Tektronix TDS2014B repair - Page 1
Forum section: electronics / repair

author: TheKellerman
author_rank: Contributor
timestamp: February 23, 2023, 08:05:04 pm
content: Hi,I got a TDS2014B that is not booting up. The three green LEDs light up and the frequency on the probe comp is 1.8kHz.Initially I thought the firmware got corrupted so I desoldered the flash and reflashed it with the FW from a TDS1001C (as described here:https://www.eevblog.com/forum/testgear/tektronix-tds1000b-series-hacks/). But the scope is still not booting.The UART near the USB controller shows this output:Code:dprint driver V0.aApLoader_Version=DevB6809fwupdate V0.8Firmware length = 9cf8, checksum = fd89Calculated Checksum = 0000*****cypRunApp received, resetting ...æ`�øfæ``Ãøfæ~f`f�)ûTektronix Nautilus Driver: Ap_Version= 1.053Giving message to 68K = 0x000d, = runAppOK:::::::;dprint driver V0.aApLoader_Version=DevB6809fwupdate V0.8Firmware length = 9cf8, checksum = fd89Calculated Checksum = 0000****cypRunApp received, resetting ...*æ`�øfæ``Ãøfæ~f`f�)ûTektronix Nautilus Driver: Ap_Version= 1.053Giving message to 68K = 0x000d, = runAppOK:::::;*******************************dprint offSo it tries three times and gives up. Before reflashing the main flash, the output was the same (but it was resetting forever, not only three times). It also had Firmware length = 9cf8, checksum = fd89.It seems the "Firmware length" does not refer to the main firmware.There is also a small i2c flash on the board. Maybe there is the problem? When the right adapter arrives I will read the i2c flash.Could someone with a working TDS2000B/C please connect to the UART and post the output? 56000 baud, 8 data, 1 stop, no parityGreetings

author: mikehank
author_rank: Regular Contributor
timestamp: February 24, 2023, 08:53:32 pm
content: Your error script looks like incompatible or corrupt FW.

author: TheKellerman
author_rank: Contributor
timestamp: February 24, 2023, 09:20:55 pm
content: Yes it looks like it, but replacing the original FW with the FW from a C model made no difference. So I wonder why the expected FW length and checksum is the same.I checked the i2c EEPROM and the content is the same as herehttps://www.eevblog.com/forum/testgear/tektronix-tds1000b-series-hacks/msg2021134/#msg2021134Any suggestions on what to check next?

author: mikehank
author_rank: Regular Contributor
timestamp: February 24, 2023, 10:01:33 pm
content: Dart boarding here but maybe the volatile memory. These scopes are more than 15 years old and memory doesn't last forever.

author: Fieroluke
author_rank: Contributor
timestamp: February 24, 2023, 10:10:21 pm
content: “CypRunApp” points to the Cypress USB Controller.The way I understand it from the Cypress datasheet this is a completely autonomous processor. It seems to boot from the I2C close to it. This would allow it to take over control and possibly tri-state the 68000 (DMA) and then access the Flash directly. I would guess that it leaves at least the last 64K of the flash ($7Fxxxx) alone since this is where model code, serial number, filter coefficients, etc. are stored. If it tri-states the 68K and then crashes, the scope will appear dead.Some people had corrosion on the USB processor and had it die. I don’t know if that’s what’s wrong with your scope…

author: tautech
author_rank: Super Contributor
timestamp: February 24, 2023, 10:31:01 pm
content: Quote from: TheKellerman on February 24, 2023, 09:20:55 pmCorrosion.I have a TDS2012B that with their convection cooling and vented upper case allowed some muck to fall into the scope and onto an IC pin where is sat for years absorbing atmospheric moisture and finally corroding through the IC pin.Quite difficult to find as it was just a dark spot on a SMD IC lead but when cleaned with a scalpel is was evident it was corroded completely through.I no longer haveanytop vented convection cooled equipment.

author: mikehank
author_rank: Regular Contributor
timestamp: February 24, 2023, 11:28:25 pm
content: Yes convection cooling is a bad idea. These scope were never my favorite. They aren't very good performance wise and are surprisingly hard to fix.

author: 66bono
author_rank: Contributor
timestamp: February 25, 2023, 08:58:44 am
content: I've already assembled an oscilloscope like, I don't want to risk it. As I continue to experiment, I will read the memory.

author: TheKellerman
author_rank: Contributor
timestamp: February 26, 2023, 08:33:34 am
content: QuoteI found some dried goo around pins 21 and 22 on U400 (the NS chip). The Cypress looks ok so far. Cleaning everything made no difference.Also I noticed a significant delay between the lines "Firmware length = 9cf8, checksum = fd89" and "Calculated Checksum = 0000*****" so i assume thats when the Cypress is reading some data.And Checsum 0000 indicates that it didn't got any data, right?

author: sean0118
author_rank: Frequent Contributor
timestamp: February 26, 2023, 09:40:03 am
content: Are power supply voltages stable?

author: TheKellerman
author_rank: Contributor
timestamp: February 26, 2023, 05:54:08 pm
content: Yes, I checked all the voltages according to the service manual and everything is stable.

author: TheKellerman
author_rank: Contributor
timestamp: February 28, 2023, 08:05:58 pm
content: I think I now understand the UART log. It seems like the i2c EEPROM for the Cypress is divided into two parts, the ApLoader (at the start) and the actual Ap (starting at 0x10004 with the length 0x9cf8).During the delay between the lines "Firmware length = 9cf8, checksum = fd89" and "Calculated Checksum = 0000*****" the Cypress is accessing the EEPROM but there is something wrong with the SDA line as it sometimes cant reach 3.3V and goes only to about 1V (see attachments).Any ideas on what could cause this? I cant find any other chip on the i2c that would pull the signal low. And my TL866 could read the EEPROM just fine.

author: analogRF
author_rank: Super Contributor
timestamp: April 05, 2023, 12:36:03 am
content: Quote from: TheKellerman on February 23, 2023, 08:05:04 pmI am getting a similar log on that same UART on TDS3034C but my scope boots fine and passes self test. However, it generates a "System error occured" and the USB port does not work at all (has power). But this error does not even show up in the full self test (it passes).I am out of ideas at this point...is there another debug port that shows the log of the main scope firmware?

author: analogRF
author_rank: Super Contributor
timestamp: April 05, 2023, 12:48:35 am
content: the cypress chip in my scope is CY7C67300-100AXI and there is no I2C eeprom next to itI can only see an IDT71V016 (64Kx16) SRAM next to it. Unless the eeprom is on the back of the board?

author: TheKellerman
author_rank: Contributor
timestamp: June 15, 2023, 12:24:49 pm
content: I revisited the repair and was able to get it running. The problem was indeed the main firmware. I flashed the FW from a working B model and now its booting up. So the FW from a TDS1001C-EDU will not run on a B or regular C model.Interesting to note is that the USB is working fine but the cypress still reports "Calculated Checksum = 0000****"

author: analogRF
author_rank: Super Contributor
timestamp: May 09, 2024, 03:10:59 pm
content: Quote from: TheKellerman on June 15, 2023, 12:24:49 pmso do you mean that earlier boot log didnt change even though the scope now works fine?

author: Brandy
author_rank: Newbie
timestamp: May 10, 2024, 03:23:59 pm
content: My Tek 2014B didn't start either, also no LEDs during startup, but a gentle click noise from inside the scope.On the power supply C23 was defective, should have 120uF/25V and was 55nF.I replaced it with 220uF / 25V and the device started up normally.In fact I've replaced all caps, just in case.

author: kejo
author_rank: Newbie
timestamp: May 18, 2025, 04:22:13 pm
content: hiI bought a broken Tektronix TDS2014B from Ebay,now only three LED indicators and backlight is up.I checked all the voltages according to the service manual and everything is stable.UART output:dprint driver V0.aApLoader_Version=DevB6809fwupdate V0.8Firmware length = 9cf8, checksum = fd89Calculated Checksum = 0000********JTAG output:Device ID #1: 0000 0010000010100001 00001101110 1 (0x020A10DD)-> Manufacturer ID: 0x06E-> Part Number: 0x20A1-> Version: 0x0IR: 00 00000101 (0x005) -> DR: 240IR: 00 00000110 (0x006) -> DR: 32IR: 00 00000111 (0x007) -> DR: 32--IR: 00 00001111 (0x00F) -> DR: 240----------IR: 00 01010111 (0x057) -> DR: 142-------------------------------------------------------IR: 10 00000011 (0x203) -> DR: 13-IR: 10 00000101 (0x205) -> DR: 16IR: 10 00000110 (0x206) -> DR: 16IR: 10 00000111 (0x207) -> DR: 16-------------------------------IR: 10 11110100 (0x2F4) -> DR: 16----------------------------------IR/DR discovery complete.Also I check MC68SEC000:Pin 5 (VCC) = 3.36VPin 6 (CLK) = 10.1Mhz 3.76V peak to peakPin 9 (HALT) = 3.35VPin 10 (RESET) = 3.36VPin 41(VCC) = 3.36VLook like is corrupted firmware, Dose anyone have a ROM dump file for TDS2014B model?please.