thats another order in the books and hopefully a happy customer!
Damn, this one looks like a headache. Nice work J.
Thank you! And yeah, these things SUCK to recap and the board was a mess but just glad to get it all fixed up and save another one!