Please HELP with a TDS784a

Hello everybody, and...HEEELP! HEEEELP!!!!.<br> <br> It seems that I have erased the data inside the Dallas DS1486-120 Watchdog timer chip. I wanted to try my dexterity with the Dremel, and everything went well. I found a couple of 3V batteries inside (one of them with 2.9V, and the another with 2.7V...no need to change, but...lithium, ya know...suddenly zero...or very close to). The thing is I am sure I did not damage any internal part. But I am almost sure that I disconnect the main battery with the Dremel (the negative pin) before applying new battery (a 2,300 mA one...). The secondary battery was fine, untouched and connected (I mean here the one which is deeper inside the Dallas chip, the one which is mounted farther from the pin #1). I don't have any backup of this chip (silly me, I thought it was only for real time generation and storage).<br> <br> First of all, I socketed the 3 main ICs (EPROM and the two Dallas chips). I have do it so to buy a programmer and extract its contents, as a safety precaution, and for sharing. I tested the scope with the new sockets installed and it worked as ever. Perfect, no problems at all. BUT when I make the change of batteries in the Dallas DS1486-120 chip, connected to the socket in the scope, turned it on...everything seems fine (video tests on screen, relay clicks, etc.), but the scope is stuck in the clock screen!!!. I am not able to boot it up again!!!. And I cutted the negative from the second battery once I connected the new one. That's for sure.<br> <br> So...what can I do?. Of course, it seems to be very clear that my problem is in the above mentioned Dallas chip (I thought it has no data inside, only realtime clock, but obviously it had data).<br> <br> I readed in another forum -just in case-, which programmer will be fine. I've found this one. It does support both Dallas chips, and also the EPROM:<br> <br> <a href="https://www.batronix.com/shop/programmer/BX32P/index.html#tabs-4" target=_blank>https://www.batronix.com/shop/programmer/BX32P/index.html#tabs-4</a><br> <br> Please, I need your help. I know that I will have it.<br> <br> I needed to connect both positive terminals of both batteries, because connecting the new one to the one closest to pin #1 does not make that the second battery inside the Dallas chip have voltage (maybe a diode between the two, or a supervisor IC?...if so, I did not use a diode, and I can install one...hope this will help).<br> <br> Thank you all.

Jesus,<br> You can buy replacement DS1486 chips on greedbay.&#160; Most are clones or refurbished chips from China.&#160; However, some of them seem to work ok.&#160; You can also buy a new manufacture DS1486/DS1650 pair of built up circuits that are available.&#160; Cost is about $100.&#160; Look on the same source.<br> <br> Big deal is that you have to have certain TEK unique information in the first part of the chip that tells the scope about options and other information.&#160; Without it, the scope won't boot fully.&#160;<br> <br> As part of my repair process on these TEK scopes, I record the NVram contents before and after calibration on each scope. Thus, I have several 784A images.&#160; If you want a couple, let me know.<br> <br> To burn to the chip, you can either use a rom burner or Tektool (discussed in length in the old TEK forum) through gpib.&#160; You can also record and reinstall using the floppy system, but I don't currently have a 784A on hand to get the proper image.&#160; Some other reader might.<br> <br> One issue with the rom burner is that you cannot write to the first &quot;D&quot; bytes of the DS1486 chip and there is a test byte that will probably fail your calibration on first startup.&#160; cycling or rerunning the POST should clear it as the calibration is stored on the ACQ board, not the CPU board.<br> <br> Strick

Thanks a lot, Strick!. I will receive tomorrow the new programmer which does support all the chips inside the processor board of the TDS784A (both Dallas and the EPROM). I will order new chipsets thru greedbay as you mention. I will google it.<br> <br> My only problem is that I don't have any previous copy of the watchdog contents. Silly me.<br> <br> Please, I beg you that if it is possible for you, send me the images you have. I can try them out, and I hope one will make it work again.<br> <br> Just in case, this is my email: jngpro@gmail.com<br> <br> Of course, I will inform you here about how the process is going.<br> <br> TIA, a big hug from Madrid, and let me know if I can be of any help for you. I also own another Tek scopes with Dallas chip inside, and I can make dumps to share them with you, or with anyone in trouble.<br> <br> &#160;

Sorry Peter...I can not find greedbay as a place to buy the chips...could you put me a link?.<br> <br> Thank you.<br> <br> Jesus<br> &#160;

<p>Jesus,</p> <p>here is one link from the US:&#160;&#160;<span style="font-size:11pt;"><span style="line-height:115%;"><span style="font-family:Calibri,&quot;sans-serif&quot;;">https://www.ebay.com/itm/153848991230?hash=item23d21d4dfe:g:EvQAAOSw-F1eWjYs&amp;amdata=enc%3AAQAIAAAA4Elfm2%2FlVsmuV2GfmDzBUVYnuIV1RIuWG%2BY0chpldiktcBvvLzDTC5TYe8E%2FxSSHLmmmjVDGzjO6wL8h3b8VA38jQdCL06mwbgWq1Qy074kn1p59cW%2Fm4COQLIWCkGVmJwY%2B%2FlB6odn9BB9Ro7dMFsMO%2Bgf3L%2F2dKXn%2F1xZwTYgtB1hmmlini8pMfI7ksDh0xJY2%2B4gYz%2FxrrK65d2EaCdTXabA8M9O%2BZrRRr8eKucrvfuHIX%2BXSlZ1kYTjoHD7JgGmOhAN2C3lr1Az5l5F1ZbsA7PvqejHi%2BcN9CfOXx%2BgN%7Ctkp%3ABk9SR_a8ppuUYg</span></span></span></p> <p>And another from China:&#160;<span style="font-size:11pt;"><span style="line-height:115%;"><span style="font-family:Calibri,&quot;sans-serif&quot;;">https://www.ebay.com/itm/181266663238?hash=item2a3455c746:g:gx4AAMXQfvlSjtrN&amp;amdata=enc%3AAQAIAAAAwKQk1Xj4AW%2FB3Kk%2FDchkZeR9uL9y3iVzPICfS9NR0TEo%2F3flQ1y7zqudPpwQnMy%2BgAAjytKsqnJBQLGgIqO639Ww2E9sHUa5xxpRg4OkSCBy33VLVET5MvB8wrduvRp5hRQBmKjMxJ1Fq65hQ3wNTmKqSadGVW6ixYf3PyxsYkDvgVcmXT9cN9%2FTjzWO%2FLX4KVGwExBYetWlef4nCk4Ss2yq0zSbaLl77JE3sKsSd02Ktu9if%2BPTlwH%2Bd15e7qEWbA%3D%3D%7Ctkp%3ABk9SR57wyJuUYg</span></span></span></p> <p>I'm attaching the image from the DS1486 and DS1650 alone as well as the combined images of the DS1486 and DS1650 (or DS1250).&#160; The combined image is written with Tektool and avoids the error when writing to the DS1486.&#160; Your rom burner may be different from mine and not care about trying to write to the first &quot;D&quot; bytes.&#160;&#160;</p> <p>The DS1486 file is 131,072 bytes, the DS1650 file is 524,280 bytes and the combined file is 1,048,575.&#160; If you decide to try Tektool, let me know and I'll send the proper parameters.&#160;&#160;</p> <p>I'm also enclosing the DS1486 document.</p> <p>Strick</p> <p></p> <p></p> <p></p> <p></p>

For some reason, the site will only allow one file... all three zipped below.<br> <br> Strick

G-R-E-A-T !!! Both the links and specially the files. Next Monday I will receive the programmer, and I will program the watchdog chip.&#160;<br> <br> Of course, I’ll keep you informed of the (I hope) progress.&#160;<br> <br> Thanks a lot&#160;<br> <br> Jesus<br> &#160;

<p>Only one question, Strick: of the three files...which is which?. I mean, which one is for rhe DS1486, etc?.</p> <p></p> <p>Thank You</p> <p></p> <p>Jesus</p> <p></p>

<p>The 131K (20000 hex) file is for the DS1486 and the 524K (80000) file is for the DS1650.&#160; Quite frankly, I think you could leave the DS1650 blank and it wouldn't matter.&#160; I've seen them with nothing in them and the scope still works.&#160; TEK put the necessary stuff in the earlier part of the memory.&#160; The memory starts at 4000000 and the DS1486 ends at 4020000.&#160; the DS1650 starts at 4080000 and occupies 80000 bytes.</p> <p>When using Tektool, I read and write to both chips with the following:</p> <p>Tektool -r Nvram.bin -b 0x4000000 -l 0xfffff&#160;&#160;&#160;&#160; This covers both chips and works fine.</p> <p></p> <p>Remember, your burner will probably complain about the first 14 bytes (D hex) when flashing the DS1486, as these are owned by Timekeeper.&#160; Also, there is one byte that indicates that the scope is calibrated and you may have to restart to clear or reset it.&#160; Reading and Writing using Tektool avoids this issue and it's handled by the CPU, not a burner.</p> <p>Strick</p>

<p>Thanks a lot for your invaluable help, Strick.<br> <br> The truth is today I received the new programmer, and it was unable to write -even fully erase- the DS1486-120. Maybe I need to adjust the limits of the data to be written...or maybe the best way is using one GPIB to USB adapter, which I don’t have.<br> &#160;</p> <p>Fortunately -and a bit desperate- I’ve found in Ebay the new version of the two chips already programmed for my scope. I hope this will put it back in service again.And yes: I deducted by myself that the smallest file is the one for the DS1486.</p> <p>I will post here the results, once I have the new chips (with them installed you are able to check the battery voltage).</p> <p>Cheers,</p> <p>Jesus</p>

Hello again, Strick:<br> <br> I didn't received the new pre programmed chips yet, but I bought 2 USB programmers, which supposedly supports the DS1486-120.<br> As you told, when I'm going to use your file (the smaller one, 128k), the problem is that I have no way to avoid to write the chip from the beginning; that is, from zero.<br> You know (and told so) that at the very beginning of the file is the clock data, and this part is always changing (due to the fact it has an osillator inside, and the clock is marching). So I wanted to program the chip after this small amount of data; just put inside the rest of your file. I was thinking about diconnecting the batteries. But I'm not sure if this will have any effect on the programming or not.<br> <br> I am doing this because the chips will take time to arrive from Texas to Madrid, and because I need the scope (which, BTW, it was working fine, but taked ages to startup, even with the #3 DIP switch in the 0 position).<br> <br> Thanks again for all your help, Strick.<br> <br> Jesus<br> &#160;

<p>Dear Strick: Here you have a capture of the window in which I can adjust the range to be programmed in the chip (DS1486-120). Maybe this will help.</p> <p>Thank you</p> <p></p> <p>Jesus</p> <p></p> <p><img></p>

Here it is

Jesus,
Sorry for late reply, we were on a vacation in Canada.  
My old programmer (a CQ-3 made by MCUmall would refuse to write to the first "D" (hex) and would immediately stop writing the file.  My new CQ-4x4 that I just bought has no problems writing to the chip from the beginning.  
Have you tried just writing the file to the chip?  When you read it after writing, (or if it verifies), it will certainly fail as the first 3 bytes will have changed.  the remaining 11 bytes of the "D" (or 14 decimal) bytes don't change rapidly.

Anyway, if your programmer refuses to write like my old CQ-3, then when you read the file, do an offset of -D and when you write to the chip, do an offset of D.  you need to look at your documentation to see how you do that.  For my CQ-3, when you request to open a file, it asks if you want to off set and when you write, it displays that offset and requests any offset for the write.  Doing a -D read and +D offset will include all the important stuff from the file and the timekeeper will fill in the first D all by itself.

Strick

Wow! Canada! Lucky you, man. It seems to me that Canada is a very nice place (even to play with our toys!).

Of course, don’t worry about the time you took. I have your invaluable help, which is the important thing. 
 

For me it is a bit like Chinese language. I understand it just a little. Of course, I understand you, and what you tell about data offset. 
 

I’ll try it out once again, taking into account all your comments. I’m very sure that it will be possible to program the 1486 again. 
 

I do have another scopes (analog ones), also with the Dallas chip (this time with the 28 pin DIL package). These are the 2465B (I have one B and one BDM). I hope I can read the chips, and program new ones (I saw new chips in Mouser).

Thanks a lot for your invaluable help, and I hope you have recharged your batteries!

Cheers

Jesus