CPCWiki forum

General Category => Technical Support => Hardware related => Topic started by: Flonky_Tash on 14:59, 11 April 18

Title: Side Switch Problem
Post by: Flonky_Tash on 14:59, 11 April 18
Hello,

I'm having issues trying to get a side switch working on my 3.5 disk drive. I've followed the procedure on the wiki but can't seem to get it working. The drive can only read from side A, whichever position the switch is in.

I'm using an FD1 cable, where I've cut the wire on pin 32 and wired it to the switch as stated on the wiki.

Any ideas on where I might have gone wrong?
Title: Re: Side Switch Problem
Post by: Bryce on 20:06, 11 April 18
You're not giving us enough info. A picture of the mod might help.

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 21:21, 13 April 18
You're not giving us enough info. A picture of the mod might help.

Bryce.

Okay, I've taken a picture in an attempt to make it clearer.

(Please excuse the crudity of the ribbon cable, I had an accident whilst i was cutting wire 32 and ended up cutting through 30, 31, 33 and 34  :doh: So they've been spliced back together with the purple wires you see there.)

So, on wire 32 I've got the green wire going towards the disk drive and the white wire going towards the CPC end of the cable. For ground I wired it to one of the ground connectors on the molex connector there. (I wasn't sure, as the instructions don't indicate where the ideal ground should go.)

Hope this helps, please let me know you need anything further, your help is very much appreciated!
Title: Re: Side Switch Problem
Post by: tjohnson on 23:08, 13 April 18

I think the you are trying to use a switch to switch between side a and side b.


I wonder if its not working as you are only grounding one side of your cable with your switch.


On my cable it had other connectors on the lead so ground 32 to 31 when required.
Title: Re: Side Switch Problem
Post by: Bryce on 11:46, 15 April 18
You seem to have the green and white wire swapped. The centre pin of the switch should go to the connector side of the cut. Take a look at the picture here:

http://www.cpcwiki.eu/index.php/Side_Select_Switch

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 19:13, 15 April 18

Thanks, Bryce. I had a go at swapping the green and white wires around as you suggested, but it hasn't seemed to of made any difference. The investigation continues. Do you reckon I may have got the grounding wrong perhaps?




You seem to have the green and white wire swapped. The centre pin of the switch should go to the connector side of the cut. Take a look at the picture here:

http://www.cpcwiki.eu/index.php/Side_Select_Switch (http://www.cpcwiki.eu/index.php/Side_Select_Switch)

Bryce.
Title: Re: Side Switch Problem
Post by: tjohnson on 22:07, 15 April 18

Thanks, Bryce. I had a go at swapping the green and white wires around as you suggested, but it hasn't seemed to of made any difference. The investigation continues. Do you reckon I may have got the grounding wrong perhaps?


What is you join the green and white on the switch in the middle. so as per the photo, when switched to the left there will be connected and right they will be ground.
Title: Re: Side Switch Problem
Post by: Bryce on 11:09, 16 April 18
Every second wire on the flat cable is a ground, why haven't you taken one of those instead of a ground that's electrically very far away?

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 12:55, 16 April 18

My shortest answer - my electronics knowledge is a bit rubbish.  :picard: But I'm learning! :)

Every second wire on the flat cable is a ground, why haven't you taken one of those instead of a ground that's electrically very far away?

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 13:02, 16 April 18

Well, I thought I followed what was on the photo. But I think I understand what you mean, so I'll give that a go. Cheers!


What is you join the green and white on the switch in the middle. so as per the photo, when switched to the left there will be connected and right they will be ground.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 15:09, 16 April 18
Okay I have started again with a fresh cable I've crimped myself. I've taken both of your advice...


Starting with Bryce's advice I've taken a more suitable ground, in this case I've used wire 31.


Taking Tjohnson's advice I have joined wire 32 to the middle of the switch.


Still no joy. I am really confused as to where I'm going wrong.


I've attached a photo of this attempt.
Title: Re: Side Switch Problem
Post by: Bryce on 15:24, 16 April 18
I think you miss understood Tjohnsons advice. The yellow wire (32 of the disk drive side) should go to the middle. The blue wire (32 from the CPC) should go to the contact you haven't used at the moment.

To test if it works, the yellow wire (centre pin of switch) should read 0V when the switch is in one position and 5V when in the other position.

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 17:10, 16 April 18

I have just attempted that as well, but still no avail. Please see latest attachment. How does that look to you? 


Haven't tested with my multimeter yet. How exactly would I go about doing this?


This has become quite a saga!  :picard:

I think you miss understood Tjohnsons advice. The yellow wire (32 of the disk drive side) should go to the middle. The blue wire (32 from the CPC) should go to the contact you haven't used at the moment.

To test if it works, the yellow wire (centre pin of switch) should read 0V when the switch is in one position and 5V when in the other position.

Bryce.
Title: Re: Side Switch Problem
Post by: Bryce on 17:17, 16 April 18
Looks fine. To test = Negative probe to the ground pin, positive probe to yellow wire. Meter set to voltage.

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 17:51, 16 April 18

Thanks, Bryce.


Tested with meter, I'm getting 5.22v in both switch positions. Seems that they aren't disconnecting when they should be?


Do you reckon it could be anything to do with the drive itself? It's a Sony MPF920, works as it should normally with pins 33 and 34 soldered together on the drive itself. I'm sure I read somewhere that Sony drives are bit a finicky?





Looks fine. To test = Negative probe to the ground pin, positive probe to yellow wire. Meter set to voltage.

Bryce.
Title: Re: Side Switch Problem
Post by: tjohnson on 20:27, 16 April 18
Double check the measurement on the switch, I think as per the photo earlier with the switch to the right you should get 0v and to the left you should get 5v.  Double check your switch doesn't have continuity between the left and right poles, you never know but seems unlikely.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 21:11, 16 April 18

Yep, I've double checked the measurement and I just seem to be getting 5V either way. There's no continuity either. I'm going to try with a different drive and see what happens, as I'm confident I've wired the switch properly.

Double check the measurement on the switch, I think as per the photo earlier with the switch to the right you should get 0v and to the left you should get 5v.  Double check your switch doesn't have continuity between the left and right poles, you never know but seems unlikely.
Title: Re: Side Switch Problem
Post by: Bryce on 21:41, 16 April 18
With the switch in the position "leaning towards the blue wire" there is no way on earth that you could measure 5.22V on the yellow wire because the yellow wire is a direct connection to ground in that case. Unless - A. The ground wire isn't really connected to ground, B. The switch doesn't work.

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 22:58, 16 April 18
I've got some ideas I'm going to try over the next couple of days. I WILL get this working! Thank you both for your help, you've definitely steered me in the right directions and I'm learning a lot, which is always a benefit :) I'll keep you updated!
Title: Re: Side Switch Problem
Post by: tjohnson on 23:20, 16 April 18
It really shouldn't be more complex than grounding pin 31 and 32 together to switch sides!  As I say I achieved this by adding a switch onto a spare connector on the cable, if you have any spare connectors this will be the easiest and you can test it simply by using a paperclip between them.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 00:10, 17 April 18

I found a very short floppy cable with a spare connector and using a jumper cable on pins 31 and 32 that works. So I think the problem was a mixture of me getting the pin numbering backwards and the wiki procedure being a little bit misleading. I know what I need to do to get the switch working, which I'll hopefully get done tomorrow evening.


Thanks a lot for your help! I owe you guys some big beers.





It really shouldn't be more complex than grounding pin 31 and 32 together to switch sides!  As I say I achieved this by adding a switch onto a spare connector on the cable, if you have any spare connectors this will be the easiest and you can test it simply by using a paperclip between them.
Title: Re: Side Switch Problem
Post by: Bryce on 00:16, 17 April 18
Looks like the flat cable is made incorrectly. The red wire should be pin 1, but seems to be pin 34 in your case.

Bryce.
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 18:47, 22 April 18
Just to get you guys know I've successfully managed to get my side switch working using a less messy method of wiring the switch to the pins on the underside of the floppy drive. Works like a charm! Thank you both for your help, I've learned a lot from your advice :)
Title: Re: Side Switch Problem
Post by: tjohnson on 23:39, 22 April 18

Just to get you guys know I've successfully managed to get my side switch working using a less messy method of wiring the switch to the pins on the underside of the floppy drive. Works like a charm! Thank you both for your help, I've learned a lot from your advice :)


Glad you got it working,  any pictures of your final modification?
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 00:24, 23 April 18

There will be soon! I'm in the process of writing a procedure for the wiki :)


Glad you got it working,  any pictures of your final modification?
Title: Re: Side Switch Problem
Post by: Flonky_Tash on 11:41, 05 May 18

So I wrote my procedure, photos will be added eventually :)

http://www.cpcwiki.eu/index.php/Side_Select_Switch_-_Alternative_Method