Subject: Re: [TI994A] Re: HRD 4000 problem

From: "jacques" <[email-masked]>
Date: Mon, 17 Oct 2011 19:54:06 -0300

I have finally gotten around to try and figure out what is wrong with my 
HRD4000 card. Amazing how as a retired person I always seem to be so busy.

Here is a list of the chips on my card:

M1 to M16, 16 chips consisting of 8 chips labelled HM628128LP-8, 4 chips 
labelled HM628128LP-7 and 4 chips labelled HM628128LP-10

M32 is empty 32K memory chip is on my SAMS card

U1  MC74HC154N
U2  empty
U3  SNL42S259N
U4  SNL42S259N
U5  HD74LS00P
U6  SN74LS139N
U7  SN74LS156N
U8  SN74LS241N
U9  CDM62256E10
U10 T74LS138B1
U11 empty
U12  T74LS138B1
U13 SN74LS138N

If I pull U4 as suggested by Tony do I replace it with U13?

From looking at the construction guide that I received when I got this 
HRD4000 card I am having difficulty in matching the error code that I got 
from running the TST program with something that points to U4. I intend to 
run the TST program again to see if I get the same error code.

Remember that I am not a hardware person because I am an accountant who 
knows his debits and credits. I have previously pulled and replaced chips 
using a chip puller and I can do this carefully.

Jacques

----- Original Message ----- 
From: "Tony Knerr" <[email-masked]>
To: <[email-masked]>
Sent: Friday, September 30, 2011 11:57 PM
Subject: [TI994A] Re: HRD 4000 problem

> Looks as if you've got a bad chip in the U4 socket if I'm reading the
> test docs correctly, Jacques. Try taking that chip out and moving the 
> 'last' chip to that socket. You'll have less ramdisk size, but it
> should test without error.
>
> If that doesn't fix the problem, and you get the same error, try
> replacing the 74LS154 (might be a 74HC154N). That's the logic chip
> that turns the Ram chips on and off, it may have a bad gate.
>
> Tony
>
>
> --- In [email-masked], "epergrem" <epergrem@...> wrote:
>>
>> Hi Jacques,
>> Gary Bowser wrote a chart which displayed the various error message bit 
>> combinations and the chips.
>>
>> It's dated 1991, so hopefully it's relevant to the HRD4000.
>>
>> My copy is a bit difficult to read, but I will upload it to the files 
>> section anyway.
>>
>> Ernie
>>
>>
>> > Based on this I feel that one chip is bad. How do I find out which one 
>> > and
>> > what should I do next?
>> >
>> > Jacques
>> >
My original message on September 30th.

For a month or so I have been having problems with my HRD 4000 card.
Initially I was not even able to load the ROS file because the CFG program
would not show the card. Periodically CFG would show the card but would
crash if I tried to load a number of files and then the card would again not
show when CFG was run. Since I have two smaller HRD cards installed, today I
was testing an XB program written by a friend. My TI had been on for a long
time so I tried running CFG again and the HRD 4000 card popped up again. I
reloaded ROS and then proceeded to configure it as 5 DSDD disks including
from DSK3 to DSK7.  I then proceeded to load DSK5 with files from a backup.
This backup of about  100 files includes all the Funnelweb files and some
other programs that I use. All loaded except for two small files at the very
end. However I could not run any of these files from BOOT installed on
another HRD card configured as DSK8 or from a floppy  copy of Funnelweb
DiskReview contained on a floppy in DSK1. Both of these programs will
catalogue DSK5 and the other empty configured DSK but report 'not found' if
I attempt to run any program files contained on DSK5.

I have just finished running the TST program included with the HRD 4000
package. Test 1 being the non destructive test ran OK. Test 2 one of the two
destructive tests also ran fine. Test 3 , the Addr/Page test, ran fine until
it hit CRU Bits Bus 00000110 10000000 when it started counting errors and it
stopped at 00000110 11111111 after reporting 32718 errors. The test then
resumed for a short time and then it indicated that it was finished.

Based on this I feel that one chip is bad. How do I find out which one and
what should I do next?

Jacques

---

From: Tony Knerr <[email-masked]>
Date: Tue, 18 Oct 2011 06:20:18 -0400

Sorry, Jacques, I mistyped. The chart indicates the M chips, not the U 
chips.
I'm surprised no one corrected it by now. Since you've also indicated that
you're using 128k rams instead of 512k chips, the problem appears to be
in either M13 or M14. It's a little unclear which one the way the chart 
is constructed.
My suggestion would be to pull them both, put the chips from M15 and M16 
in their
places, and seeing if all is then ok. You could then try the 2 pulled 
chips one at a time
in the M15 socket until you found the bad one. Leave the good one in M15 
and then
get a new chip for the M16 socket, or not if you don't really need it.

Tony

On 10/17/2011 6:54 PM, jacques wrote:
> From: "Tony Knerr" <[email-masked] 
> <mailto:tonyknerr%40comcast.net>>
> To: <[email-masked] <mailto:TI994A%40yahoogroups.com>>
> > --- In [email-masked] <mailto:TI994A%40yahoogroups.com>, 
> "epergrem" <epergrem@...> wrote:
> >>
> >> Hi Jacques,
> __

---

From: "jacques" <[email-masked]>
Date: Fri, 21 Oct 2011 21:10:32 -0300

I have now pulled M13 and M14 and replaced them with the chips that were at 
M15 and M16. I then ran test 3 from the HRD TST program and no errors were 
reported. I added one of the chips that I had removed and ran test 3 from 
TST again and no error was reported. I then added the last chip and to my 
surprise no error was reported.

I ran CFG and partitioned memory as 5 DSDD disks and loaded my previous DSK5 
which contains mainly Funnelweb files. Using DM-100 and BOOT/U I was able to 
show a listing of DSK5 and to show that the other drives were empty, however 
I cannot run any programs on DSK5 using BOOT. It reports no file found. I 
even tried to run a small XB that is on DSK5 and I get IO error 07. Also no 
success if I try and run programs from Funnelweb running from DSK1.

My  conclusion is that all the memory chips are fine but some other chip is 
preventing programs from running. Tony's original reply suggested that I 
next 'try replacing the 74LS154 (might be a 74HC154N)'. I do not have an 
inventory of spare chips so I looked at the chips that are on my two other 
ram disk cards. Another HRD 512K card has a chip labelled 74HCT154N and the 
other non-HRD 192 K card  has a chip labelled  DM74LS154N. The chip at U1 on 
my HRD 4000  card is labelled MC74HC154N.

Which LS154 chip should I swap from the two running ram disks with U1 on my 
HRD 4000 card?

I would like to get the HRD 4000 running and then worry about replacing the 
defective chip to replace the swapped chip on the other card. If this does 
not work what chip should I check next.

Jacques

---

From: Tony Knerr <[email-masked]>
Date: Sat, 22 Oct 2011 22:24:55 -0400

Jacques,

I was avoiding answering immediately with the hope that someone would 
jump in,
but no one has yet 'rescued' me.  :(

At this point the problem could be a number of places.

If the test program runs to completion without error, it is not likely 
that the error is in the 74LS154 chip,
it is apparently selecting the SRAMS correctly.

My guess that your ram chips are ok, and the problem lies in either one 
of the logic chips (74xxxxx), or a flaky solder joint,
or an intermittent 7805 regulator (not likely if the test program 
succeeded). It could also be dirty card contacts, have you
cleaned them with a pencil eraser?

If no one else wants to take on the job of repairing your card, here are 
your options as I see them.

1. Reheat all the solder joints one by one and see if that fixes the 
problem.

2. Replace the 7805 regulator.

3. Swap chips one-for-one with one of the 2 working Horizon 4000 
ramdisks that I have and will gladly send you to help resole this problem.

4. Send me your card, and I'll try #1, #2, & #3. Whattaya got to lose? :)

Tony

---

From: "jacques" <[email-masked]>
Date: Sun, 23 Oct 2011 10:08:11 -0300

Tony,

Thank you for volunteering. <grin> We may want to continue our exchange of 
messages privately so as not to bore other members in the group with my 
problems. I do not filter incoming messages so you can reply to:

jgroslou at nbnet dot nb dot ca

Of the three steps that you have suggested I would only be capable of doing 
#3. My soldering skills were never very good and are now non-existent 
because of my age which causes an unsteady hand and poor eyesight for 
close-up work. Also, I am not a hardware person so I would not be able to 
recognize an 7805 regulator and even if I did I would not know how to 
replace it.

I have no objection to sending you my card. Send me your mailing address and 
perhaps a suggestion on how much insurance to place on my parcel as it sets 
outs on its journey across our common border.

I will again clean the card contacts in case this is the cause of the 
problem. It probably is not the cause of the problem but I also want to try 
installing an original copy of ROS. It will be later this week before I am 
ready to send the card. Based on previous experience in sending or receiving 
articles that cross our border it will take a week and perhaps 10 days for 
the card to reach you.

Again, thank you very much for offering.

Bye for now,

Jacques

---

From: Marc Hull <[email-masked]>
Date: Sun, 23 Oct 2011 11:07:25 -0700 (PDT)

Actually I have been following this subject and have a vested interest in the outcome so please keep the vitals public if you don't mind...

--- On Sun, 10/23/11, jacques <[email-masked]> wrote:

From: jacques <[email-masked]>
Subject: Re: [TI994A] Re: HRD 4000 problem
To: [email-masked]
Date: Sunday, October 23, 2011, 8:08 AM

  

      Tony,

replace it.

the card to reach you.

Bye for now,

Jacques

----- Original Message ----- 

>> I have now pulled M13 and M14 and replaced them with the chips that

>> were at

>> M15 and M16. I then ran test 3 from the HRD TST program and no errors

>> were

>> I ran CFG and partitioned memory as 5 DSDD disks and loaded my

>> previous DSK5

>> which contains mainly Funnelweb files. Using DM-100 and BOOT/U I was

>> able to

>> show a listing of DSK5 and to show that the other drives were empty,

>> however

>> even tried to run a small XB that is on DSK5 and I get IO error 07.

>> Also no

>> My conclusion is that all the memory chips are fine but some other

>> chip is

>> inventory of spare chips so I looked at the chips that are on my two

>> other

>> ram disk cards. Another HRD 512K card has a chip labelled 74HCT154N

>> and the

>> other non-HRD 192 K card has a chip labelled DM74LS154N. The chip at

>> U1 on

>> Which LS154 chip should I swap from the two running ram disks with U1

>> on my

>> I would like to get the HRD 4000 running and then worry about

>> replacing the

>> defective chip to replace the swapped chip on the other card. If this

>> does

---

From: "jacques" <[email-masked]>
Date: Sun, 23 Oct 2011 15:26:04 -0300

Marc,

Some mundane information such as when and how I send the card or whether or 
not I should remove batteries before sending will be handled privately. Once 
the card is working I will undertake to report to the group what was wrong 
and how it was found.

Jacques

----- Original Message ----- 
From: "Marc Hull" <[email-masked]>
To: <[email-masked]>
Sent: Sunday, October 23, 2011 3:07 PM
Subject: Re: [TI994A] Re: HRD 4000 problem

Actually I have been following this subject and have a vested interest in 
the outcome so please keep the vitals public if you don't mind...

      Tony,

replace it.

the card to reach you.

Bye for now,

Jacques

---

From: Marc Hull <[email-masked]>
Date: Sun, 23 Oct 2011 12:48:14 -0700 (PDT)

Well OK but don't forget to include your credit card information ;-)....

Thank you  jack......

Marcus...

From: jacques <[email-masked]>
Subject: Re: [TI994A] Re: HRD 4000 problem
To: [email-masked]
Date: Sunday, October 23, 2011, 1:26 PM

  

      Marc,

and how it was found.

Jacques

----- Original Message ----- 

Tony,

replace it.

the card to reach you.

Bye for now,

Jacques

---

From: "jacques" <[email-masked]>
Date: Sun, 30 Oct 2011 11:01:22 -0300

An update.

For reasons unknown, yesterday my HRD 4000 card again became usable. I 
reloaded from backup disks all the files that it previously held and it is 
now working properly.

I can only speculate that this happened because during the last few days I 
have made extensive use of my TI-99/4A with the HRD 4000 card still inserted 
in the PEB and with the card switch turned to the ON position. I had 
previously followed Tony's suggestion about cleaning the contacts but 
without success. Even reinstalling a new ROS did not seem to help.

Perhaps the card did not look forward to a trip south of the border and 
decided to shape up or else. <grin>

Jacques

----- Original Message ----- 
From: "Marc Hull" <[email-masked]>
To: <[email-masked]>
Sent: Sunday, October 23, 2011 4:48 PM
Subject: Re: [TI994A] Re: HRD 4000 problem

Thank you jack......

Marcus...

      Marc,

and how it was found.

Jacques

----- Original Message ----- 

Tony,

replace it.

the card to reach you.

Bye for now,

Jacques