Core Grafx II just died on me

scanline99 · 07/03/2013, 08:29 AM

Hello all! I should probably introduce myself first. My name is scanline, I'm 26 and from the UK and a big fan of shmups - hence why I finally got myself a PC-Engine this week

!! I should add, I'm also a fledgling modder.

I've been chuffed to bits with the little guy, and the seller on eBay I'd bought it from had also done an RGB mod which I thought was a bonus. However, when I got the unit I noticed it wasn't amped (and also wouldn't sync on my Sony PVM) so I figured I'd take things into my own hands and put together an amp, as per the recommended schematic which I've seen all around the web - http://www.gamesx.com/grafx/pce_rgb.jpg

Anyways, after a good couple of hour's careful soldering last night, I got the amp put together and it all seemed to work well on my LCD downstairs, but, still no sync on the PVM, shame. On the sync line of the amp, I had substituted the 300 ohm resistor connecting to the 5v line for a 330 ohm as this was the closest I had available. I figured maybe this was the problem and tried experimenting with some other resistors (75, 100, 400) to no avail.

I also tried removing the resistor altogether and that's when the system gave up giving me anything at all - no video, no sound, from any pins in the SCART lead on the multimeter even... it's a shame there's no power LED, but I'm guessing it's stone dead at this point. I obviously noticed the fuse while I was working on the system and so did the logical thing and checked it - seems perfectly intact and the multi meter registers a voltage through it when the power's plugged in (unless I'm checking it incorrectly). So, I guess my question is - can anyone suggest where I should go from here? Have I completely borked the system from simply removing that resistor connecting the transistor to the 5v line in the amp? I have at this point completely desoldered the amp and additional wiring from the EXT port and so we're back to a no-frills vanilla machine which should also eliminate any shorting concerns and still no dice - or so it would seem, I don't have a standard AV lead, but I'm still not getting a reading from the EXT pins, so that would lead me to assume it's still on the fritz.

I have to point out again that I am new to troubleshooting electronics so, please go easy on me guys, I'm still wet behind the ears

!

NecroPhile · 07/03/2013, 09:25 AM

Welcome to the forum! I'm too dumb to help ya, but I'm sure one of the knowledgeable peeps will pop in soon to give you some leads.

turboswimbz · 07/03/2013, 10:14 AM

Welcome Comrade. Sorry to hear of your troubles. However, The normal crew should be along to help you quite soon. most pop in sometime in the afternnon here in the US. They are some of the best around!

scanline99 · 07/03/2013, 12:00 PM

Thank you very kindly for the warm welcome, chaps

.

Hopefully if we can get this baby fired up again, I'd really look forward to getting down to some deep, thoughtful discussion about pixellated things that go boom with you all ;).

Arkhan Asylum · 07/03/2013, 12:18 PM

The problem is, you live in the UK.

That broke it. That also kinda sucks since the fixer-dudes of choice live in USA and the USPS hates us all and charges like 40$ to ship things to you.

Did you try hacking together some AV cables on the appropriate pins and sticking it on some sort of screen?

How long ago did you get this thing? File an ebay claim and say it arrived broken, lol. SCAM THE SYSTEMMMMMMMMMMMMMM.

Don't do that.

turbokon · 07/03/2013, 12:26 PM

Check the fuse for continuity. Your meter should have a continuity setting?

scanline99 · 07/03/2013, 01:29 PM

Arkhan, I would blame my Britishness for alot of things, but on this occasion, it was just plain and simple universal clumsiness on my part!! I shall however look into some AV cables for safety - if any of you chaps know where I could find some for under a fiver, let me know. Got the machine on Monday, won it last week - the (evil) thought flashed through my mind, but I was a bit of a bastard to the seller and really argued him down on the price anyways. No doubt he's glad to see the back of me.

Turbokon, it's extremely embarrassing that I didn't just trust the continuity setting on my meter to begin with when it didn't beep. Tried it on another fuse just to make sure I was doing it right (but come on, how hard is that) and it worked, so yes, it would seem as though I blew the fuse. Sorry for the long winded post in the first instance! Can I just solder in a regular 1A fuse (like you'd get for a wall plug) or does it have to be one of these (fast blow?) glass ones? Probably a really ridiculous question, but I just want to be totally sure.

Once I get a new one in, I'll report back, then maybe see about grilling you lot on this whole amp business and where I'm going wrong on the sync + PVM front!!

Edit: Having done a bit of research, and checked what the pcb asks for, I'm guessing the fuse has to be 125v - and here we're 240v. Looks like the only 125v I can pick up easily in this country are the Pico II fuses, much like what are used in the SEGA CD. Would one of these work the same?

Arkhan Asylum · 07/03/2013, 01:51 PM

aw yeah. blowing all the fuses.

at least you aren't blowing all the guys.

That's my job.

I'm not sure on the fuses. I would assume yes, but you should probably find out from thesteve or BlueBMW to be sure.

wildfruit · 07/03/2013, 03:48 PM

i say old chap grab yourself a PAL turbografx and come and live life in the slow lane. slow but steady and being a patron of the realm you must be used to 50hz eh what?

Arkhan Asylum · 07/03/2013, 04:41 PM

Quote from: wildfruit on 07/03/2013, 03:48 PMi say old chap grab yourself a PAL turbografx and come and live life on the short bus. slow but steady and being a patron of the realm you must be used to 50hz eh what?

It's like picking to watch Metallica live in 2012 instead of 1986

wildfruit · 07/03/2013, 05:10 PM

Quote from: guest on 07/03/2013, 04:41 PM
Quote from: wildfruit on 07/03/2013, 03:48 PMi say old chap grab yourself a PAL turbografx and come and live life on the short bus. slow but steady and being a patron of the realm you must be used to 50hz eh what?
It's like picking to watch Metallica live in 2012 instead of 1986

could we have some smooth jazz instead?

NecroPhile · 07/03/2013, 05:16 PM

Quote from: wildfruit on 07/03/2013, 05:10 PMcould we have some smooth jazz instead?

Vasteel?

Arkhan Asylum · 07/03/2013, 05:17 PM

If you play it on a PALBob, it'll be more like Assteel.

esteban · 07/04/2013, 11:17 PM

Quote from: guest on 07/03/2013, 05:16 PM
Quote from: wildfruit on 07/03/2013, 05:10 PMcould we have some smooth jazz instead?
Vasteel?

WHEN I AM LOCKED IN PIVOTAL BATTLES THAT DEFINE THE VERY SUCCESS (OR FAILURE) OF MY OVERALL WAR CAMPAIGN, I listen to smooooth jazzzz in Vasteelz.

True story.

scanline99 · 07/05/2013, 10:40 AM

Just to update you guys, I popped in a cheeky pico 1A fuse and all seems to be well - we have life in the system again!

Still no sync on my old school PVM or 1084s though (but syncs fine on my LCD). Will start a new thread to see if we can route this out.

blueraven · 07/05/2013, 11:20 PM

This thread makes me realize how much I've missed this forum.

The fuse might do that. It MIGHT. I've only seen one blown fuse in the entirety of my repair days. it was a glass tube-type and was blackened on the inside instead of just broken.

Makes me think he plugged it into a 220V outlet, which would be insane.

I'm also wondering about the Amp. thesteve is the guy to talk to on that one.

BlueBMW · 07/06/2013, 12:15 AM

Quote from: guest on 07/03/2013, 01:51 PMaw yeah. blowing all the fuses.

at least you aren't blowing all the guys.

That's my job.

I'm not sure on the fuses. I would assume yes, but you should probably find out from thesteve or BlueBMW to be sure.

I about died laughing when I read this post... damn ark you crazy son!!

scanline99 · 07/06/2013, 03:32 PM

Clearly you're all nutters, so I've found myself in the right place

.

Blueraven, I think the fuse blew because I shorted out my amp on the controller port at the front. I've now got that coated in electrical tape and stuck a strip of foam to the underside of my amp. I wrote in another topic about the sync issue on the PVM and 1084 and about an hour later, managed to fix it myself by ensuring that pins 8 and 16 on the SCART end were both getting 5v, thus powering my LM1881 and allowing the signal to pass through. So in summary, we're firing on all 4 cylinders now!!

I'll add that despite what some may say about me, it's really not insane to plug the system into a 240v outlet here in the UK (why there's a 20v discrepancy between here and the rest of Europe, I don't know). It's perfectly safe as the transformer I'm using is rated for the correct output for the PCE, that's the beauty of DC! I've been using the same one on my Jap Neo Geo AES system for years without trouble, and that's a machine I really wouldn't want to risk blowing up!

Again, thanks for all your help and good spirits guys!

Bardoly · 07/08/2013, 09:13 PM

Welcome to Pcenginefx!

There are definitely a lot of great shoot-'em-ups to discuss here. I'll start. Have you yet lost your sanity trying to beat Zero Wing?

scanline99 · 07/09/2013, 12:29 PM

Somewhat embarrassingly I didn't even know Zero Wing was on PCE. Played it a bit on the Mega Drive of course and was never that blown away - is it any better on PCE, Bardoly?

Been kicking back with some Final Soldier and Salamander at the moment. Had some friends over the other night and ended up blitzing our way into the second loop of Salamander, then things got ugly! I also have a copy of Super Star Soldier on the way which I'm very much looking forward to. Biding my time looking for a decent price on Gunhed as I really enjoyed it on Wii Virtual Console (which was basically my "in" to the whole TG-16/PCE scene if you like).

Bardoly · 07/09/2013, 06:49 PM

Well, I've never owned a Mega Drive/Genesis, and my play time is virtually nil, so I have no way to compare the different console conversions. I just know that the PCE version is excruciatingly difficult!

I played Life Force (Salamander) on the NES a lot in my younger years, but I haven't been able to play much PCE Salamander yet. I REALLY enjoy 2-player simultaneous shoot-'em-ups, though, so I'm planning on playing it with a friend before too long. Do you get to play 2-player simultaneous shoot-'em-ups much?

scanline99 · 07/10/2013, 08:15 AM

I've noticed it's a CD game anyway, so it'd be some time before I'd even consider it as a Super CD-Rom² unit seems to command the princely sum of roughly... one mortgage

.

PCE Salamander gets my recommendation - I know it has arcade perfect ports on the Saturn/PSX, but it's damn good for the time and the music is "punchier" than the arcade in my opinion. Considering alot of the Gradius series is single player only, this was a refreshing change of pace. When it comes to me playing games with friends, they usually prefer to play modern/casual stuff, so typically classic co-op shmups are off the menu sadly, added to which, if someone agrees to play, I find it's better if you can start from the same level of skill (which is what happened with Salamander, we were both new to that game). If there's a large discrepancy between the two players, the balance of fun seems to be wildly skewed because someone is dying alot and/or some is hoovering up all the points and power-ups.