Compaq Portable I Lo-Tech ISA XT CF adapter boot issues

[Malc]

The 5170 and 5162 (IBM AT and XT-286) can't use XT-IDE cards as there is an incompatibility with the XUB and the BIOS on those systems. The only way the XUB works on them is if the BIOS is replaced with one from AMD. So the 5170 and 5162 are not good systems to test XT-IDE cards in.

That's true, more so for the 5170 though now it seems, Fitting just the lo-tech isa - cf adapter with nothing attached should be enough to see if it still exhibits the same issue's, The OP doesn't seem to have a more suitable PC to test in, An XT 5150 / 5160 would be more suitable.

 

[acenewman]

May have inadvertently stumbled onto the source of the problem. Or apparent problem might be more accurate. Got a text from the guy I got the Compaq Portable from, he found the missing original manuals. So I picked them up after work on Friday. He had all three plus a cool brochure highlighting the differences between the standard portable and the plus. Was reading through them and found an interesting comment on page 5-3 of the operations guide.

"Note: When you turn your Compaq computer off, you need to wait 15 seconds before turning it back on. There is a safety mechanism built into the power input circuits to safeguard your computer from power surges, such as those caused by lightning. If you do not wait 15 seconds, this protection mechanism sees the break in power as a power surge, and will not allow the computer to come back on."

After some experimentation, it would seem that it always powers back up after anything over about 13 seconds.

 

[ibmapc]

OH! I didn't realize when you said "power cycle" that you meant "rapid power cycle". I guess you must not have tried the "rapid power cycle" after the XT-IDE was removed or you would have seen similar behavior.
I always wait at least 15 seconds after turning off a PC before turning it back on. Sometimes, one needs to wait more than 30 seconds or 1 minuet to allow residual charges to dissipate in capacitors and even RAM.
This is one reason that a reset button is a good idea. The old machines that didn't come with one can benefit from having one hooked up.

Greg

 

[TO.]

"Note: When you turn your Compaq computer off, you need to wait 15 seconds before turning it back on. There is a safety mechanism built into the power input circuits to safeguard your computer from power surges, such as those caused by lightning. If you do not wait 15 seconds, this protection mechanism sees the break in power as a power surge, and will not allow the computer to come back on."

So this is what's been happening! My machine does this all the time. I think the fan comes on, but nothing else... makes troubleshooting/testing really hard sometimes.

 

[acenewman]

yeah, pretty annoying when you are troubleshooting. I have learned to live with it though. Chris

 

[cuvtixo]

The 5170 and 5162 (IBM AT and XT-286) can't use XT-IDE cards as there is an incompatibility with the XUB and the BIOS on those systems. The only way the XUB works on them is if the BIOS is replaced with one from AMD. So the 5170 and 5162 are not good systems to test XT-IDE cards in.

I'm not clear about this conflict between the "XUB" -XTIDE Universal BIOS and AT and XT-286 BIOS. Couldn't one just take out the original BIOS completely? I mean, I have a Compaq Portable, so that;s not an issue for me, and I'm fairly new to XTIDE and certainly XUB. In fact, looking at upgrades like XT-IDE boards, it seems difficult to avoid XUB. I have a AST sixpak that has a BIOS (the sticker came off the window, I don't know if it's functional). I see a product at monotech- "Compaq Portable RAM Decoder PROM", what seems like lots of options and I'm worried about getting any new upgrade with conflicting XUBs, actually. Couldn't one burn a XUB, use it as a replacement for an original ROM. (If desoldering is required, that wouldn't be a dealbreaker for me!)

 

[modem7]

I'm not clear about this conflict between the "XUB" -XTIDE Universal BIOS and AT and XT-286 BIOS. Couldn't one just take out the original BIOS completely? I mean, I have a Compaq Portable, so that;s not an issue for me, and I'm fairly new to XTIDE and certainly XUB. In fact, looking at upgrades like XT-IDE boards, it seems difficult to avoid XUB. I have a AST sixpak that has a BIOS (the sticker came off the window, I don't know if it's functional). I see a product at monotech- "Compaq Portable RAM Decoder PROM", what seems like lots of options and I'm worried about getting any new upgrade with conflicting XUBs, actually. Couldn't one burn a XUB, use it as a replacement for an original ROM. (If desoldering is required, that wouldn't be a dealbreaker for me!)

When I read your post, I got the feeling that you think that the XTIDE Universal BIOS (XUB) is a BIOS designed as a replacement for a motherboard BIOS. The XTIDE Universal BIOS (XUB) complements the motherboard BIOS.

PC-class and XT-class
---------------------

The motherboard BIOS of PC-class and XT-class computers does not contain any code for interacting with hard disk controllers. Therefore, hard disk controllers for those computers need to provide their own code. That is normally done by way of a 'BIOS expansion ROM' located on the controller. The code in the BIOS expansion ROM 'knows' about the particular controller:
* Addresses, ports, and interrupt.
* How to interact (commands and responses) with the particular controller chip soldered to the controller card. Different controller chips behave differently.

See top half of diagram at [here], which is for an XT-class MFM controller.

In the case of the XT-IDE card, the XTIDE Universal BIOS (XUB) is the 'BIOS expansion ROM' code that 'knows' how to interact with the XT-IDE card.

Normally, the XUB code resides in the XT-IDE's EEPROM. Alternatively, if desired, it may reside elsewhere in the computer (in a location where 'BIOS expansion ROM' code will be executed).

AT-class
--------

The motherboard BIOS of an AT-class computer contains code for interacting with CERTAIN hard disk controllers. The XT-IDE card is not one of those. Therefore, for 'motherboard unsupported' controllers, 'BIOS expansion ROM' code that 'knows' how to interact with the particular controller needs to be in place somewhere. In the case of the XT-IDE card, the XUB 'knows' how to interact with the XT-IDE card, and is the 'BIOS expansion ROM' code used.

Normally, the XUB code resides in the XT-IDE's EEPROM. Alternatively, if desired, it may reside elsewhere in the computer (in a location where 'BIOS expansion ROM' code will be executed).

I have a AST sixpak that has a BIOS (the sticker came off the window, I don't know if it's functional).

Are you sure that is a SixPak? I have not heard of a SixPak that has an EPROM fitted.