C64 Floppy's and Mitsubishi M4854-362US
#1
Hello everyone,
thank you for taking the time to read this. I am a beginner in 5,25 Floppy Tech and appreciate every little bit of help I can get. 

What I try to Accomplish:
- Make Backups a Stack of c64 Floppy Disks, to Save their Content.
- maybe be able to access the content in a Emulator so i can look what is on there

What i have as Hardware:
- A Super Card Pro
- a 64 Bit PC with Windows 10
- a Mitsubishi Model M4854-362US
- about 100 Floppy Discs from my Dads C64

Resources:
- I found the Description of the Drive I am using: https://retrocmp.de/fdd/mitsubi/m4854_i.htm
It also shows the Jumper settings and what they mean. (Sadly I barely understand them)

- 2 Documents of this Forum. Super Card Pro - Using with Commodore 64 / 128 disks and 5.25 Jumpers

The problem:
I am Able to Read the Frontside of a C64 Floppy and make a Backup of it as a .D64 File. I am also able to "Read" the Files with a Program called "DirMaster v3.1.5"
Trying to read the Backside only shows me Read Errors. I have set the Drive Options to ignore Index on Read. Before doing that i got an Error saying no index found.
Now the Drive Reads the discs but only with errors. I guess it has something to do with Jumpers. But to be Honest. I don't understand the Jumper Settings and i am afraid to mess something up. on https://retrocmp.de/fdd/mitsubi/m4854_i.htm there is a Guide to the Jumpers. But I don't Understand it and like I said I don't want to ruin the Drive. I Included the following Pictures, maybe someone can help me.

Thank you in advance for every little bit of help 
Friendly greetings 
Tony

Dir Master from the Frontside of the Disk that was Successful
[Image: 41256816lu.png]

SCP of the Backside:
[Image: 41256815lp.png]


Pictures of the Drive:
[Image: 41256883mi.jpg]
[Image: 41256882tw.jpg]
[Image: 41256881sb.jpg]
[Image: 41256880ow.jpg]
[Image: 41256884pz.jpg]
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#2
Well, at least you know where the jumper blocks are ! DO NOT change the jumper labled "DS". It is currently set to DS1, and that is correct. That is the drive select jumper. Everything else might need to be experimented with to determine which one(s) of those control reading/writing when the index pulse sensor is not found. From looking at the info you linked to, I would look at IH-1 and IH-2 first. Unfortunately, there is not much detail here. Does the drive spin when the disk is in upside down and the copier started?
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#3
(05-23-2021, 04:10 AM)admin Wrote: Well, at least you know where the jumper blocks are !  DO NOT change the jumper labled "DS".  It is currently set to DS1, and that is correct.  That is the drive select jumper.  Everything else might need to be experimented with to determine which one(s) of those control reading/writing when the index pulse sensor is not found.  From looking at the info you linked to, I would look at IH-1 and IH-2 first.  Unfortunately, there is not much detail here.  Does the drive spin when the disk is in upside down and the copier started?

Thank you very much for your answer. Yes the Drive does spin when the Floppy is inserted on side B. The Interesting part is, that as soon as i turn the index off, it even goes true all 38 Tracks but reports them as Red. I will experiment with the IH jumpers like you suggested. Thank you very much for that. (i made pictures of the Jumpers so i can set them back if i do something wrong)
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#4
ok i have made some Progress. The Drive has apparently 2 heads. One for the Frontside and one for the Backside. What i have noticed when inserting the Disk Backwards is, that the Head does not fully latch on and the Floppy does not stop spinning. When the Floppy is inserted the right way, it however stops and after shortly turning. (Index hole?)
Is there a Way to Tell SCP to use the second Head? Also i noticed that DC (Disc change) has a jumper on it, on the Documents it says that this Jumper was open on factory. The Jumper also has a different color as the others. (maybe added later on by previous owner?)
I am very sorry that i make Mistakes, it is all very new to me but also so interesting. i have read true all kinds of Documents regarding jumper settings in the meantime( which was very fun to me)
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#5
ok i am writing here the original Jumper Settings (as seen in the pictures)

TD - jumper on booth pins [ Drive select Termination ]

ND - Nothing [ Unknown ]
DS3 - Nothing [ Drive select 3 ]
DS0 - Nothing [ Drive select 0 ]
DS1 - Jumper on booth pins [ Drive select 1 ]
DS2 - Nothing [ Drive select 2 ]
MX - Nothing [ Drive select Continuous ]*( permanent drive selection for 1 drive systems? not sure)

RR - Jumper on booth pins [ Radial Output ] ()
UD - Nothing [ head load unload delay ]
IS - Jumper on 1 pin but not connected to 2nd pin (to not lose the Jumper?) [in use no drive selected]
IL - Jumper on booth pins [in use latched]

SS - Jumper on booth pins [no clue]

IG - Set to IG1 (i though that was IH because the text is covered by a resistor) [ IH1 -Normal | IH2 - Head Load ] (is it the same as IH?)

DC - Jumper on booth pins [ready Disc change ] (?)
2S - nothing [ ready held ready ] (?)
MM - Nothing [Motor on]
MS - Jumper on booth pins [Drive select] (guess motor gets signal from drive?)
IU - Jumper on 1 pin again not connected [ in use input]

SB - nothing [no clue]

HS - Nothing [head load drive select]
HC - Jumper on booth pins [head load Constant]
HM - Nothing [head load motor on]
HL - Nothing [head load in use]
HH - Nothing [head load spare]
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#6
You can't use the back side head to read the back side of a disk because the head is shifted (offset) by 4 tracks! This is how all PC drives are made.

It may be that you will need a different disk drive in order to read the back side of a disk if you can't determine a jumper setting that ignores the index hole sensor.
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#7
(05-24-2021, 01:16 AM)admin Wrote: You can't use the back side head to read the back side of a disk because the head is shifted (offset) by 4 tracks!  This is how all PC drives are made.

It may be that you will need a different disk drive in order to read the back side of a disk if you can't determine a jumper setting that ignores the index hole sensor.

Thank you for your Help. Smile 
It is quite the journey as I have to learn. But it is fun and i can save some old tec from the Dump. I will look for a Drive that can be set to ignore index mode or a Single sided disk. 

The Problem with this Drive is, it does not engage the Upper Head if you put the Floppy wrong in. Also i tryed a lot of Jumper settings without luck. But it will still be a good Drive that i can use in my New Retro Computer Big Grin
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