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Author Topic: G7000 joystick always "up" after connecting joystick "live" *SOLVED*  (Read 5724 times)
emuola
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« on: September 18, 2014, 09:17:50 PM »

So sad... We just had a retro event at the local newspaper. The theme was 70's retro games and I put my shiny composite modded G7000 on display. I've grown up with C64, so I just fired the unit up and then connected the joysticks (apparently I should not have done that...). As soon as I connected the other (don't remember which) joystickthe unit reseted. After the reboot the unit seemed to think the other joystick is always "up". Ok, I then disconnected the joysicks and so on, but again the unit seems to think the other joystick is "up". I then looked at the joystick connector(s) and one of the pins had "sunk" a few mm in. Ok, that's the problem and I pulled the pin back with pliers. Unfortunately, no help.

What did I broke? I hope I can change the stuff that I broke.  Cry
« Last Edit: October 09, 2014, 06:58:28 PM by emuola » Logged
Janzl
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« Reply #1 on: September 18, 2014, 11:33:15 PM »

I don't think there is a problem. I am sure that that your Videopac is one off the Special Viagra Edition series.

 Wink
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emuola
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« Reply #2 on: September 19, 2014, 08:24:16 AM »

Ok, seriously, my friend said to change the 74LS365N of the broken joyport. Anyone here agree with this?
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Rene_G7400
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« Reply #3 on: September 19, 2014, 09:10:52 AM »

Ok, seriously, my friend said to change the 74LS365N of the broken joyport. Anyone here agree with this?

Yes, I do.

Connecting a joystick "live" won't harm the console, as the joystick doesn't contain any electronic circuits, just 5 switches.
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emuola
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« Reply #4 on: September 19, 2014, 09:20:04 AM »

Ok, seriously, my friend said to change the 74LS365N of the broken joyport. Anyone here agree with this?

Yes, I do.

Connecting a joystick "live" won't harm the console, as the joystick doesn't contain any electronic circuits, just 5 switches.


Ok, I figured that also, but I guess the "sunken" pin caused somekind of short somewhere? I haven't opened the console yet so I don't know exactly if the sunken pin actually can cause a short, but for some reason the console "reseted" as I attached the joystick (and the pin was down for ~5mm).

I just ordered a few 74LS365N. I'm no pro with soldering iron, is it gonna be too hard (74LS365N has 16 pins)?
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Rene_G7400
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« Reply #5 on: September 19, 2014, 01:28:00 PM »

Maybe the console was reset just because the cartridge didn't make contact for a short while.
Soldering the 74LS365 isn't hard, just make sure you don't damage any of the copper traces when removing the old IC.
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Seob
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« Reply #6 on: September 21, 2014, 09:25:24 AM »

Did the unit work before you tryed it? You said you modded it. Did you mod the joystickports? Or did you're unit already have detachable joysticks? Could be that the up pin shorted with ground. If you solder to hot the plastic surrounding the pins will melt.
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emuola
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« Reply #7 on: September 21, 2014, 12:42:20 PM »

Did the unit work before you tryed it? You said you modded it. Did you mod the joystick ports? Or did you're unit already have detachable joysticks? Could be that the up pin shorted with ground. If you solder to hot the plastic surrounding the pins will melt.

I modded it for the composite output months ago and it has worked perfectly. It has the detachable joysticks and they are original. I opened the comsole up today and it seems there's some kind of modification on the mb (done by someone else). My mb has the Motorola "replacements" for the original 74LS365N. The one that leads to the broken port (or at least to the port that had the pin "sunk" down) can be seen in the pictures. Unfortunately it looks like it's too hard for me to even try to change the ic there Sad Can someone tell me what might be the reason for the additional jump wire/capacitor there?

http://1drv.ms/1AZ4zKC
http://1drv.ms/1AZ4N4p
http://1drv.ms/1AZ4Op7

As stated before the console works perfectly otherwise. Games work ok, but the other joy is always up.

One more picture of the whole mb:

http://1drv.ms/1qWn3LO
« Last Edit: September 21, 2014, 12:53:49 PM by emuola » Logged
gertk
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« Reply #8 on: September 22, 2014, 12:43:18 PM »

Quote
I modded it for the composite output months ago and it has worked perfectly. It has the detachable joysticks and they are original. I opened the comsole up today and it seems there's some kind of modification on the mb (done by someone else). My mb has the Motorola "replacements" for the original 74LS365N. The one that leads to the broken port (or at least to the port that had the pin "sunk" down) can be seen in the pictures. Unfortunately it looks like it's too hard for me to even try to change the ic there Sad Can someone tell me what might be the reason for the additional jump wire/capacitor there?

The jumper wires look original to me, except for some nasty soldering of the one leading to the capacitor.

You should try and check the signals coming from the joystick and compare them with the signals from the working joystick (use a simple multimeter for this)
The one input signalling 'up' is probably constant at a low level (less than 2 Volts). Try to trace the path leading to the LS365 and check the voltage at the input pin. If it is also low, and there are no ugly solder blobs between the pins, then the LS365 is damaged. (Could be by static electricity but with TTL chips not very likely)

Replacing can be a bit of a pain if you haven't got the right equipment but as a stopgap you can use a small pair of cutters and cut the pins next to the body of the chip. You will end up with 16 'stumps'  on your board and you could simply put a new LS365 over the stumps and solder them together pin by pin. It won't be pretty but it will do the least damage to your board. Check and recheck for shorts and try if it works OK now.
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emuola
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« Reply #9 on: September 22, 2014, 05:00:12 PM »

Quote
I modded it for the composite output months ago and it has worked perfectly. It has the detachable joysticks and they are original. I opened the comsole up today and it seems there's some kind of modification on the mb (done by someone else). My mb has the Motorola "replacements" for the original 74LS365N. The one that leads to the broken port (or at least to the port that had the pin "sunk" down) can be seen in the pictures. Unfortunately it looks like it's too hard for me to even try to change the ic there Sad Can someone tell me what might be the reason for the additional jump wire/capacitor there?

The jumper wires look original to me, except for some nasty soldering of the one leading to the capacitor.

You should try and check the signals coming from the joystick and compare them with the signals from the working joystick (use a simple multimeter for this)
The one input signalling 'up' is probably constant at a low level (less than 2 Volts). Try to trace the path leading to the LS365 and check the voltage at the input pin. If it is also low, and there are no ugly solder blobs between the pins, then the LS365 is damaged. (Could be by static electricity but with TTL chips not very likely)

Replacing can be a bit of a pain if you haven't got the right equipment but as a stopgap you can use a small pair of cutters and cut the pins next to the body of the chip. You will end up with 16 'stumps'  on your board and you could simply put a new LS365 over the stumps and solder them together pin by pin. It won't be pretty but it will do the least damage to your board. Check and recheck for shorts and try if it works OK now.


Ok, I did some measuring with a simple multimeter. If I measure the voltages from the back of the joystick ports it's something like this:

Port 1: ~1v
Port2: ~1.3v (but one pin 1.6v)

I also measured the voltages from the chip, and the pin where the "sunken" pin leads gives ~1v

Would someone happen to have the pinout of the joystick ports? I tried to google, but only came up with some joystick mod info.
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Seob
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« Reply #10 on: September 22, 2014, 06:32:24 PM »

http://gamesmuseum.pixesthesia.com/history/gen2/odyssey2/o2stick.txt

Pinouts for the Odyssey2 joystick port:
 ________
( 1 2 3 4 5 )
 \ 6 7 8 9 /
  \_____/

1 - Ground
2 - Fire
3 - Left
4 - Down
5 - Right
6 - Up
7,8,9 - not connected
 

Pinouts for the Atari 2600 (etc) port, just for reference:
 ________
( 1 2 3 4 5 )
 \ 6 7 8 9 /
  \_____/

1 - Up
2 - Down
3 - Left
4 - Right
6 - Fire
8 - Ground
5,7,9 - not connected (actually, paddle inputs, etc)
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emuola
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« Reply #11 on: September 22, 2014, 08:01:16 PM »

http://gamesmuseum.pixesthesia.com/history/gen2/odyssey2/o2stick.txt

Pinouts for the Odyssey2 joystick port:
 ________
( 1 2 3 4 5 )
 \ 6 7 8 9 /
  \_____/

1 - Ground
2 - Fire
3 - Left
4 - Down
5 - Right
6 - Up
7,8,9 - not connected
 

Pinouts for the Atari 2600 (etc) port, just for reference:
 ________
( 1 2 3 4 5 )
 \ 6 7 8 9 /
  \_____/

1 - Up
2 - Down
3 - Left
4 - Right
6 - Fire
8 - Ground
5,7,9 - not connected (actually, paddle inputs, etc)


Thanks Smiley Some corrections to the measurements:

-Voltage from both LS365 pin 1 ~3.4v

LS365 #1:

-Voltage from the pin 2 (where the pin 6 of the port=up leads, checked with multimeter also) ~0.90v, when joystick is centered and 0v when joystick is "up".  I guess it works ok then?

For comparison:

Voltage from pin 6 (where the pin 4 of the port=down leads, checked with multimeter also) ~1.0v when joystick is centered and 0v when joystick is "down".

LS365 #2:

-Voltage from the other LS365 pin 2 (where the pin 6 of the port=up leads, checked with multimeter also) ~0.95v when joystick is centered and 0v when joystick is "up".

For comparison:

Voltage from pin 6 (where the pin 4 of the port=down leads, checked with multimeter also) ~1.6v when joystick is centered and 0v when joystick is "down".

I'm really no pro here, what does this mean (if anything)? Roll Eyes
« Last Edit: September 22, 2014, 08:16:19 PM by emuola » Logged
gertk
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« Reply #12 on: September 22, 2014, 09:19:18 PM »

The voltages you mention are all on the low side but on your G7000 (the one with the external power supply?) you probably have no pull-up resistors on the inputs, later models do have these and the voltages might be higher then. Also there are quite a few small capacitors connected to the joystickports, maybe one of those is faulty.

You might check the voltage on pin 16 of both 74LS365 to make sure both get 5 Volts
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emuola
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« Reply #13 on: September 22, 2014, 09:24:37 PM »

The voltages you mention are all on the low side but on your G7000 (the one with the external power supply?) you probably have no pull-up resistors on the inputs, later models do have these and the voltages might be higher then. Also there are quite a few small capacitors connected to the joystickports, maybe one of those is faulty.

You might check the voltage on pin 16 of both 74LS365 to make sure both get 5 Volts


Yes, my G7000 has an external psu. Both 74LS365 get ~5v ok. How can I figure out which of the small caps is broken? Is there any other component that could cause this?
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Rene_G7400
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« Reply #14 on: September 23, 2014, 09:27:00 AM »

How can I figure out which of the small caps is broken?

That would be highly unlikely. If it had a short-cicuit the voltage across it would be 0V (which it isn't), if an internal connection would be broken it would not cause a permanent 'up' signal.
I've fixed several G7000/G7400 consoles with a broken 74LS365, so that's probaly the case with your console too.
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