[time-nuts] huntron tracker advice & troubleshooting without schematic advise

[Jeroen Bastemeijer]

Hi Magnus,

I totally agree with you. But doing a quick repair is more an art than a 
science ;-) By having some feeling for common faults it is easier to 
locate them.

The Huntron tracker was of use for equipment which was almost impossible 
to service when under power. For example power-electronics with high 
voltages and nice little radios which consisted of a stack of boards, 
here it was impossible to probe around. The only solution was soldeing a 
wire to a component, assemble the whole thing, switch on measure... for 
testing another point, the whole procedure had to be repeated. Ok, for 
some equipment we used extension cables, but it was not always possible 
to use them.

Some failures are very difficult to track: Firmware related problems. 
The only solution to that, was finding a working unit and copy the 
firmware to the faulty machine (e.g. EEPROM copying)....

But as I indicated in the beginning: Repairing is more like an art than 
a science. Over the years a whole bunch of tricks and strategies was 
developed to locate the faults and fix them. Repairing needs a solid 
background in electronics and a lot of experience.

But: When you manage to repair something, it usually gives a lot of 
satisfaction! ;-)

Best regards, Jeroen
Magnus Danielson wrote:
> Jeroen Bastemeijer skrev:
>   
>> Hi Patrick,
>>
>> I saw a lot of replies to your question. Here are my five cents:
>>
>> The Huntron Tracker is very nice if you have two similar pieces of 
>> equipment (or circuit boards). From which: one is faulty, the other one 
>> still okay, or has a different fault. By probing around you can easily 
>> find the faulty part or component, by looking for differences in the 
>> Huntrons display. E.g. a faulty transitor will give a different curve, 
>> even when other circuitry is connected to it.
>>     
>
> You can do that, but you need to know what is expected. The easiest way 
> to know that is to probe the same point on a working board. Otherwise 
> you would need to think for yourself and here a factor of confusion 
> comes in. Add the factor of unknown when you don't have a schematic.
>
> With two boards and no schematic you have a chance. There are a class of 
> errors the Huntron can't find, errors internal to a chip or module. They 
> do not need to show up at all. Consider for instance a bit error in an 
> EPROM. One or a few bit errors may be exactly what is needed for a total 
> failure.
>
>   
>> However, I used to work at an small repair shop. Here we also got lots 
>> of equipment for which the schematics were not available (usually it was 
>> classified or obsolete). Although we had access to a Huntron Tracker, we 
>> didn't use it much. Most of the time, a multimeter and some "common 
>> sense" did the trick.
>>     
>
> Indeed. But you do develop your strategies based on the tools you have. 
> You could have chosen a tracker based strategy.
>
>   
>> One final remark, about the reply from Bruce; There are oscilloscopes 
>> out there who have the component tester (that is what he reffered to) 
>> built in. My first oscilloscope I bought, a Handykit, has the 
>> component-tester built-in. For that reason that scope is still with me ;-)
>>     
>
> If nothing else, it is a very good educational tool.
>
> Cheers,
> Magnus
>
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