Need help with Panasonic fs-a1f FDD issues

Supporter (9)

28-05-2023, 18:27

Hello,
This is my first post on this forum!

So here's my story:
I bought a Panasonic fs-a1f a while back and the FDD was aged as to expect.
I replaced the rubber band and started to receive an error (in Basic) "Disk I/O Error" or something.
and then I realized I screwed up the FDD by touching the lens screw... yea... I know... I didn't do enough research that moment....
So I found a blog on internet how to replace the FDD with a band-less PC Floppy Drive.
here: https://hansotten.file-hunter.com/do-it-yourself/msx-floppy-...
So I built the converter according to this page.
https://i.imgur.com/66NoP2g.jpg
https://i.imgur.com/U3IKyrd.jpg
Soldering looks quite messy but I checked everything with a multimeter and it seems all good.
I bought a fully new unused Samsung SFD-321B like they said on in this blog but it was a Japanese model so the main board had a completely different layout.
So I contacted the original creator of this mod and he told me how to make the adjustments on this model.
(I'm a total noob at electronics. I can solder, but that's about it)
https://i.imgur.com/aWvrSne.jpg
(Jumper from DC to RDY, Cut trace from pin12 and connected pin10 to that trace and cut trace at start of pin2 and connected pin2 to lower point of the DC jumper)
So I tested the FDD but got the error "Disk offline". Tried all kinds of things.
Bought another FDD, one from Sony. No idea how to do the mod on this one honestly...
https://i.imgur.com/tGMvp41.jpg
(I only figured out that I had to move the jumper from JC31 to JC30)
I tried everything with 2 different cables, straight cable and cable with a little twist in the middle.
https://i.imgur.com/VnbmRMl.jpg
Both just gave me "disk offline"
Then I connected the official drive again and when I turned on the MSX, I started to smell something burned.
Some smoke came from the FDD... X.X
I thought that maybe the lens started burning up..? I loosened the screw a bit... maybe it was the cap under the board that some people seem to replace....? anyway still gave me "Disk offline".
is there another possible cause for this error? something broken on the motherboard of the MSX?
I'm really lost...
What am I doing wrong? : /
any tips on what I can do to make this mod work?

By Wierzbowsky

Guardian (3648)

29-05-2023, 00:05

Better have a Gotek installed with the special adapter board. Or you can still install a PC drive with the same adapter board. The motherboard needs one wire to be soldered if you want to use a PC drive.

https://www.msx.org/forum/msx-talk/hardware/installing-gotek...

By Croes_C

Supporter (9)

29-05-2023, 04:25

Thank you for the reply. I saw your post while searching for answers.
The small pcb you made, is it the same as what I made or is there a different in wiring?
also, what wire do I have to solder and is it not too destructive towards the MSX's main board?
Otherwise I might indeed go for a Gotek... I love floppies though! : D

By gdx

Enlighted (6421)

29-05-2023, 09:52

A Japanese had the same problem as you but he managed to replace the original drive with the same Samsung SFD-321B as yours.

http://poorcore.blog.fc2.com/blog-entry-17.html

Quote:

34ピンをREADY信号にするには、DCとプリントされている側についている
0オーム抵抗をRDYとプリントされている側につなぎ替えます。このとき、黒と赤のケーブル(モーターの電源ケーブル?)が邪魔になりますのでいったん外して作業した方が楽です。

Translation: To make pin 34 a READY signal, attach it to the side printed with DC. Reconnect the 0 ohm resistor to the side labeled RDY. It's easier if you remove the black and red cables (motor power cables?) that are in the way to do the modification.

Quote:

TurboR以外ではDISK CHANGE信号は必要ないようですが、必要であれば、
以下の箇所の0オーム抵抗を外して2ピンにDISK CHANGE信号を接続します。

Translation: It seems that the DISK CHANGE signal is not necessary except for TurboR. If necessary, remove the 0 ohm resistors below and connect the DISK CHANGE signal to pin 2.

Quote:

Drive Select信号を変更するためのパターンは無くなっているので、
ソニー機に直接接続するなどで10ピンに接続する必要がある場合は、
QFP LSIの38ピンからFDDコネクタの12ピンに出ている信号を
パターンカットして10ピンにつなぎ替える必要があります。
(なお、34ピンのコネクタ形状の関係でソニー機の34ピンコネクタを
直接接続しようとすると筐体と干渉します)

Translation: There is no pattern to change the Drive Select signal, so if you need to connect to pin 10, such as directly connecting to a Sony device, the signal from pin 38 of the QFP LSI to pin 12 of the FDD connector It is necessary to cut the track and replace it with 10 pins.
(In addition, due to the shape of the 34-pin connector, if you try to directly connect the 34-pin connector of the Sony machine, it will interfere with the housing.)

By Croes_C

Supporter (9)

29-05-2023, 13:36

I read the blog before. It is indeed the same drive and did the same modifications to the drive.
But it's unclear if he did something to the MSX itself and what 24pin to 34pin converter he used.
The last picture it looks like the yellow cable from the drive power connector goes somewhere. is it supposed to be connected somewhere? Does the drive need extra power?

By gdx

Enlighted (6421)

29-05-2023, 15:22

He doesn't speak about the 26pin to 34pin converter but you can found it here:
http://sankichi.backdrop.jp/fsa1drive.html

By Wierzbowsky

Guardian (3648)

30-05-2023, 00:12

Croes_C wrote:

My board has the same wiring, but it offers using a cable or a socket for the FDD's power connector. I will post a photo of the required wire for the PC FDD in a couple of days.

By Croes_C

Supporter (9)

30-05-2023, 03:44

Thank you! : )
If I can't get it to work after that, and if you still have some converters left, I'd like to buy one and maybe also consider getting a Gotek.

By Croes_C

Supporter (9)

30-05-2023, 03:45

gdx wrote:

He doesn't speak about the 26pin to 34pin converter but you can found it here:
http://sankichi.backdrop.jp/fsa1drive.html

This guide is quite complex. Probably a lot of info lost in translation.

By gdx

Enlighted (6421)

31-05-2023, 10:39

Wierzbowsky, It would be nice to put your productions in the wiki (or on web site in English).

By Wierzbowsky

Guardian (3648)

01-06-2023, 22:52

gdx wrote:

Wierzbowsky, It would be nice to put your productions in the wiki (or on web site in English).

Most of the stuff I or we (RBSC) do is open-source and it can be found in RBSC's or my own Github repository:
https://github.com/RBSC
https://github.com/wierzbowsky

There are some exceptions though, those are usually the devices that were created for my friends or customers. Those can be sold only as bare boards, DYI kits or as fully assembled devices.