Problem with the game port.Amiga 600

ivan · 14 May 2015, 13:22

Hi, I have a problem with the game port when I press up on the pad is as if you pressed up more left.
The problem is not in control because I check with a cable directly to the DB9 port and the same can be active up more left.

if anyone can help me I would be very grateful because I can not play many games .
A greeting.

fitzsteve · 14 May 2015, 15:40

Do you have any other hardware in your A600 and does the problem persist if you remove said hardware?

ivan · 14 May 2015, 16:41

I have only one command but when I do the test with the cable to pin 1 and ground does the same but up left.
I think it may be something internal .

ivan · 14 May 2015, 20:12

It may be the 74LS157 multiplexer??

jimbob · 14 May 2015, 21:53

This can be caused by low 5V. That muliplexor is a long way from the power input. Check this thread -

http://eab.abime.net/showthread.php?t=67044

ivan · 15 May 2015, 09:39

Hello, I measured the voltage 74LS157 in the leg 16 and gives me 4.56v .
It is within the specifications of the dataset .

ivan · 15 May 2015, 11:00

I put a 20K resistor between the legs 16 and 3, the result is the same .

ivan · 15 May 2015, 17:33

I tried the 20k resistor between pin 16 to 10 and 16 to 11 the result is the same .

jimbob · 15 May 2015, 19:28

Quote:

Originally Posted by ivan

Hello, I measured the voltage 74LS157 in the leg 16 and gives me 4.56v .
It is within the specifications of the dataset .

The problem occured for me below ~4.6V. It might meet the chip spec for Vcc but the output is driving some of the longest traces on the board so the spec would be derated.

A replacement multiplexor might help, but I'm pretty sure a solid 5V will remove the problem, at least for a while. Do you have an alternative PSU to try?

I never had any luck adjusting the pull ups.

Lord Aga · 15 May 2015, 19:44

Had the same problem for a while. Couldn't solve it. And then the mobo died

It was rev 2D. What's yours ?

ivan · 15 May 2015, 20:26

Yes rev 2d.

ivan · 15 May 2015, 20:30

The idea is to feed leg 16 vcc 5v .
Would have to unsolder the R370 resistance.

ivan · 15 May 2015, 21:14

On pin 7 of the DB9 gives a voltage of 4.5v

ivan · 15 May 2015, 21:23

To power the computer I use a PC ATX,The source values are normal gives 5V accurate.

ivan · 17 May 2015, 15:32

I removed the resistance will VCC and the voltage rises from 4.56 to 4.65 but the control remains the same.
The mouse works perfect on port 1 but the pad on port 1 does the same.

ivan · 21 May 2015, 09:51

He changed the multipexor For a 74HC157 and the result m is the same.

14 May 2015, 13:22	#1
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	Problem with the game port.Amiga 600 Hi, I have a problem with the game port when I press up on the pad is as if you pressed up more left. The problem is not in control because I check with a cable directly to the DB9 port and the same can be active up more left. if anyone can help me I would be very grateful because I can not play many games . A greeting.

15 May 2015, 21:23	#14
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	To power the computer I use a PC ATX,The source values are normal gives 5V accurate. Last edited by ivan; 16 May 2015 at 12:45.

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14 May 2015, 15:40	#2
fitzsteve Professional slacker! Join Date: Jul 2009 Location: Kent, UK Age: 44 Posts: 6,683	Do you have any other hardware in your A600 and does the problem persist if you remove said hardware?

14 May 2015, 16:41	#3
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	I have only one command but when I do the test with the cable to pin 1 and ground does the same but up left. I think it may be something internal .

14 May 2015, 20:12	#4
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	It may be the 74LS157 multiplexer??

14 May 2015, 21:53	#5
jimbob Registered User Join Date: May 2006 Location: Kilmacolm Age: 45 Posts: 632	This can be caused by low 5V. That muliplexor is a long way from the power input. Check this thread - http://eab.abime.net/showthread.php?t=67044

15 May 2015, 09:39	#6
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	Hello, I measured the voltage 74LS157 in the leg 16 and gives me 4.56v . It is within the specifications of the dataset .

15 May 2015, 11:00	#7
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	I put a 20K resistor between the legs 16 and 3, the result is the same .

15 May 2015, 17:33	#8
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	I tried the 20k resistor between pin 16 to 10 and 16 to 11 the result is the same .

15 May 2015, 19:44	#10
Lord Aga MI clan prevails Join Date: Jul 2010 Location: Belgrade, Serbia Posts: 1,443	Had the same problem for a while. Couldn't solve it. And then the mobo died It was rev 2D. What's yours ?

15 May 2015, 20:26	#11
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	Yes rev 2d.

15 May 2015, 20:30	#12
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	The idea is to feed leg 16 vcc 5v . Would have to unsolder the R370 resistance.

15 May 2015, 21:14	#13
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	On pin 7 of the DB9 gives a voltage of 4.5v

17 May 2015, 15:32	#15
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	I removed the resistance will VCC and the voltage rises from 4.56 to 4.65 but the control remains the same. The mouse works perfect on port 1 but the pad on port 1 does the same.

21 May 2015, 09:51	#16
ivan Registered User Join Date: Jan 2015 Location: spain Posts: 19	He changed the multipexor For a 74HC157 and the result m is the same.

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