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Model II: No memory available

NeXT said:
would that be something a can of compressed air would show? I can't really put my hands on the chips while it is in action as it's in the middle of the card cage.
Click to expand...

Hmm...not sure. I know my faulty OS Challenge 1 RAM IC wasn't hot. It just didn't work, and seem to take all the memory downstream of it offline so the machine didn't even know it was there.

Fortunately there was no cage and the RAM was socketed so swapping ICS out for a test was easy.

Tez
 
NeXT said:
would that be something a can of compressed air would show? I can't really put my hands on the chips while it is in action as it's in the middle of the card cage.
Click to expand...

I suggest you remove the cards and reseat all chips. I seem to remember the memory chips are socketed. And while you're at it, look for oxydation on the chips' legs. Mostek and TI chips are especially prone to oxydation. If the legs are black, use a pencil eraser to remove the oxydation, but be careful not to break a pin. I also suggest you clean the edge connector contacts with a pencil eraser, and then with alcool or lighter fuel. My Model II didn't work until I did that with every card.

As Tezza pointed out, a single faulty chip is likely to cause an entire bank to stop working, because the computer performs some memory tests when it boots.
 
NeXT said:
would that be something a can of compressed air would show? I can't really put my hands on the chips while it is in action as it's in the middle of the card cage.
Click to expand...
I think you're probably confusing two different kinds of fault here: faults caused by heat and faults that happen to generate heat.

If heat is the cause of the problem, you'll often see that things work fine for a while and then fail when heat builds up. Resetting or power-cycling doesn't have any effect, but if you leave the equipment to cool down, it works again. In this case it can be useful to artificially cool suspect parts down to see if they've become over-sensitive to heat. Compressed air does have some cooling effect, but there's also "freeze spray" which is specifically made for this purpose.

However, sometimes the problem itself is the cause of the heat and a prime example of this is a shorted RAM chip. So while it's a good idea to check for hot chips, which are a tell-tale sign of a short, but no amount of cooling is going to magically fix the problem. Then again, just to keep things interesting, chips can also fail in many other ways which cause no measurable difference in temperature ;-)

If, as our amphibian friend suggests, all the RAM is socketed, a thourough clean up and reseating is a good start. If that doesn't work, try swapping chips around to see if that makes any difference in order to figure out which is/are bad.
 
Well it's my Monday tomorrow and I'm off next week to Vancouver so this will have to wait for a while.
I guess the one good thing about graduating high school is that I still have a surplus of erasers.
 
Someplace on one of my hard-Drives I have a copy of "Pickles and Trout" he sent me for my TRS model II. Also a system boot for one of my KayPros. He was very specific on what was the BIOS # etched on the chip. Angry wives, perhaps understandably if they can't understand computer mythology, can be a plague.

Lawrence

MikeS said:
--
His memory definitely lives on; I also just sent someone an image of a boot disk that Don had sent me years ago...
Click to expand...
 
Micom 2000 said:
Someplace on one of my hard-Drives I have a copy of "Pickles and Trout" he sent me for my TRS model II. Also a system boot for one of my KayPros. He was very specific on what was the BIOS # etched on the chip. Angry wives, perhaps understandably if they can't understand computer mythology, can be a plague.

Lawrence
Click to expand...

The voice of experience?
 
BuMP.

Okay so I still have not solved the problem. Even after reseating ships, cleaning pins with erasers, using cans of compressed air and plain and simply letting it sit it still gives the same error when I try to get into BASIC.
I do however now own a nice Tektronix 335 scope so could it possibly be of use?
 
neXT:
Just curious. When you attempted to load BASIC, did you boot with CP/M or TSDOS.

Good Luck
 
I don't have TSDOS
All I own are copies of CP/M 2.25 and 2.23. There's not much else I can do until I can find the time to finish modifying the floppy expansion box to fit a 5 1/4" floppy drive. Then at least I can try loading other software.
 
NeXT said:
Are you implying that the OS itself is not properly configured? It's entirely possible as these are my first steps into CP/M. I assumed that it would "just work" regardless.
Click to expand...

Yes... that does it tell you once CP/M is up & running? :confused:

Edit:
I looked again at my last post...
It LOOKS LIKE this version of BASIC you are running expects BANKED MEMORY... something CP/M 2.x does not do...
(tho I was under the impression that progs written for vers 3 would test for it...)

Have you tried running MBASIC?
Or is this MBASIC? The version I have for my 4p does not say anything about banking... (not in version 3 either...)

Any memory-testers available on the disks you have?
 
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I don't see any memory testers on the disks. All I got was just enough to boot and configure CP/M, dump stuff like disks into hex and initilize hard drives. There really isn't much else.
 
Mega BuMP.

I dropped by my parents to drop off some goodies for my Model II (hard disk controller, three port serial card and a M68000 CPU with 2mb ram) and I also drpped off some software and documentation, notably a copy of TRSDOS v2.

I ran the full 8 minute ram test on all 64k of memory and the result was no problems so to TRSDOS at least there are no bad or unallocated banks of memory, yet according to the BASIC interpreter on the CP/M disks there is no memory to work with. I'm confused.
 
So then keep in mind leeb's advice and if you have it present in the disks, try to use MBASIC.COM as the Level II BASIC must be incompatible with the memory map used by CP/M. To test if you have more memory installed you can try to initialize a RAM disk with the MEMDISK.COM tool (don't remember the exact name).
 
NeXT said:
I ran the full 8 minute ram test on all 64k of memory and the result was no problems so to TRSDOS at least there are no bad or unallocated banks of memory, yet according to the BASIC interpreter on the CP/M disks there is no memory to work with. I'm confused.
Click to expand...

The Pickles & Trout CP/M has a program that can check all RAM pages, not just page 0 (0h-7FFFh) and page 1 (first page at 8000h-FFFh). Some more information on RAM and jumpers in the MII at http://fjkraan.home.xs4all.nl/comp/trs80m2/. It might be that your Basic actually wants more RAM pages.
 
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