Tektronix THS7xxx Scope Hack/Teardown/Discussion - FW 1.16 found

[Zucca]

Hello,

PC SW to manage the Scope and take screenshots

Thanks to mrprecision

https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/msg3566625/#msg3566625

Video on how to install LED backlight

Thanks to mrprecision

In german language:
https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/msg3590917/#msg3590917

FW UPDATE

Thanks to superman13

https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/msg1480909/#msg1480909

Thanks to yaromka, here the FW1.16

FW 1.16

HACK

Thanks to TurboTom

https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/msg1073777/#msg1073777

SCHEMATICS

Thanks to R_G_B_

https://www.eevblog.com/forum/testgear/tektronix-ths700-tekscope-component-level-information-package-and-schematic/

ORIGINAL POST ON THS720A

I just got a Tek THS720A on Ebay. I like this device a lot, there is isolation everywhere: each scope CH and also the DMM input are isolated from each other. For a portable scope a good isolation is a must. The price range is much affordable than a Fluke scope which cost an arm and a leg.

It is a 100Mhz scope 2 CH, see some specifications here:

Oscilloscope
Bandwidth    100-MHz Digital Real Time    
Sample Rate    500 MS/s each channel
Time/Division Range    5 ns to 50 s/div
Channels    Two
Sensitivity    5 mV to 50 mV/div (to 500 V/div with 10X probe)
Vertical Resolution    8 bits
Record Length    2500 points
Time Bases    Main or delayed run after
Display Modes    Vectors, dots, vector accumulate, dot accumulate, YT, XY
Triggering    Main only, edge, pulse, video lines, video fields
Acquisition Modes    Sample, envelope, average, peak detect
Autorange    Controls volts/div, time/div, trig level and acquisition mode
Waveform Maths    Ch1 + Ch2, Ch1 - Ch2, CH1 x Ch2
Cursors     H bars, V bars, paired (volts @ time)
Measurements    Pk-Pk, mean, min, max, rms, +width, -width, frequency, period, +duty, -duty, rise, fall

Multimeter
Resolution    4000 counts, 3.75 digits
DC Volts    400 mV-880 V True RMS
AC Volts    400 mV-640 V True RMS
Resistance    400-40 MW (with continuity beeper)
Diode Test    Up to 2 V
Other DMM Features    Autorange, true rms, average meas., hold, statistics, Min/Max Alarm

General Features
NV Storage    10 waveforms, 10 setups, 100 DMM saved screens
User Interface    Simplified TDS 320 with pop-up menus
I/O    RS-232 (to 38.4K baud)
Chassis    Battery Operated, hand-held
Reliability    Calculated MTBF 20,000 hours @ 25 degrees Celsius

The device needs 502mA (400mA when the LCD back light is off) from the 12VDC jack with no battery connected. In standby the current goes down to 8.45mA. With 5.5VDC on the 12VDC Jack the device was still on, but I did not went below that limit because I heard some funky noises (surely some switching DC/DC converter was screaming on me).

Regarding the battery, it is a 4.8V Ni-Cd (4xSize C) 2.8Ah. At 4.8V Battery voltage the device is asking 1.2A (1A when the back light LCD is off) to stay on. "Low Battery" warning appears at 4.6V. The power cuts off at 4.2V. In standby the current is about 176µA.
I performed a full discharge and then I charged it for 16 hours at C/10 280mA. Afterwards I did discharge test @1.2A CC:


 
not bad, 2.71 Ah Capacity and simulated 2:14 Lifetime to reach 4.2V (power cuts off).

The battery charger works like this (according to my reverse engineering):

VBatt <3.5V: CC charge at 110mA
VBatt >3.8V: charge current [mA]= -187.27*VBatt[V]+1283.63
3.5V<VBatt <3.8V: Previous state

Unfortunately It has a problem, see here for details
https://www.eevblog.com/forum/repair/tek-ths720a-thinks-there-are-110v-on-the-input-but-there-is-just-a-50-ohm-r/msg490731/
so I decided to tear it down. I hope I can fix it.

Here we go:

Under the front panel, solid metal panel for EMI with on top the the flex keyboard


below we can find the inverter board for the back light and the LCD


inverter top side


inverter bottom side


Nice touch, very practical to remove the rear battery case


without the inverter and the LCD


rear panel with battery holder


Battery contacts, in this way you can´t use regular 4 Size C batteries


main board bottom side; clearly CH 1, CH 2 and DMM are isolated


CH 1 circuit bottom side


DMM input bottom side


central digital stuff, bottom side


LCD output and power supply circuit, bottom side


Main board top side, funny those two transformer for each channel


Power supply, top side


CH circuits, I don´t want to desolder the cans yet


Interesting DMM input, extra PCB piece above the main board for EMI?


Main processor stuff, top side. Debug/Service port on the top?


Todo List:

1) Fix the offset Problem in CH1
2) Upgrade FW from 1.14 to 1.16, any advice? Looks like the FW is in U1 (from Memory_Erasure_071181500.pdf):

156--7404--01

U1

IC, MEMORY; CMOS, FLASH ;1MEG X 8, 5.0
VOLT--ONLY, SECTOR ERASE;
AM29F080--120EC , 40PIN TSOPT&R

Flash memory which contains instrument
firmware, current setup, saved setups, saved
waveforms, saved data, waveforms, and
calibration constants.

3) Calibration


Possible Mods:

Does anybody has the schematics?

1) Build a switch to manage the back light LCD (turn off and on the inverter board). If there is enough ambient light, there is no need to use that energy. Why Tektronix did not built a back light switch?

2) Reverse Engineering the power supply and and battery charge circuit. Upgrade to Li ion by using three of those ones:
http://www.battery-matrix.com/3-2V26650-3300mah-LIFEPO4-IFR26650-3300mah.html
which just fit perfectly in the 4xSize C battery compartment. Target is to achieve a battery life between 2x and 3x than the current one.

3) Develop a 4 leds battery gauge.

------

High resolution pictures here:

http://postimg.org/gallery/6dfgsp1i/

Sorry I did everything with an IPhone 5, a Canon 60D will be in my hands soon.

[BravoV]

Congratulation on the score and nice tear down. 

Glad I can see the inner gut of this scope cause all this time I was curious how it looks like inside, thank you ! 

Too bad, sorry to hear it has problem, mine doesn't have that. Also does it came with the P6117 probes ? These P6117 probes are designed and built specifically for isolated probing, and its hard to find and quite expensive even its used. 

Btw, I made a discussion thread when I bought my THS710A -> HERE while ago.

About the NiCd battery pack, since the original Tek's batt pack is stupidly expensive  , I modded 3 pieces of AA->C adapter, and made the battery pack for it, and used Eneloop Pro 2450 mAH batteries. It performs a lot better than that shitty NiCd cells, cause these NiCd is well known to have a really high self drain, mine will be fully discharged when left unused just for less than 2 weeks. 

Too bad currently I don't have the modded battery pack with me, but it looks very similar to Jay's one at above pointed THS710A discussion thread, but with slightly modded with a long cut across the battery pack to allow the AA batteries to be released as the adapters have hinges. Its very handy as I can charge each of them properly in externally NiMH charger Maha MH-C9000. Also the standard slow charging method at the scope is using low current & overnight method which is not suitable for NiMh cells. Attached below photo shows my other spare AA to C adapters that I planned to build another battery pack for my THS710A soon.

[Zucca]

Also does it came with the P6117 probes ? These P6117 probes are designed and built specifically for isolated probing, and its hard to find and quite expensive even its used. 

Btw, I made a discussion thread when I bought my THS710A -> HERE while ago.

Very nice thread! Thx!

One P6117 was there, and I already got a P5102 65$, eBay auction: #111429274915, as a second probe. Yes I am stupid I should had wait to see if my unit can be fixed or not.

Regarding the Battery, your solution is very reasonable. Still I would like to investigate the possibility to fit a Li ion with a properly charge system (inside the unit or outside through the 12VDC).

[marshallh]

Regarding the firmware if I still had my ths720a I would dump it for you. However it may be possible to upgrade with a PC serial port connection app. You'll have a build a cable first and run the software in a VM

[Zucca]

Thank you marshallh, it would be fantastic. I would love to get my hands on the 1.16 FW (according to my investigation this is the latest released FW by Tektronix) and surely a lot of people out there will love that.

However it may be possible to upgrade with a PC serial port connection app. You'll have a build a cable first and run the software in a VM

I have the RJ-45 to Sub-D9 RS232 cable, I mean this one:
http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

What app are is the one you are talking about? I searched in the www but no hope to find anything related to your suggestion. Is a VM a Linux Virtual Machine? If yes I have a FreeBSD box which should do the job.

[SoundTech-LG]

Nice teardown photos!

I also did the Eneloop Pro  NiMh mod. Blows NiCd out of the water!!!

[Zucca]

Looks like now we have the schematics... 

https://www.eevblog.com/forum/testgear/tektronix-ths700-tekscope-component-level-information-package-and-schematic/

[nixxon]

Regarding the firmware if I still had my ths720a I would dump it for you. However it may be possible to upgrade with a PC serial port connection app. You'll have a build a cable first and run the software in a VM

I bought your THS720A, marshallh . If it is of interest, I could try to dump the firmware. I have not figured out the serial connection yet, though.

What is the difference between FW 1.14 and 1.16?

I also have the Service Manual for the THS 710 & THS 720 (no "A") TekScope 070-9246-03 if it is of interest to anyone the get a copy.

[Zucca]

What is the difference between FW 1.14 and 1.16?

http://www1.tek.com/forum/viewtopic.php?f=5&t=6499&sid=877fe8805d6d2c8dd8540e62e3f2365a

looks like we (you and me) are not alone, but the question is still open.

If it is of interest, I could try to dump the firmware. I have not figured out the serial connection yet, though.

Maybe the schematics can help us....
I am still interested, unfortunately I have to close up other projects before to continue this one. Keep us posted please.

[R_G_B_]

sieral connection pin out can be found here:


http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

[R_G_B_]

What is the difference between FW 1.14 and 1.16?

The firmware version 1.6 is for the 720P which  has the power measurement option.

R_G_B

[nixxon]

sieral connection pin out can be found here:


http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

I have tried the somewhat ambigous pinout you link to (at tek.com/support) and multiple other pinout variants, unfortunately with no success. If anyone has a working THS700-series rj45-DB9* cable and could measure all pins at both ends, I would be grateful. Anyone?

*DB-9 is actually a DE-9 (9-pin connector with an E size shell), according to http://en.wikipedia.org/wiki/D-subminiature

[R_G_B_]

Another usefull link:

http://w140.com/tekwiki/wiki/THS700

[R_G_B_]

,

[R_G_B_]

p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B

[R_G_B_]

I may be wrong with regards to the firmware:
http://ko4bb.com/dokuwiki/doku.php?id=test_equipment:tds_series_firmware

[Zucca]

Thanks R_G_B, I was just going to double check that. It looks like the 1.16 goes also on the THS720a too.

Oh man I need a day with 48 hours to work on all my projects... can´t wait to start again on this one.

[nixxon]

p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B

Is the left column in your table ("p2" etc.) the RJ45 pins and the right column ("D8" etc.) the DB9 connector pins?
Is your table based on a continuity test of a working cable?
If so, the actual wiring of a working cable is totally different from the answer on Tektronix FAQ : http://www.tek.com/support/faqs/what-pin-out-ths700-rj45-connector-rs232

I have illustrated a cable that I made a while ago that doesn't work, based on the Tektronix FAQ.
EDIT: THE RJ45 CONNECTOR IN THE ILLUSTRATION HAS WRONG A REVERSED PIN NUMBERING.

When I was trying to get this to work a year or two ago, I tried various pinouts. Based on a post on the tektronix forum, I also tried to swap the DCD and DSR pins of the RJ-45 connector (pins 1 and 2). It did not work.
At http://www1.tek.com/forum/viewtopic.php?f=5&t=5449 JeanPaul wrote:

Having plan to communicate with my recently bought (used) THS720 Std, unfortunately delivered without needed RJ45 to DB9 adapter, Tek part 103-0403-00, I have to build one myself.
In short, I’m not very sure said Tek’s information is correct, because therein two RS-232 signals, DCD and DSR, might be changed. I have reviewed following information precisely.
As the RJ45 pinout on page 1-8, table 1-3 of Tek’s Service Manual THS 710 & THS 720 TekScope, document no. 070-9246-03, seems to contradict the EIA-561 standard concerning RS-232.
Found two resources about said standard:
http://www.interfacebus.com/Design_Connector_RS232.html
/EIA-232 Bus Pin-Out
/RS232 RJ-45 Connector Pin Out
http://wiki.secretlab.ca/RS232_EIA-561_ ... DB9_wiring
/EIA-561 RJ45 to DB9 adapter pinout
Otherwise, said Tek manual is right as there is a reason said signals are wired as shown indeed. I would be happy if Tek could understand my point of doubt and clarify that point.
Having clarified Tek's RJ45 pinout is right, else which is, would help. A wiring diagram of the whole RS-232 connection even would be great. Thanks in advance.

[Zucca]

Is your table based on a continuity test of a working cable?

I have a tested OK cable, let me know if you need the pinouts...

[nixxon]

Is your table based on a continuity test of a working cable?

I have a tested OK cable, let me know if you need the pinouts...

I would be really be happy if you could measure your working cable and present your findings here 

[R_G_B_]

P1 Grey    D7
p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B

Is the left column in your table ("p2" etc.) the RJ45 pins and the right column ("D8" etc.) the DB9 connector pins?
Is your table based on a continuity test of a working cable?
]

Yes to all your questions    with the D connector pin numbers in reverse order to the tektronix illustration  R_G_B

[nixxon]

p2 Orange D8
P3 Black  D4
p4 RED    D3
P5 GREEN  D1
P6 Yellow D9
P7 Blue   D2
P8 Brown  D8

R_G_B

Is the left column in your table ("p2" etc.) the RJ45 pins and the right column ("D8" etc.) the DB9 connector pins?
Is your table based on a continuity test of a working cable?
]

Yes to all your questions R_G_B

Great! Thanks   Is the numbering of both connector pins the same as shown in my illustration 4 posts above?

[z01z]

Not likely, as D5 (GND) is missing. There should be a line P4-D5.
However there is P5-D1, which indicates that both connectors are numbered in reverse order.

Edit: there is also a RJ-45 Connector pinout in the user manual:
1 DCD
2 DSR
3 DTR
4 GND
5 RXD
6 TXD
7 CTS
8 RTS

[nixxon]

Not likely, as D5 (GND) is missing. There should be a line P4-D5.
However there is P5-D1, which indicates that both connectors are numbered in reverse order.

Edit: there is also a RJ-45 Connector pinout in the user manual:
1 DCD
2 DSR
3 DTR
4 GND
5 RXD
6 TXD
7 CTS
8 RTS

When I reverse R_G_B_'s numbering of both connectors, the measured pins by R_G_B_ matches the info on the Tek FAQ. Pin 8 (on RJ-45) seems not to be connected though.

So, when unscrambled the R_G_B_ values are:

RJ-45 --> DB-9
1 -------> 7
2 -------> 4
3 -------> 6
4 -------> 5
5 -------> 3
6 -------> 2
7 -------> 7
8 -------> not connected

There should be continuity between RJ-45 pins 1 and 7
Could anyone please check if there is continuity between DB-9 pins 1 and 8?
And if RJ-45 pin 8 is connected to DB-9 pin 1 and/or pin 8?

[nixxon]

Thanks R_G_B, I was just going to double check that. It looks like the 1.16 goes also on the THS720a too.

Oh man I need a day with 48 hours to work on all my projects... can´t wait to start again on this one.

My THS720A info screen says "Version: FV:v.1.16", "Wed Dec 16 11:48:07 PST 1998".

If it is possible to dump firmware by the RS-232 connection, I will give my RJ-45 <---> DB-9 cable another try when I get back home on Sunday after sailing The Færderen* 2015  - hmm, I wonder if the King** will participate this year...

*the world's largest overnight regatta: http://www.færdern.com/index.php/nb/home-english
** King Harald V of Norway http://en.wikipedia.org/wiki/Harald_V_of_Norway