SYMBiFACE edge connector issues

[Munchausen]

So I've got a SYMBiFACE and it's great and all, but I have real problems getting it to connect properly. I have to wiggle the connector, turn on and see if it worked, repeat many times, etc. I've only managed to get it to actually boot symbos from ROM once, and it crashed shortly afterwards.


I think this is an issue with the edge style connector. Anyone else have the same problems? I've cleaned the contacts with q-tips etc and while it helped a bit it didn't make the problem go away.


Presumably it's not too hard to actually add centronics connectors to the CPC if you can find them - I note the holes seem to be present in the PCB at least. Has anyone done this, anyone know where I can find connectors?


Other suggestions? Cleaning tips?


Thanks as always

[Bryce]

Have you cleaned the contacts in the connector too?

If the PCB edge is really dirty, try using an Ink eraser to clean the contacts.

Bryce.

[Munchausen]

Next time I'm at the shop I'll grab one of those to try. You mean the ones with an ink eraser on one side and a pen on the other? (Basically bleach, aren't they?)


EDIT: No I didn't clean the contacts in the connector. I figured with it being new they weren't suspect. You think I should?

[TFM]

Yes, you should! Use Ethonol or Propanol, but no 'hard' stuff for cleaning. Repeat cleaning until you get no more dirt (= dark dust on Q-Tips) off.

Also take a look at a picture to be sure that you have connected the cable right around.

Try to disconnect any hard-disc to see if the power supply could cause problems.

And finally: Good luck!
(It's a great expansion and it works very reliable in my hands, but my CPC has Centronics connectors, no PCB blade).

[Joss]

Hi! I was having the same problem as you and decided to use a Schneider CPC with centronic interface. The change was successful.
In this post symbiface was said that edge connector could not align always as it should and perhaps it is our problem .....


Before using the Schneider I was thinking about how to connect the CPC w/o an edge connector. I got one 464 from ebay with this mod at the printer port:


It could be an alternative if you don't find the centronics connector. Something like this:

but soldered.

[TFM]

Thanks' for sharing the pics. Nice idea.

IMHO the new batch of SF2's has no problems with the connectors, I stick with cleaning ;-)

[Munchausen]

Yes, you should! Use Ethonol or Propanol, but no 'hard' stuff for cleaning. Repeat cleaning until you get no more dirt (= dark dust on Q-Tips) off.

Also take a look at a picture to be sure that you have connected the cable right around.

Try to disconnect any hard-disc to see if the power supply could cause problems.

And finally: Good luck!
(It's a great expansion and it works very reliable in my hands, but my CPC has Centronics connectors, no PCB blade).

I will try this.

The cable is definitely the right way around - 90% of the time I get the colourful symbos boot instead of the standard basic bootup, but typing "|SYM" it wont boot to Symbos. I did get it to boot to symbos twice, once it crashed shortly after (screen corruption) and the other it only got halfway to showing the desktop. Normally it gives a "press play then any key" message, sometimes I get a black screen. If I try with holding the ctrl key down and resetting it normally just gives me a blue/red/yellow corrupted screen.

I don't have a HDD connected at present so that isn't the problem.

[Munchausen]

Hi! I was having the same problem as you and decided to use a Schneider CPC with centronic interface. The change was successful.
In this post symbiface was said that edge connector could not align always as it should and perhaps it is our problem .....

I'm honestly surprised that any expansions work well. Mind you, maybe I just have a cleaning issue. Also, I don't have any trouble with my external floppy.

It could be an alternative if you don't find the centronics connector. Something like this:

but soldered.

That's AWESOME! I didn't think of it. And I have a few 50pin IDC SCSI cables I could use with it. If the cleaning doesn't work then I think I will go this route...

BTW, at least on my 6128 behind the edge connectors there are holes for, I presume, centronics connectors to be soldered. But this mod looks far easier (and maybe with adding centronics connectors you would need to remove part of the PCB where the edge connectors are for it to fit).

[TFM]

Well, your floppy works, but the SF2 doesn't!  That's a first hint. Now I have two ideas... which may be both rubbish, but hey....

1. It's an issue with the connector. Can you compare the connector of the DDI-1 floppy and the SF2? Do they look similar? Sorry, I mean the exact spacing of the pins.

2. Have you tried to install other ROMs like Maxam or Protext into the SF2? Do they work?

[Joss]

I was getting a couple of SCSI cables from ebay for a nice price, just for the future 


As I see, the pcb side of the edge connections from 464/664/6128 have a hole/line between the connections but not in the middle. Perhaps it helped not only to find the right orientation of the cable but too to have the connections at the right positions.

[Munchausen]

Well, your floppy works, but the SF2 doesn't!  That's a first hint. Now I have two ideas... which may be both rubbish, but hey....

1. It's an issue with the connector. Can you compare the connector of the DDI-1 floppy and the SF2? Do they look similar? Sorry, I mean the exact spacing of the pins.

2. Have you tried to install other ROMs like Maxam or Protext into the SF2? Do they work?

I have a 6128 - so I use a 3.5" floppy on the second floppy connector. I also have a 464, but I haven't tried it with the symbiface, I don't have it with me right now though (and it is quite broken, well at least the case is trashed and the tape player destroyed - it ought to work for connecting a symbiface though).

I haven't tried installing any other ROMs, maybe I should do this...

[Munchausen]

I was getting a couple of SCSI cables from ebay for a nice price, just for the future 


As I see, the pcb side of the edge connections from 464/664/6128 have a hole/line between the connections but not in the middle. Perhaps it helped not only to find the right orientation of the cable but too to have the connections at the right positions.

I'm not sure I follow what you mean... you mean where the slot is for getting correct orientation? The connector is pretty tight, I don't think it can move sideways really at all - I tried this in case it was somehow misaligned.

Tomorrow I'm going to get some ethanol and try cleaning it better.

[Bryce]

It could be an alternative if you don't find the centronics connector. Something like this:

but soldered.

I have this mod on my 464. It's the most reliable connection you can have and the connection
cables are simple.

Bryce.

[TFM]

I haven't tried installing any other ROMs, maybe I should do this...

Well, you can try my ROManager and install a ROM, to see if it works. If other ROMs work then maybe the Symbos ROMs may have some bits changed. Just an idea. (Hey, I'm not telling you to install FutureOS and check if it works, but you could ;-))

[Joss]

I'm not sure I follow what you mean... you mean where the slot is for getting correct orientation? The connector is pretty tight, I don't think it can move sideways really at all - I tried this in case it was somehow misaligned.

you got what I meant 

[Munchausen]

Ok, this is driving me insane! I've been very busy and didn't have time to try again until now, but I've just spent some time soldering IDC pin headers to the CPC, and it has made absolutely no difference.


Here's what happens on boot (correct, I think):
[attach=2]


Here's what happens if I hold down control to try and get it to boot Symbos after boot (it first displays "booting symbos..."):
[attach=3]


And here's what happens if I try to boot symbos from floppy drive with the symbiface connected:
[attach=4]


If I try to boot by typing "|SYM" or "|SYMBOS" it just says "Press play then any key".


I also tried disabling all the ROMs with the jumper and booting from floppy - it made no difference.


Does anyone have any clues? I'm now using a very short cable between the symbiface and EXT port. Could it be power supply related (I'm powering everything from one of those external hard drive power adapters with a molex connector - the SYMBiFACE is connected to the 12V and the 6128 5V)?


I really don't know what to do next. 

[Bryce]

My bet is on a bad connection on one of the address lines, probably to the SymbiFaces RAM IC. Have you tried removing and re-seating the ICs? You'll have to re-install SymBOS on the RAM afterwards of course.

Bryce.

[Munchausen]

That does sound like it's on the right lines (heh, a pun), but the RAM is not socketed.. the CPLDs, RTC and AVR micro (PS/2 controller) are though.


Do you think I should try re-seating the CPLDs? They're some sort of QFP package though and I'm not certain about removing them without damaging the socket. Also, you think it'll be ok to remove them with the RAM battery connected?


What else could it be... the only other thing I can think of is a dry joint (which seems unlikely)?


Thanks!

[Munchausen]

I just tried the symbiface with my 464 and nothing happens at all there... it just boots as normal. However, I haven't soldered IDC headers so it could be that the connection is bad. I'll solder some tomorrow and see what happens, but not holding out much hope.

[TFM]

Have you installed Amsdos on ROM 7 ? Stupid quesiton, I know, but have not other idea? (Don't know it you need it for Symbos, but I guess 'press play' does maybe indicate that.


Are the ROMs ok, or are there some bits corrupted?

[Munchausen]

So I don't have the AMSDOS rom installed in ROM 7... maybe that is why it does nothing on the 464? But it shouldn't matter for the 6128 because I just leave ROM 7 disabled. BTW, is it rom 7 or rom 8? The switches go from 1 to 8, so I thought it is the 8th switch right?

I can't run the rom manager right now because I have no way to make floppy disks (I'm living at my girlfriends now and my desktop is at my place). But next weekend I am going back, so I'll try to make some disks when I do, and try running some things (FutureOS, ROM manager, etc)

I will also try to find another way to power the SYMBiFACE, in case that is the problem.


Also, I guess the ROMs are not corrupt, but how can I know for sure?!


I don't have a hard drive connected, but from what I understand that shouldn't be a problem.

[Munchausen]

So the 464 doesn't show anything on boot because it doesn't initialise ROMs past 7. Is there a way I can do this manually? As far as I can tell I need to manually poke some values into registers and then call an intialisation routine... but I'm having trouble figuring out how to do it. Otherwise I'm stuck with the 464 because the tape drive is broken so I can't load anything...


Ok, so after looking here I guess this isn't easily possible without loading some software to do it. So I won't really be able to test this with the 464...

[TFM]

So I don't have the AMSDOS rom installed in ROM 7... maybe that is why it does nothing on the 464? But it shouldn't matter for the 6128 because I just leave ROM 7 disabled. BTW, is it rom 7 or rom 8? The switches go from 1 to 8, so I thought it is the 8th switch right?

That's right. Since it's ROM 7 when starting at ROM 0.

[Munchausen]

I haven't been able to do much testing of this; I needed to make disks with the rom manager and some other roms - the MAXAM assembler ROM for example would be good, because it does a checksum of itself. But I have no way to make floppy disks at the moment, as I'm away from home until July so I don't have any PC with floppy drive to make discs with - I brought an old laptop with floppy drive with me just for making disks, but it turns out the machine is irrevocably deceased.


However, a couple of days ago I got some goodies in the post from Bryce This included the LowerROM. And after testing just now, my CPC will not boot with FW3.1 on the LowerROM - it never finishes booting, or cycles infinitely. Since Bryce tested the LowerROM before sending it to me, this means that there almost certainly is a bad connection somewhere (be it cable, connector, or in the CPC itself), if my thinking is right? This is actually a really good and somewhat relieving result for me - as more than likely my Symbiface is working but I have a connection problem.


Tomorrow I will check the signal lines with a multimeter and resolder as necessary (the IDC pin header I added could be bad). Hopefully I can get everything working and be good to go - fingers crossed anyway!

[Bryce]

If the LowerROM is cycling, I'd say you have a Data line not getting through. Check all the connections again. Judging by the description of what you were getting on the SF2 my money is on D2.

Bryce.