NEC PC Engine Restore, Composite Mod & Repair Part 1 

+GadgetUK164 another Mod Idea.......Want auto fire? install a 555 Timer.

Yeah that's a good idea, but the board also supports another 74 chip which provides the autofire - just needs 2 switches adding I think.

You mentioned adding in Schottky diodes and I'm curious what particular specifications would be appropriate for composite in this case? I know this is an old video, but it's all I could find on the matter of making sure the audio-video for an AV mod was done safely.

+StigsWorld Thanks =D They are really tiny - must be the most compact of all the old 8 and 16 bit systems. I really want the CD-ROM add on now lol.

+FourX2k3 Don't get too excited about part 2 lol - the RAM didn't fix it, but I did make some progress tonight and come to the conclusion that the GPU is probably dead =/ I think from what I've seen and heard, the CPU and audio is fine, as is the VRAM as I swapped that out as well just for good measure. Hehe, I wish the C64 had RGB too! =/

+Craig Somerfield Haha =D Look on eBay, but change shipping to "Worldwide". There are tonnes in Japan at around £50 to £60 with controller, cables and games etc.

+Yakuza Games Yeah, it looks like it's possible to mod these controllers to add auto fire. Just the switches might be hard to source. I guess another type of switch could be used... I might try that at some point.

+David Elvin I used the 'Gold' version which is selling in the UK atm. I must have put 4 or 5 scoops into a sink where the water was just a few centi metres higher than the case parts. Then every 3 or 4 hours I just put another scoop in there for good measure. In total I probably used half a container of Vanish Gold to clean 2 cases and the controller. I think with the Amiga you might find that TAED (Vanish) might not work - it tends to be discoloured plastic in the Amiga, so H2O2 is what you might need there.

+GadgetUK164 Many thanks for your reply! I noticed that the 'gold' version appears to come in 2 versions, one labelled 'our best for whites' so wasn't sure. I also have a PC Engine where the controller is not its best so might try that out. I'm UK based so getting hold of it shouldn't be a problem. Regarding the H2O2, if I used 35% rather than 12%, would that possibly destroy the plastics/bleach them too far?

You should check the fuse inside the PC Engine. If the wrong AC adapter has been used in the past the fuse may have blown. The fuse is soldered on, you can see how to replace a soldered on fuse in my Supergrafx repair video.

+Beatertech They can be a pain in the arse to repair! That one I've just shown - the RAM chip didn't fix it, but I've worked out the CPU and sound chip are likely OK, so its probably the GPU, infact I am sure its the GPU as tonight I swapped out the VRAM and its just the same. Only way you can easily fix one is if you get lucky and its a RAM fault or a power problem. The alternative is to make one system out of two faulty ones, and you've got to hope both systems don't have the same fault. That said, there are tonnes of working PC Engines on eBay. I've not done anything with the CD-ROM systems yet, hoping to get one later in the year I think. I am going to keep this console, and the spare. Hopefully I might get another faulty one at some point then I should be able to get my spare working too. You only need to use a step down if you want to use a Japanese PSU - They are just 9v ~1.5A, so you can use a Megadrive PSU (after you've checked polarity), or just buy a cheap UK PSU (which i have done yesterday).

+GadgetUK164 I have been checking out some of Lukemorse1 videos and he has some real interesting fixes on the TG16 and also a review on the shuttle version. I also noticed that he has some good common fixes with the TG Express .. a little scarce in the wild ( don't think i have ever seen on as faulty on eBay or even in real life for all that ( looks like fun though) :) - Good luck with that GPU, most likely cheaper to buy a working one from japan ?

Yeah, easier to just get a working one, but that's always the case, and I don't like easy ;) Got my eyes out for more faulty units now to see if I can find a working GPU. Just another quick update - if you get one, don't use a Megadrive PSU. You will see why in the next video - nothing bad happened but I made the choice to get another PSU rather than use the Megadrive one. There is a chance a Megadrive PSU could shorted the life of the PC Engine, and that might be what happened to the faulty one I have.

GadgetUK164 gamedoctorhk.com/index.php?main_page=product_info&products_id=2133 Is this the chip you are looking for? Can't seem to find replacements for these boards unless you get a carcass one from somewhere.

Thanks, you are a STAR!!! I've ordered a GPU and CPU (just to be on the safe side). Thanks to you this little PCEngine might get a new lease of life =D

Yeah, in this case it was the GPU (covered in the next parts).

@@GadgetUK164 Sorry, didn't saw them. :/

Honestly without investigating I am not sure! The best place to ask this is Voultar probably!

+atarimonkey I've not tried it on the famicom, but I guess it might work. It's worth a try! H2O2 will remove it if the vanish doesn't.

+GadgetUK164 I guess I'll give it a shot and find out!

If all the colours are changing I would suspect the Hu6260 or Hu6270. I think unlikely to be the VRAM.

thank you for your answer yes indeed the software wants this launch from time to time but it makes a jerky image, which goes from top to bottom with vertical or horizontal lines at times here

Yep, I didn't see that at the time - and its always useful to see techniques on how to work out polarity.

same for power adapters, they provide the polarity of the barrel and internal pin, I was able to use my Sega Genesis power adapter for the PC Engine console with no issues (outer barrel = negative, internal pin = positive)

Just check on eBay! They are the same size as the SNES and N64!

Thanks

+yamumishot2001 Only when i am messing around with my retro stuff. Most of the time I work from a desk, so the crawling around does me good lol. I know what you mean though, it's not good to do it for too long!

+gamerdude0 I would like one of the briefcase CD systems at some point! Regards damaging the connections between the card socket and PCB - that's quite common, it's not the easiest thing to region mod.

+GadgetUK164 Yes that's true about the connections easily being damaged, the ribbon connector just came away and took some traces with it, not really repairable with my skills. I was attempting an rgb mod, i'd removed the rf module which was a pain to remove, I won't mod the other one but I may mod the ifu unit and tap the rgb signals from there. Yours came up well with the vanish oxy clean.

+pas7680 Yes, the 2nd one did still have a slight tint - the vanish brought it up later though with a 2nd soaking. The problem with that bblonde is its pretty pricey =/

£1.60 a bottle??? hardly expensive

Hmmm, maybe I am looking in the wrong place! The last bottle I bought was 75ml and was almost £4! Where do you buy it - Boots?

+GadgetUK164 i get mine from wilko £1.65 for 75ml

Thanks =D

+trigg99 Thanks =D I've got some LM1881's and everything I need thanks - just waiting on some SMD resistors and a PCB.

+Leon Kiriliuk Yes, I've got on my list of things to do to at the very least feed outputs through capacitors. It's working OK without an audio amp at the moment, but I will be feeding the audio through a simple transistor amp when I come to do the the RGB mod soon.

Awesome! Tim Worthington (of NESRGB fame) makes a very good amp just for this console. The AV Driver has specific settings for NEC consoles and includes an audio amp. It's what I use in all TG16 RGB mods.

According to dbElectronics “Everything wrong” article about Adam Koralik, the composite video needs amplification too.

+custardo Yes! I love it so far =D Awesome system!!!

+GadgetUK164 It's a great system indeed. A pity it didn't get more recognition in the west.

Yeah, I wish I could have afforded one back in the day. I remember reading about them in C&VG magazine and really wanting one.

+The Pumpking King The standard version doesn't, but the CD versions seem to use SMD caps which do nearly always leak.