Revival of a TRS-80 Model II

I don't know the type C FDC.
It seems to me that with the jumpers you can set the 34 pins connector on the FDC to active.

If you set the FDC to the default settings, and you set the jumper on the DiskDrive to drive 1 and
the HxC to drive 0, it must be possible to boot from the HxC drive.

There actually isn't a 34 pin IDC on the board. There is a spot where one might go, but it is unpopulated.

I'll have to see if I have any headers with the right pitch in my box and solder one on.

Hans01 said:

I don't know the type C FDC.
It seems to me that with the jumpers you can set the 34 pins connector on the FDC to active.

If you set the FDC to the default settings, and you set the jumper on the DiskDrive to drive 1 and
the HxC to drive 0, it must be possible to boot from the HxC drive.

Click to expand...

I don't think it is necessary to do this. As far as I know this connector is not fully supported in the software.
Please reset all the jumpers on the FDC to their default position and use the internal and external
50 pins cable and connector and connect the HxC with external connector.
You should read data with this setup.

Can you make a video of the readout of the HxC display during test.
It might be helpful.

Here is a video with everything set back to defaults. First, the HxC as Drive 0 and then as Drive 1, always connected to external connector.

Don't be distracted by "dir" changing to "dip" when I have it as drive 1. This is a video corruption artifact that I haven't gotten around to fixing yet. It's only video RAM that's corrupting, nothing else. It's been very thoroughly tested.

Thanks for looking! Any suggestions or thoughts, please let me know! The video should be processed on Youtube in about 10 minutes.

Hans01 said:

I don't think it is necessary to do this. As far as I know this connector is not fully supported in the software.
Please reset all the jumpers on the FDC to their default position and use the internal and external
50 pins cable and connector and connect the HxC with external connector.
You should read data with this setup.

Can you make a video of the readout of the HxC display during test.
It might be helpful.

Click to expand...

Listening to the background sound and looking at the video at the same time. It sounds as if the drive in the computer is
enabled on the same drive number as the HxC.

If you choose to set the HxC as drive 0, then you have to set the internal drive to 1 or 2.
If they both are selected on the same number, they both supply data at the same time.
The drive select jumper is on the right side near the power connector. I have connected the DS0; DS1 and DS2 to a switch on the outside of the computer
for easy changing.

You can try to remove the ready jumper as an option.

The readings on the HxC shows that it is working oke.

To do a test, just set the internal drive on 1 and the HxC on 0 and use the LS-Dos image to boot from the HxC, it should work.

Stupid question since I have forgotten a lot of CP/M
Do you have to do something like a sysgen on ls-dos if you add a new drive?

ls-dos won't see new drives until you tell it

Nope, no good.

I've tried setting the internal drive to 1, completely disconnecting the internal drive, etc. Nothing seems to make a difference.

**Update**

Though, looking at this very carefully, I just noticed something that may point to a much easier problem. When I had first connected my cable to the external port I had thought that pin 1 was to the far right when facing the rear of the computer, but it didn't respond, so I assumed that i had it inverted. I just connected my connector directly to the 50 pin header and have realized that I may have inadvertently reversed the cable somehow when I went to the 34 pin connector... Very weird... It definitely tracks, as you can see, on DS0, but this could explain why nothing else works and why it doesn't work on its own. I'll make a new cable and let you folks know what I find.

Hans01 said:

Listening to the background sound and looking at the video at the same time. It sounds as if the drive in the computer is
enabled on the same drive number as the HxC.

If you choose to set the HxC as drive 0, then you have to set the internal drive to 1 or 2.
If they both are selected on the same number, they both supply data at the same time.
The drive select jumper is on the right side near the power connector. I have connected the DS0; DS1 and DS2 to a switch on the outside of the computer
for easy changing.

You can try to remove the ready jumper as an option.

The readings on the HxC shows that it is working oke.

To do a test, just set the internal drive on 1 and the HxC on 0 and use the LS-Dos image to boot from the HxC, it should work.

Click to expand...

Ok... Either I'm crazy or there's something really weird here. I was about to make a new cable and took a good look at the original that I made... But the cable appears to be perfect. Notice, red marked line 1 is to the far left, lined up with the pin 1 marker on the IDC connector. The 34 pin IDC has the identical orientation with pin 1 where expected. Am I crazy? This cable looks just fine.

Please tell me if you see something wrong here. If not, I really do not understand why the HxC does nothing when I connect cable pin 1 to pin 1 but has the previously discussed almost working behavior when connected backwards?!?

If you have a Model II.
Take a look at the backside of the computer.
The 50 pins FDD floppy extension connector is down at the left side
and pin1 is on the left side.

Can you push the connector far enough in the male connector.
I have removed the notch on the female connector for better insertion.

Well, what I had actually done is to hook my cable up directly to the FDC connector and bypass that completely. That's what's weird. When my pin 1 is connected to the marked pin 1 on the board I get nothing. When I flip the cable I get the behavior I videoed. I posted the photo of the cable showing pin one to the left and the ribbon in the hopes someone would look at it and tell me that I had done something obviously stupid, because it appears to be correct to me..

Hans01 said:

If you have a Model II.
Take a look at the backside of the computer.
The 50 pins FDD floppy extension connector is down at the left side
and pin1 is on the left side.

Can you push the connector far enough in the male connector.
I have removed the notch on the female connector for better insertion.

Click to expand...

Please take a look at this page.
http://electrickery.xs4all.nl/comp/trs80m2/ModelIIBusCardZoo.html
Do you have a Rev. 3 FDC or a "Late design" controller, because it makes a big difference.

I don't know this FDC but in that case it could be necessary to use the external connector.
If it is the last one, there is an internal connector for drive 0 and one for external drives.
If this is the FDC you have, then the internal connector is only for drive 0 and could
possibly not address other drive numbers.
In that case you should use the external connector.

Yes, it is the "Late Design."

It does have jumpers to set the external port for drive 0. I'm still weirded out by the cable situation, though. I may remake it just to remove it as a possibility. I think I'll also add a 50 pin edge connector to it so that I can connect it to the internal port for testing too.

Hans01 said:

Please take a look at this page.
http://electrickery.xs4all.nl/comp/trs80m2/ModelIIBusCardZoo.html
Do you have a Rev. 3 FDC or a "Late design" controller, because it makes a big difference.

I don't know this FDC but in that case it could be necessary to use the external connector.
If it is the last one, there is an internal connector for drive 0 and one for external drives.
If this is the FDC you have, then the internal connector is only for drive 0 and could
possibly not address other drive numbers.
In that case you should use the external connector.

Click to expand...

So, I have the HxC working well as drive 0 on the MII. I can boot the MII into LDOS on the HxC A drive as drive 0 fine. However, I cannot get the HxC drive B to work as drive 1 in LDOS. @Hans01, @dhoelzer, or anyone else with a working HxC on MII, have you been able to get the second HxC drive working as a second drive on the MII?

@Hans01, @dhoelzer, or anyone else with a working HxC on MII, have you been able to get the second HxC drive working as a second drive on the MII?

Click to expand...

There are no problems with this configuration.

HxC drive A is MII drive :0 and HxC drive B is MII drive :1.
Boot from drive A and read data from drive B, no problems.

I have a first series FDC, this could make the difference.