UT61E digital multimeter schematics and integrated circuit datasheet

Uni-t UT61E Multimeter - Circuit diagram

ES51922 application circuit for ES51922 datasheet.

ES51922 application circuit.png

In UT61E 1some features of ES51922 are not used and can be enabled by simple hardware diy:

112 APOSEL I Idle time selection for auto power off feature.

58 SLEEP O Sleep mode indicator, asserts low in SLEEP mode.

105 BKOUT O If BKLIT function is enabled, this pin will change from –3V to +3V
For 60 sec, once press BKLIT pin again within 60 sec, this pin will
Change back to –3V

102 BKLIT I Back light function. Pulse low to set BKOUT pin output.

113 BKSEL I Set to V- to change the backlight idle time from 60 sec. to 180 sec.

UT61 series Operation manual.

 

 

Adjusting and calibrating Hameg HM-605 channel gain

Yesterday I have noticed that voltage or gain of channel 1 in my scope is a little bit off ( noticed that by analyzing one circuit on same output with dual signal ). I have Hameg HM-605 service manual (you can download it at the bottom) and I found there instruction of adjusting channel gain. Basically you just provide square wave signal ( I used scopes calibration output ) and adjust corresponding pot. Its an easy fix as you can see in a video below.

Download HAMEG HM-605 oscilloscope service manual here.

And users manual in English.

Getting cheap oscilloscope on ebay

As casual electronics tinkerer I have always wanted to add an oscilloscope to my tools collection but never did so. There are many reasons why, for example, oscilloscopes are expensive and you don’t want to spend a huge amounts of money on thing that will be used just occasionally and basically is a “toy”, or, for example,  I have never owned one and there are gazillions of them and I was not sure which one or with what specs should I get. You can have modern digital ones, older analog, cheap Chinese DSO’s, PC scopes etc. Those Chinese DSO`s are tempting, but finally, one video from EEVblog convinced me that I should probably look for decent old analog one:

So, after this video, I have started looking for an old analog scope, dual channel, 20MHz and up, known brand. Some looking here and there revealed that I probably will not get a scope for 20 bucks, at least not here in Europe. Starting price for more or less decent ones was somewhere about 50 Eur. One day on eBay.de I have noticed HAMEG HM605 for sale. Starting price 50eur, seller says it has some triggering problems.

hm605 bid.png

Some investigation revealed that this is the kinda decent scope and usually is more or less easily fixable. That was it, decided that 70eur was top price for it, made a bid and finally bought it for 65eur. Whoohooo! It arrived after a week or so and the first test showed that everything works ok except correct triggering as it was stated by seller. Luckily my assumptions were correct and I could fix it without huge efforts. You can read about fixing it here.

So, here I am, proud owner of HM605 analog oscilloscope that I plan to use for some time. It works like a charm and is a huge help for me while learning the art of electronic, literally 🙂

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