New 664 in house - black screen.

[SerErris]

Hi all,

I do have a new toy in da house - a Schneider CPC664. 
You cannot view this attachment.

So it looks pretty good - quite dusty, but the keys are in very good shape (looking at the yellowing).

Now to the problems:
It is black screen - I had only limited time to test it but that is what I found so far:

1. PowerSupply from CTM644 is 5.1V without load, and with load it drops to 4.7V. That can be an issue and I wonder where this massive drop is coming from. I have never measured it on any other CPC, so maybe that is normal. For my liking at the edge of low.
2. No beep on DEL key press.
3. Checked the Clock from GA to CPU - looks very good. Solid Clock.
4. Checked addresses on the CPU - looks good.
5. Checked datalines ... wow, that looks strange.
6. Checked ROM data line output:
You cannot view this attachment.

So that should be nice square waves with 5V output ... but this is what I get on all the lines. 

I attached the Diagnostic board (which will disable lower rom) and tried to run it. But no difference. Also the data lines on the expansion port look strange. Address lines are good, also ROMDIS looks good.

Other observations:
Reset Line is okay. On Power up it is low and then goes high. 

CPU is executing, but as it always get 0 on the data lines it is executing NOPs. That is also reflected in M1 line, that is having a frequency of 1Mhz, so that means every M cycle is a M1 cycle, and that can only happen with all NOPs. 

So questions is:
What could cause that? Checking everything directly connected to the data bus and affects all data lines in the same way.
1. ROM obviously
2. IC106 Printer Latch 
3. IC115 DATA Buffer
4. IC114 DATA Latch (maybe it is driven down all the time)
5. CRTC
6. PIO

For now I would consider both CRTC and PIO not really the problem.

What I also recognized, that I do have a vsync of 110hz and no hsync. But that might come from CRTC not initialized, because we do not have any rom working. 

Any obvious I miss?

[eto]

Ah, so you are the one who overbid me by 1.13€ ;-) 


I had a similar situation on a 464 where overvoltage fried the ROM and created a short on the data line(s). The external ROM will not work as the data lines will always be low even if the external ROM is accessed.

[Audronic]

@SerErris 

Wow.
My thoughts would be :
CPU change. Check Data lines
Extract the Rom. Check Data lines

 ? Perhaps Memory ?? Maybe

Keep Safe

Ray

[Rabs]

Hi all,

I do have a new toy in da house - a Schneider CPC664.
You cannot view this attachment.

So it looks pretty good - quite dusty, but the keys are in very good shape (looking at the yellowing).

Now to the problems:
It is black screen - I had only limited time to test it but that is what I found so far:

1. PowerSupply from CTM644 is 5.1V without load, and with load it drops to 4.7V. That can be an issue and I wonder where this massive drop is coming from. I have never measured it on any other CPC, so maybe that is normal. For my liking at the edge of low.
2. No beep on DEL key press.
3. Checked the Clock from GA to CPU - looks very good. Solid Clock.
4. Checked addresses on the CPU - looks good.
5. Checked datalines ... wow, that looks strange.
6. Checked ROM data line output:
You cannot view this attachment.

So that should be nice square waves with 5V output ... but this is what I get on all the lines.

I attached the Diagnostic board (which will disable lower rom) and tried to run it. But no difference. Also the data lines on the expansion port look strange. Address lines are good, also ROMDIS looks good.

Other observations:
Reset Line is okay. On Power up it is low and then goes high.

CPU is executing, but as it always get 0 on the data lines it is executing NOPs. That is also reflected in M1 line, that is having a frequency of 1Mhz, so that means every M cycle is a M1 cycle, and that can only happen with all NOPs.

So questions is:
What could cause that? Checking everything directly connected to the data bus and affects all data lines in the same way.
1. ROM obviously
2. IC106 Printer Latch
3. IC115 DATA Buffer
4. IC114 DATA Latch (maybe it is driven down all the time)
5. CRTC
6. PIO

For now I would consider both CRTC and PIO not really the problem.

What I also recognized, that I do have a vsync of 110hz and no hsync. But that might come from CRTC not initialized, because we do not have any rom working.

Any obvious I miss?

Disk Controller, or the control logic. I have had discontrollers corrupt the bus before now, which gave the symptom of a black screen.

So you think the GateArray is possibly OK because of the clock. I would agree and as the CPU is running, ish, may be that is OK. I would eliminate both with a swap into a known CPC.

Diagnostics ROM is still black screen, so sort of eliminates ROM alone.

It's a matter of eliminating Bus corruption potentials one by one.

What's the state of the PCB?

[SerErris]

PCB looks fantastic (only have looked at the component side). A little bit dusty, but nothing obvious.

So I will desolder the ROM first (then I also can inspect the bottom of the PCB).

It looks pretty much untouched. All capacitors are original (which is something I would need to change as well) all components are untouched. So all TTL logic are original.

It has a 40010 GA. I am not sure if that is normal, but it matches the Schematic.

I also have a suspicion on IC114, if that is always enabled, because of a fault of IC112, then it would output always 00 as the RAM is not initialized. That would also corrupt the data bus in a way, that no operation is possible anymore.

I currently have limited time, so maybe updates are coming slow on this. But I will bring it back to live, even if I have to replace all the chips. If the ROM died it would be a pitty as you can hardly get a new original ROM. An Eprom will then need to replace it :-(

It has such a nice looking keyboard.

[Rabs]

PCB looks fantastic (only have looked at the component side). A little bit dusty, but nothing obvious.

So I will desolder the ROM first (then I also can inspect the bottom of the PCB).

It looks pretty much untouched. All capacitors are original (which is something I would need to change as well) all components are untouched. So all TTL logic are original.

It has a 40010 GA. I am not sure if that is normal, but it matches the Schematic.

I also have a suspicion on IC114, if that is always enabled, because of a fault of IC112, then it would output always 00 as the RAM is not initialized. That would also corrupt the data bus in a way, that no operation is possible anymore.

I currently have limited time, so maybe updates are coming slow on this. But I will bring it back to live, even if I have to replace all the chips. If the ROM died it would be a pitty as you can hardly get a new original ROM. An Eprom will then need to replace it :-(

It has such a nice looking keyboard.

Have a look at 664 ROM

I made made my own but later replaced with an original and it worked.

If you need me to check any signals traces on my 664, just let me know.

[Rabs]

PCB looks fantastic (only have looked at the component side). A little bit dusty, but nothing obvious.

So I will desolder the ROM first (then I also can inspect the bottom of the PCB).

It looks pretty much untouched. All capacitors are original (which is something I would need to change as well) all components are untouched. So all TTL logic are original.

It has a 40010 GA. I am not sure if that is normal, but it matches the Schematic.

I also have a suspicion on IC114, if that is always enabled, because of a fault of IC112, then it would output always 00 as the RAM is not initialized. That would also corrupt the data bus in a way, that no operation is possible anymore.

I currently have limited time, so maybe updates are coming slow on this. But I will bring it back to live, even if I have to replace all the chips. If the ROM died it would be a pitty as you can hardly get a new original ROM. An Eprom will then need to replace it :-(

It has such a nice looking keyboard.

Yep my GA is a 40010.

[SerErris]

Its Alive :-)

I quickly measured IC112 and it was outputting the correct square wave of high and low for enable and disable. All good.

Then I desoldered/butchered off the ROM. I could not desolder it properly, it did not want to let go. So i actually needed to cut all pins to not to harm the mainboard.

After removing the rom, Diagnostic ROM booted right away. 

Keyboard needs definately cleaning as some keys did not want to work in the beginning, but after some typing, they started to work. Only the 0 key on the numpad is still stuck. As it is this single key it is the keyboard and no other component.

I then put in a 664 OS rom into the diagnostic board (for lower Rom support) and a 664 Basic ROM into upper 0 of my Revaldinho ROM board.

Voila, Basic is greeting me and M4 board is also directly coming up. 

So tested some very old school games: Manic Miner. But there was no sound. 

And then I saw it, the sound cable to the speaker was cut. And someone just taped it together with some isolation tape   
That did not work and the cable was just disconnected. Resoldered it for the moment and put a shrink tubing on it, sound on :-)

I have not tested the disc drive yet and there was a botch wire hanging around the 3" drive. It was only connected to one end, the other end was floating without any contact - not sure what the intention was.

So beneath the discdrive and beneath I do not have any 28 pin sockets left in my stock - it is working great. After I get the 28pin socket, I will solder that in and replace the ROM with an EPROM. 

One last thing I cannot get my head around.

I tried to run "Logon's demo" (3D meets the aging bits), but I could not get it to run via the M4. It crashes. That might be because it needs an actual drive (not M4), but I am not sure.

Can you run "logon's demo" on your 664 and check if it runs, or if it is potentially not compatible with 664? 
http://quasar.cpcscene.net/lib/exe/fetch.php?media=tmp:logon_s_run_-_3d_meets_the_aging_bits.zip

[SerErris]

Strange ... I am 100% sure that I have run it on my 464 to test the Sound Chip from vRetro. 

But I cannot run it on the emulator (winape) on a 464, neither on a 664. Only on a 6128 it runs.

I simply do not understand it.

[SerErris]

As soon as I put 128k in my emulator it works ... ?!?

[Rabs]

Its Alive :-)

I quickly measured IC112 and it was outputting the correct square wave of high and low for enable and disable. All good.

Then I desoldered/butchered off the ROM. I could not desolder it properly, it did not want to let go. So i actually needed to cut all pins to not to harm the mainboard.

After removing the rom, Diagnostic ROM booted right away.

Keyboard needs definately cleaning as some keys did not want to work in the beginning, but after some typing, they started to work. Only the 0 key on the numpad is still stuck. As it is this single key it is the keyboard and no other component.

I then put in a 664 OS rom into the diagnostic board (for lower Rom support) and a 664 Basic ROM into upper 0 of my Revaldinho ROM board.

Voila, Basic is greeting me and M4 board is also directly coming up.

So tested some very old school games: Manic Miner. But there was no sound.

And then I saw it, the sound cable to the speaker was cut. And someone just taped it together with some isolation tape 
That did not work and the cable was just disconnected. Resoldered it for the moment and put a shrink tubing on it, sound on :-)

I have not tested the disc drive yet and there was a botch wire hanging around the 3" drive. It was only connected to one end, the other end was floating without any contact - not sure what the intention was.

So beneath the discdrive and beneath I do not have any 28 pin sockets left in my stock - it is working great. After I get the 28pin socket, I will solder that in and replace the ROM with an EPROM.

One last thing I cannot get my head around.

I tried to run "Logon's demo" (3D meets the aging bits), but I could not get it to run via the M4. It crashes. That might be because it needs an actual drive (not M4), but I am not sure.

Can you run "logon's demo" on your 664 and check if it runs, or if it is potentially not compatible with 664?
http://quasar.cpcscene.net/lib/exe/fetch.php?media=tmp:logon_s_run_-_3d_meets_the_aging_bits.zip

Will give Logon's demo a go at the weekend.


I had to carefully scrape at the surface of the key contacts to get a good response and I had to replace the membrane.

You cannot view this attachment.

[Rabs]

Could not resist, loaded Logon's Demo, on my Dandanator, nice. Only runs on the 6128. Not selectable on 464 or 664.

[SerErris]

Okay, than it needs 128k .. still puzzled how I actually ran it on my 464 .. I am pretty sure I used it to test the AY3 and I had it in multiple 464s ... 

It is just strange.

Okay I could not resist and checked the drive. Changed the belt, but other than that it looks pretty good.

It is an EME-150A.

So I tried to insert a disk - and to my surprise I am not able to fully insert it. It will not lock down and comes out again - also as the felt is not getting pulled up the feld is now nearly ripped of :-( need to find a new felt and glue it to the top holder.

But any idea what could prevent the disk to get fully inserted and the disk locking down?

[Rabs]

Okay, than it needs 128k .. still puzzled how I actually ran it on my 464 .. I am pretty sure I used it to test the AY3 and I had it in multiple 464s ...

It is just strange.

Okay I could not resist and checked the drive. Changed the belt, but other than that it looks pretty good.

It is an EME-150A.

So I tried to insert a disk - and to my surprise I am not able to fully insert it. It will not lock down and comes out again - also as the felt is not getting pulled up the feld is now nearly ripped of :-( need to find a new felt and glue it to the top holder.

But any idea what could prevent the disk to get fully inserted and the disk locking down?

Indeed, if I attach a RAM card to my 464 the demo runs OK.

Sorry disk drives is one area I need to learn more about.

[SerErris]

Okay,

I checked it a little bit more.

The problem is that the slide is not going backwards when I insert a disk.

If I push the eject button during the insertion, than it can lock into place. Something is missing that needs to move the slide just slightly backwards and then with pushing against a part in the back will allow to lock it down.

Now I have no idea if there is a part missing, or something is broken ...

I will take some picture, which hopefully explains it better.

At least I will be able to test the drive with that way of inserting a disk.

Still would appreciate any clue on how to fix this.

[Audronic]

@SerErris

I have used a Light GREASE (NOT oil or a Spray) on some of the moving parts
Molybdenum (Spelling) Grease (Looks Black) is also good as it is a light grease
and perhaps get an old disk and use it to work the mechanism as the Drive  probably has not been used for years
Good luck

Keep Safe

Ray

[SerErris]

Working the mechanism does not work. It has been worked a lot and the problem is that moving part that moves the entire thing a little back and up does not work. It is not stuck as the eject button has the same effect, it is just not triggered when inserting a disk.

I still have no idea what could cause it - will post pictures of how it works. 

I am also considering a complete teardown, however that would missalig everything and would complete new calibration.

[Audronic]

@SerErris

Have you lubricated the mechanism ??
Do the test after Lubricating  ?

Keep Safe

Ray

[Rabs]

Okay, than it needs 128k .. still puzzled how I actually ran it on my 464 .. I am pretty sure I used it to test the AY3 and I had it in multiple 464s ...

It is just strange.

Okay I could not resist and checked the drive. Changed the belt, but other than that it looks pretty good.

It is an EME-150A.

So I tried to insert a disk - and to my surprise I am not able to fully insert it. It will not lock down and comes out again - also as the felt is not getting pulled up the feld is now nearly ripped of :-( need to find a new felt and glue it to the top holder.

But any idea what could prevent the disk to get fully inserted and the disk locking down?

I have an EME-150A if you want any pics.

You cannot view this attachment.

[SerErris]

Hi all, thanks for your input.

Yes I have lubricated it, but to no avail. The problem was a bend metal sheet. 

Luckily I had another EME-150A in an external Schneider FD-1 and could disassemble it (it anyhow needs belt replacement and stuff).

This is how the lock mechanism works:
You cannot view this attachment.

The disk pushes to this lever when inserting and the lever then release the lock and the disk drops down.

You cannot view this attachment.

This is the working drive.
So you can see the two parts. The blue outlined part is the lever from the first picture but inside the floppy cage. It has a hook. The red part is the metal sheet coming from the eject button. If you press the eject button the hook locks into the red part and then the drive is "open" and locked in that position. 

You cannot view this attachment.


If you put in a disk, it goes to the end, pushes the lever, which pulls the blue part up and then the red part is getting released, springs to the front (via a tension spring) and the whole disk shaft pops into place (down). The eject button pops out.

So the broken one was different:

You cannot view this attachment. 

This is with both parts in lock position - you can see there is this large open gap and the hook is somehow pretty close to the far edge of the eject sheet.
You cannot view this attachment.

And here you can see the whole problem (unlocked). The issue was that the metal hook was just bent down and therefore it locked to deep, so that the lever on the end could not release it anymore.

Actually both metal sheets need to be straight and it is about 1mm in thickness, that the lever need to overcome.

So I repaired it. I thought a little bit about how to best get this bend back into the original position and ... in the open position I pressed down with a screwdriver. Below the hook is actually a plane of metal so it cannot go really wrong. 

As soon as this was corrected, the hook did work properly and now the drive eject and insert is fully restored.

This drive must have someone looking at it and trying to do some repair. Because 2 screws are missing and I really wonder how you could get this hook so badly bent. I really trying to understand what people are doing with their hardware.

The rest of the drive looks pristine, just that was bad.

And working with the eject I killed the drive felt - so something I now need to replace :-( I ordered already some furniture gliders.

I do not know if the drive is actually working, but that is for another day, because I do need to recap the FD-1 anyhow and will do the rest of the drive checks there. 

Maybe that helps someone else if they ever come to this issue. However I assume that this is a real edge case of people messing with their precious hardware.

[SerErris]

Intrestingly my 2 EMEs do look different (and different to yours).

The first one has a different PCB on the upper side (also a white plastic cable holder). And it has a metal drive wheel.

The second one has the same PCB as yours, but a plastic drive wheel.

One has a black felt, and one has a white felt.

So it is strange, they even have revisions within the same drive mode (EME-150A).

[Audronic]

Hi all, thanks for your input.

Yes I have lubricated it, but to no avail. The problem was a bend metal sheet.

Luckily I had another EME-150A in an external Schneider FD-1 and could disassemble it (it anyhow needs belt replacement and stuff).

This is how the lock mechanism works:
You cannot view this attachment.

The disk pushes to this lever when inserting and the lever then release the lock and the disk drops down.

You cannot view this attachment.

This is the working drive.
So you can see the two parts. The blue outlined part is the lever from the first picture but inside the floppy cage. It has a hook. The red part is the metal sheet coming from the eject button. If you press the eject button the hook locks into the red part and then the drive is "open" and locked in that position.

You cannot view this attachment.


If you put in a disk, it goes to the end, pushes the lever, which pulls the blue part up and then the red part is getting released, springs to the front (via a tension spring) and the whole disk shaft pops into place (down). The eject button pops out.

So the broken one was different:

You cannot view this attachment.

This is with both parts in lock position - you can see there is this large open gap and the hook is somehow pretty close to the far edge of the eject sheet.
You cannot view this attachment.

And here you can see the whole problem (unlocked). The issue was that the metal hook was just bent down and therefore it locked to deep, so that the lever on the end could not release it anymore.

Actually both metal sheets need to be straight and it is about 1mm in thickness, that the lever need to overcome.

So I repaired it. I thought a little bit about how to best get this bend back into the original position and ... in the open position I pressed down with a screwdriver. Below the hook is actually a plane of metal so it cannot go really wrong.

As soon as this was corrected, the hook did work properly and now the drive eject and insert is fully restored.

This drive must have someone looking at it and trying to do some repair. Because 2 screws are missing and I really wonder how you could get this hook so badly bent. I really trying to understand what people are doing with their hardware.

The rest of the drive looks pristine, just that was bad.

And working with the eject I killed the drive felt - so something I now need to replace :-( I ordered already some furniture gliders.

I do not know if the drive is actually working, but that is for another day, because I do need to recap the FD-1 anyhow and will do the rest of the drive checks there.

Maybe that helps someone else if they ever come to this issue. However I assume that this is a real edge case of people messing with their precious hardware.

@SerErris

Thanks for the Photos and it will be helpfull in the future
Well done

Keep Safe

Ray

[Strike4711]

Funny coincidence...
I'm currently working in this same area on my CPC664 

@SelEriris 
I have also followed this CPC on EBay. 
Seems to be in very good condition.
No yellowed keys 👍

[SerErris]

I still need to test the drive but other than the ROM nothing was broken. 

[SerErris]

Okay, than it needs 128k .. still puzzled how I actually ran it on my 464 .. I am pretty sure I used it to test the AY3 and I had it in multiple 464s ...

It is just strange.

Okay I could not resist and checked the drive. Changed the belt, but other than that it looks pretty good.

It is an EME-150A.

So I tried to insert a disk - and to my surprise I am not able to fully insert it. It will not lock down and comes out again - also as the felt is not getting pulled up the feld is now nearly ripped of :-( need to find a new felt and glue it to the top holder.

But any idea what could prevent the disk to get fully inserted and the disk locking down?

Indeed, if I attach a RAM card to my 464 the demo runs OK.

Sorry disk drives is one area I need to learn more about.

This Version here actually runs on a 464 without RAM expansion ... I have no clue where I got it from: