Videopac / Odyssey2 forum

Videopac / Odyssey2 => Hardware => Topic started by: ArcadeTV on January 10, 2014, 03:28:27 AM



Title: Games are suddenly freezing
Post by: ArcadeTV on January 10, 2014, 03:28:27 AM
After I had some time to play around with my G7000 a bit I experienced a problem...
Games are hanging/freezing randomly after playing a while.
I might be wrong but noticed that the freezing occurs when one player dies and the system is supposed the 'die sound'. But it happens randomly, not all the time. I checked other game-cartridges and the freezes are not related to a single game, it happens on 1/Racing and on 4/Air and Sea War.

I didn't try to clean the carts or the slot yet as I suspect something else is wrong...

Has anybody experienced something similar on a stock G7000?

Any help is very much appreciated, Thanks guys!


Title: Re: Games are suddenly freezing
Post by: Define on January 10, 2014, 07:09:30 PM
I always clean a Videopac system but try to open it, maybe you can see dirt or something strange on the print?
Seems something is about ..or died onboard?


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 10, 2014, 07:24:13 PM
Thanks! I already opened the system and I will post some pictures shortly.
In the meantime I'd like to ask for a replacement power supply.
I would love to kick the original one and use something more modern.
I believe it's 5V DC, is that correct?
Does anybody know of a guide to make use of a new power supply?

Thanks again!
I'll be back.


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 10, 2014, 11:59:21 PM
I was a bit worried about corrosion on the ICs' legs, but after I cleaned them with a fibre brush it didn't look so bad..
Here's an image before I cleaned it:
(https://lh6.googleusercontent.com/-AWxb0_GGoiM/UtB5LW_sn2I/AAAAAAAADQQ/SlRiXpAOYXs/s640/IMG_20140110_220142.jpg)

I couldn't spot any bad solder joints or disconnected traces - all in all the system seems to be in quita a good shape.

Here's a link to my Picasa Gallery where you can see all the pictures I made of that unit:
https://picasaweb.google.com/115948745418514736250/Videopac?authuser=0&feat=directlink&noredirect=1


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 11, 2014, 06:29:31 PM
The G7000 needs 5V DC (1.1A), but I don't think the power supply of your console is causing the problems. The corrosion on the pins of the ICs shouldn't be a problem either as long as the solder joints are fine. I haven't seen this issue before, maybe a problem with the 8048 processor getting hot after a while?


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 11, 2014, 06:33:53 PM
Yes INDEED!
I also noticed that the Intel chip is getting hot immediately. But since I didn't know better I thought that was a usual thing.
Is this an issue??
Thanks!!


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 11, 2014, 09:58:06 PM
The larger ICs should get warm, but not hot. Does the power supply deliver the right voltage? (5V, max 5.2V)


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 11, 2014, 10:06:18 PM
I measured 5.57V when I had it on the table.
Right now it doesn't do anything :(
Only Blackscreen.
Voltage is still present, even on the Video Out connector on the mainboard.


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 12, 2014, 03:03:28 PM
5.57V is too much. The voltage can be adjusted with R172.
But it sounds like something has died. Maybe the Intel 8245? (Video chip)


Title: Re: Games are suddenly freezing
Post by: Define on January 13, 2014, 01:07:42 PM
I think something has died...

And the look of the processor pins is not normal also and maybe THE reason why...

Try heating the pins with some solder and a iron (for a few seconds at most!)

Or else there is a way of making all lines works again, but that means you got to have an oven at a certain heat, putting the whole board in with plastic parts covered with some silver foil.
(better look that one up with Google...)

Sometimes old boards need that last bit but i never tried that ;)


Maybe a nice add-on is a small fan inside a G-console, i'm not suggesting heat pipes or that kind of modern cooling but i think it's not a bad idea!
Although back in the day we spent hours and hours with the units and all went well.
But... why not ;)





Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 13, 2014, 08:47:27 PM
I adjusted it to 5.2V
Could it be that it does not boot because i have no keyboard or Joysticks attached at this time?


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 13, 2014, 08:58:16 PM
Could it be that it does not boot because i have no keyboard or Joysticks attached at this time?

No, but pressing reset sometimes helps, so you would either need the keyboard or briefly connect the reset input of the 8048 to ground.
Does it produce the start-up (SELECT GAME) sound when you turn the console on with a cartridge inserted?


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 13, 2014, 09:04:42 PM
No, it does nothing  ???


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 13, 2014, 11:46:09 PM
What kind of equipment do you have that could be used to test the console? (Oscilloscope, frequency counter?)


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 14, 2014, 12:05:19 AM
Unfortunately I have nothing to test logic elements, I have a good weller soldering station, a desoldering station, a multimeter and other modding tools. I'm no electrician or engineer so I'm always lost when it comes to this :(
But I'm always interested  in learning. Can you recommend an oscilloscope?
Thanks very much for your help! Can't say that often enough.


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 14, 2014, 09:36:07 AM
Tektronix is a well-known brand for oscilloscopes, but I only have experience with old-fashioned analog oscilloscopes.
A good oscilloscope is expensive, a cheaper option would be to buy another G7000 console and either use that one or use it for parts.
Does your multimeter have a built-in frequency counter option?


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 14, 2014, 12:49:04 PM
Well. I COULD just get another G7000... But where's the fun in that?  :P
I am really willing to spend some money on equipment and learn.

What frequency-range should I look for?

I have found these nearby to pick up:
http://kleinanzeigen.ebay.de/anzeigen/s-anzeige/phillips-pm-3217-oszilloskop/171493766-168-1574?ref=search
http://kleinanzeigen.ebay.de/anzeigen/s-anzeige/oszilloskop/155413028-226-1160?ref=search
http://kleinanzeigen.ebay.de/anzeigen/s-anzeige/hameg-hm203-7-2-kanal-oszilloskop,-bandbreite-20-mhz/172354754-168-1496?ref=search

Thanks!


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 14, 2014, 02:20:36 PM
A range of 20MHz would be enough.
The thing is: if the 8048 or 8245 isn't working anymore you'll need a second G7000 anyway for the parts.
If you want to spend money on test equipment you could buy a G7000 testcart as well:
http://www.bas-ditta.info/videopac/teksten/stc.htm (http://www.bas-ditta.info/videopac/teksten/stc.htm)


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 15, 2014, 03:04:20 PM
Quick update from my end:

-If all goes well I'll get a Tektronix 2430A for a reasonable price.
-bought another G7000, contrary to my /22 this one has detachable joysticks and an external psu

So I'll be set if that stuff arrives here.


Just a question to be sure about this:
-connecting the CPU's pin 4 and pin 20 should trigger a reset, is that correct?


Title: Re: Games are suddenly freezing
Post by: Rene_G7400 on January 15, 2014, 03:32:16 PM
Just a question to be sure about this:
-connecting the CPU's pin 4 and pin 20 should trigger a reset, is that correct?

That's correct. If you don't have the circuit diagram yet, you can find it here:
http://home.kpn.nl/rene_g7400/vp_info.html (http://home.kpn.nl/rene_g7400/vp_info.html)


Title: Re: Games are suddenly freezing
Post by: ArcadeTV on January 16, 2014, 01:09:03 AM
 >:D Oh my god, I got it working again!
I reflowed the PAL encoder chip, plus I reworked several other random solder joints - voilá - SELECT GAME.

Need to reassamble it to check if the games are still freezing. Let's hope for the best.

Thanks to all of you!


Title: Re: Games are suddenly freezing
Post by: Define on January 16, 2014, 11:03:15 PM
Yep that's usually the case with old stuff ;)

Just flooooow the solder and let it set again!