Author Topic: Amstrad PCW 9512 problems.  (Read 3083 times)

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Offline FixMePlease

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Amstrad PCW 9512 problems.
« on: 02:51, 10 June 20 »
Hello all,

[/size]New to the site, so please forgive any breaches of protocol .. and please point me in the right direction if needed.
[/size]
[/size]Have recently been given a Amstrad PCW 9512, not working.[/size]Without going into a lot of detail, here's what I've done so far:The disk drive belt was shot, so I've replaced that.  I've measured 5V and 12V at connection CP005. The drive light comes on, as does the shift lock on the keyboard, but nothing happens when a disk is inserted .. no flashing, no beeps at all. The monitor has power and the CRT lights up, but all I have are what appear to be horizontal scan lines when the brightness is turned up almost full.


Any and all help greatly appreciated,


Thanks

Offline tjohnson

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Re: Amstrad PCW 9512 problems.
« Reply #1 on: 14:43, 10 June 20 »
Have you tried turning it the right way up? Maybe the disk drive doesn't like being vertical rather than horizontal.

Offline GeoffB17

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Re: Amstrad PCW 9512 problems.
« Reply #2 on: 16:33, 10 June 20 »
Hello,

Well, they do say that a picture tells a thousand words, but in this case, at least a few words would have been a massive help!

So, a few questions!

Was the machine working, and then stopped, or what?

When you turned it on, and inserted the disk, what happened.   incl any noises?   I think I can see that the disk light is on, that's something.   Was there any other sound from the drive?

These disk drives have a rubber band in, and the band corrodes (turns to goo) and breaks.   Have you tried to replace it?   You can buy repl drive bands for a couple ££ via ebay.

If the disk tried to read/load, it may NOT be a boot disk, but the screen is the wrong colour for that (?).   Only a specific 'boot' disk will work, a 'System' disk with a specific prog on it.   What does the label say the disk is.   If the disk is NOT a boot disk, have you any other disks, have you tried them.   Maybe marked 'Start of Day' or LocoScript or CP/M.

If you've just got the machine, and this is your first attempt to get it running, you should say so, and detail what disks you got with it.   If any.   You may need to find suitable disks (one for CP/M, another for LocoScript).   You'll need the High capacity ones for this machine, CF2DD type for the 9512, although the machine can READ the smaller capacity disks once it's booted.

So, a few more of the thousand words, please.   When we get to VERY specifics, then a picture might help!

Geoff
« Last Edit: 16:39, 10 June 20 by GeoffB17 »

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #3 on: 18:55, 10 June 20 »
Thanks for the replies, and my apologies for lack of words and a sideways picture .. new to not just this forum, but any forum.


The disk drive belt was shot, so I've replaced that.  I've measured 5V and 12V at connection CP005. The drive light comes on, as does the caps lock on the keyboard, but nothing happens when a disk is inserted. The monitor lights up, but all I have are what appear to be horizontal scan lines. There are no sounds or beeps of any kind emanating from the machine.

Before I replaced the disk belt, there was a sound coming from the area of the disk which I think may have been the sled (or whatever they're called in these drives) moving .. but now I do not hear this.

The disks I have are  CP/M PLUS ..  LOCOSCRIPT 2 ..  and a CF2 disk labelled with a written "Locoscript Start Of Day"

This is a new type of computing for me, I've only ever having messed with PC's, along with a few Macs and some old Commodore 64's
So .. any and all help will be greatly appreciated on my learning journey.
« Last Edit: 10:09, 29 June 20 by Gryzor »

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #4 on: 19:04, 10 June 20 »
The disk drive belt was shot, so I've replaced that.  I've measured 5V and 12V at connection CP005. The drive light comes on, as does the caps lock on the keyboard, but nothing happens when a disk is inserted. The monitor lights up, but all I have are what appear to be horizontal scan lines.  There are no sounds or beeps emanating from the machine.
Before I replaced the disk belt, there was a sound coming from the area of the disk that sounded like the sled mechanism
(of whatever it's called in these drives) .. but I no longer hear that sound.
« Last Edit: 10:10, 29 June 20 by Gryzor »

Offline GeoffB17

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Re: Amstrad PCW 9512 problems.
« Reply #5 on: 19:12, 10 June 20 »
Hello,

Hm, another picture, answers one question, other questions outstanding...

The three disks illustrated are the original system disks for the system, i.e. that for LocoScript and that for CP/M.   The other disk is marked by the user to say it's a 'Start of Day' disk, and this should be a copy of the LocoScript system disk, but available as a working copy that can be written to.

So, all three disks should boot.   Assuming undamaged by time, etc.  So back to the original question, what did the machine do when you turned it on and inserted the disk?  Could you hear the disk spinning?   Was there any clicking sound as the system tried to read the disk?  Any sound at all?  Help please.

Do all three disks do the same thing if you try to boot from them?

Geoff

Offline GeoffB17

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Re: Amstrad PCW 9512 problems.
« Reply #6 on: 19:19, 10 June 20 »
There are two motors in the drive.  One spins the disk, if that is working you should hear a slight noise as the disk spins.   The other motor is the stepper motor, and this tries to move the head over the disk surface, and should return the head to the start (track 1) position.

If the rubber band has disintegrated, did you make sure there were no bits of the band anywhere to jam up anythinf that should NOT be jammed?

Geoff

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #7 on: 19:33, 10 June 20 »

Hello,
I'm quite sure I removed all debris when I had the drive apart, although if necessary I could go in there again and look for problems .. anything else I should be looking for other than belt fragments ?  I should mention that when I had the drive apart, I heard a 'pin drop' .. which turned out to be a small brass pin which I think is part of a write or write protect mechanism.  I could find only one place and one way to reinsert it near to the micro-switch, which is where it now sits.
« Last Edit: 10:11, 29 June 20 by Gryzor »

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Re: Amstrad PCW 9512 problems.
« Reply #8 on: 20:09, 10 June 20 »

The size of text to small, this is the text to the first post:



New to the site, so please forgive any breaches of protocol .. and please point me in the right direction if needed.
Have recently been given a Amstrad PCW 9512, not working.Without Have recently been given a Amstrad PCW 9512, not working.
Without going into a lot of detail, here's what I've done so far:
The disk drive belt was shot, so I've replaced that. 
I've measured 5V and 12V at connection CP005.
The drive light comes on, as does the shift lock on the keyboard, but nothing happens when a disk is inserted .. no flashing, no beeps at all.
The monitor has power and the CRT lights up, but all I have are what appear to be horizontal scan lines when the brightness is turned up almost full.
Any and all help greatly appreciated,


Hello all,



Thanks
« Last Edit: 10:11, 29 June 20 by Gryzor »

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Re: Amstrad PCW 9512 problems.
« Reply #9 on: 20:19, 10 June 20 »
The second post from by FixMePlease had also small text:

Thanks for the replies, and my apologies for lack of words and a sideways picture .. new to not just this forum, but any forum.


The disk drive belt was shot, so I've replaced that.  I've measured 5V and 12V at connection CP005. The drive light comes on, as does the caps lock on the keyboard, but nothing happens when a disk is inserted. The monitor lights up, but all I have are what appear to be horizontal scan lines. There are no sounds or beeps of any kind emanating from the machine.

Before I replaced the disk belt, there was a sound coming from the area of the disk which I think may have been the sled (or whatever they're called in these drives) moving .. but now I do not hear this.

The disks I have are  CP/M PLUS ..  LOCOSCRIPT 2 ..  and a CF2 disk labelled with a written "Locoscript Start Of Day"
This is a new type of computing for me, I've only ever having messed with PC's, along with a few Macs and some old Commodore 64's

So .. any and all help will be greatly appreciated on my learning journey.

Offline GeoffB17

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Re: Amstrad PCW 9512 problems.
« Reply #10 on: 20:58, 10 June 20 »
Thank you for the clarification that there WAS text there all along.   I never use the 'cosmetic' features of the system, so I was not aware of the implications of the 'mess' that I could see on the screen.   I never thought that it might be relevant text.   I still can see no way to display it within the forum process, although I'd guess that if I use the browser to View Source of the HTML code this might do the job, but I'd have to extract the text from all the HTML tags, etc.  My apologies for helping with the confusion.

Regarding the pin that dropped, yes, this will be a write protect pin.   One fell out of my drive some time ago, but Bryce put it back in for me when he fixed the drive.   I thought that this mechanism was only used in the older drives, yours should be a newer one that does not have this problem?   But clearly, it does!

You need to try to operate the drive outside the computer, i.e. take the drive out, get it as bare as you can, reconnect, and try to operate.   I've done this with my PCW8256, I'm not sure if it's still possible with the 9512.   This will allow you to see if the disk is spinning, and if the stepper motor is stepping.  BOTH need to operate.   My stepper motor failed totally, again something inside had rotted, and something else had broken.   Bryce managed to take the motor apart and fix it, to return even better than new!  I understand this is a fix that he's done for a number of others since.   If this is the problem, and the disk motor is spinning OK, then you may hear that the stepper motor is trying to do something but the worm thread is not doing anything so the head is not moving.

Yes, just tried it.  View Source does let me see the missing text, but it's as tedious as hell to read it with all the scrolling etc.

Geoff
« Last Edit: 21:04, 10 June 20 by GeoffB17 »

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #11 on: 22:20, 11 June 20 »
I've done as you suggested with the drive out and observable, but there is nothing happening other than a solid red light.
I know the spindle motor works as I've applied power to that and had it run alright. I'd like to do the same with the stepper, but not sure how and I don't want to cause any or further damage, although a continuity check of the coils with a multimeter suggests to me that they may be alright. I tried powering the drive from a desktop pc power supply (with the red and orange wires reversed), and while the spindle motor starts right away by carefully plugging in so as to connect to its wires only, as soon as the stepper motor wires are connected the drive becomes lifeless.  Before I go tearing apart the stepper motor, I'd like to ask if I should be getting any beeps at all, even with the drive as it is I'd have expected some sort of error or alert. And, how about the screen .. are horizontal scan lines normal when a drive is faulty or a machine won't boot ?  Oh, if this means anything, the guy who gave this machine to me said that "The power light comes on when it is switched on, but it does not boot. I think I remember that the on / off switch at the back had to be pushed a few times towards the end of the time that I was using it" .. The fun continues

Offline GeoffB17

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Re: Amstrad PCW 9512 problems.
« Reply #12 on: 00:30, 12 June 20 »
Hello,

Oops, I think I missed part of my meaning.   The idea was that you should try to reconnect the drive to the PCW so that everything was connected as normal, but the drive was visible.  then you could operate the machine normally, insert disk, etc, but be able to see what's happening.   This is possible with my 8256, as I've done this when I was trying to work out the problem with my drive, when I determined that the stepper motor was trying but was not actually doing anything.   If it's OK, you will clearly see that the head is stepping, with purpose, and that the disk is spinning, and that the head is moving and closing on the disk to read the track

It adds postage to the cost, but I sent my drive to Bryce.   He greased it, re-aligned the heads (this will be necessary after it's been taken apart and put back together) and it was better than new!  Not something you should try yourself.  If this IS necessary (yet to be determined) then contact him directly via PM.

Oh, there are beeps if there IS a disk, but it's not the correct one (i.e. no System).

Does the 9512 have a brightness knob?   Could be that this is in the wrong position?  Try this at both extremes, and in the middle.   But you'd get some sign of activity if the drive was working.   And some sign if the disks were being tried to be read, but not read.   Sounds more like your's isn't even trying to read.

If the stepper motor has the sort of problem mine had, then the problem is totally mechanical inside.   The meter would show things normal.   Do a search for 'Amstrad PCW stepper motor' and you'll find Bryce's article about the problem and what he did.

Geoff
« Last Edit: 00:39, 12 June 20 by GeoffB17 »

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #13 on: 08:38, 12 June 20 »
Hello,


No, none of your meaning was missed.  I had the drive out and connected as it should be by routing the cables through the apex where the drive usually sits, I also had all the covers off the drive so as to observe the flurry of inactivity .. the only sign of drive life is the red light, and when the power is applied there is a very, very slight movement of both the spindle motor and the stepper motor .. after that, nothing more either with or without a disk in the drive.


Even if the stepper motor is shot, shouldn't the spindle motor at least try to do something ? It's this lack of any motor life in the drive that's making me think the issue is further back in the electronics.


Yes there is a brightness control, but all that does is let me see a bright screen-full of scanning lines at full-up setting. Anywhere around the half-way mark is a completely dark screen, which is where my concern comes in, shouldn't there at least be the nice green glow that I seem to be seeing in most depictions of these systems ?


Usually, I'm like a dog with a bone when it comes to troubleshooting and repairing anything, I won't give up .. but I'm almost ready to bury this bone.

Offline CanonMan

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Re: Amstrad PCW 9512 problems.
« Reply #14 on: 15:00, 12 June 20 »
Have you checked all the supply rails are present? Maybe the 5 volt rail is down.


Offline GeoffB17

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Re: Amstrad PCW 9512 problems.
« Reply #15 on: 15:32, 12 June 20 »
Right, yes.

I've re-read your earlier message, and I now see that you were observing BOTH motors, and reporting that neither of the two, the 'spindle' motor as you refer to it, and the stepper motor, are working.   So, yes, it is more likely that there's something wrong with the power supply, and as the latest message suggests, there are two lines, for 12v and 5v, and one might be working giving indication of life, but the other is NOT.   As suggested, there may be a problem with the 5v line, which is more relevant to the disk drive, the scan lines on the screen suggests that the 12v line is OK.

As you were applying your own voltage to the motors, I'd guess that you were not getting any reading of volts when you tested.

You can find a circuit diag for these on the web.   I don't know how different the setup is between the 8256 and the 9512, prog just in detail and layout.   Amstrad published technical manuals for all their kit, I have the one for the 8256, I'm sure you'll find the one you need.   Might even be just a fuse?

Geoff

Offline CanonMan

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Re: Amstrad PCW 9512 problems.
« Reply #16 on: 16:20, 12 June 20 »
You should be able to measure the 5v and 12v rails where the wires come from the main PCB to the floppy drive power cables.


Judging by the lack of action, I still think your 5v rail is down, in which case the monitor chassis will need a repair.


Schematics and manuals are easily found. Google is your friend!

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #17 on: 17:03, 12 June 20 »
Hello, and thanks for the further input. 


Already downloaded a service manual. I've measured 5.2V (red) 12.1V (orange) and 24.3V (yellow) going into the the board at connection CP005.


At the connection to the drive, I get the same voltages of 5.2V (red) and 12.1V (orange) .. same readings with or without a disk in the drive.


I've gone over both boards very meticulously, can't see any sign of anything burnt nor is there that classic stink of anything fried.
Checked all known fuses (as per schematic) as well .. all good there, and for anyone wondering, I do observe ESD precautions .. I lived in Canada for 40 years, where the winters are cold and dry, so I'm well aware of static discharge.


No leaking or bulging capacitors to be found, really no obvious visible sign of anything amiss ... sigh, why do I never get the easy fix ?  :-(

Offline CanonMan

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Re: Amstrad PCW 9512 problems.
« Reply #18 on: 17:45, 12 June 20 »
The next thing to check is that the Z80 is getting a stable clock pulse on pin 6 and a short reset pulse on pin 26 (active low).

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #19 on: 19:09, 12 June 20 »
Thanks. Forgive the noobiness, but do I need a logic probe for that ?  If so, I’ll get a cheapie while I’m out. Other than that, I do have a good meter and an old oscilloscope.

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #20 on: 20:36, 17 June 20 »
Hello,


Picked up a logic probe (RS C-MOS 424-096)  and have tested as suggested.  Pin 6 gives a result of both lights on, which supposedly indicates a square wave or repetitive wide pulses frequency >100Hz.  Pin 26 result is 'I' on, indicating above logic 'I' threshold.
I'm new to this, but I think these readings are not in line with what Canon Man said I should expect .. can someone please advise ?  Thanks

Offline CanonMan

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Re: Amstrad PCW 9512 problems.
« Reply #21 on: 16:29, 20 June 20 »
Sorry, I just don't have the time or patience to guide you through a step-by-step repair at the moment.


There are plenty of other people on this forum who could help, hopefully one of them will chip in soon.

Offline FixMePlease

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Re: Amstrad PCW 9512 problems.
« Reply #22 on: 19:43, 20 June 20 »
Bummer :-(   Is there anyone out there who may be able and willing to assist ?  It would be very much appreciated.