Tex-Elec Quad-flop ISA: Diskette boot failure \ VOGONS

Tex-Elec Quad-flop ISA: Diskette boot failure

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First post, by popcalent

Posted on 2026-07-22, 18:27

popcalent Offline

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Posts: 66
Joined: 2024-02-22, 21:34

Hello,

I'm trying to use the quad-flop ISA card from Tex-Elec. So far I have configured one 1.44MB drive, but my intention is to add three more drives. I try to boot the computer using a 6.22, 4.01, and 3.30 MS-DOS boot disk (I have these three), and the drive's LED turns on, it attempts to read the disk, but then it says "Diskette boot failure".

I have all switches on, except R3 (beeps if it's on, an address conflict I guess?) and IOSEL (FDD controller failure if off). Also TG43 I tried both positions and it doesn't make a difference? Any idea? Thanks!

Reply 1 of 2, by Guld

Posted on 2026-07-23, 01:00

Guld Offline

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Joined: 2021-10-10, 00:25
Location: Virginia, USA

Is this the only floppy controller on the system? Did you disable any onboard floppy controller?

Are you trying to use this with an XTIDE?

Did you configure the card (github site for it says F2 during boot process, it's been a long time since I used mine but I recall that you have to configure it.)

TG43 should be off.
IOSEL should be 0x3F0 by default

ROM address depends on what you have free on the system, ON-ON-OFF puts you at 0xC800-0xCFFF, default for that appears to be 0xC000 ON-ON-ON. But could be another device using that ROM address.

I know there are tools you can use to see what ROMs are currently on the system, hoping someone else can point you to one as I don't recall off hand.
I think Brutman's ROM dumping utility can do it, but there may be an easier way, but it is here, look for pcjrcart.zip.
https://www.brutman.com/PCjr/pcjr_downloads.html
It will dump all the valid ROMs it finds on the system IIRC, and works on more than just the PCJr, it's simply looking for valid headers in upper memory and dumping them to files.

Reply 2 of 2, by akimmet

Posted on 2026-07-23, 01:16

akimmet Offline

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Joined: 2024-05-31, 01:16
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Do you have more than one floppy controller installed?

If so there will be resource conflicts. A PC compatable floppy controller needs IRQ6 and DMA2.

You are unlikely to need the BIOS extension right now.
So try:
off,off,off,off,on,on,off,off

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