white PC engine - trying to figure out if it is still working

[darshie]

Hi all

Finally after many years, was able to get back into my passion of collecting old console, and got few of them.

After a successful purchase of a GT and a CGII with the CD unit (which I am still waiting to receive from Japan), I've got also a white non tested PCE for few bucks.

I've got an AC adapter at the local electronic store, so I can power the console, but I am not sure exactly how do you check if the console is working or not, since has no led and I have no RF unit cable to hook it up to a TV.

I've heard of mods that you can do to get the video signal and pass it on a RCA cable (so you end up with the standard composite out), but the best that I was able to find was a diagram with the rear expansion connector of the console...I am a total newbie with electronic stuff, so would be awesome if there is anywhere a post with detailed instructions about how to make this mod.

Also I was wondering if there is anything that I should check on the console itself...I've take it apart and checked with my multimeter that the power is in fact reaching the console, and so far I can read 9V on the connector pins; the fuse seems to be intact (but when I tried to switch the console on and test the fuse contacts, there was no current going trough).

Is there something that is known to be faulty on the white models, that I should replace or fix...before even starting to do the video mod?

I would not mind to send it to someone to have it fixed (if it would not cost a fortune of course), but it is also fun to do some DYI

You guys here have a huge amount of expertise, so I hope that someone can give me some advices.

Thanks!

[soop]

It probably is working, they're pretty indestructable.  There are various mods you can use - the simplest one is simply soldering right onto the expansion pins (though it's not the nicest mod).

If you're a real soldering newbie and don't want to take any risks, then you can use an AV Booster, but they cost as much as a Core Grafx in my experience.

Your other option is to mail it to one of the guys here for modding - TheSteve and BlueBMW spring to mind.

However, if you have basic soldering skills, you should be able to mod it simply yourself in one way or another.

[darshie]

Thanks soop for the reply.

So basically the first step is to make a quick soldering on the expansion connector and see if I get any video out?

Which pin should I solder on the center connector and which pin for the outer connector, on the RCA jack? if the pin are not too small I can make decent blob without doing any short circuit...paid that thing 20 bucks so can't really complain if in fact is just broken.

Thanks!

[soop]

I'd wait till you hear a confirm from someone who know's what they're doing, but to get video, you should be able to wire the RCA to 22A, and I guess ground it (the outside) to 21A and give it a test.

http://www.made-by-bacteria.com/viewtopic.php?f=144&t=821

[Frank_fjs]

See my post here for some details on how to make a quick and crude AV cable for testing purposes: http://www.pcenginefx.com/forums/index.php?topic=12775.msg252214#msg252214

[Neurosis138]

If you have a nes/snes or genesis 1 rf unit, you can use that to test the system.  It should display on channel 95 or 96.  Just a thought before you go the modding route.

[soop]

If you have a nes/snes or genesis 1 rf unit, you can use that to test the system.  It should display on channel 95 or 96.  Just a thought before you go the modding route.

Oh snap, I didn't even think of that.  Sorry, I'm in the UK, and we can't use NTSC over here.  This is a much better idea.

[SignOfZeta]

Also I was wondering if there is anything that I should check on the console itself...I've take it apart and checked with my multimeter that the power is in fact reaching the console, and so far I can read 9V on the connector pins; the fuse seems to be intact (but when I tried to switch the console on and test the fuse contacts, there was no current going trough).

Well, assuming you are using the meter correctly, then this would mean the fuse is blown. This isn't all that uncommon, but I'm still wondering if you are doing it right.

You can use Frank_fjs's suggestion or you can just wait until your CDROM2 shows up and just plug it in there to test it.

[darshie]

Thanks guys for your reply!

The fuse seems intact, not sure why I cannot read any current there at all; I also have a very cheap multimeter....I would not be surprised if that thing won't work as expected (or I am not setting it correctly...altho I am not sure then why I can get a correct reading at the connector).

Today I was able to get a loaner from a friend: a CD interface!

So I have plugged in my other core graft (which I know is in working conditions), using the cd interface AV cables and AC adapter, and the CG works just fine.

Then I swapped my white PCE and it boots, but there is no video. I can hear the game music going, and it respond to the pad buttons (i hear the sound effects, meaning that in fact the console works), but no video.

At this point I know that the little white fella is alive, so now I assume that I shall start to look in the video area to see why I get nothing. There is no signal at all from the AV cable, only the audio works.

Anything that I should check? Is this even possible to be fixed or should I just sell it for parts on ebay?

Thanks!!!!!

[soop]

You might not get much for it - I say you make it a little project.

First get your multimeter and see if there's voltage coming through any of the video pins in the external bus.  Try composite and RGB.

[SignOfZeta]

The fuse seems intact, not sure why I cannot read any current there at all; I also have a very cheap multimeter....I would not be surprised if that thing won't work as expected (or I am not setting it correctly...altho I am not sure then why I can get a correct reading at the connector).

Do you mean voltage? The only way to check current with a normal meter is to make a break in the circuit somewhere (for example, remove the fuse) and with the meter in Ammeter mode install hook it up across the opening in the circuit. With the circuit intact you can only check voltage.

Voltmeters measure voltage difference. If the fuse is in tact and you are measuring across it in Voltmeter mode you will get nothing on a working system. With the power on there will be zero difference in voltage because fuses have no resistance. With the system off you'll have nothing because...its off. You will only see voltage across a fuse if the fuse is blown.

The best way to check a soldered-in fuse is to hook the ground wire of the meter to a chassis ground, power the system up, and measure voltage on one side of the fuse and then the other. They should read the same.

Not that this matters, evidently, since you seem to have a good fuse.

Then I swapped my white PCE and it boots, but there is no video. I can hear the game music going, and it respond to the pad buttons (i hear the sound effects, meaning that in fact the console works), but no video.

At this point I know that the little white fella is alive, so now I assume that I shall start to look in the video area to see why I get nothing. There is no signal at all from the AV cable, only the audio works.

Anything that I should check? Is this even possible to be fixed or should I just sell it for parts on ebay?

That's not common. My first question is, is there any evidence of mods being done to this system? If its never been hacked then its probably a blown cap or resistor. Maybe it has one of those bullshit HK PAL mods and your TV just isn't syncing with it?

[darshie]

You might not get much for it - I say you make it a little project.

First get your multimeter and see if there's voltage coming through any of the video pins in the external bus.  Try composite and RGB.

Sounds good; will go for a hunt on the board to see what is going on. I know that they are cheap so I was in fact wondering if it is even worth to give it to someone to have it fixed

[darshie]

The fuse seems intact, not sure why I cannot read any current there at all; I also have a very cheap multimeter....I would not be surprised if that thing won't work as expected (or I am not setting it correctly...altho I am not sure then why I can get a correct reading at the connector).

Do you mean voltage? The only way to check current with a normal meter is to make a break in the circuit somewhere (for example, remove the fuse) and with the meter in Ammeter mode install hook it up across the opening in the circuit. With the circuit intact you can only check voltage.

Voltmeters measure voltage difference. If the fuse is in tact and you are measuring across it in Voltmeter mode you will get nothing on a working system. With the power on there will be zero difference in voltage because fuses have no resistance. With the system off you'll have nothing because...its off. You will only see voltage across a fuse if the fuse is blown.

The best way to check a soldered-in fuse is to hook the ground wire of the meter to a chassis ground, power the system up, and measure voltage on one side of the fuse and then the other. They should read the same.

Not that this matters, evidently, since you seem to have a good fuse.

Then I swapped my white PCE and it boots, but there is no video. I can hear the game music going, and it respond to the pad buttons (i hear the sound effects, meaning that in fact the console works), but no video.

At this point I know that the little white fella is alive, so now I assume that I shall start to look in the video area to see why I get nothing. There is no signal at all from the AV cable, only the audio works.

Anything that I should check? Is this even possible to be fixed or should I just sell it for parts on ebay?

That's not common. My first question is, is there any evidence of mods being done to this system? If its never been hacked then its probably a blown cap or resistor. Maybe it has one of those bullshit HK PAL mods and your TV just isn't syncing with it?

Sorry, I meant Voltage (V); I am quite rusty on my electronic...has been probably 25 years since my last exam at college (i just remember Voltage and current intensity applied to resistors...and few formulas to calculate ).

That makes sense now....all that i know about a fuse is that it has a connection, so if the electricity pass trough it, you should be able to catch it, but I forgot that V is in fact the difference of potential energy among the electrons, so in fact, it is equal to 0 in an open circuit (and a fuse is an open circuit, unless is blown). Thanks for giving me the spark (pun intended ), about this I need to measure the current intensity (i), to see if in fact there is any activity going on....but my multimeter seems to read only V and ohm....gotta check the instructions.

Regarding the pre-existing modding:
Now that I think about it....there was a wire going across the board; plus I can see residual of some soldering points made after (they are quite big, so I exclude that they are in fact from the factory)...I removed it since it was attached only on one point, and I don't remember to ever see any wire across any PC Engine board.

I will take a picture of the bottom of the board so you can see what I am talking about...maybe they tried to do some sort of mod and blew up something...I didn't tried to check cap by cap yet, so for now I am preparing to see where to focus to find out what is wrong
BTW I am using a CD interface, so the RF unit should be totally bypassed, and the signal should be taken from the rear connector....which means that if I hook up some wires there, most likely there will be no signal.

I wonder if anyone ever posted the schematics for the origina PCE, or some repair guide/troubleshooting...I keep religiously the original schematics of the Commodore Amiga, just in case that I need to repair mine, but I can't find too much material on PCE, unless you need pure schematics (which requires a degree in IC design and engineering I assume ).

If it won't work, I will probably use the case to put in a micro computer and make my own PCE mod