I'm currently waiting for some printed circuit boards, and since I'm on the Drumulator topic, I decided to try to troubleshoot another machine from EMU: the Emulator 1.
This machine was offered to me by someone who wanted to part with it. It had obviously suffered some damage to the frame, following a fall I imagine, because it is really very heavy.
I turned it on once. It started, it smoked, then nothing since then. In fact it was tantalum capacitors that smoked. Nothing serious a priori.
In the past, I took it all apart and changed the front panel capacitors. I also redid the power supply. Then, I put everything back together, scrupulously, and then nothing. This EMU never wanted to restart. The keyboard has been sitting in a corner of my workshop for years. So, having studied the Z80 processor quite a bit during my work on FPGA, I thought it might be interesting to start troubleshooting it. After all, I have managed to troubleshoot several Drumulatore and SP12!
The interior of this EMU1 is in very good condition. Given the 'historical' nature of this machine, I find it increasingly difficult to look at it half dying in its corner!
So I removed the motherboard from the machine once again.
Will I finally be able to boot this motherboard from its floppy drive? The question remains!
It starts badly, the disk rotation motor gives a very slight knock and then stops. I have already spent some time checking the functioning of the motherboard by testing the behavior of the components. And, while I have already done this work years ago, I can't find anything dysfunctional. I don't have a diagnostic ROM for this machine, so for now, it's just a matter of testing the components. I haven't noticed anything glaring. Now I have to try to discover a functional malfunction. This is not going to be easy and may take a lot of time. But hey, I figure that by working on the subject a little regularly, I should get there! This machine only has standard components so....