This is a poor #PCEngine DUO that was sent to me for the possibility of undoing the death knell that had already been sounded. It had been previously looked at by other people who solder.
No short detected, powers up ok but no video output via composite video.
Let's have a look.
No short detected, powers up ok but no video output via composite video.
Let's have a look.
Jesus Christ.
The insanity didn't stop there either, it continued on and on.
Someone had also attempted to RGB mod this DUO at some point and managed to snap all the vital legs needed off of the HuC6260. Sigh.
Someone had also attempted to RGB mod this DUO at some point and managed to snap all the vital legs needed off of the HuC6260. Sigh.
Lots of damaged vias too. Noticed a pin likely to have a hand in generation of composite video was floating (pin 40). After a quick leg repair, a huge lump of solder pump swarf fell out from under an IC.
Someone seriously hurt this poor DUO.
Someone seriously hurt this poor DUO.
Still no video out despite the "miracle" that is the board not shorting out and actually booting.
Had another look at the back and noticed someone had drilled the board and fitted their own DIN (with a bloody pull-up bar). With that in mind, I wondered how good were the joins?
Had another look at the back and noticed someone had drilled the board and fitted their own DIN (with a bloody pull-up bar). With that in mind, I wondered how good were the joins?
And there is the composite video. This is going to be a anything but a quick repair. Still no sound but given the state of that area, sound is a luxury.
Apparently the optical drive was dead but given nothing else described in the notes married up, a quick clean revealed life?
Apparently the optical drive was dead but given nothing else described in the notes married up, a quick clean revealed life?
Closer inspection of prior work presented a few issues.
Decided it would be easier to discount everything that had been done for AV output.
Decided it would be easier to discount everything that had been done for AV output.
Then my eye cast over the rest of the board and the state of what hadn't yet been worked on.
Then decided to do something about the areas that apparently had been, including "the new forest". The pads from the SMD caps are still under the trees here + electrolyte corrosion.
Then decided to do something about the areas that apparently had been, including "the new forest". The pads from the SMD caps are still under the trees here + electrolyte corrosion.
Trees uprooted revealing very diseased pads in need of a dire clean. New Nichicon SMD capacitors fitted. I like to try to match the original SMD form factor these days unless there are no pads or material left to work with (fine after a clean in this case).
Whilst awaiting components & parts, I decided to have a crack at that damaged HuC6260. If I wasn't going to get sound, I wanted to at least see if this could be made to live again.
Removing material was fairly straight forward but I didn't account for the die legs being like hair
Removing material was fairly straight forward but I didn't account for the die legs being like hair
Soldering these using kynar and avoiding bridged joins was not my idea of fun. Persistence (or stubbornness) paid off and I had new "legs" to route to an amp circuit. Used resin to hold these in place as there is no package material left to isolate / prevent shorts.
Back to the AV port. New 8-pin screened DIN from CPC turned up, Quality difference is immediately noticeable and the correct mounting footprint.
Modified rear legs and used resin on the filed back legs to stop any possibility of a short. Cut audio traces repaired.
Modified rear legs and used resin on the filed back legs to stop any possibility of a short. Cut audio traces repaired.
Started on the audio circuit working from the outside in. Wicked off all the crap and it become very apparently how bad the capacitor electrolyte damage was and that it had seeped into just about everything; including this poor stereo volume control wheel. Attempted to clean it.
With the output area continuity now resolved and the board area clean, it was on to OPAMP's next.
All three showing signs of damage and outputting a combination of full input / gain voltage (close to it). Lots of electrolyte under each IC.
All three showing signs of damage and outputting a combination of full input / gain voltage (close to it). Lots of electrolyte under each IC.
Headphone area finished off. Moving back along the board cleaning and checking continuity. Replaced most of the existing repair solder but the pad damage was catastrophic. Justified use of trees and vias in this case sadly.
The OPAMP that was replaced originally had also shorted.
The OPAMP that was replaced originally had also shorted.
The traces leading to the OPAMP that had been replaced by my predecessors had been eaten quite a bit so when I went to remove it, some needed help establishing continuity with the new incumbent replacement.
Also, the controller port had a similar bath treatment.
Also, the controller port had a similar bath treatment.
Fitted some vero board and wired up the RGB amp. If anything, I'm getting RGB out of this board. Success!
And like a certain moment in a certain optical disc based RPG, it suddenly died - power off.
Laser had failed and was soaking up as much power as could be delivered. Noticed someone had indeed dicked with the gain.
Ordered a replacement and went back to the audio circuit etc
Laser had failed and was soaking up as much power as could be delivered. Noticed someone had indeed dicked with the gain.
Ordered a replacement and went back to the audio circuit etc
Pads cleaned and new Panasonic SMD capacitors all-round.
New laser pick-up arrived and during the installation I noticed *yet another* human introduced fault - a wire was hanging on with a single strand.
Into Yak shaving territory with this one.
Into Yak shaving territory with this one.
After further Yak shaving, I can finally install the new pick-up. Turns out this one came from the same company who I'd previously purchased ones from with no success. Current mood: deeply concerned.
New pick-up installed. Onto installation of the new M51131L which had also failed due to being shorted out from electrolyte damage. With any luck this will bring both audio channels back to working order.
Quick test and right audio is perfect now. However left sounds like it's stuck at full + volume wheel gain. I checked every bloody resistor in the circuit then found the very last one reading 0hms - you utter bastard. Eaten by electrolyte, no edge flashing. Replaced.
Cleanup time
Cleanup time
This is now a happy little board. It's had a rough existence but it will soon be back to giving enjoyment and entertainment to any whom come to play games on it.
With stereo sound.
With stereo sound.
Internal repairs complete. Audio is back (via both headphone jack and AV port) and sounds excellent:
It can also do RGB. It even reads CD-ROM's again!
Going to give the case a bit of a clean up and then it'll be ready to be reunited with it's owner. 👍
It can also do RGB. It even reads CD-ROM's again!
Going to give the case a bit of a clean up and then it'll be ready to be reunited with it's owner. 👍
Wasn't happy with the replacement controller port (wiggles a fair bit) and discovered I had another part type perfect for use with the PC Engine. Found some capacitors I hadn't replaced yet as well.
Turns out the Japanese consoles love a bit of DIO.
Turns out the Japanese consoles love a bit of DIO.
Exterior cleaned up & reassembled.
Encountered an almost heart-stopping moment when the laser decided to stop reading discs. Turned out this was just due to laser harness encountering some friction. Rerouted and now no repeated issues. Such unnecessary stress 😟
Encountered an almost heart-stopping moment when the laser decided to stop reading discs. Turned out this was just due to laser harness encountering some friction. Rerouted and now no repeated issues. Such unnecessary stress 😟
