FDD controller stops 5160 from booting

[Lurch]

Evening all
This is one that has me scratching my head.
I have a stock, original XT with its 10mb Miniscribe HDD. The only addition is an 8087 with the dip switch set accordingly.
Short version, with a known working original FDD controller it will run through its memory count and..... stop.
Cursor below the ram count just flashes and the boot process doesn’t go any further.
The drive connected is a known working one too. With the drive disconnected I don’t get the expected 601 error either.
Any ideas?

 

[daver2]

Does the amount of RAM indicated on the screen match that fitted and match that set on the DIP switches?

Do you get a single beep after the memory test or not?

With the hard disk and hard disk controller removed does that cause it to boot further?

After that, I would suggest removing the 8087 and swapping the DIP switch to try and get the system back to minimum stock settings.

What are the DIP switch settings out of interest?

Dave

 

[Lurch]

Yup
Nope
Nope
Ok, I’ll try that in the morning.
Off Off Off Off On Off On On (Normal boot, 8087 installed, All banks used, CGA, One FDD)

Does the amount of RAM indicated on the screen match that fitted and match that set on the DIP switches?

Do you get a single beep after the memory test or not?

With the hard disk and hard disk controller removed does that cause it to boot further?

After that, I would suggest removing the 8087 and swapping the DIP switch to try and get the system back to minimum stock settings.

What are the DIP switch settings out of interest?

Dave

 

[Lurch]

Also to note, with the FDD Controller out, it DOES produce a 601, hit F1, machine boots fine from the HDD.

 

[daver2]

Ah, so does that mean that the problem is isolated to the floppy disk controller or the floppy drive I ask myself?

Dave

 

[Lurch]

Both work fine in another 5160, even with all the same hardware from the first machine.

 

[jafir]

Do they have the same revision of the BIOS?

Perhaps the POST breakdown here would help: http://www.minuszerodegrees.net/5160/post/5160 - POST - Detailed breakdown.htm

Or I wonder if the landmark diagnostic ROMs would help. Do you have a way to burn an eeprom?

http://www.minuszerodegrees.net/supersoft_landmark/Supersoft Landmark ROM.htm

 

[kc8eyt]

I'm assuming you tried plugging the FDC into different ISA slots?