Hello,

I'm looking for your help. It's my first topic here but I'm used to read the forum and always found interesting informations.
THANKS for sharing your knowledge !

Who am I ?
I'm an electronic engineer, my speciality is repairing electronic systems. From train high power, to computer mother board.
Now I work for the R&D team as electronic developer.

THE ISSUE :
I want to save a very old HDD. It's a Conner Periphals CP3041 HDD of only 40MB It was installed in a COMPAQ Computer
https://www.redhill.net.au/d/140.php


The disk has 1 platter and 2 heads.
A little sticker on it claims :
Phys 1026Cyl, 2heads, 40 sectors/track
BIOS settings : 524 cyl, 4 heads, 40 sectors/track

On gparted or debian system:
hdparm : geometry 5/255/63, sectors 84240, start = 0

I've been able to save 20MB of data from this one. Thanks to DDRescue !!!


- I've send this disk to a datarecovery company DAFOTEC in France.
* They've not been able to recover anything.
* They have open the disk as the warranty sticker has been removed.
* I've bought the same disk en eBay USA and send them but they told me the disk as the same issue.
* After 2 months I asked the disk back as they never found any solution a I was waiting for nothing !!!

- I have now both disks back.
* Still able to recover 50% of datas but that's not enough unfortunatly.
* The second disk is not moving the head. But unpark coil is OK and spin correctly. I didn't try it before sending.
* I've tried to swap PCB. I've checked PCBs and they seems to be correct.

* I've tried to swap heads. Same result about 50% recovered.

* HDD is using RLL 2.7
* Head is equipped with a VM117R2POM IC.

* PCB with ML8464C https://bitsavers.trailing-edge.com/pdf ... L8464C.pdf
* The magnet had a rubber on a side, I know it's to avoid the head hit the side but it was inflated, on the original disk the rubber was sticky and inflated, on the second one it was yellow and very breakable. Came loose in parts.

* I've checked ferro head coils and the connections from head to amp to PCB. OK
* I've checked spinning motors = OK
* I've checked coils for moving the head, original is 18 Ohms, donor is 27 Ohms. Strange but both moves.
* I've checked the power supply of amp on the head unit. It's switching from 0 to 5V while reading...
* I've checked HS0 (head selection pin) signal while ddrescue the disk to know if I had a head related issue. And it seems data are collected from both sides of the disk alternatively while reading is OK.
* But HS0 stay to 1 in the end of the data recovery process by ddrescue.

- I have an old version of ACELabs PC3000 !
* But it's not compatible with this disk as it's written in LBA and not CHS mode !
* The disk is not in database and they've never been able to tell me if I buy the new 1 year support and update I will have it...
* Do you have it in your database?


I've tried WinHEX, ddrescue, testDisk, Norton Ghost...

Do you have an idea? A better solution?

I'm waiting for another donor disk !

Thanks a lot

You should be working inside a dust-free "clean cabinet".

How are you keeping the two heads apart? They should not be allowed to touch each other.

Your BIOS translation parameters exceed the capacity of the drive, so I expect that your drive would reject them.

1026 cyl x 2 heads x 40 sectors/track = 82080 sectors <-- native CHS

524 cyl x 4 heads x 40 sectors/track = 83840 sectors <-- BIOS CHS

5 x 255 x 63 = 80325 sectors <-- hdparm CHS

Can you show us the hexadecimal content of LBA 0 (CHS = 0/0/1)? The partition table will tell us how the drive was originally configured.

_________________
A backup a day keeps DR away.

this is something i would need hands-on and a decent pricing to think about dealing with. and feel the chi flowing
though it's an old drive and 'only' 40MB, it can be a real challenge.

pepe

_________________
Adatmentés - Data recovery

Hello,

Yes, you're right. I'd better open it in a clean cabinet or grey area.
I'm wearing gloves and a white blouse when opening the disk I wanna save data.
For the moment it stays clean.

On the picture, the open one is the donor.

I don't keep heads appart on this disk.
Because it's ferromagnetic heads. They are flat


Here is a close up view of th coil connections.
I've opened one side to measure the coil and reverse engineer the wiring on the amplifier circuit.


Here are the first data I've been able to save before sending the disk to a professional company !

We need to see the end of the first sector. That's where the partition table lives.

https://thestarman.pcministry.com/asm/mbr/STDMBR.htm

Here is the datasheet for your preamp:

https://www.datasheetarchive.com/datasheet/VM117R2POP/VTC?id=5ffb8017d0023fd0&term=VM117

http://bitsavers.trailing-edge.com/components/microLinear/_dataBooks/1991_Micro_Linear_Semi-Standard_Analog_Data_Book.pdf (page 389)

ISTM that you could test the heads by comparing the coil resistance, and you could examine them for contamination under your microscope.

_________________
A backup a day keeps DR away.

Thanks, I've found the datasheet for the amp.
And already did the schematic and measured the Head Selection Signal.
Seems to be fine...


Here is the first sector, right?

The ddrescue log :
# Mapfile. Created by GNU ddrescue version 1.23
# Command line: ddrescue /dev/sdb SAT2.img logdisk.log -r1 -R
# Start time: 2024-11-14 13:37:24
# Current time: 2024-11-14 15:49:20
# Scraping failed blocks... (backwards)
# current_pos current_status current_pass
0x016B1600 / 1
# pos size status
0x00000000 0x01496000 +
0x01496000 0x0021B600 -
0x016B1600 0x01270800 /
0x02921E00 0x00000200 -

The partition starts at CHS = 0/1/1 and ends at CHS = 522/3/40.

The capacity of the partition is 83640 sectors = (523 x 4 x 40) - 40.

Therefore the correct translation mode is 524/4/40 (1 x maintenance cylinder), which is your BIOS translation mode. This is larger than the capacity on the sticker.

_________________
A backup a day keeps DR away.

Can you retrieve the 512-byte Identify Device data block from the drive? That should contain the current CHS parameters and the native CHS parameters.

_________________
A backup a day keeps DR away.

Could this be helpful???

Raw buffer:
0: 5a 0a 1d 04 00 00 02 00 d1 62 69 02 28 00 32 00 Z........bi.(.2.
10: 0c 00 00 00 30 45 48 48 50 36 20 20 20 20 00 00 ....0EHHP6 ..
20: 00 00 00 00 00 00 00 00 03 00 10 00 04 00 32 53 ..............2S
30: 32 2e 20 35 20 20 6f 43 6e 6e 72 65 50 20 72 65 2. 5 oCnnreP re
40: 70 69 65 68 61 72 73 6c 34 20 4d 30 20 42 20 2d pieharsl4 M0 B -
50: 50 43 30 33 31 34 20 20 20 20 20 20 20 20 10 00 PC0314 ..
60: 00 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
Model= Conner Peripherals 40MB - CP3041
Serial= E0HH6P
Firmware revision= S2.25
supports 48 bit commands = 0
total addressable sectors= 0
words per logical sector= 0
Size in bytes= 0
Size in MiB= 0
logical sectors per physical sector(2^x)= 0
enhanced_security_erase_supported= 0
security_count_expired= 0
security_frozen= 0
security_locked= 0
security_enabled= 0
security_supported= 0
error_recovery_control= 0
long_sector_access =0
drive look ahead supported= 0
drive look ahead status= 0
write_uncorrectable supported= 0

A picture of the HDD with the label :

This is what I get:


The current translation mode is not populated.

_________________
A backup a day keeps DR away.

1053 x 2 x 40 = 84120 sectors
And 84120 x 512 = 43 069 440 bytes.

So around 41Mb. Seems to be correct !

HDD capacities were advertised in MB rather than MiB.

I'm wondering how you are getting all the different translation modes when BIOS is set for 524/4/40. The drive has 1053 cylinders, but CHS can only handle a maximum of 1024 cylinders. BIOS then halves the number of cylinders and doubles the number of heads to circumvent this limitation. It then sends an ATA Initialize Drive Parameters command to the drive using these new CHS values, after which the drive changes its translation mode and reports these new parameters in words #54 - 58. I suppose that Linux can also do the same thing in those cases where a modern BIOS has no CHS support.

In short, I can't see how you can clone the first 20MB of your drive without error if either head has a problem. Instead I would expect to see stripes in your data as the drive switches between the good and bad head.

BTW, I'm not a data recovery professional, so there may be errors in my logic.

_________________
A backup a day keeps DR away.

The content of the 27C256-15/L EEPROM version S2.25 :

EDIT: I cannot provide the .hex or .bin file here

EDIT2: but the rar file YES

I've pluged the HDD to a more recent computer with a Linux Debian. I leave the bios adapt itself...

The BIOS Settings on the label were used for the old COMPAQ XEROX 386 computer !

Some more datas I've found :

http://matthieu.benoit.free.fr/182.htm

J1 connector from PCB to the inside of the disk to the amplifier :


I'm reversing J4, it seems to be a external access port...
Serial Communication?

Datas extracted from the second disk by J4 connector !!!

I hear this splatter spinning and stopping.

I don't know why but with the other platter it spins.

Speed = 7200 bauds !!!

Sierra - S2.25

Begin test 40
Intf
Ref 20 - Xsition 20 - Full spd 083 - Spin timeout
Ref 1F - Xsition 1F - Full spd 081 - Spin timeout
Ref 1E - Xsition 27 - Full spd 07F - Data lock -................................ ................................................................................ ................................................................................ ...................................................*............................ .*.......................*...................................................... ................................................................................ ................................................................................ ................................................................................ ................................................................................ .......................................................................*........ ................................................................................ ................................................................................ ................................................................................ ..........................*..................................................... ................................................................................ .......*.........................................*............................*. ................................................................................ ................................................................................ ................................................................................ ................................................................................ ................................................................................
...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Spin timeout
Ref 1E - Xsition 21 - Full spd 082 - Spin timeout
Ref 1E - Xsition 26 - Full spd 080 - Spin timeout
Ref 1E - Xsition 25 - Full spd 07E - Data lock -...............................................................................................................................................................................................................................................................................................*..............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................*....................................................*.................................................*...............................................................*........................................................................................................................................*............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................*.........................................................................................................................................................................................................................................................................................Spin down
Ref 1E - Xsition 23 - Full spd 083 - Spin timeout
Ref 1E - Xsition 21 - Full spd 083 - Spin timeout


J4
1 1 de J6 2 2 de J6
3 NC 4 NC
5 GND 6 GND
7 Pin 34 de SC80566FN=>TX 8 Pin 33 de SC80566FN => ?
9 Pin 29 de SC80566FN=>spinning frq? 10 Pin 21 de SC80566FN => ?
11 VCC +5V 12 VCC
13 VDD +12V 14 NC

Veery dumb question, but the PCB doesn't have broken components? (You've probably checked it already gazilion times) Had an film capacitor make an st2383n not initialize.

No dumb question. Yes I’ve swapped PCBs and checked components!
No failures on the electronic side