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MiniScribe 8438 flashing error code

RWIndiana said:
I don't know if it would help at all, but I have a number of PCBs and even disk assemblies from the Miniscribe 8425/8438 twins that are faulty and malfunctioning. Would be glad to give them to a good home. ;)
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Hey, thanks for the offer. I'd be interested if shipping is not too expensive.
RWIndiana said:
Track 0 on most Miniscribes is adjustable by rotating the interrupter on the stepper motor shaft (I acquired a 8425 about 10 years ago that had a totally worn out track 0, could not format. Adjusted it so track 0 is closer to the outside of the platters, and the drive is happily chirping away to this day, with a batch of bad sectors where the old track 0 was). If adjusted too far in either direction though, it will have problems finding the sensor. In that case you will get a 1701 error from the system. Could it be that your donor drive has a misplaced interrupter?
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It could be that it is misplaced, as it looks like someone had messed with the drive before.

I attempted to scope the stepper motor driver ICs now, but it's cumbersome because I have to power cycle the drive and wait for it to spin down and up again each time to catch the event. If I find out how to reset the controller that would speed up troubleshooting. I also tried to find a track 0 pulse, but no success yet.
 
powerlot said:
Hi all

I have an XT clone with a Transteque HC-101 A1 controller card and a MiniScribe 8438 hard disk. It was working fine a few weeks ago but now it spins up and a moment later down again, then flashes an error code:

According to this it's "Code 4 - Index pulse not detected during spinup", if I got this right?

Where do I start? I reseated the ICs on the controller and tried different slots, but the problem is probably the drive itself, right? I also didn't find any documentation about the controller card... I hope it'll be fine.

Thanks for any hints!
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Please do not use Stason. It's just a copy of TH99 but formatted worse and covered in ads.
http://th99.infania.net/h/txt/2714.txt

The controller will make zero difference to the drive, this is a "dumb" ST-412 control disk. It has no idea what controller or machine it is attached to, or even if it is attached to one.

The Miniscribe 8400 series drives was not known for their great reliability.

Here is the technical manual for the 8400 series drives: http://cd.textfiles.com/crawlycrypt2/txtfiles/misc/hd_data/miniscrb/m8pm.txt
It looks like your drive is flashing "0100" which would be code 4, index pulse not detected. The index pulse is generated by a sensor near the spindle motor, under the controller, which picks up a pulse once per revolution. This signal is used to tell the controller where the "start" of the first sector should be, typically.

A lack of index pulse means that the controller will never know where data "should be" so to speak, and so the drive fails to diagnostic code. Pull the controller off the bottom and hope the index sensor is just out of adjustment or unplugged. Otherwise, the sensor or spindle motor are junk. The sensor will be easier to get a hold of if you really want. A spindle hub will be significantly more difficult to find and will probably have to come from a donor drive.

To be clear, this is a rotating mechanism problem, not a track 0 sensor issue. The index sensor is on the bottom of the drive. If you are looking for the signal, it is provided on the control interface connector. Pin 20 is "INDEX" and is active low. the pulse should be around 300 microseconds as per the service manual. Pin 1 is towards the notch, and with the notch to your left and the edge of the PCB facing you, the top of the drive should be the signals. Pin 20 will be tenth from the left or seventh from the right. To get the signal out this way, you should change the drive to be on select #4 and ground the second pin from the right (pin 32) which will select it perpetually. You can do this with a small alligator clamp from top to bottom on the correct pin.
 
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famicomaster2 said:
Please do not use Stason. It's just a copy of TH99 but formatted worse and covered in ads.
http://th99.infania.net/h/txt/2714.txt
Click to expand...
Didn't know that, I will in the future. I have an ad blocker so I didn't really notice it.
famicomaster2 said:
The controller will make zero difference to the drive, this is a "dumb" ST-412 control disk. It has no idea what controller or machine it is attached to, or even if it is attached to one.

The Miniscribe 8400 series drives was not known for their great reliability.

Here is the technical manual for the 8400 series drives: http://cd.textfiles.com/crawlycrypt2/txtfiles/misc/hd_data/miniscrb/m8pm.txt
It looks like your drive is flashing "0100" which would be code 4, index pulse not detected. The index pulse is generated by a sensor near the spindle motor, under the controller, which picks up a pulse once per revolution. This signal is used to tell the controller where the "start" of the first sector should be, typically.

A lack of index pulse means that the controller will never know where data "should be" so to speak, and so the drive fails to diagnostic code. Pull the controller off the bottom and hope the index sensor is just out of adjustment or unplugged. Otherwise, the sensor or spindle motor are junk. The sensor will be easier to get a hold of if you really want. A spindle hub will be significantly more difficult to find and will probably have to come from a donor drive.
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In the middle of the thread I obtained a donor drive for parts (Miniscribe 3650, not the same model but was cheap so why not), but then discovered that the problem is in the wiring or the connector of the sensor/spindle motor. It is becoming intermittent again so I have to replace that connector and hope it's not a broken wire or something on spindle side. Can I remove the spindle motor for further inspections?
famicomaster2 said:
To be clear, this is a rotating mechanism problem, not a track 0 sensor issue.
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I started troubleshooting the other drive halfway through, which was in a slightly sorry condition and has the track 0 error code. I thought I'd try to repair the other drive too and didn't open a second thread as the mode of operation looks to be similar for both drives.
famicomaster2 said:
The index sensor is on the bottom of the drive. If you are looking for the signal, it is provided on the control interface connector. Pin 20 is "INDEX" and is active low. the pulse should be around 300 microseconds as per the service manual. Pin 1 is towards the notch, and with the notch to your left and the edge of the PCB facing you, the top of the drive should be the signals. Pin 20 will be tenth from the left or seventh from the right. To get the signal out this way, you should change the drive to be on select #4 and ground the second pin from the right (pin 32) which will select it perpetually. You can do this with a small alligator clamp from top to bottom on the correct pin.
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I found the signal, the actual problem was the intermittent connection causing the index signal not to go below TTL levels for the controller to register as zero.
 
I managed to get the 3650 going. My oil flask didn't reach properly into the stepper motor so I unscrewed the interrupter arm, lifted it a bit and dropped more oil into the motor.

After reassembly and startup it headbanged (whoops), but at the second startup it looks like it stepped properly.

The controller recognizes something, but the drive isn't accessible to the controller. Now I'm not sure if my controller supports this drive and I have to jumper it properly, of if there's still an issue with track 0.
 
The 3650 also has blink codes which are different. The 8400 series has a track 0 sensor adjustment mode by putting the drive into exercise mode and removing the jumper before it begins exercise, but I am unsure if the 3650 has the same.

You should not have to remove the interrupter to oil the stepper of a 3650, remove the controller and access the shaft of the stepper from the bottom. It is much easier this way.

As far to my knowledge, the 3650 and 8400 have two different spindle motors.

Good to hear you got it working! The 3650 will be easy to get running too, if you oil it a little bit and put it in exercise mode it should go back to working. That said, the Miniscribe 3650 is the original "Bad" MFM hard drive, second only to the CMI 6000 series, so be warned that they are not known for their reliability. Do not run them in RLL duty (more than 17 sectors per track) because they absolutely cannot handle it.
 
famicomaster2 said:
The 3650 also has blink codes which are different. The 8400 series has a track 0 sensor adjustment mode by putting the drive into exercise mode and removing the jumper before it begins exercise, but I am unsure if the 3650 has the same.

You should not have to remove the interrupter to oil the stepper of a 3650, remove the controller and access the shaft of the stepper from the bottom. It is much easier this way.

As far to my knowledge, the 3650 and 8400 have two different spindle motors.
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Have you disassembled or removed such a spindle motor? On the 8438, I've noticed that the problem with the index pulses is most likely not in the connector, but somewhere down the line. It's intermittent and sometimes it starts up correctly when I wiggle on the red wire specifically.

famicomaster2 said:
Good to hear you got it working! The 3650 will be easy to get running too, if you oil it a little bit and put it in exercise mode it should go back to working. That said, the Miniscribe 3650 is the original "Bad" MFM hard drive, second only to the CMI 6000 series, so be warned that they are not known for their reliability. Do not run them in RLL duty (more than 17 sectors per track) because they absolutely cannot handle it.
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No great hopes for this one, but I'll try to see if I can get some use out of it if not for gaining experience. I learned that without the MFM controller that was originally used to format the drive there's no way to read the data on it and with me messing with the track 0 interrupter it's probably out of whack anyway. So the next step is trying to low level format the drive and find out if it works.

I don't have a manual for my controller (Transteque HC-101), but I hope that the programs on the ROMs are similar to this one: https://minuszerodegrees.net/manuals/Transteque model HC-100.pdf
3. You may physical format your hard disk by using debug.com file in your DOS SUPPLEMENTAL PROGRAMS diskette.
Insert DOS SUPPLEMENTAL PROGRAMS diskette in drive a: and type "debug" and press the "Enter" key. The computer will respond with a "-".

Type g=c800:6 [Enter] [Enter] is to press the "Enter" key The same display as mentioned in step 2 will appear and the formatting procedures are the same.
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If not, I guess I have to disassemble the data on the ROM.
 
Hello, I tried formatting the Miniscribe 3650 by calling this address c800:6 and it brought up a formatting program, but I'm getting an error code:

Code 03 -WRITE FAULT will not reset


It asked me to enter all in decimal, and this is what I did:
miniscribe3650-format.jpg

Any ideas? :/

When I call the head parking program it parks the heads and upon next startup it headbangs a bit. The drive also emits a high pitched noise, so I guess it's broken?
 
Is the code 3 set by the flashing lamp on the front of the drive as well or just the controller?

Write fault latch might be enabled when it should not be. There should be a jumper to disable it, though I think Miniscribe drives do not even have this option. There may be an electronic issue with the disk drive.

Why are you running the drive as two LUNs? You should not do this for normal operation of the drive. You are "splitting" it's capacity across BOTH drive IDs on the controller which will confuse a lot of software looking at the physical geometry. If possible you should specify the factory defects on the top of the drive as well.

The seek test (from parked position) of a Miniscribe 3650 is almost identical to other Miniscribe III disks, and the 8000 series as well. The head banging against the inward stop is normal, and the high pitched noise should last about half a second of the drive pulling it's heads back to cylinder 0.

It is probably not worth your effort, the Miniscribe 3650 was a notoriously unreliable drive during it's own time and they have not aged gracefully. They do not auto-park on power down, it was optional to set the drive up with auto-parking after 30 seconds of inactivity (drive is not selected) and this was not a commonly selected option, I find, so many of these drives are left with physical damage in cylinder 0, 1, 2 etc which means they are not useful in DOS nor for booting a machine.
 
famicomaster2 said:
Is the code 3 set by the flashing lamp on the front of the drive as well or just the controller?
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Just the controller, the LED on the drive flashes briefly on access
famicomaster2 said:
Write fault latch might be enabled when it should not be. There should be a jumper to disable it, though I think Miniscribe drives do not even have this option. There may be an electronic issue with the disk drive.

Why are you running the drive as two LUNs? You should not do this for normal operation of the drive. You are "splitting" it's capacity across BOTH drive IDs on the controller which will confuse a lot of software looking at the physical geometry. If possible you should specify the factory defects on the top of the drive as well.
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I followed the Miniscribe technical support manual page 23 since it's the closest I have to instructions and there are Adaptec branded ICs on the controller
1668119632338.png
No defects on the label either
famicomaster2 said:
The seek test (from parked position) of a Miniscribe 3650 is almost identical to other Miniscribe III disks, and the 8000 series as well. The head banging against the inward stop is normal, and the high pitched noise should last about half a second of the drive pulling it's heads back to cylinder 0.
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It's not a loud but noticeable whine, like from a CRTs high voltage. Maybe one of the heads crashed.
famicomaster2 said:
It is probably not worth your effort, the Miniscribe 3650 was a notoriously unreliable drive during it's own time and they have not aged gracefully. They do not auto-park on power down, it was optional to set the drive up with auto-parking after 30 seconds of inactivity (drive is not selected) and this was not a commonly selected option, I find, so many of these drives are left with physical damage in cylinder 0, 1, 2 etc which means they are not useful in DOS nor for booting a machine.
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Then I'll assume the same fate happened to this one. It was interesting though, to find out how it works.

EDIT: The high pitched noise seems to vary in modulation when I flex the board. It also seems to be emitted from the area where component get really hot. So possibly something broken on the PCB
 
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That sounds like a transistor whining, then. There is something electrically wrong with the control PCB on the bottom of the drive - Often times, this can be the result of an unstable power supply, but more likely than not there is a transistor that is shorting when it warms up and eating a bunch of power. Drives with unhealthy spindle motors will do this just from the power they are drawing to stay spinning - You can try to oil them through the ground strap but that's about it.
This is probably why the write fault is not clearing either.
 
Where would you apply the oil for the spindle motor? It's the area of the stepper motor circuitry where it gets hot though, but I'll try to identify the whining component and test it.
 
RWIndiana said:
I don't know if it would help at all, but I have a number of PCBs and even disk assemblies from the Miniscribe 8425/8438 twins that are faulty and malfunctioning. Would be glad to give them to a good home. ;)

Track 0 on most Miniscribes is adjustable by rotating the interrupter on the stepper motor shaft (I acquired a 8425 about 10 years ago that had a totally worn out track 0, could not format. Adjusted it so track 0 is closer to the outside of the platters, and the drive is happily chirping away to this day, with a batch of bad sectors where the old track 0 was). If adjusted too far in either direction though, it will have problems finding the sensor. In that case you will get a 1701 error from the system. Could it be that your donor drive has a misplaced interrupter?
Click to expand...
I have a broken DIP22 SGCC 04460100 8847 on the PCBA of a 8450 which is a ST506 interface. I also have a 8425 with a good PCBA but the disks were scratched or worn to the point nothing could write to them. Any chance that offer is still good? I would like to try different DIP22's to see if I can swap them out. I have a socket installed there now.
 
powerlot said:
Where would you apply the oil for the spindle motor? It's the area of the stepper motor circuitry where it gets hot though, but I'll try to identify the whining component and test it.
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Pull the PCB off and the spindle motor has a single, central ball bearing poking through as a grounding point. You can put a few drops of oil here and hope for the best. Leave it sit upside down like this for a few hours or days if possible. This is the most that can be done.

mrwebber35 said:
I have a broken DIP22 SGCC 04460100 8847 on the PCBA of a 8450 which is a ST506 interface. I also have a 8425 with a good PCBA but the disks were scratched or worn to the point nothing could write to them. Any chance that offer is still good? I would like to try different DIP22's to see if I can swap them out. I have a socket installed there now.
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8450 is the ST-412 interface, as it deprecates the RWC pin and supports buffered seek.
 
famicomaster2 said:
Pull the PCB off and the spindle motor has a single, central ball bearing poking through as a grounding point. You can put a few drops of oil here and hope for the best. Leave it sit upside down like this for a few hours or days if possible. This is the most that can be done.


8450 is the ST-412 interface, as it deprecates the RWC pin and supports buffered seek.
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Is that right, thanks for messing with me.
stason.org

Hard Drive: MINISCRIBE: M8450 41MB 3.5"/HH RLL ST506

Manufacturer: MINISCRIBE model: M8450 capacity: 41MB, physical size: 3.5in/HH , interface: RLL ST506 , hard driver specs and jumper settings, layout and features
stason.org stason.org
 
modem7 said:
I think he means that you are saying, "ST-412 interface", but the information that he pointed to in post #35 indicates "ST506".

In my opinion, the "ST506" in the pointed to information is simply a shorted form of "ST-506/ST-412 Interface".
View attachment 1257402
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Ah, I see. Yes, ST-412 drives can be used with an ST-506 controller so long as RWC is set outside the maximum cylinder of the drive. However, the reverse is not true, and you cannot use an ST-506 drive on an ST-412 controller without modification. Whether or not RWC is required is highly debated, but rest assured that the unbuffered 3ms seek is a pretty hard requirement. I've tried!

For clarification, the ST-412 is an updated variant of the standard which includes provisions for drive-controlled seek profiling and write current reduction. Calling such a late drive "ST-506" would not entirely be correct, as it follows the more modern standard. The 8450 is actually a step beyond this, even, using the ST-412HP standard which allows 7.5 million transitions across the data lines, aka "RLL." Although, due to their simple nature, really any drive can be driven in this manner at the risk of losing data.

Lastly, I would strongly recommend *against* using stason.org, they are a mirror of the famously bad (but free!) Total Hardware 99. The main difference is that stason puts ads on his site and tries to sell his book as well. Use one of the free copies instead.
 
famicomaster2 said:
Lastly, I would strongly recommend *against* using stason.org, they are a mirror of the famously bad (but free!) Total Hardware 99. The main difference is that stason puts ads on his site and tries to sell his book as well. Use one of the free copies instead.
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Yes. You will see that on my web page at [here], I point to a different provider of Total Hardware 99.
 
I have a MiniScribe 8450. There is no letter designation after the number.
It is the 3.5" 1/2 height drive. I am assuming it is an 8 bit drive.
Is that the same as 8450F and <or> 8450A? You guys seem to know what this really is.
A YouTube video said certain drives can be RLL or MFM. Maybe this can be if the letter
at the end is the same thing for A , F and nothing?
Seems the 8450XT = 771 cyl. and 8450AT = 805 cyl. Is there a chart of all 8450's somewhere with all specs?
I have a 8bit DTC-5150CR control card that can do MFM only but standard BIOs doesn't show the HD 8450 size.
It has only an 8 Kbit BIOS and the specs claim it needs a 16 Kbit BIOS to set the parameters manually with "special parameters".
I would have to get the DTC-5160CR or DTC-5160X card to do DLL. I suppose that is where the 16kbit BIOS can be found, maybe?
Below Wayback specs right from Maxor/MiniScribe say it is 8450A that can be DLL or MFM but it is a 16 bit IDE interface.
I believe IDE means it is a newer drive than what I have with the single IDE cable rather than the two separate control ribbon and data ribbon.
 
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