Amiga A500 red screen after attaching HD+

[Gartnex]

Hello Guys,

Is just resurrected my good old Amiga and he's actually doing just fine. I've just the tiny problem that every time I attach my A500 HD+ to the system, I get for a few seconds a red screen which is afterwards changing in a dark-grey screen. At this point nothing happens anymore.
Do you have any ideas how to fix that problem?
I'm very thankful for every answer.

Greets,
Gartnex

[Gartnex]

First of all: Thanks for the replys.

I have already checked all connections on both, the Amiga itself/herself and the HD+.

And yes it is a GVP A500-HD+. I cleaned the contacts from corrosion (if there was any).

And also the power supply is present. I always power up the H before I start the Amiga.

@pyrre
I'm absolutely sorry! Of course is the Amiga a 'she'! And the Lady is such a beauty. It is just that 'computer' is masculine in German. So when I wrote the post I thought way to German. I'm really sorry.