Hello all,
I'm new to the AppleII world, and am trying to resurrect an Apple IIe Platinum, but am having an issue.
The problem is that the machine boots fine when cold (and is able to run some very simple BASIC programs), but in a few minutes after startup, it freezes. Rebooting at that point brings up "Apple IIe" title screen but NO command prompt. Once I let it cool for an hour or so, it boots normally again.
In my investigations, I noticed that the HAL chip gets extremely hot after the machine has been on for just a few minutes -- hot enough that I cannot hold my finger on it for more than a couple seconds.
I thought -- no problem, replace the HAL chip and try again. But I have had zero luck finding a replacement AppleIIe HAL chip.
Are there sources for replacement HAL chips? From googling the only suggestions I saw was to purchase a replacement logic board or buy another logic board and try harvesting the HAL from that. Is that REALLY the only option? I've got a T-48 EPROM burner if that would help.
Or if anyone thinks the HAL chip replacement is going down the wrong path to a fix, I would appreciate any other advice.
Thanks all -- I'd like to get this IIe back up and running, as it is in decent shape.
I'd verify that the HAL chip is really your issue. They do tend to run a bit hot.
When the machine freezes, try hitting the chip with some freeze spray (or is it now "anti-freeze"?) or perhaps just blow some air on it. If that's really the problem, a reset or power cycle should then start to work again.
Thanks Jeff. I'll get the canned air and give that a try.
An ATMEL ATF16V8-15 can replace the HAL. The JED file can be found here: https://downloads.reactivemicro.com/Apple%20II%20Items/ROM_and_JEDEC/IIe/TMG_Unit_aka_HAL/
This replacement is running fine since serveral month on my //e.
A Lattice GAL 16V8 should also work, but the Atmel part is generally easier to find these days. The OP mentioned having an XGecu Pro T-48, and that programmer should be able to handle either of those 16V8 chips w/o issue.
This is one of those threads I need to save forever.... That's for sharing that, I'm sure I'll need it one day!
UPDATE: Well, I got it working and it WASN'T the PAL chip. (tip of the hat to Jeff!)
My supposedly "good" power supply turned out to be the problem. It tested fine on the bench, but then after a short time being powered on, it apparently wasn't so fine after all.
I replaced the PSU with a ReactiveMicro internal upgrade, and everything seems to be working well again with none of the symptoms I described before. Thanks to all for the advice and the encouragement to keep digging! The HAL does seem to run hot -- 130 degrees F or higher, but so far it hasn't caused any apparent problems.
For my future information, when the +5v and +12v are checked, what are the acceptable voltage ranges for those rails on an AppleII PSU? I've got another PSU that seems to be ok, but the meter says +4.88v and +11.82v -- are those ok? Seems a bit low but perhaps the AppleII doesn't mind?
Thanks again to all for the help!
When you said "it tested fine on the bench", what kind of testing was that?
Testing the output of a PSU with no load is not particularly useful.