system goes bonkers during autoexec

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Creekmore34
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system goes bonkers during autoexec

Post by Creekmore34 »

Greetings Everyone,

I've come across a head-scratcher and I thought someone on the forum may be able to offer some insight.

My Jr (prior to me messing with it recently) was successfully running with Chuck's tandy and com2 boards, 2 lpt side cars, and a jride with an 8GB DOM. The jride is situated in the outside position.

The system is powered with a picopsu (https://www.mini-box.com/picoPSU-80) and motherboard adapter.

As I said, all was working well... Until I added a second drive and tried to power it from the picopsu (using a 4-wire molex splitter).

I should also say that I haven't wired up Chuck's three-flop board yet, as I was doing some testing back and forth with a new 3.5" drive (which is an old internal IBM 720KB drive). It works fine by the way, swapping it for the 5.25" drive.

Back to powering both drives off of the single picopsu... I thought that I should be fine since the thing is rated for 80W. However, when I boot up the system (which won't see the second drive yet, but is powering the drive via the splitter), it boots normally and starts to run through my autoexec.bat

But, it gets a few lines in and says something about an error in the config.sys and having a bad ANSI.SYS file. Then it continues a little further, and then the screen goes to some color graphics garbage full screen and freezes up, or reboots itself (sort of like what the output looks like in an out of memory case).

I immediately assumed that I must have fried my DOM, moving it around and tearing down and rebuilding the system so many times. I pulled the DOM and look at it on my laptop this morning. Everything appears to be in order. All the files look fine.

So I'm wondering what else I could have triggered. It seems like a hardware malfunction would hang me up before I got into my autoexec. I'm going to test a little more with it this weekend, booting from floppies and trying to pinpoint more areas of trouble, but I thought I would ask the forum for ideas.

Also, this leads me to a question specifically for Chuck. I noticed in the pictures of your three color system (here on the site) that you have some sort of modified power supply sitting in the second drive housing. I also have a housing, which I've carefully removed all of the original RACORE internals and bagged up. I'm planning on just using the housing, my second drive and your three-flop board. But, if needed I could use the space (like I'm assuming you did) to add a more appropriate power supply. Chuck, do you have any alternative power recommendations?

I should also say that the jride BIOS looks normal at boot up and all of the PCjr system tests pass without errors. Yet, the problem persists even after switching everything back to the way it was before the trouble.

Thanks much for any thoughts/ideas regarding this predicament.
RLumpy
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Re: system goes bonkers during autoexec

Post by RLumpy »

I wonder if this in an issue that Chuck has written previously about a fanout issue on the PCjr expansion bus. He has shown modifications with pullup resistors for the jride. I would suggest you try removing the 2 parallel port side cars and try with only the jride connected to see if the system behaves in this config.
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chuckphd53
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Re: system goes bonkers during autoexec

Post by chuckphd53 »

My first thought was the same as Rlumpy, try removing thr LPT side cars and putting the JRIDE directly next to the Jr case.
let us know what happens then at boot up...

Chuck

Edit:

I noticed you said in your last comment you put everthing back and it was still bad, what was the hardware config? Still with the two LPTs?
“I never commit to memory anything that can easily be looked up in a book.” (AE)
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chuckphd53
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Re: system goes bonkers during autoexec

Post by chuckphd53 »

Another thought, when I was using my DOM, it crashed 3 times and had to reformat and load files...
Not sure why, but since I put a regular hard drive on, no problems, may be a speed timing issue, just a guess..

if you have a hard drive, that may be the answer.

Note I was doing alot of Turbo Pascal at the time and making / changing folders etc....
so just a guess, but it never did crash with the real hard drive running.



chuck
“I never commit to memory anything that can easily be looked up in a book.” (AE)
jneuhaus
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Re: system goes bonkers during autoexec

Post by jneuhaus »

I've got a jrATX with the 90W PicoATX power supply similar to yours and a jrIDE. I've run it with a parallel port sidecare and connected it to an expansion board which adds a 5 1/4" high density drive. And although I've never had your issue, I have had an odd issue where KQ1 fails to boot and run 95% of the time.

My symptoms are, strip the computer down to just jrATX, extra 64k video memory card, floppy controller, standard 5 1/4" DSDD drive, boot KQ1 and watch the ensuing chaos of getting different behaviors each time the game boots. One time it even kept running the drive head until it hit the track limit and it kept trying to drive it. I swapped out every part and narrowed it down to the jrATX. The original power supply works flawlessly 100% of the time with KQ1, but the jrATX almost always fails. Current theory is that there is excessive ripple in the picoATX power supply (a much larger full size ATX power supply works just fine BTW). I'm trying out a few things to see if I can reduce the ripple and get a more stable system.

Long story short. Try the same config with either an original power supply (if it's not too much for it), or try connecting a standard ATX power supply to the jrATX. Your symptoms are not the same as mine but could be the same root cause.
Creekmore34
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Re: system goes bonkers during autoexec

Post by Creekmore34 »

Greetings All,

Thanks to everyone who has offered some ideas to test. After further inspection, I can report the following:

1) With a bare system (128k, and two lpt ports, no jride or extra memory) everything works fine.

2) The placement of the jride has no affect on the problem behavior (which in itself is varied and wonky).

3) I began to assume that it was the jride and took a spare 8GB DOM and installed it in the jride and partitioned and formatted it with dos 5 fdisk (via diskette). Everything seemed great until I rebooted and then got a "missing operating system" message following the BIOS boot. I redid all of the partitioning and formatting steps, and I got the same message.

4) Frustrated, I swapped back in my original 8GB DOM and tried again for the heck of it. What do you know? I got an identical "missing operating system message", which among all the varied weird instability, I'd never gotten before. This led me to believe that actually both DOMs are just fine.

5) As a last ditch effort, I removed the sidecar shell from the jride (which is one of the last rev B boards that Alan ever built) and tried it with my original 8GB DOM; bare without the shell. LOW AND BEHOLD, everything works perfectly! I used the system for several hours, rebooting many times, doing lots of different activities, and all worked well.

6) So, is there a solution for this (aside from just leaving the board hanging off the end of the machine)?

7) All of this testing has been with my picopsu only powering 1 drive. I'm wondering if attaching the second drive power has anything to do with this at all. I ordered an external power supply to do some testing with but I really would like to come up with a neat, and clean power solution for a system with two internal drives.

I will post new info once I try with the new external atx power supply.
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chuckphd53
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Re: system goes bonkers during autoexec

Post by chuckphd53 »

I have a test unit with JRIde , LPT side card, regular power brick, TandyMod and PCsprint. and Serial Card.

All works well booting from a Standard mechancial Hard drive, but had issues with a DOM...
“I never commit to memory anything that can easily be looked up in a book.” (AE)
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chuckphd53
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Re: system goes bonkers during autoexec

Post by chuckphd53 »

the jr cases have a conductive coating, if you use an ohm meter you cantest this...
Not sure why this would matter, but more so I am thinking the side case is keeping the JRIDE connector from properly seating and without
the case it can plug in more deeply...

can you see if this is a possible issue, should not need the ouside shell, just the plate that goes betweenthe Jr case and the JRIde..
“I never commit to memory anything that can easily be looked up in a book.” (AE)
Creekmore34
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Re: system goes bonkers during autoexec

Post by Creekmore34 »

Good idea. Will try it.
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