uTracer (Micro Curve Tracer)

[bluesbreaker62]

Nah, can't get it to connect, keeps spitting out error messages at me.
Been trying to run both from the browser GUI as well as the desktop one from Ronald but it's not cooperating.
Not sure where the fault lies, software, laptop or tester

[martin manning]

Have you checked voltages on the uTracer? You should have +/-15, +5, and -40

Here are my notes for getting uTracerJS up and running:

The Home directory “martinmanning” has a folder called uTracerJS, containing the following:
1) uTracerJS-macos-arm64 (executable)
2) uTracerJS.txt (two lines that identify the data port):
/dev/tty.usbserial-FT1CHUY2 <this is the USB-UART cable ID>
80
3) A folder called Data, that contains the following:
The eeprom file (cal file, .csv),
The last used plot and qt configs (.csv),
Saved set-up files (.uts), and
Saved results (.utd)

To run:
Connect USB-serial adapter cable to uTracer comm port and to USB port on PC
Switch uTracer main power on
Go to uTracer JS folder, and double-click uTracerJS executable, “uTracerJS-macos-arm64”
A terminal window will open, displaying following:

[bluesbreaker62]

Thanks again Martin! Really appreciate your help

I'll give that a try when I have some free time later this week and report back

[bluesbreaker62]

Double post

[martin manning]

Looks like the uTracer 3 line has reached its end. Kits are no longer being offered for sale. It has had a long run, and proved to be remarkably resilient, accepting modifications and upgrades over 13 years.

The good news is R Dekker has started work on NXTracer ("Next Tracer") as a replacement. Details and progress reports can be seen here: https://www.dos4ever.com/uTracerlogNXT/ ... newsletter

[Poimandres]

Is this the heater power supply that folks are using? Is there a better option?

https://a.co/d/054q3mI3

[martin manning]

That one will work fine for heaters requiring less than 20V. There is a boost-buck version that can provide up to 36V, but that may not be of much value if you are only tracing tubes with 5V, 6V, or 12V heaters.

[Poimandres]

Hey Martin thanks for the help, what is the part number of the buck boost version?

[martin manning]

Not exactly sure about a specific part number, but this one appears to have the right spec: https://www.amazon.com/Adjustable-Regul ... r=8-3&th=1

The heater supply in the uTracer NXT has been improved, operating at 1.2 kHz vs.18.5 kHz, same as the uT6. The on-board supply might be fine for typical audio tubes now, and high-current directly heated rectifiers can use an external AC supply with the NXT's zero-crossing synchronization circuit. That is a better solution than a high-current DC supply, as the rectifier filament voltage will not produce an offset in the I-V curve.

[Poimandres]

Nice, so for non rectifiers you would recommend just using the NXT’s internal power. What would you recommend for external AC for rectifiers?

[martin manning]

What would you recommend for external AC for rectifiers?

I would use a small transformer fed by a Variac, and a true RMS multimeter to set the voltage accurately.

[M Fowler]

I never did get a chance to build my kit, just a pile of parts collecting dust.

Mark

[Poimandres]

It appears that I need to do some reading, there are some diy variable ac power supplies out there. I would prefer something that tops out around 30V or less.

[martin manning]

It appears that I need to do some reading, there are some diy variable ac power supplies out there. I would prefer something that tops out around 30V or less.

I just use my bench top Variac and connect a small transformer to it and to the uTracer when needed.

[martin manning]

The first uTracer NXT’s are beginning to ship, and I am on the waiting list.

Some nice features have been added:

- Nominal 500V 350 mA capability
- Current and voltage ranges can be adjusted using jumpers
- Improved on-board heater supply with lower frequency PWM to reduce lead inductance effects
- Zero crossing sync for external AC heater supply (good for measuring directly heated rectifiers)
- Same board size, mounting centers and (similar) terminal positioning for drop-in replacement of uT3 or 3+ board

As far as I can tell NXT is compatible with all of the added circuits described for the uT3 in this thread without modification, except the shorts and leakage test circuit, which requires new resistor values to work with the -105V raw negative voltage as shown here.