Amiga 4000D repair of mouse/joy ports

[Jacob]

Hi.

A year or so, ago, I wanted to put all my stuff from my A4000T into my other A4000D (to keep it small).

In the process I needed to make a backplate that would allow me to fit both my CyberVisionPPC (2 connectors) and my AmigaDisplayToVGA (1 connector).
After finishing that I had it powered on (but had forgotten to screw down the backplate, so when I accidently pushed the amiga, the displayconnectors hit the wall, and pushed the AmigaDisplayToVGA card into the amiga, hitting some of the connectors (10 pins) in front of the mouse/joy ports (I guess these are internal connectors for the mouse port), and so after that, I could see no movement of my mouse, although I could click both mouse buttons ;-( (I can go into the bootmenu)

I have an idea that there needs to be changed one chip ... I cannot remember the name of it, but think I remember that it might be one of those chips that most often were to be changed on the amiga 500/2000 (Atleast from reading other peoples problems, I never had any such problem) but I am not sure, that that will fix it.

Anyone have any suggestions as what to do to make it work again?

thank you in advance.

Best regards: Jacob

[redrumloa]

I have an idea that there needs to be changed one chip ..

Well on the Amiga 5000 there are 2 CIA chips, one of which controllers mouse/joystick ports. The Amiga 4000D doesn't use the same CIA chips.

[chsedge]

this isn't true. the cia (one of them) control only the mouse/joy buttons. the movement of mouse and joy is managed by denise chip. also paula has some function related.

[voxel]

Hello Jacob :-)

Unfortunally for you the 10 pins header near the mouse ports is a feature connector with various signals fed to Lisa :-( as you can see below :

"Mystery" Header (courtesy of Dave Haynie)

 "There is a 12 pin header (DIL, J975) near the mouse ports. This feeds the 'extra' shift register in Lisa. Unlike OCS/ECS systems, which simply multiplex the four quadrature signals from each mouse port with one another, the AA systems serialize all eight bits of mouse data. While they were at it, the AA designers added a second 8-bits to the mouse port registers. These don't hook into mouse logic or anything, but they can be read by the CPU."

So if you made a shortcut to these pins, it can be necessary to send the motheboard to a repair service like www.amiga.fr per example. (BTW as all the chips are surface mounted it will be obligatory).

[voxel]

The Amiga 4000D doesn't use the same CIA chips.

Not entirelly true red ;-) same chips, different package :-)

[X-ray]

@ Jacob: was your A4000T an original Amiga Technologies case? If so what did you do with that case?

[Jacob]

Hi.

and thanks for the fast answers.

X-ray: no, it wasn't an Amiga Technologies case, it was the original Commodore A4000T case (One I acquired from Commodore Denmark when it went into liquidation in 1994). So its actually quite rare (I just looked for the serials on some of the boards):
 A4000T Ports:    8511294365337001000001 (apparantly the FIRST massproduced A4000T Ports card)
 A4000T Disk MDL: 8511294365257001000009
 A4000T PCBA:     8511394365150002000032

The Box itself is in my addict, so I don't have the exact number, but I think that it ended with 70.

I was told that this was one of the very few working amiga 4000T ever manufactured by Commodore, so I am very sorry, but I wont part with the case as it is too valuable to me.

btw. someone mentioned amiga.fr for repairs, does anyone know of other amiga repair facilities in europe?

Best regards: Jacob

[X-ray]

@ Jacob: You're absolutely right, don't sell that original Commodore case...that is rare.

A bit off topic: can you post pics of it in the images section?

[JimS]

If you've got a voltmeter check between pins 7 and 8 on either joystick port. There should be 5v there to power the electronics in the mouse. The buttons don't need it since they are just switches. If the 5v isn't there you'll get no mouse movement but still have the buttons. I've seen a lot of 2000's fail thia way. On the original 2000s a short here would melt a trace on the motherboard. The updated it to include a 'pico fuse' to protect the circuit. It was right by the joystick ports on a 2000, but I don't know about the 4000. My schematics for the 4000 shows a fuse F175 in the 5v user line (all external ports with 5v). I don't have a board layout, so I can't tell you where that is.
Good luck