Tektronix WFM601 A E or M NVRAM Replacement & Reconfigure - Page 1
Forum section: electronics / repair

author: dexters_lab
author_rank: Unknown
timestamp: June 18, 2021, 11:09:17 am
content: Help! i just picked up this Tek WFM-601A SDI video analyser and all i get on the screen is "configuration error contact tektronix service"quick google says it's the NVRAM and sure enough there's the usual Dallas job inside.Replacing the Dallas is easy enough, but what about the recalibration and configuring?has anyone fixed one of these before?I would like to restore back to working condition

author: dexters_lab
author_rank: Unknown
timestamp: June 19, 2021, 08:32:36 am
content: had a lot of help thrown at me through my twitter and discord so i thought i'd sum up.Internal Dallas DS1643 NVRAM should be easy fix, there's a direct equivalent in the ST M48T08 or i might attempt a battery hackCalibration software has been located, i have attached it in case anyone ends up here with the same issue. The service manuals are easily available online.I will attempt to repair, recalibration might be another matter as i don't have the equipment to do it, but i will post up here when something happens

author: andy2000
author_rank: Frequent Contributor
timestamp: June 19, 2021, 03:33:01 pm
content: I have a non-working WFM-601A that I could try to read the NVRAM from if it helps.I also have a 1755A that I would like to locate the calibration software for. It's currently working, but the CRT is tired, and I would need the calibration software if I replaced the CRT. I already replaced the Dallas NVRAM with an FRAM chip.

author: dexters_lab
author_rank: Unknown
timestamp: June 30, 2021, 09:56:56 am
content: UPDATE:After must effort i have some answers on the NVRAM chip and how it's used and configured in the WFM601 Waveform Monitors and what it all means...What NVRAM is used?The NVRAM used in these waveform monitors is a Dallas DS1643, it's a 8k NVRAM with clock, the DS1643 is no longer available but ST Micro make an alternative in the M48T08.What's stored in the NVRAM?The NVRAM stores the model, serial number and calibration data for the monitor, although some adjustments are made with physical adjustment pots most adjustment is made with software and stored in the NVRAM.What happens when the NVRAM goes flat?When the battery goes flat the Monitor will no longer boot and will report 'CONFIGURATION ERROR CONTACT TEKTRONIX SERVICE'How do i fixed a monitor with a flat battery?Step 1:You will need to remove the old one and replace it or perform a battery hack to remote locate an external battery onto it.Step 2:Using the UPGRADE.EXE software running under DOS or the Windows98 command prompt in DOS mode you need to configure the NVRAM with the correct model, serial number and date. A RS232 cable is also needed between your PC and the monitor.To do this type:Code:UPGRADE -CThis will clear the NVRAM and configure it enough to boot. But it will be completely un-calibrated, although you will be able to see everything workingyou will find much of it will be so far out of specification it's essentially unusable as a reference instrument!!Can i re-calibrate the monitor?Yes it can be re-calibrated but it does involve 100s of steps and a very good selection of electronic test equipment (oscilloscopes, signal generators) and broadcast test equipment (SDI test pattern generator).I have a working monitor, can i make a backup of the NVRAM?YES! Using the UPGRADE.EXE software running under DOS or the Windows98 command prompt in DOS mode, A RS232 cable is also needed between your PC and the monitor.To backup typeCode:UPGRADE -STo restore typeCode:UPGRADE -RCan the original Dallas be battery hacked so i don't need to remove it?Yes it can be battery hacked if you want to keep the original and save yourself some £/€/$. The battery is located on in the potting compound slightly to the right hand side of the device.Is there any official documentation on all this?Yes, all software and documentation is attached file with the exception of the service manual which is easily available online (it's too large to attach here)

author: dexters_lab
author_rank: Unknown
timestamp: June 30, 2021, 11:08:21 am
content: So with all this info i was able to remove the NVRAM, hack on some temporary batteries and get it back up and running.Lack of calibration though is a major issue, this is far worse than using something that has been 20 years since it was calibrated, because the chances are it would be pretty close to calibrated but with some drift but with an instrument with factory defaults it is so far out it can't be trusted for anything other than making pretty patterns!So if you have one of these monitors that is working,MAKE A BACKUP OF YOUR NVRAM!

author: kriss166
author_rank: Newbie
timestamp: May 23, 2023, 11:21:19 pm
content: Bonsoir j'ai des wfm601A et 601i pour piece si il y a des personnes intéréssé

author: Ozmo
author_rank: Newbie
timestamp: June 03, 2023, 08:58:10 pm
content: Thanks for the software - I will try use that to back mine up - I have the lesser WFM601E (no audio analysis)- it seems to work without issue - but I have no access to an SDI signal to test...- it doesn't handle regular composite video at all.I'm not sure how useful it is to anyone as it is - there is no XY mode on my model.So I was thinking of doing a - non permanent - mod to turn it into a high quality XY oscilloscope display...Any thoughts on this? Where best would it be to break the signal path from and which of the many DACs in there?Thinking to maybe control the display from an ESP32 or pico.. get it doing some vector music, art or games?ta.

author: dexters_lab
author_rank: Unknown
timestamp: June 04, 2023, 09:44:27 am
content: Quote from: Ozmo on June 03, 2023, 08:58:10 pmAnyone who has a hobby in broadcast video equipment would find one usefulThe service manual should reveal anything you need to hack ithttps://elektrotanya.com/tektronix_wfm601_waveform_monitor.pdf/download.html

author: TEKhacker
author_rank: Newbie
timestamp: September 25, 2023, 02:08:13 pm
content: Tek WFM601E fixedThanks to dexters_lab for posting this, it has allowed me to revive a brain dead Tek 601.When I first powered up this Tek 601E it came up with“CONFIGURATION ERROR CONTACT TEKTRONIC SERVICE”Having read this post & studied the photo’s I decided to give the battery hack a go.I machined into the Dallas chip with a small drill & domed head burr to reveal the negative terminal at the top & the positive terminal at the bottom. I carefully machined out enough compound to get the old battery out, I soldered on two lengths of equipment wire which led out of the case to 2 x AA battery pack, providing 3volts.I made up the serial cable as shown in the Software update manual.I used an ASUS notebook PC running Windows XP to run the software, I created a new Folder called TEK in My Documents and copied Upgrade.EXE, Software.DAT Cal.exe & WFM601X.prc into it. I connected to the WFM601 through a Prolific USB to RS232 converter, set up with the correct driver and set as Comm1. I used Run>CMD to access DOS, then CD “Tek” to set the “Tek” folder as the Current Directory then Upgrade -c to run the software. A new window will open, asking which comm port to use, enter the comm port in use and the software should communicate with the WFM601. The software reported that the device software was corrupt and asked would you like to repair it, it then asks for the Device serial number (on a sticker on the rear panel) and the date (mm/dd/yy), confirm the action and if the software on the PC is good it will start copying to the WFM601, it takes about 35 minutes to copy.Restart the WFM601 and it should look like a Waveform Monitor again.Having proved that the Dallas chip is still good I removed the temporary 3v supply and glued on a CR2032 button cell holder scavenged from an old PC board, restart and re-programme again.Note the Tek WFM601i has a Dallas DS1225AD SRAM chip.

author: dexters_lab
author_rank: Unknown
timestamp: September 26, 2023, 07:07:51 am
content: great to know another has been saved!Don't forget though, the calibration settings that are unique to your unit have gone and will be on default values. it means it wont be accurate but if you have the right test equipment and time it can be recalibrated.Quote from: TEKhacker on September 25, 2023, 02:08:13 pm

author: TEKhacker
author_rank: Newbie
timestamp: October 01, 2023, 09:54:17 am
content: Thanks to a source of SDI Colour Bars & Pictures I have now been able to recalibrate this device for most displays apart from BowTie.Video levels were quite close, calibration signal out of timing, vector & lightning display well off.I did not make any internal adjustments, just the PC ones.Configured saved out for future use.Photo showing Dallas chip in WFM601A which currently has a dead power supply.

author: dexters_lab
author_rank: Unknown
timestamp: October 01, 2023, 10:27:59 am
content: excellent work... how close did you manage to get the Gamut view?I never tried to calibrate mine properly, i ended up picking up an OmniTek XR from a friend just after, it was more capable so the WFM601 got shelved for another day unfortunately.