Date   

Re: Is my Tek 468 beyond repair?

Chuck Harris
 

He was trying to tell you that until you have a working CPU,
all of your other tests are wasted.

The clock has to work, and the processor has to be latching
addresses.

If it doesn't, it doesn't matter what your RAM and EPROM are
doing, or how good they are.

I would be more inclined to suspect the oscillator than the
crystal.

-Chuck Harris

John wrote:

I was not getting anything at all on ALE. I removed and re-seated the 8085. Unlike the TTL logic chips, the pins on the processor were shiny and clean. However, since I have disconnected the A19 board (timing and power supply) I will not know the effect of this re-seating until I reconnect everything together again.

In the meantime, the oscillator crystall is a weird problem. I checked the power supplies on the A19 board and found there were all good. I was a little concerned about the 5V line because it had somewhat short of 100mVpp ripple on the CRT display, but the service manual shows a nominal 80mmVpp, so this is probably OK as well. I checked the output from the oscillator crystal (pin 8) and found that it started at about 3V and sank to about 1V after a few seconds. The result was that the output from the 74LS112 was OK at first, but destabilized after a few seconds, faded (the trace got blurred) and then flat-lined as the signal dropped below the TTL threshold. This is exactly what I was seeing at U272 and pin 1 of the 8085 on the microprocessor board. I therefore surmise that the 74LS112 is probably OK, and the problem is the crystal itself.

I am curious as to why you suggest that I should not bother going any further? Do you mean with the logic analyser or repair of the oscilloscope in general? If the latter, then no worries. The scope only cost me a trip to pick it up and although it was a bit daunting at first, delving into the computer side of things has been interesting and I have learned something. Cost wise, so far I am looking at a replacement crystal and possibly a 8085 processor which I think I can pick up for around £12. On the other hand the RAM board, storage board, display board are untested at present and I know that repair of the analogue side will incur some additional cost so I appreciate that at some point one has to ask whether it is worthwhile. I am not sure I have reached that point yet, but am happy to entertain other viewpoints?






Re: TDS 3000B-family 'scope (TDS 3014B) has problem with LAN interface

 

I'm pretty sure I've found the answer to my problem, though maybe not a solution.
In my earlier message, I forgot to mention that I replaced the battery in the Clock/NVRAM module, since the time indication was intermittent, as was the functioning of the LAN connection. I was hoping to not only restore the functionality of the clock but also to restore the LAN's functionality, although the RAM would have continued to work even without battery backup. What I hadn't realized was that the NVRAM module could have stored the LAN adapter's MAC address, which of course was lost after disconnecting the old battery and reconnecting a new one. It turns out that the NVRAM does indeed store the LAN adapter's MAC address.
I found that information here:
https://www.eevblog.com/forum/testgear/tds3012b-ethernet-configure-failure/
Unfortunately, I don't think a copy of the MAC address is still stored in my router so, unless any valid MAC address will do, I guess I'm stuck because I don't think there's a label containing the MAC address anywhere on or in the 'scope. I guess the MAC address on an old adapter, no longer in use, would be valid but whether it'll be accepted and how to enter it remains to be seen.
Local time where I live is 2:55 (AM) so it's time to quit for the night.

Raymond


Re: Which programmer to use to read/write dallas DS1486?

Bruce Lane
 

On 19-Sep-20 15:15, Siggi wrote:

(snippage)

All that being said, I'd love to know what people here are using to read
and write NVRAMs ;).
It's not often I have to, for the very reasons you point out, but
pretty much any of the Data I/O 'Unifamily' programmers (Unisite, 2900,
3900, 3980) will easily handle those chips. I usually end up using my
Unisite. Most of the programmers from Advin should work as well.

For the best flexibility with any device programmer, look for one which
uses a design called 'pin driver.'

Keep the peace(es).



--
---
Bruce Lane, ARS KC7GR
http://www.bluefeathertech.com
kyrrin (at) bluefeathertech dot com
"Quando Omni Flunkus Moritati" (Red Green)


Re: Which programmer to use to read/write dallas DS1486?

J. L. Trantham
 

Where are you located? I can read, archive, and program these chips if you would like.

These chips are supported by BP Micro Programmers including the BP 1410 and BP 1600 and later programmers. They are likely supported by other programmers I have but I do not have access to my 'usual' resources to be able to verify this.

Sometimes, you can find these older programmers at very reasonable prices but you would need a WinXP computer with a parallel port to be able to use them. The later programmers, with a '10', such as the 1610, connect with USB and would have software that would support a later version of Win.

I'm happy to help if I can. I'm in NW FL USA.

Joe

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Rogerio O
Sent: Saturday, September 19, 2020 5:02 PM
To: TekScopes@groups.io
Subject: [TekScopes] Which programmer to use to read/write dallas DS1486?

Dear all,
I will have to replace the dallas chips (DS1486/DS1650) of my TDS684A.
I have ordered the replacement kits (not fake China chip) from a source I have found in EEVBlog.
While I wait, I have dowloaded the contents of the chips to a floppy using a tool that does that.
My question is about the next step.
I intent to read the chips (just in case) and I will have to write one image to them.
I currently have a TL866A and a GQ-4X, but I have seen posts that say that neither programmers will work.
I can’t afford spending $500 or more in another programmer.
Is there any consensus out there if any of these can be used?
Any special recommendation about programming. Which chips should be used as “target device” for the DS1486 and the DS1650?
Thank you


Re: TDS 3000B-family 'scope (TDS 3014B) has problem with LAN interface

Dave Casey
 

I didn't experience the issue myself; I have always used static IP. I
haven't used it hours on end, but I've had no issues for relatively short
uses of the scope.
Remember to pick a static IP in the range allocated by your router to avoid
the DHCP server from assigning the same IP address to another client.

Dave Casey

On Sat, Sep 19, 2020 at 5:49 PM Raymond Domp Frank <hewpatek@gmail.com>
wrote:

On Sun, Sep 20, 2020 at 12:36 AM, Dave Casey wrote:


I seem to recall there being a known issue with these and DHCP.
Have you tried setting a static IP appropriate to your network, leaving
DHCP turned off?
Hi Dave,
Thanks for your response. I have tried not using DHCP and using the static
address that the 'scope acquired when the LAN interface was still working.
I could find it in the router's configuration.
Since the lock-up really looks like the 'scope's program crashing and the
instrument becoming blocked, I was thinking about a hardware/firmware
problem and processing my disappointment.
In my worries about it being such a problem, I haven't yet configured a
different (static) IP address from the time when it still worked and try
(ping) that. I'll be in the lab on Monday and will try.

Do you by any chance remember whether the problem you're referring to
blocked the instrument altogether?

Raymond






Re: Which programmer to use to read/write dallas DS1486?

KeepIt SimpleStupid
 

I think I have the GQ-4X and I looked into it programming another dallas part for the TDS320.  What i remember is not all DALLAS parts are directly supported.  Your not going to need a programming voltage and you have to restrict the addresses copied because they won't verify.
Compare the dallas 1486 to the 27128 or 27C128 chips.  See: http://www.unitechelectronics.com/EPROM_data.htm
the 27128 and 27C128 is supported by the GQ-4X(V4),GQ-4x4
The DS1225Y (64K and DS1235Y (256K) are supported.  They are likely closer, because they don't require Vpp.Battery backed up RAM.

So, look at the datasheets and the programming entries and figure out how to not program the clock area.

On Saturday, September 19, 2020, 6:15:39 PM EDT, Siggi <siggi@undo.com> wrote:

Hey Roger,

I don't know the answer to your question regarding reading and writing the
NVRAM. But I wonder why you feel you need to save and restore the NVRAM
data.

The calibration information for the scope is not stored in NVRAM, it's in
EEPROM on the acquisition board, so you don't need to worry about the
calibration information. AFAIK the only information of value in the NVRAM
is the options bits, and it's well known how to write to them to enable
whatever options you have and/or want to enable.
Also, if you install the new NVRAM in a socket, you should be able to
safely defer the decision on buying a programmer. In the worst case
scenario, you'll still have the old NVRAM, and to program the new one,
you'd only need to pop it out of its socket.

All that being said, I'd love to know what people here are using to read
and write NVRAMs ;).

Siggi

On Sat, Sep 19, 2020 at 6:01 PM Rogerio O <rodd414@gmail.com> wrote:

Dear all,
I will have to replace the dallas chips (DS1486/DS1650) of my TDS684A.
I have ordered the replacement kits (not fake China chip) from a source I
have found in EEVBlog.
While I wait, I have dowloaded the contents of the chips to a floppy using
a tool that does that.
My question is about the next step.
I intent to read the chips (just in case) and I will have to write one
image to them.
I currently have a TL866A and a GQ-4X, but I have seen posts that say that
neither programmers will work.
I can’t afford spending $500 or more in another programmer.
Is there any consensus out there if any of these can be used?
Any special recommendation about programming. Which chips should be used
as “target device” for the DS1486 and the DS1650?
Thank you






Re: TDS 3000B-family 'scope (TDS 3014B) has problem with LAN interface

 

On Sun, Sep 20, 2020 at 12:36 AM, Dave Casey wrote:


I seem to recall there being a known issue with these and DHCP.
Have you tried setting a static IP appropriate to your network, leaving
DHCP turned off?
Hi Dave,
Thanks for your response. I have tried not using DHCP and using the static address that the 'scope acquired when the LAN interface was still working. I could find it in the router's configuration.
Since the lock-up really looks like the 'scope's program crashing and the instrument becoming blocked, I was thinking about a hardware/firmware problem and processing my disappointment.
In my worries about it being such a problem, I haven't yet configured a different (static) IP address from the time when it still worked and try (ping) that. I'll be in the lab on Monday and will try.

Do you by any chance remember whether the problem you're referring to blocked the instrument altogether?

Raymond


Re: TDS 3000B-family 'scope (TDS 3014B) has problem with LAN interface

Dave Casey
 

I seem to recall there being a known issue with these and DHCP.
Have you tried setting a static IP appropriate to your network, leaving
DHCP turned off?

Dave Casey

On Sat, Sep 19, 2020 at 5:33 PM Raymond Domp Frank <hewpatek@gmail.com>
wrote:

On Sun, Sep 20, 2020 at 12:30 AM, Raymond Domp Frank wrote:


This to me looks like a hardware/firmware failure. I haven't found a way
to
completely disable/enable the LAN interface, thereby possibly resetting
the
thing.

I'd very much appreciate any remedies, ideas or info.
I forgot to mention that after the problem appeared, I upgraded the 'scope
from firmware version 3.27 to 3.39 and even to 3.41 (the latest version) to
no avail.

Raymond






Re: TDS 3000B-family 'scope (TDS 3014B) has problem with LAN interface

 

On Sun, Sep 20, 2020 at 12:30 AM, Raymond Domp Frank wrote:


This to me looks like a hardware/firmware failure. I haven't found a way to
completely disable/enable the LAN interface, thereby possibly resetting the
thing.

I'd very much appreciate any remedies, ideas or info.
I forgot to mention that after the problem appeared, I upgraded the 'scope from firmware version 3.27 to 3.39 and even to 3.41 (the latest version) to no avail.

Raymond


TDS 3000B-family 'scope (TDS 3014B) has problem with LAN interface

 

I recently acquired a TDS 3014B 'scope.
It looks fine and operates as it should, except for its LAN interface.
In the beginning (first half day since I got the 'scope), it could sometimes be configured and would be OK for a while, then stop after a few minutes.
Now, after a few days, the LAN interface does not work at all and even hangs up (blocks) the 'scope when I select the DHCP button in the LAN setup menu:

Immediately after I press the DHCP enabling button, the usual popup telling me it'll try and acquire an IP address appears. After that, everything stays frozen and no buttons or knobs respond. The only way to get out of that situation is power cycling, however after that, the scope shows its normal background, graticule, numbers etc. but no traces appear and it does not respond to operating keys or knobs.
The only remedy seems to be power cycling while doing a Reset by keeping the "B Trig" button depressed during power up.
This to me looks like a hardware/firmware failure. I haven't found a way to completely disable/enable the LAN interface, thereby possibly resetting the thing.

I'd very much appreciate any remedies, ideas or info.

Raymond


Re: Which programmer to use to read/write dallas DS1486?

Siggi
 

Hey Roger,

I don't know the answer to your question regarding reading and writing the
NVRAM. But I wonder why you feel you need to save and restore the NVRAM
data.

The calibration information for the scope is not stored in NVRAM, it's in
EEPROM on the acquisition board, so you don't need to worry about the
calibration information. AFAIK the only information of value in the NVRAM
is the options bits, and it's well known how to write to them to enable
whatever options you have and/or want to enable.
Also, if you install the new NVRAM in a socket, you should be able to
safely defer the decision on buying a programmer. In the worst case
scenario, you'll still have the old NVRAM, and to program the new one,
you'd only need to pop it out of its socket.

All that being said, I'd love to know what people here are using to read
and write NVRAMs ;).

Siggi

On Sat, Sep 19, 2020 at 6:01 PM Rogerio O <rodd414@gmail.com> wrote:

Dear all,
I will have to replace the dallas chips (DS1486/DS1650) of my TDS684A.
I have ordered the replacement kits (not fake China chip) from a source I
have found in EEVBlog.
While I wait, I have dowloaded the contents of the chips to a floppy using
a tool that does that.
My question is about the next step.
I intent to read the chips (just in case) and I will have to write one
image to them.
I currently have a TL866A and a GQ-4X, but I have seen posts that say that
neither programmers will work.
I can’t afford spending $500 or more in another programmer.
Is there any consensus out there if any of these can be used?
Any special recommendation about programming. Which chips should be used
as “target device” for the DS1486 and the DS1650?
Thank you






Which programmer to use to read/write dallas DS1486?

Rogerio O
 

Dear all,
I will have to replace the dallas chips (DS1486/DS1650) of my TDS684A.
I have ordered the replacement kits (not fake China chip) from a source I have found in EEVBlog.
While I wait, I have dowloaded the contents of the chips to a floppy using a tool that does that.
My question is about the next step.
I intent to read the chips (just in case) and I will have to write one image to them.
I currently have a TL866A and a GQ-4X, but I have seen posts that say that neither programmers will work.
I can’t afford spending $500 or more in another programmer.
Is there any consensus out there if any of these can be used?
Any special recommendation about programming. Which chips should be used as “target device” for the DS1486 and the DS1650?
Thank you


Re: Is my Tek 468 beyond repair?

 

On Sat, Sep 19, 2020 at 11:45 PM, John wrote:


Cost wise, so far I am looking at a replacement crystal and possibly a 8085
processor which I think I can pick up for around £12
In case you or someone else needs one or more: I've got hundreds of NOS 8085's (OKI) in their original rails at a few €/$/£'s each. Shipment from NL.

Raymond


Re: Is my Tek 468 beyond repair?

John
 

I was not getting anything at all on ALE. I removed and re-seated the 8085. Unlike the TTL logic chips, the pins on the processor were shiny and clean. However, since I have disconnected the A19 board (timing and power supply) I will not know the effect of this re-seating until I reconnect everything together again.

In the meantime, the oscillator crystall is a weird problem. I checked the power supplies on the A19 board and found there were all good. I was a little concerned about the 5V line because it had somewhat short of 100mVpp ripple on the CRT display, but the service manual shows a nominal 80mmVpp, so this is probably OK as well. I checked the output from the oscillator crystal (pin 8) and found that it started at about 3V and sank to about 1V after a few seconds. The result was that the output from the 74LS112 was OK at first, but destabilized after a few seconds, faded (the trace got blurred) and then flat-lined as the signal dropped below the TTL threshold. This is exactly what I was seeing at U272 and pin 1 of the 8085 on the microprocessor board. I therefore surmise that the 74LS112 is probably OK, and the problem is the crystal itself.

I am curious as to why you suggest that I should not bother going any further? Do you mean with the logic analyser or repair of the oscilloscope in general? If the latter, then no worries. The scope only cost me a trip to pick it up and although it was a bit daunting at first, delving into the computer side of things has been interesting and I have learned something. Cost wise, so far I am looking at a replacement crystal and possibly a 8085 processor which I think I can pick up for around £12. On the other hand the RAM board, storage board, display board are untested at present and I know that repair of the analogue side will incur some additional cost so I appreciate that at some point one has to ask whether it is worthwhile. I am not sure I have reached that point yet, but am happy to entertain other viewpoints?


Re: Is my Tek 468 beyond repair?

Bert Haskins
 

On 9/19/2020 10:15 AM, John wrote:
Chuck, thanks. I will have a look at the crystal driver. Will need to remove that board.

Regarding the processor, I get what you are saying. I put the jumper in reset mode which holds the RESET line down to ground. Processor should be halted. When I pull the jumper, it brings the RESET line back up and I am expecting the processor to start and do something, but all I get on the LA trace is RESET going up and no other activity. Even though I don't have the address lines connected to the LA, I expected to see the status of S0 and S1 change in response to a read operation and at least some ALE pulses before the processor halted again, but my understanding here is admittedly limited. I am learning as I go along.
If you are not getting a TTL level pulse(s) on the ALE pin after reset, I would not bother going any further.

Is the 8085 sitting in one of those POS TI sockets?

Try rocking the core chips in their sockets several times.

FWIW I still have working development boards for most of the early procs, I've been doing this since the 74181 was the leading edge.

-- Bert




Re: TDS6604 Acquisition Board Replacement

Charlie Conger
 

As I recall I think the ACQ board and the computer board are "married" . I do not know how to arrange divorce and re-marry.
If your effort does not work I would change back to the original ACQ board an try to run SPC.


Re: Is my Tek 468 beyond repair?

John
 

Indeed, my suspicions were also heading in that direction, but its good to have another view.

HOLD is connected directly to GND and I confirmed a ground connection there. READY is connected to 5V via a 1k resistor. I did check that 5V was present, but didn't monitor it during start-up. Will have a look at that and pin 2 on U272 once I've sorted the clock and put everything back together. It seems that the diagra,s do not provide the power arrangements for the oscillator, just showing pin 8 as the output from the 50MHz oscillator box. I'm going to have to remove the board from the chassis and visually determine how its wired up and what is going on.

I did find an OKI branded 8085 on eBay for a fiver. I guess it is probable NOS although since he has more than 10 available I'm not sure. The china ones seem to be stamped "Infineon". Someone has a nice "rare ceramic" one with gold top but rather pricey!


Re: Is my Tek 468 beyond repair? Trap and Kernel test procedure

Heitor Lima
 

Hi Tony.
First I want to thank you for your kindness in answering me. Both scopes show code 3000 in the POST. I have the service manual. Reading pags 5.36 and 5.37 of the manual, they tell you to check if the trap test and kernel test routines were successful. However, the manual does not inform how each routine is checked. So I put my questions to the group.
I thank you and any other member of the group if you can help me.

Regards

Heitor Lima

PS: The serial numbers are : B010194 and 301977

On Saturday, September 19, 2020, 02:52:43 AM GMT-3, tgerbic <tgerbic@gmail.com> wrote:

Heitor,

What are the symptoms of the two scopes and what have you already identified as problems?  Perhaps that would help us figure out ways we can help you. Please keep the symptoms of each scope completely separate in your posts so we don't get them confused.

Regards
Tony


Re: Is my Tek 468 beyond repair?

Roger Evans
 

John,

I think suspicions may be moving from ROM rot to a bad CPU or at least a need to clean the CPU pins. Before condemning the CPU check that the voltage swing on the clock input, pin 1, comfortably exceeds the TTL thresholds, < 0.4V for Low and > 2.4V for HIGH. With the 1k pull up resistor on U272 the clock signal should be more like 4V at the high level but frequently does not have a flat top. It switches very fast to the TTL high level then more gradually as the resistor pulls it higher. Check also that pin 2 isn't doing anything, it should sit close to +5V. You could also put a couple of logic analyser clips on HOLD and READY just to be sure they don't do anything strange in the startup phase. I have built several single board computers over the last couple of years and when they fail to do _anything_ coming out of reset it is either forgetting to get all the control inputs in the right states or a duff processor (the peril of buying parts from China!).

Regards,

Roger


Re: Is my Tek 468 beyond repair?

Harvey White
 

One technique to "trap" a bad microprocessor is to have a series of jump or branch instructions surrounding a halt instruction.  If the mandatory jump or branch failed, then the processor would halt, or would do a jump to the current location and freeze operation.  The supposition is that some instructions may fail but the halt instruction won't.

Tektronix did that, IIRC, in the 468 and some other systems.  The practice may still be alive in some military equipment, but modern microprocessors are reliable enough that such measures are not likely to be needed

Harvey

On 9/19/2020 4:06 AM, Roger Evans via groups.io wrote:
Chuck, John,

The insight into 8085 programming wisdom is very illuminating. I am guessing that the 160-0459 ROM is mapped to $0000 and there are many HALT instructions (hex $76) scattered through the first 100 bytes of code that look as if they are intended to catch a corrupted jump instruction that then falls through to the HALTs. The 8085 still has to execute a small number of instructions before hitting the HALT. I think the minimum would be five memory references and so five ALEs and five RDs before the HALT. It should be fairly straightforward to capture that on John's DSO.

Roger




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