I sold a transistor matcher and curve tracer on ebay.
Seller got back to me saying he just doesnt understand it and so has bought an Atlas tester instead.
Fair enough.
The Atlas tester is battery powered so only puts a couple of milliamps through the transistor so is a poor test.
Mine puts through 40mA so is a bit nearer real life.
The Atlas tester displays hfe for one point on the curve.
Mine plots full hfe curve from 0 to 9 volts.
Atlas tester has a tiny screen.
Mine uses pc screen and can be zoomed in on curves and you can pan around.
Mine isnt hard to use, you just connect a transistor and press "read channel 1" on the pc screen. You then connect second transistor and press "read channel 2" and it displays the full curve on the pc screen.
You can do this with up to 5 transistors.
You can then compare curves for matching.
If they are close its a good match otherwise no good.
Vented....
Seller got back to me saying he just doesnt understand it and so has bought an Atlas tester instead.
Fair enough.
The Atlas tester is battery powered so only puts a couple of milliamps through the transistor so is a poor test.
Mine puts through 40mA so is a bit nearer real life.
The Atlas tester displays hfe for one point on the curve.
Mine plots full hfe curve from 0 to 9 volts.
Atlas tester has a tiny screen.
Mine uses pc screen and can be zoomed in on curves and you can pan around.
Mine isnt hard to use, you just connect a transistor and press "read channel 1" on the pc screen. You then connect second transistor and press "read channel 2" and it displays the full curve on the pc screen.
You can do this with up to 5 transistors.
You can then compare curves for matching.
If they are close its a good match otherwise no good.
Vented....
I get the occasional problem on ebay.
Latest one is my PCBCAD software.
Bloke has come from Eagle and wants some cheaper software.
So he buys mine then complains its not as good as Eagle.
Mine is £4 and Eagle is $300 !
Sold a USB scope too.
Got accused of lying about scope speed.
Its 3.3 mega samples/s so 1.6 mega samples/s per channel.
Turns out he thought 3.3 was MHz and not samples per second.
You need about 30 samples to get a half decent sinewave of about 100KHz at full speed.
Latest one is my PCBCAD software.
Bloke has come from Eagle and wants some cheaper software.
So he buys mine then complains its not as good as Eagle.
Mine is £4 and Eagle is $300 !
Sold a USB scope too.
Got accused of lying about scope speed.
Its 3.3 mega samples/s so 1.6 mega samples/s per channel.
Turns out he thought 3.3 was MHz and not samples per second.
You need about 30 samples to get a half decent sinewave of about 100KHz at full speed.
He has started a return but has now come back and wants to know if I will hand hold him through working it.
You connect transistor and click on "Read channel 1" on screen
There's not a lot to it !
In my repair shop, part of our work was having to assume that the customer is an idiot, because in many cases that was true. (part of the Dumbing Down of Society?)
Apparently, reading an instruction manual, or even following instructions is simply too boring, tedious, and time consuming.
So we posted a sign at the front counter and also included with each repair, a paper with warnings and disclaimers regarding repaired equipment.
And even then we occasionally got returned equipment because the idiots ignored the warnings.
And we just charged them AGAIN for repairs.
Apparently, reading an instruction manual, or even following instructions is simply too boring, tedious, and time consuming.
So we posted a sign at the front counter and also included with each repair, a paper with warnings and disclaimers regarding repaired equipment.
And even then we occasionally got returned equipment because the idiots ignored the warnings.
And we just charged them AGAIN for repairs.
To be kind, without those so-called 'idiots' you would probably be destitute! 
And they simply don't believe you when you tell them it's not possible to connect their new doo-dah to their old widget.
They invariably reply that YOU are wrong and that they'll jolly well go and buy the non-existent cable elsewhere!
And they simply don't believe you when you tell them it's not possible to connect their new doo-dah to their old widget.
They invariably reply that YOU are wrong and that they'll jolly well go and buy the non-existent cable elsewhere!
I blew up a power amplifier.
I fixed the outputs but it still had fault.
I tested every component on the pcb including transistors with diode check.
Still couldnt find the porblem.
So got my multi-meter out and started testing hfe's.
Found one of the LTP transistors had a gain of 1.
Bought in a Maplin 50 watt amp that was faulty.
Pretty much same story. Then found a transistor was npn instead of pnp.
Someone had been there before me and messed things up.
The transistors number had worn off.
A diode checked worked ok but was wrong way around which I missed.
I fixed the outputs but it still had fault.
I tested every component on the pcb including transistors with diode check.
Still couldnt find the porblem.
So got my multi-meter out and started testing hfe's.
Found one of the LTP transistors had a gain of 1.
Bought in a Maplin 50 watt amp that was faulty.
Pretty much same story. Then found a transistor was npn instead of pnp.
Someone had been there before me and messed things up.
The transistors number had worn off.
A diode checked worked ok but was wrong way around which I missed.
£30.
Its pretty basic, just an inverting transistor stage.
Can test bi polar and enhancement type mosfets but not JFET's.
It takes in up to 5 transistor tests and displays them in different colours.
You can then run a marker along the curves reading off voltages, hfe and currents.
It mostly works ok but struggles with high hfe's due to micro currents in them.
If the curves match then good if not a bad match.
You can zoom and pan around on the curves for more detail.
A few years back, the company boss purchased the contents of a service company workshop. When I went up to see the content, I was overjoyed; 20,000 service manuals, hundreds of thousands of components and replacement boards.
Of the service manuals. When I looked at them, they were meticulously Dewey Decimal catalogued. Did they come to our workshop? No, he rented a room half a mile away, and had two men with a van stack them in the room. The thousands of hours spent cataloguing the manuals went out of the window as they were simply stacked them wherever they found a space.
Ever tried to find a service manual, which may or may not be there, in a mountain of 20,000? I did, on numerous occasions, rarely successful.
Spare parts? These were brought to our workshop by the same men with a van, who were tasked with the job of picking up the racks and boxes, and transporting them to us – with no supervision. I was puzzled as to why the Racco cabinets contained hundreds of each of larger components, but only a very few SMT semiconductors.
I questioned one of the van lads. How did you carry the cabinets, did anything get dropped out of them? Don’t know, we carried them on their back, I did notice toward the end of the day; there were many thousands of bits of black plastic on the floor!
Included in the parts were a great many replacement LCD and plasma screens, including ten 60” plasmas. Each box was clearly marked, DO NOT STACK, STAND THIS WAY UP etc.
Said van lads obviously could not read, the whole lot were stacked, and then a few hundredweight of dismantled racking bays were stood on top of them. None survived.
So, to catalogue the spare parts, he would ask his techs to do that surely?
Nope, four youngsters off the street were employed for four weeks to make a list of all the parts, well, anyone can tell what an electronic component or replacement electronic board is can’t they?
I looked at the list of after four weeks. A lot of the television main boards somehow had the same part number. The youngsters had no idea of how television boards are identified, and so they wrote down the first number that their eyes were drawn to, the tuner socket part number.
Semiconductors, passive components. These were lumped into big boxes and vaguely described; “e.g. round thing with wire at each end”.
When the boss finally saw sense, and allowed the techs to catalogue and index things, it took many weeks of careful work to undo the carnage that had been caused.
In the words of an old MOD technician who once worked for me. “Prior Planning and Preparation Prevents @iss Poor Performance”
Were the components and service manuals not on a computer database you may ask? Quite probably yes, there was a massive mainframe server, even had its own satellite microwave TX/RX high speed internet link.
Was it any use? No idea; never got to see it or switch it on. Said boss got a local “computer technician” to look at it. Since the technology was way beyond anything he had ever had experience of, he deemed it to be scrap, and it was sold as such; I only saw some photographs.
Of the service manuals. When I looked at them, they were meticulously Dewey Decimal catalogued. Did they come to our workshop? No, he rented a room half a mile away, and had two men with a van stack them in the room. The thousands of hours spent cataloguing the manuals went out of the window as they were simply stacked them wherever they found a space.
Ever tried to find a service manual, which may or may not be there, in a mountain of 20,000? I did, on numerous occasions, rarely successful.
Spare parts? These were brought to our workshop by the same men with a van, who were tasked with the job of picking up the racks and boxes, and transporting them to us – with no supervision. I was puzzled as to why the Racco cabinets contained hundreds of each of larger components, but only a very few SMT semiconductors.
I questioned one of the van lads. How did you carry the cabinets, did anything get dropped out of them? Don’t know, we carried them on their back, I did notice toward the end of the day; there were many thousands of bits of black plastic on the floor!
Included in the parts were a great many replacement LCD and plasma screens, including ten 60” plasmas. Each box was clearly marked, DO NOT STACK, STAND THIS WAY UP etc.
Said van lads obviously could not read, the whole lot were stacked, and then a few hundredweight of dismantled racking bays were stood on top of them. None survived.
So, to catalogue the spare parts, he would ask his techs to do that surely?
Nope, four youngsters off the street were employed for four weeks to make a list of all the parts, well, anyone can tell what an electronic component or replacement electronic board is can’t they?
I looked at the list of after four weeks. A lot of the television main boards somehow had the same part number. The youngsters had no idea of how television boards are identified, and so they wrote down the first number that their eyes were drawn to, the tuner socket part number.
Semiconductors, passive components. These were lumped into big boxes and vaguely described; “e.g. round thing with wire at each end”.
When the boss finally saw sense, and allowed the techs to catalogue and index things, it took many weeks of careful work to undo the carnage that had been caused.
In the words of an old MOD technician who once worked for me. “Prior Planning and Preparation Prevents @iss Poor Performance”
Were the components and service manuals not on a computer database you may ask? Quite probably yes, there was a massive mainframe server, even had its own satellite microwave TX/RX high speed internet link.
Was it any use? No idea; never got to see it or switch it on. Said boss got a local “computer technician” to look at it. Since the technology was way beyond anything he had ever had experience of, he deemed it to be scrap, and it was sold as such; I only saw some photographs.
I used to work for a small electronics company in1981.
Started off in test and worked my way up to R&D.
They took on some more "new" engineers.
The boss in his wisdom decided one of these new lads would get my job and I was relegated back on to test.
So new lad set about building up a prototype and found it was too difficult for him.
So the boss asked me to do it. Cheeky blighter.
As time went on I became software engineer for the business.
I wrote loads of software for various projects, some of them quite complex.
I then met up with a competitor and they offered me a job so I took it.
What goes around, comes around..........
Started off in test and worked my way up to R&D.
They took on some more "new" engineers.
The boss in his wisdom decided one of these new lads would get my job and I was relegated back on to test.
So new lad set about building up a prototype and found it was too difficult for him.
So the boss asked me to do it. Cheeky blighter.
As time went on I became software engineer for the business.
I wrote loads of software for various projects, some of them quite complex.
I then met up with a competitor and they offered me a job so I took it.
What goes around, comes around..........
To be kind, without those so-called 'idiots' you would probably be destitute!
And they simply don't believe you when you tell them it's not possible to connect their new doo-dah to their old widget.
They invariably reply that YOU are wrong and that they'll jolly well go and buy the non-existent cable elsewhere!
Yet.... those "idiots" came to ME to repair/correct their equipment.
As it was, I was standing BEHIND the counter, THEY came though MY front door for help.
I'm not one to really argue with them, but when you come to me for help, I tell it like it is.
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