Author Topic: PCW8512 - Solved my drive problems (i think) now into the four beeps realm  (Read 2845 times)

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Offline OinkEsFabuloso

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Hi!

Last year I asked here about my PCW8512: [last year's post
last year's post
]. Some of you advised to change the drive belt (thanks once again!!), so I finally put myself to the task during the christmas holidays  :D

Here are some pictures, if you want to see how the old belts looked (I changed the belt on both drives): [pictures!]

So, even with the new belt, the main drive (the top one) didn't seem to work. Nothing happened after inserting any diskette. So I've tried by switching drives. The secondary (bottom) drive is now the primary (at the top). I decided to do this because they didn't seem to be exactly the same model. Primary seems to have 1 reader while secondary seems to have 2 (double sided drive, maybe?).

With that, whenever I insert a diskette I get a few blinks from the screen and four beeps: [short video!].

Any ideas?

I've read that this could be happening because the disks are faulty/don't have an OS. I've tried both sides on all my disks: [disks]. The exact same thing happens with each of them, so I'm guessing is related to the drive  :(

As usual, any help will be greatly appreciated  :)


Offline OCT

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Haven't even been near a PCW/Joyce in decades, hence checked if memory served correctly (and it did, why always for these tidbits  ??? ):
"the PCW 8512's upper one were single-sided [single-density one ought to add, SSSD], while the 8512's lower one was double-sided and double-density" [DSDD]
(please read on at Amstrad PCW - Wikipedia, the free encyclopedia for further implications)
i.e. after switching them, the remaining one may only be able to read 180k rather than 720k disks if the DSDD one was broken.
Quote from: OinkEsFabuloso
this could be happening because the disks are faulty/don't have an OS
...or because the remaining read head is just one SSSD twice as wide as the track (and unable to reach the other side either of course) if your system disk was written on the double-density drive.
« Last Edit: 04:27, 03 January 16 by OCT »

Offline Terje_Norway

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Hi,


First of all I'm NOT an PCW expert, even if I have a LOT of machines and other hardware for it.


The PCW8xxx series Drive A: (Upper drive) is a single head disc drive. Capacity about 180K . This is the same kind of disc drive that the CPC has. Probably a EME-155 or EME-156 disc drive (at least mine does)
The PCW8xxx series Drive B: (Lower drive) is a double sided double density. Capacity about 720K. This drive is probably a EME-231 drive (mine is). It was a hell to get hold of one of these I do remember.
The PCW9xxx series Drive A: (Left drive) is a double sided double density. This drive is most likely a EME-232 drive. These drives a quite common, and easy to get hold of.


So to the problems, the EME-231 and EME-232 are NOT compatible. My guess it's a kind of hardwired configuration on the drives them.


- Who would have wanted a 720K drive as drive A: on a PCW8512 back in 1985-87 ? ? ?


You can read more about the different Amstrad disc drives for the CPC/PCW series on the following links :


Amstrad FDD part - CPCWiki
CPC Mainboard Versions
Three 6128 and a lot of screws
How to dismantle a CPC 6128 and replace the drivebelt


Now for the four beep problem. Again taken from memory, I haven't had time to test it tonight ::)


I think it indicates that there is no disc in the drive A:


If You have connected the EME-231 drive as drive A: that would definitively be a problem.


Well that has to be it for tonight.


Yours

Terje Grind
NORWAY


Offline FloppySoftware

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With the beeps and flashing the PCW is telling that can't boot with that disc in the drive A: due to bad format or missing boot sector or EMS file.

But in your case I think the problem is that the standard CP/M PCW8512 / 8256 version is not able to boot from a DSDD drive.

You need one of the last CP/M versions for the PCW8256 / 8512.

I have one of these runing in my PCW8256 with a 3 1/2" in A: and the old 3" in B:.

PS: You need a twisted cable also.
« Last Edit: 12:56, 03 January 16 by FloppySoftware »
floppysoftware.es < NEW URL!!!
cpm-connections.blogspot.com.es

Offline OinkEsFabuloso

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Thank you guys for your great help! :-) The drives didn't seem the same. Now I know why  :D It makes great sense, btw. The bottom one (now I know it's a EME-231 drive - DSDD) has 2 reader heads, one on each side of the disk once inserted. The top one (EME-155 or EME-156 - SSSD) has 1 head and a spring activated arm which kind of pushes the disk against the head [picture].


Now for the four beep problem. Again taken from memory, I haven't had time to test it tonight ::)

I think it indicates that there is no disc in the drive A:

If You have connected the EME-231 drive as drive A: that would definitively be a problem.

So, I can't boot up from the DSDD drive. I guess I need to investigate further into the SSSD drive (fix it or find a replacement).

I have one of these runing in my PCW8256 with a 3 1/2" in A: and the old 3" in B:.

That's probably my safest bet: learn how to plug a "new" 3 1/2" drive and boot from that.

I'm now back at home (my own home, not my parent's), so I won't be able to try anything else for a few weeks/months, but I'm determined to make it work, so I'll be back ;-)

Thanks once again for your great help! :-)


Offline OCT

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Thank you guys for your great help! :-) The drives didn't seem the same. Now I know why  :D It makes great sense, btw. The bottom one (now I know it's a EME-231 drive - DSDD) has 2 reader heads, one on each side of the disk once inserted. The top one (EME-155 or EME-156 - SSSD) has 1 head and a spring activated arm which kind of pushes the disk against the head [picture].


So, I can't boot up from the DSDD drive. I guess I need to investigate further into the SSSD drive (fix it or find a replacement).
Speaking of which, an EME-156 (3" SSSD) has been sitting on my shelf for 2 decades.
On its board, at least transistor Q2 has blown (scorch mark and all) in a spike of overvoltage (max. 12-14V, cf. CPC6128 Parados and Internal 3.5&quot; floppy drive mod
CPC6128 Parados and Internal 3.5" floppy drive mod).
Would anyone (Bryce?) like to try their hand at reviving this one?  8)

Quote
That's probably my safest bet: learn how to plug a "new" 3 1/2" drive and boot from that.
Or get an HxC floppy disk emulator.
Or if the CP/M system disk was the SSSD one, (have someone) copy its first 40 tracks to side 0 of a DSDD floppy (might also be a 3.5" one, but it does need a READY signal, cf. Known-working jumper assignment for TEAC FD-235HF-3240-U5 as B: on CPC6128plus? with further references posted to a thread while the Wiki was in migration) - so jumpered to DS0, it should (at least as far as my PCW theory goes) be able to boot from there too.
Or temporarily connect your 3" DSDD drive through a so-called double-step circuit (but avoid writing with the narrower head in that setup).
« Last Edit: 02:24, 07 January 16 by OCT »