Franklin FDC

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Franklin FDC

This is a long shot, but...

 

I am going to replace some components on my Ace 1200 to tr to get the normal hardwired Slot 6 drives to work again. I sspect the r/w/ motor control at H12, but if it should end up being H10, the 'Franklin FDC' gate array ASIC (this combines several aspects of the Disk ][ card onto an ASIC, then I have two options.

 

1. Find another Fanklin FDC chip. I am open to this, if anyone has spares. This was used on the Ace 1200 and on some Franklin Slot 6 Disk ][ clone cards.

 

2. Map out what the ASIC does, and use off the shelf components on a PDB with a header to plug into the FDC chip socket to make it work.

 

I do not know what to do if it falls on the latter. Franklin had excellent schematics of their PCBs, but not their ASICs. If anyone has anything that'd be of use, please LMK.

 

THis system, NOS as it is, is a doorstop unless I can get it to work off of normal Slot/Jumper 6 disk drives. No CP/M, and a lot of normal software won;t run, because it all expects Slot/Jumper 6. 

 

My pther option, is to cut out all f the cstom FDD logic and make slot 6 work normally, but this seems an absolute last-resort, and I would sooner do it on another 1200 board, than demolish a NOS board to do it. 

 

If anyone has parts that can help, or knowledge that can help, please LMK. I am never selling this system, even if it becomes a paperweight. It is one of the best hybrid systems available, especialy given the excellent CP/M support built into it. 

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Its meant to be possible to

Its meant to be possible to boot for the life of me I can't remember the version off hand of CP/M from a slot other than 6 by modifying the system file?  Not that even if this works solves your other issues, but it might work as an interim measure.  Are you using the Franklin ACE80?

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Spectre wrote:Its meant to be
Spectre wrote:

Its meant to be possible to boot for the life of me I can't remember the version off hand of CP/M from a slot other than 6 by modifying the system file?  Not that even if this works solves your other issues, but it might work as an interim measure.  Are you using the Franklin ACE80?

 

Aye. The system is a NOS fully stock Ace 1200. Two Ace-drives, Ace-80, Ace memory board, Ace Videx clone, and so forth. I have a second one of those Ace Videx clone cards that I am trying to get working inside my ][+.

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Spectre wrote:Its meant to be
Spectre wrote:

Its meant to be possible to boot for the life of me I can't remember the version off hand of CP/M from a slot other than 6 by modifying the system file?  Not that even if this works solves your other issues, but it might work as an interim measure.  Are you using the Franklin ACE80?

 

I'm going to try pulling the FDC (it seems to be something like the IWM Disk ][ chip, I cannot find a datasheet, but the p/n details are: "USI 5B-2012 4003000 8350", the last bit likely a date code), the AND gate, and the 9334. With luck, if I disable all of that w/o cuttting traces, it may resolve slot 6 conflicts, so that I can use a normal Disk II controller. 

 

Futzing with the 9334, I can get power to the drive, but the system still drops to FBASIC, so either it is not sensing the FDC, or the EPROM used for this is suffering from bit rot after 37 years in storage. 

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Good luck! Be interesting to

Good luck! Be interesting to see how you get on.

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Franklin ACE 1200

I just dug my ACE 1200 out, and ordered the parts I need to recreate a missing keyboard cable. Once I have that built (and if you are still interested) I'd be happy to work with you on getting your FDC operational.

Harold Miller

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MajorPeabody wrote:I just dug
MajorPeabody wrote:

I just dug my ACE 1200 out, and ordered the parts I need to recreate a missing keyboard cable. Once I have that built (and if you are still interested) I'd be happy to work with you on getting your FDC operational.

Harold Miller

That would be lovely, and I'd appreciate it most kindly. It's a great system, and I have absolutely no idea why it would simply stop working. I have considered cutting out the circuit for it, bypassing it and using a normal Disk II controller, but that is a lot of benchwork. The Franklin 1200 FDC is essentially undocumented. 

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MajorPeabody wrote:I just dug
MajorPeabody wrote:

I just dug my ACE 1200 out, and ordered the parts I need to recreate a missing keyboard cable. Once I have that built (and if you are still interested) I'd be happy to work with you on getting your FDC operational.

Harold Miller

Hello Harold, have you had any time to look at the design?

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