Technical Issue with 3x Tracker 2700 and 2700S

Technical Issue with 3x Tracker 2700 and 2700S
« on: June 15, 2010, 04:00:28 am »
Hi,

We have now 2x Huntron 2700/2700s faulty, unfortunately for us they are both not in warranty.
We have on both the same symptoms:
- What we see on the display is not the true representation of the circuit tested
- When not connection is made to the circuit instead of having a flat line on the display we have an oval circle.

Changing the motherboard at over $1200 is not an option for us. We have also a similar problem at another repair center in main Europe. In total 3x 2700 down.

Could you help us to diagnose the fault at component level?

Thanks

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #1 on: June 15, 2010, 01:21:22 pm »
Does the oval signature appear in all channels, resistance, voltage and frequencies?

Is a vertical line signature dsplayed if channel A is shorted to Common?

Have Diags been ran with nothing connected to the Tracker 2700?

We are no longer able to supply Tracker 2700 main boards.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #2 on: June 15, 2010, 01:39:00 pm »

Thanks for the prompt reply.

Does the oval signature appear in all channels, resistance, voltage and frequencies? Yes

Is a vertical line signature dsplayed if channel A is shorted to Common? That's correct but not very vertical I would say mishapped

Have Diags been ran with nothing connected to the Tracker 2700? Diags have been ran but to not avail.

We are no longer able to supply Tracker 2700 main boards. It is the case could you direct us to the faulty component or where to look for

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #3 on: June 15, 2010, 01:59:01 pm »
Go to Menu->Control->Diags and select Wave then go back to the main screen and take digital photos of the display with open and short and email to support@huntron.com. This will help determine area possible faults.


Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #4 on: June 15, 2010, 02:40:17 pm »
Thanks again

We will contact you tomorrow with the requested pictures.


Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #5 on: June 16, 2010, 09:21:42 am »
It appears the unit has been damaged by probing in a live circuit or one without large capacitors not discharged. The problem is probably around AR12-F2 and/or AR14-F1 where the sinewave output is generated. To verify you could check to see if the sinewave at the banana jacks matches the selected voltage.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #6 on: February 06, 2018, 02:57:56 am »
I had a broken 2700 (cap discharge) that was many years in the storage room I tried to repair it using another working 2700 as model. I removed some ICs from the good board to make some measurements using a 3rd tracker(2800s) and put it back together but it doesn't work anymore. It shows a circle like it was measuring a capacitor even without the cables conected. When I short the leads it shows a vertical line so it is kinda working. I tried to diagnose it but the offset doesnt avail.

The ICs that I removed or swapped are AR3,4,7,9,12 and U48

The bad board was pretty much blown by the cap discharge. AR3 and U48 were completely explosed, the caps and the resistors  r304 and r63 were damaged by it.
I removed r64 and found a short circuit going to U11 (74hc4051) I swapped it for another one from the same board and the short is gone.  Q1, q2, q12 and q13 showed different signatures compared to the good (now bad too) board but I dint replace them yet.

I think i maybe swapped ar12 from the bad board to the good board and it made kill another IC. Maybe this high speed buffer IC is too sensitive to temperature, I dont know...

Can I have some help to repair at least the good board again. My boss is gonna kill me if this tracker isn't repaires by the end of the week.

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Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #7 on: February 06, 2018, 07:11:24 am »
Hi Emanuxelz and welcome to the Users Forum.
I would check the most obvious possibilities such as open or shorted solder joints first (you probably already have...). Try running the internal Diags. This may provide a clue where the issue may be.
The schematic for  the main PCB is available here:
http://www.huntron.com/privatesales/technical/2700main-pca.pdf

The most important troubleshooting tool is your eyes.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #8 on: February 06, 2018, 09:50:50 am »
Thanks very much for the schematics it will help me a lot. I will report again.

Btw its impressive how the fuses didnt blow up and are just fine.

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Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #9 on: February 06, 2018, 11:11:42 am »
Heh, heh. The first 2700 versions had regular, soldered-in micro-fuses that had to be replaced when blown. The fuses on the later versions of the Tracker 2700 main board were "self-resetting".
The most important troubleshooting tool is your eyes.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #10 on: February 08, 2018, 08:22:31 am »
I found others HC4051s deads.

Everything suplied with +5v, -5va, +5va are shorted.

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Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #11 on: February 08, 2018, 09:15:23 am »
Sounds like a shorted cap (or caps). You might need to start removing them (start with the tantalums) and watch for the short to disappear.
The most important troubleshooting tool is your eyes.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #12 on: February 08, 2018, 06:50:04 pm »
I was wondering, is there any way to separate at least parts of the circuit from the same 5v supply? Like removing zero ohms resistances for instance.

Also, how can 3 voltages from 3 different regulators(wich I already removed) can be shorted? That would mean I have at least 2 shorts one from 5v-gnd and other from +5va-gnd-5va.

Thanks for your help, I will try the caps tomorrow.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #13 on: February 09, 2018, 09:07:08 am »
I removed the 3 zero ohms resistor to separate the circuit.

5v and gnd(d) from r180 are shorted.

+5va and -5va are shorted but their middle ground isnt shorted.

My last resource would be supply it with 5v and wait for the smoke with a Fluke thermal camera.

Re: Technical Issue with 3x Tracker 2700 and 2700S
« Reply #14 on: February 22, 2018, 09:29:04 am »
Unfortunatelly I couldnt repair the boards. The one that was shorted I found the sine wave chip shorted (+5 -5) but the other 5v short i couldnt find.

The board that was good before still hasnt been fixed. I replaced the lf412s and the high speed buffers.
I ran the diagnostics and offsets but i still can have a good signature.

On the 200mv 3v selection the display is crazy with random noise.

At 5v 1k I can start seeing things. The oval shape is now almost a flat line but it is still a ellipse/oval/circle shape like I was measuring a capacitor.

What could it be? I can't understand why it went bad just by removing a pair of ICs and putting it back even after I replace them for brand new ones.