3rd February
written by Todd Harrison

UPDATE (2/5/2016): I was just told that Circuit Specialists will offer this scope for $299 for one week only. + free shipping. I wanted to give a quick heads up to those that are considering this scope. – Todd

In this video and blog posting I will be reviewing a new $329 (US dollar) Hantek DSO5202P 200 MHz 2 channel Oscilloscope and measuring its claimed bandwidth. This is a USA sourced product distributed by Circuit Specialists out of Tempe, Arizona. I do non-biased product reviews for Circuit Specialists. They sell lots of different oscilloscopes at lower as well as higher price points based on bandwidth and features. First lets show the video if you want to watch a 1hr 15min review :\ , I know don’t say it I already agree. For those that don’t watch, below is a write up as well as over 120 hi-resolution photos for you to enjoy and get quick details.



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10th January
written by Todd Harrison

This is a Mid 1970’s model 4802 Howard Miller grandfather clock “floor clock” that I’m going to service and get working again.
Clock movement imported from Germany.
I won the bid for the clock for $875.
I contacted Howard Miller and was informed the S/N matched a 1970’s 88″ tall 5 tubular weight driven floor clock.
My movement is a No. 190 Westminster 5 Tubular Chime Weight-driven Arabic numbered.


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2nd January
written by Todd Harrison

I did the teardown of the CSI 75W solder station as well as the Hakko 936. The Hakko of course had all analog circuits using operational amplifiers and potentiometers as well as a temperature sensor in the iron tip to signal back to a triac chip controller which would trigger the triac to push 24 V AC through the heater in the iron. The CSI 75W was all digitally controlled with an internal microcontroller which was reading the temp sense line and switching the triac on/off through an opto isolator IC. And because it had a microcontroller it was also able to have the programmable set points and programmable sleep and power off timers.


The workmanship found in both soldering stations showed quality construction, soldering and manufacturing. I did not see any sloppy messy joints or poor workmanship. Most items were quality parts with the exception of the JWCO electrolytic capacitors in the CSI 75W.

For a device that was trying to save cost at any expense I found it strange that they did not use the internal oscillator in the microcontroller. I don’t see the point of having an external crystal running at 8 MHz when you could use an internal 8 MHz oscillator in such a design. If you’re not doing data communication and other high-speed tasks then an internal oscillator is more than accurate enough timekeeper. Maybe they needed this because they knew they were going to have to program and calibrate the microcontroller after production and the accurate timekeeping was necessary for the programming communications.

Also, the S3F8S19 microcontroller they used was able to store data in a small section of flash so why they needed or felt they needed an external EEPROM is a mystery to me. And when you’re trying to save costs why would you include an ICSP plug header or any other such unused connector when simple pogo pin pads would be just fine for after production code updates or calibrations.

One last mystery was why they used an optical isolator IC for controlling the triac when these 600E triacs are designed to be controlled directly from a GPIO of any microcontroller. I just don’t see what the opto isolator is adding to this design that is necessary.


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