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General Category => Technical Support => Hardware related => Topic started by: geebus on 15:36, 17 July 20

Title: Possibly killed my ddi-1
Post by: geebus on 15:36, 17 July 20
Hi folks. I thought i'd have a go at making a device that allows the connection of a 3.5" dive to a cpc 464 without modifying either the drive or the ddi-1 board.
A simple plug and play if you will.
However I'm not very clued up in electronics and possibly (definitely) should have asked someone who was if my circuit was correct before plugging everything in.


Long story short, I've accidentally plugged my ddi-1 ribbon in the wrong way round, got some magic smoke at the power connector to my board.


After plugging it in the correct way, i'm getting voltage drop across the +5v pins on the DDI-1 board where the ribbon comes in. This is making me think i've somehow made the circuit series rather than parallel or i've destroyed something.


The more i look at the diagram i drew, the more i confuse myself.

Title: Re: Possibly killed my ddi-1
Post by: Bryce on 17:44, 17 July 20
That circuit more or less shorts everything to GND. The DDI-1 is most likely damaged (the output buffers at least).

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 18:18, 17 July 20
Thanks for the reply Bryce.
Are you able to go a little more in depth as to what i've done here.
In my mind i've connected all the grounds to ground and 5v to 5v.
So where lies the problem?
As is obvious, i have very little knowledge in electronics circuitry and would really love to learn.


Edit. Does each ground line need to be allocated to it's opposite for signalling?
Title: Re: Possibly killed my ddi-1
Post by: Bryce on 18:48, 17 July 20
Eh, no. For example. Pins 29, 31 and 33 are connected to 5V on the DDI-1 side, but connect to GND on the Drive side = Direct short circuit of the PSU and hence the smoke you observed.

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 18:51, 17 July 20
But the 5v isnt going to the drive side. only the DDI..
The opposing pins on the drive side are NC
Title: Re: Possibly killed my ddi-1
Post by: Bryce on 19:05, 17 July 20
Your confusion seems to be the fact that you are mixing up the graphical symbols with the actual connections. Pin 29 goes to pin 29, no matter how you might have spun the picture. Do you have a picture of the actual hardware you built?

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 19:11, 17 July 20
Sorry I think my diagram is bad. I should have explained what this diagram is doing.
The DDI header is where i'm connecting the ribbon coming from the DDI-1. the other header is where i'm connecting my FDD.
So there is no connection between pins except where i've connected the wires if that makes sense.


Yeah i'll get a picture of the board shortly and post it up.

Title: Re: Possibly killed my ddi-1
Post by: geebus on 20:45, 17 July 20
Excuse the bird nest of a job, but i checked the continuity and made sure there weren't any shorts that i wasn't expecting.
The headers going on the edge of the board (with the blue and red wires under it) is where my FDD connector goes onto. Pins 33+34 on the end where the brown wire is (thats holding 34 low for the ready signal).The other header is where the DDI ribbon cable connects. Pins 33 + 34 on the same end.
Yes the soldering is ugly.. I know haha.
Title: Re: Possibly killed my ddi-1
Post by: VintageAdvantage on 07:30, 18 July 20
Sorry to hear. Do you think that would work for you?

https://github.com/lambdamikel/CPCDiskAdapter
Title: Re: Possibly killed my ddi-1
Post by: geebus on 14:13, 18 July 20
that certainly looks similar to the idea i was wanting but I was just after 1 drive.Still not sure if i've broken my DDI-1 or if it was already borked.
Title: Re: Possibly killed my ddi-1
Post by: VintageAdvantage on 20:32, 18 July 20
PM me if you would like one of these. 
10 $ component costs + 10 $ shipping.
It will also work with one drive only, but you need to modify the controller for the "no power mod".
As described.

But you should figure out first (and fix) your controller. Or get a DDI4 (or DDI5).
Title: Re: Possibly killed my ddi-1
Post by: geebus on 23:06, 06 August 20
So! it turns out I was just being a bit of an idiot.
I was using a| instead of |a
the ROM is now initialising but i'm getting a "bad command" error when trying to read from my floppy disk.
I've tried to use a separate PSU to power the drive in case that was the issue, but to no avail.Double checked my board and I have no shorts etc.a bit confused now.
The disks are fine as i've used them in my 3.5" b drive on my 6128.
Anyone any other ideas?
Title: Re: Possibly killed my ddi-1
Post by: Bryce on 14:08, 07 August 20
As you mixed up |a and a|.... What exact command are you using to read the disks?

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 15:04, 07 August 20
Was just using |a. (I also used |cpm to check the rom was initialised and it was. Obviously didn't load anything.)

It spun the disk drive up but I didn't hear the heads moving at all. No led's lit up either.

Thought it might have been a lack of power to the drive as the way i wired up my board the 5v line is shared for the DDI-1 interface and the drive. So I got a separate PSU to power the drive alone, no change.
I've also tried a different drive that I know works to see if it was the drive.


As I said in my previous post, I checked my board for shorts and made sure the connections are all going where they are supposed to be. They all are fine.
Last thing I need to do is clean up the edge connector and see if thats possibly the issue.


After that i'll need to see about the DDI board. make sure the chips are getting power etc. But thats where my experience fails me. This is fairly new stuff to me in this hobby.


I have an analogue scope if it comes to it. I'll need to learn how to use that too haha!
Title: Re: Possibly killed my ddi-1
Post by: Bryce on 16:12, 07 August 20
And what happens if you just type CAT and hit enter?

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 17:57, 07 August 20
sorry, should have said, done that too.
Same error. Tries to read the disk and then eventually errors. Bad Command.
Title: Re: Possibly killed my ddi-1
Post by: Bryce on 18:00, 07 August 20
Ok, questions:

1 - Are you sure the drive works at all? (Tested on a different system?)
2 - Are you sure the disk is compatible? (DD not HD and correctly formatted?)

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 18:48, 07 August 20
Yeah, just cleaned up the edge connectors in case it was a dirt issue.
no luck.
Tried two different drives and disks.
Also tested one of the two drives (as I done the ready signal mod on it already) on my 6128 as a b drive. working fine. Although I did have a slight panic until i realised I never put the power cable in.


EDIT --------
The disks i'm using are 1.44MB disks with the hole covered.
This works fine when writing my disks on my XP machine and on the 6128

Title: Re: Possibly killed my ddi-1
Post by: geebus on 11:17, 02 October 20
A little update.
I bought a floppy drive to go along with my ddi-1 and it's working fine. So I now KNOW it is (as previously suspected) my board that isn't working right.
I did have a feeling this would be the case as my electronics knowledge is minimal at best.
Learning more each time I do something though!
Title: Re: Possibly killed my ddi-1
Post by: Bryce on 11:53, 02 October 20
So the DDI-1 is broken or which "board" do you mean?

Bryce.
Title: Re: Possibly killed my ddi-1
Post by: geebus on 12:37, 02 October 20
Sorry, the board i made up (rather hillbilly looking thing).
Title: Re: Possibly killed my ddi-1
Post by: geebus on 02:34, 04 October 20
SO! I have it part way working.
Turns out I had wired a couple of pins wrong. I only found this out by doing a bit of continuity testing on my fd-1. Shall amend my circuit and reupload it soon.
Will also get some PCB's made so that it's a bit more reliable than the mess of wires I have just now.
I also need to work out of it's my drive or if it's a lack of power thats causing the drive to only read some disks and not others that I know work on my 6128 3.5" drive.Will figure that out at some point too!
EDIT:
Changed the wires on my power connector as they were a little loose.
Now have it working on the two drives that I have tried.
Might get some PCB's made now.