Broken Utracer 3+ with High Current Mod and BD138 Mod

[Rocko]

Hey guess what, I did it again.

So I was testing a tube something happened between tests.  I heard a snapping sound twice and then when I tried to make a test it showed me the following on the screen (Ronalds Software u-Tracer (V3.12.6)).

Then when I press OK I get this:

Then when I press OK the Utracer stays drawing around O.370 instead or normal on state of 0.220, and only goes back to normal after full reboot.

I did not smell anything burnt or anything just a fairly loud snap noise twice.  When I restarted and go to debug and ping this is what I get:

I will start with some preliminary testing around the power supply (need to take it out of the case) as described in the construction manual but thought I would put this out here in case it has happened before and someone recognises the issue.

Cheers,

Rocko

[Rocko]

I checked the +5 and +15 Voltages and they were good.

I checked the -15 and -40 Voltages and they were good.

My serial connector from all the unplugging and plugging in seemed a little sketchy so I made another one and I thought maybe I had it but no it still does the same thing.  Except this is the ping now.

Hopefully someone has seen this problem before or has a couple more tests I can do.  If I leave the Utracer on drawing 0.375, after a minute or so it goes to 0.160 - 0.185 draw which is lower than my normal of what it used to be between 0.195 and 0.225 at idle.

Cheers,

Rocko

[Rocko]

I ran through a Calibration,

completed Grid Bias

completed Boost Converters

completed Current Amplifiers

and everything is within a couple of decimals of where it should be, and the utracer did not crash or hang up.  

So, I tried a tube again and it works.  I am really baffled now.  Was the snap noise a soldered joint breaking free and now when it is hot it is touching again?  

Wow.

Cheers,

Rocko

[Martin Manning]

Not sure what to say about that except I have occasionally experienced communication errors. turning the tracer off and then back on seems to clear them. I don't recall any odd current draw when that has happened, though. 

What hardware are you using for your interface? There have been some issues with some cables converting between USB and RS232. When I built my tracer I configured it for USB to TTL using an FTDI cable (going direct to the PIC by removing the MAX232 IC and jumping the socket). Ronald later recommended adding a couple of resistors, as described in the Lab Notebook topic 1. 

[Rocko]

Martin,

Thank you for the reply.  I am using an  RS232 cable with an FDTI chipset that I got off amazon.  I bought the one with the highest positive reviews but who knows. 

I will take a look at the conversion you mention, it would be nice to have a second type for trouble shooting.  With my luck I may need one, lol.

Otherwise everything is back to normal so we will see.  The loud snap snap noise is still a little troubling.

One thing I have noticed since the beginning is on my power supply my draw fluctuates between 0.195 and 0.226 at idle.  It just jumps around.  Is this normal?  I use this:

https://www.amazon.ca/gp/product/B087TK6ZM2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Cheers,

Rocko

[Martin Manning]

If your current interface is working, then you are probably ok. I have experienced some arcing at the 20V DC power connector, and also when measuring the DC inlet voltage. That might be the source of the snapping you heard. Perhaps it was a power interruption or voltage spike that disrupted the communication?

My B&K power supply shows a steady current draw, at 260 mA.