Amiga 500 green screen when on...after connecting sega pad

Hy

Could you help me with such a problem with my Amiga 500

I've bought a sega mega drive pad, amiga works fine with joystick and mouse, but when i replace joy by sega pad and power on the amiga...it shows green screen (the hand does not show, no reaction from dd). The power light not blinking (it light as normal without blinking).

When I disconnect pad everything turns to normal. When I connest to mouse port everything is ok also.

In other amigas ...pad works fine without makin green screen.

Any ideas or solutions

Thanks

[Amiga1992]

Is it an official Sega pad or a knockoff? I have found varied problems with knockoffs but never with official pads.

It looks like original - its written Mega Drive Control Pad SEGA

[Photon]

Turn off any autofire switches? (none on the original controller I guess) You may also have bought one that requires more current than the Amiga can output on the joystick ports.

Also, check your Amiga inside and re-seat the socketed chips.

[Amiga1992]

Originally Posted by Cadderlik

It looks like original - its written Mega Drive Control Pad SEGA

Please post a picture of front and back.

[lesta_smsc]

I've never heard of this before... never realised such things would interfere. The worst I've had is having a controller which simply did not work at all but Amiga still ran fine. Would be interesting to know the cause of this.

[Amiga1992]

I had a non official Sega pad (that looked very much like an official one, even say it was SEGA and all) and when plugged to the Amiga it would make it do all sorts of crazy shit.

[dirkies]

I remember back in 1988 at our local computer club that an A500 had to be taken aside and sent to C= for repairs because it kept blowing the power fuses of the club asa you pressed a mouse button! We could repro at will! So anything is possible

I'll try to put fotos of pad today evening (you know wife )

I've checked at 2 otchers ami 500 the same pad (from a couple of hours) - every thing works fine, perfect

Only that one model of ami500 in slot nr 2 (for joy) - its really weird. The socket has all pins. Mobo is also fine, no leaks - so maybe I should reseat the chips (i have to buy the tool), and clean with isopropyl

May be a bus controller on mobo? - CIA??

[Toni Wilen]

Possibly marginal/partially damaged CIA chip I/O pin logic (firebutton goes to CIA-A i/o pin).

Does it boot normally if you keep fire button pressed when you switch on power? You can also try swapping CIA chips. (CIA-A to CIA-B socket and vice versa) If problem goes away: damaged CIA chip.

I had A1200 with very strange parallel port (=CIA) problem. System crashed at boot (I think it was yellow screen) if printer was not connected! I debugged it a bit and found out system boots normally without printer if parallel port data pin (I think it was data bit 2) was pulled to +5v or ground. Can't remember (It was late 1990s) Pin not connected: boot crash. Also writing to parallel port data register crashed the system..

In other words: slightly damaged CIA chip can cause all kinds of weird side-effects.