Subject: Help with my broken system

From: "Jon Vogel" <[email-masked]>
Date: Wed, 11 Nov 2009 20:05:56 -0600

Hello, hardware repair gurus.

I am puzzled.  I was lucky and had an annoying cold today, so I called in 
sick and took my TI system apart to find out why it was misbehaving. (Isn't 
this what everyone does when they are sick?)

The symptoms are that my system can't read a BASIC program from floppy. 
(Or, apparently, anything else.)  The program loads without any errors, but 
is always corrupt when listed.  After spending about 4 hours on it, here's 
what I've discovered:

1. With TI-XB cartridge and 32K MemExp, I am unable to correctly load a 
program.  I swapped XB cartridges to check if the cartridge was bad.  It 
seems that no data will load correctly, since the same thing happens with 
E/Asm cartridge and appropriate programs.  I first noticed this problem when 
my HRD seemed to have lost its mind.
2. With TI-XB cartridge and no MemExp (card removed), I am able to correctly 
load a BASIC program.  This implies a bad 32K mem expansion.  But, I 
replaced with different 32K, same results.
3. With console BASIC, I can correctly load a program.  (Console BASIC 
doesn't use 32K MemExp.)
3. I swapped the console and its power supply.  Same results.
4. I swapped the CorComp disk controller with a TI one, same results.
5. I swapped the Flex cable and card.  Same results.
6. I swapped the PEB backplane(!), same results.
7. The power supply (ATX replacement) shows ~11.7 volts on all  positive 
lines (brown and green) and -11.7 on the negative line (yellow).  I also 
measured while doing disk access and the voltage levels held steady.

So, I'm out of ideas.  Other than just buying a new stock TI PEB and using 
it to test, I don't know what else to try.  Any suggestions?

Thanks,

Jon Vogel

---

From: Insane Multitasker <[email-masked]>
Date: Wed, 11 Nov 2009 20:57:49 -0600

Jon,

Quite the interesting problem you have there.  A few thoughts:

1. You don't mention whether or not the HRD was removed during your testing.  If not, recommend doing so immediately. 

2. Your EA program load and XB program load point to 32K as you surmise.  You loaded programs successfully with BASIC and XB when the 32K was removed -- this implies VDP RAM is most likely functional, since this is where your program must load. 

3. Console Powerup seems to be working as does onboard PAD RAM.  I would venture your consoles are functioning.

4. Set up your system with 32K, Flex cable, and XB.  Try writing a program that uses the 32K memory.  Something like 

 "10 DIM A(2000)"

 "20 FOR I=1 to 2000::A(I)=I ::NEXT I  "

 "30 FOR I=1 to 2000:: PRINT A(I):: NEXT I"

Are the values corrupt when you read them back?  You can do a similar operation with VDP using a string variable.

I'm hoping the trouble is just your HRD ;)-   Good luck

> To: [email-masked]
> From: [email-masked]
> Date: Wed, 11 Nov 2009 20:05:56 -0600
> Subject: [TI994A] Help with my broken system
> 
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---

From: "Jon Vogel" <[email-masked]>
Date: Wed, 11 Nov 2009 21:25:10 -0600

From: "Insane Multitasker" <[email-masked]>

>Quite the interesting problem you have there.  A few thoughts:

Ya don't say.  :-)

>1. You don't mention whether or not the HRD was removed during your 
>testing.  If not, recommend doing so immediately.

I should have mentioned: during my testing, all cards were removed except 
the FlexCable adaptor, TI disk controller and 32K depending on the test.

>2. Your EA program load and XB program load point to 32K as you surmise. 
>You loaded programs successfully with BASIC and XB when the 32K was 
>removed -- this implies VDP RAM is most likely functional, since this is 
>where your program must load.

Right, plus VDP is in the console, and I swapped it out with another one.

>venture your consoles are functioning.

The one works fine with a CF7+.  I did pull a spare outof the closet, plug 
it in and have it immediately flame.  Literally.  Something catastrophically 
failed by the VDP chip.  I never saw anything like that before.  But, that's 
a different issue.  :-)  But, another spare also worked fine, except that 
the problem persisted.

>Are the values corrupt when you read them back?  You can do a similar 
>operation with VDP using a string variable.

The test as written worked fine.  I think that I actually did a program in 
MiniMemory that checked the entire range of the 24K expansion memory.  But, 
I don't remember the results.  :-(  I'll have to try that program again.  If 
I were smart, I stored it in the MiniMem.  I'm running the string test now. 
It ran out of memory at 1370 strings.  But, the VDP only has so much RAM, so 
I'm re-running the test with a limit of 1360.

>I'm hoping the trouble is just your HRD ;)-   Good luck

I wish it were something that Richard could easily fix ;-), but it's been 
pulled from the system since the get-go of the problem.  The HRD is too 
valuable to leave plugged in while I try to figure this out.

Thanks for the help, Tim.

Jon

---

From: "Jon Vogel" <[email-masked]>
Date: Mon, 16 Nov 2009 17:37:13 -0600

>where your program must load.

Hey, Tursi,

Well, although I hate to reinforce failure, I purchased another replacment 
32K from TexinTreasures and viola, my system now works.  So, my original 32K 
and the first replacement that I bought from TexinTreasures were both 
identically bad.  Since all the data pointed to the 32K, I should have 
followed my instincts and just ordered another immediately, instead of 
messing with this for so long.

Back in business!

Regards,

Jon

---

From: "Jon Vogel" <[email-masked]>
Date: Mon, 16 Nov 2009 17:46:45 -0600

Oops, Tim, not Tursi.  Sorry.

Regards,

Jon

---

From: "Jon Vogel" <[email-masked]>
Date: Tue, 17 Nov 2009 19:03:16 -0600

Not that anyone cares <sniff> but my TI system is still working after 24 
hours.  That's a good thing.  At least to me.

Regards,

Jon

---

From: Owen Brand <[email-masked]>
Date: Tue, 17 Nov 2009 20:12:09 -0500

Well I certainly care...  :) And I am very happy for you.  If you need  
another 32k card for your other PEB, let me know...

Owen Brand
**Oprysoft**
Opry99er.com

---

From: "Jon Vogel" <[email-masked]>
Date: Tue, 17 Nov 2009 19:18:34 -0600

From: "Owen Brand" <[email-masked]>

>another 32k card for your other PEB, let me know...

I need a nice, blue LED fan and I need to fix the two broken 32K cards that 
I currently have.  Then I can get my 2nd PEB up and running.

Hey, speaking of which, sort of, Owen, does your PEB have the original power 
supply?  I can replace it with a PC one if you wanted.  It's actually pretty 
easy and the PEB weighs a whole lot less afterwards.

Regards,

Jon

---

From: Owen Brand <[email-masked]>
Date: Tue, 17 Nov 2009 20:38:27 -0500

That sounds great!  My PEB fan is EXTREMELY loud... You can hear it's  
insanity on my TI-PC transfer video on YouTube if you are  
interested... Know any quick fix for that?  I have a 99/4 PEB that I  
have been using for parts... Would that fan work?  How hard are they  
to replace, and do you think simply replacing the fan would fix the  
jet engine sound?

Owen Brand
**Oprysoft**
Opry99er.com

---

From: "Tursi" <[email-masked]>
Date: Tue, 17 Nov 2009 20:48:33 -0500

My PEB Power Supply and Fan replacement page (not much good as a tutorial, 
too tongue-in-cheek, but gives you an idea what's inside): 
http://harmlesslion.com/text/atx_peb.htm

---

From: Jon Vogel <[email-masked]>
Date: Tue, 17 Nov 2009 20:05:55 -0600

You need a new fan. The TI PEB fan is gov't surplus jet turbines. So  
swapping one turbine for another won't help you.  But, replacing the  
power supply with a PC one means using a smaller, quieter fan.

I've been passing through Louisville a lot recently on my way to  
Cincinnati, we need to meet and I can do the operation.

Regards,

Jon

On Nov 17, 2009, at 7:38 PM, Owen Brand <[email-masked]> wrote:

>
>
> That sounds great!  My PEB fan is EXTREMELY loud... You can hear  
> it's insanity on my TI-PC transfer video on YouTube if you are

---

From: Jon Vogel <[email-masked]>
Date: Tue, 17 Nov 2009 20:11:29 -0600

This is what I used as a reference to swap my PEB power supply, so  
don't short credit yourself on how useful this page is.

Regards,

Jon

---

From: Owen Brand <[email-masked]>
Date: Tue, 17 Nov 2009 21:28:15 -0500

I live in Elizabethtown KY now... Right off I-65.  :). That would be  
great.  When I started reading this book, I tried to write a BASIC  
program to convert hex to decimal.  Got a ways into it, but had to  
turn off the TI... I was spending time in BASIC when I needed to be  
reading about A/L.  :)

Owen Brand
**Oprysoft**
Opry99er.com

On Nov 17, 2009, at 9:05 PM, Jon Vogel <[email-masked]> wrote:

>> interested... Know any quick fix for that?  I have a 99/4 PEB that  
>> I have been using for parts... Would that fan work?  How hard are  
>> they to replace, and do you think simply replacing the fan would  
>> fix the jet engine sound?
>>
>> Owen Brand
>> **Oprysoft**
>> Opry99er.com
>>

---

From: Insane Multitasker <[email-masked]>
Date: Tue, 17 Nov 2009 22:10:37 -0600

I just assumed you had already started modifying your console with 128k SRAM per Tursi's recent mod ;)-   Good to hear you tracked and fixed the problem.  Dr. Watson would be proud.  tim
 
> Date: Mon, 16 Nov 2009 17:46:45 -0600
 		 	   		  
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---

From: mark wills <[email-masked]>
Date: Tue, 17 Nov 2009 20:26:47 -0800 (PST)

HAIL JONS SACRED AND HOLY TI SYSTEM.

PRAISE BE TO THY TI GODS!

:-)

>
>From: Jon Vogel <[email-masked]>
>Sent: Wed, 18 November, 2009 2:03:16

---

From: mark wills <[email-masked]>
Date: Tue, 17 Nov 2009 20:30:17 -0800 (PST)

I have heard of people simply cutting out the metal in front of the fan, leaving a big circular hole. This reduces air turbulence, thus reduces noise.

>
>From: Owen Brand <[email-masked]>
>To: "[email-masked]" <[email-masked]>
>Sent: Wed, 18 November, 2009 2:38:27
>That sounds great!  My PEB fan is EXTREMELY loud... You can hear it's insanity on my TI-PC transfer video on YouTube if you are interested.. . Know any quick fix for that?  I have a 99/4 PEB that I have been using for parts... Would that fan work?  How hard are they to replace, and do you think simply replacing the fan would fix the jet engine sound?
>
>Owen Brand
>**Oprysoft**
>Opry99er.com
>
>On Nov 17, 2009, at 8:18 PM, "Jon Vogel" <jonpvogel@comcast. net> wrote:
>
>
>>>
>>
>>
>>  >>
>>
>> 
>>>>      
>> 
>>From: "Owen Brand" <owenbrand@opry99er. com>
>>