Morphy Richards Compact Soup Maker repair

I've had this soup maker for about 5 months. At the beginning I was ultra cautious when washing it and I studiously ensured no water got into the electrics. I stopped being so careful and then found that it wouldn't start its heating cycle without tripping the mains circuit breaker. Below is the process I followed to fix it.

First prise off the handle cover with a flat blade screwdriver. Then remove the 2 screws which fasten the handle to the jug.

Next, remove the centre screw from the base of the jug.

Check the heating element resistance with a DMM. This reads about 68 ohms which equates to a power rating of V squared / R => 240V x 240V / 68 = 847W. Actual heater rating is 700W to 900W so this looks OK.

Next, check the thermal fuse (KSD301). This reads 0.5 ohm when cold and so this looks OK too.

Now check the wiring. Here, we see what appears to be a scorch mark on the earth wire. I'm guessing here but I wonder if water got into the base and caused a short between the earth wire and one of the blue wires (which supplies power to the heater element). Maybe the insulation is not quite adequate in the presence of water or maybe there was already a break in the insulation beforehand. Even though everything is now dried out, the break in the insulation and the close proximity of the heater wire to the earth wire seems sufficient to continue to causing the contact breaker to trip.

So, if this is indeed the issue, wrap some insulating tape around the exposed earth wire and put it back together and see if it now works.

And it does! 

For reference, below is the heater wiring schematic.

Hantek DSO5102P repair

A short while ago, my Hantek DSO5102P oscilloscope simply stopped working. I discovered that the power supply was goosed. Specifically R14 (3x 1R5) and R11 (?) had popped. Unable to procure a replacement power supply board, I attempted to repair it but when this failed, I decided to reproduce the various supplies using off-the-shelf adjustable supply modules. I recorded the process I went through to achieve this. I thought it might help others in a similar situation if I shared this and so here it is. I started with investigating the power supply board in order to replace any components which I deemed faulty. Helpful links here, here and here.

Chips on power supply board are:

• CR6850T: Current mode PWM controller
• PS817C: Photocoupler
• XL1509-3.3E1: PWM buck (step-down) DC/DC converter, capable of driving a 2A load

My plan is to replace the faulty power supply with multiple buck DCDC converters all running from a single 12V mains adapter:

• 3V3: 100mA, LM2596S Buck Converter
• 5V:   2A, LM2596S Buck Converter
• 14V: 400mA, XL6009 Boost Converter
• -8V:  200mA, XL6019 Buck/Boost/Pos/Neg Converter
• 12V: ?mA, fan motor, use 12V direct from adapter
• TR-AC signal: 50Hz square wave at 5V

Power supply cabling

TR-AC signal generation circuit

CR6850 reference circuit

Looks like Hantek have used the above reference circuit ... Q1 = 4N60C, R11 = 100R, R14 = 0.5R (3x 1R5 in ||), N2 = CR6850T ... also F1 fuse = T3.15AL 250V ... have ordered all these from amazon and will attempt to fix the PSU board in 1st instance and if that fails, build own PSU with discrete buck and boost regulators.

Have replaced components with those I ordered and fuse popped immediately after switching on! Replaced fuse with wire to find where the possible short is and switched on again and this time the common mode choke burnt out!

This scope is specified at 30W max so with 240V rms, I = 30/240A = 125mA. So have ordered replacement choke (CR6850 datasheet shows T1 = 20mH) Farnell 1636281 (500mA) and Farnell 2860718 (800mA). They are not a perfect fit however. Also ordered 0.1uF/275VAC caps (Farnell 2495780) - might as well as have to pay a £10 handling charge whatever!

Replaced common mode choke and tried again and this time RT1 (in line with the fuse) popped! RT1 = NTC 5D-9 Inrush Current Limiter, Power Thermistor 5 ohm 3Amp. Also the track from mains input to RT1 and track to D4 both burnt out! DMM across D3, D4 shows a short in both directions! Also common mode choke coils are now o/c! Giving up on repairing this!

Have now made up my own DIY power supply board. Below is a photo of the new board. Need to (1) set all the voltages using the pots (2) program the Raspberry Pico to output a square wave on GPIO15 for TR-AC (3) wire up the 14V adapter to scope on/off switch.

New power supply board with schematic

The 3V3 50Hz square wave is being generated with a Raspberry Pico and then level-shifted to 5V and passed to the 'TR-AC' input. The Pico program is toggle.py (attached) which has been renamed to main.py (so it will autorun) and saved to the Pico.

Raspberry Pico program

Note that the setting of the -8V supply requires moving the pot and then waiting for the huge capacitance to charge or discharge! The scope is now working again with 14V input (from mains adaptor) and drawing 1.2A.

New power supply board in position

Scope now working again!

OK, that was short-lived. Tried scope yesterday and the display comes on OK but the trace remains at 0V with noise but is not responding to the scope probe. Checked voltages (under load) and -8V is only -5V and so increased this to -8V (which increases the +8V to +11V!). 5V is OK. 3V3 is actually only 2.6V and unable to increase it (also LM317 getting very hot) and so replaced with LM2596 buck DCDC and now getting 3V3 ... and scope trace is now working! DMM shows 14.4V/1.4A.

Unfortunately autoset keeps coming on and the trace has low frequency (32Hz) modulation on it (even when probe connected to its own 5V/1KHZ test point) and so the scope remains unusable! If I short the scope input coax connector, I still get the 32Hz modulation. Tried factory reset (power on then power off before boot complete and then power on again and select F2) and no change. Tried FW update with *.up file from Hantek website but it says no update file found on USB stick.

The autoset is perhaps not a problem after all. Maybe the light is meant to always be on and when pressing the autoset button, it takes a few secs to do its job (during which its light goes off).

The low frequency noise is certainly an issue but I've noticed that it isn't present if I turn scope on when it is cold! Have noticed that the -8V (actually now adjusted to -10V for better results?) drops gradually after switch on and it also starts to waver up and down by 1V or so. I think it's the -8V which is causing the LF noise. Need to get a better negative supply for this. Also, the -8V seems to switch off completely (down to ~0V) if left on for a few hours.

After watching the video here, I've now configured the LM2596 as an inverting converter to generate the -8V and it seems to work fine! The scope now works as it should! The only problem is that sometimes on power on, some of the button lights will flash on/off continuously and the scope never actually powers up. I guess this is due to the inverting converter because that's the only thing that's now different. Perhaps the -8V should only be switched on after the other supplies are on. Have now wired in a manual switch on the 14V to the inverting converter so it can be switched on *after* the main power comes on. Actually it is probably the inrush current on the inverting supply which is causing the 14V mains adapter to switch off and then restart over and over again. The switch on the -8V actually doesn't really help i.e. sometimes it works and sometimes it doesn't! Updated power supply board is as shown below. Tried a 15V/5A mains adapter to see if extra current capability (albeit 1V extra) might be the solution but ... LM2596 inverting converter now no longer works ... arrgghh! Fortunately, after replacing it with another LM2596 board, it's all back to working again, phew!

Updated power supply board

It's complicated

Until a few years ago, I hadn´t really thought about heaven and hell. I was a Christian because of the benefits it brought me in this life. However I began to ponder what was meant by Jesus being my Saviour. What has he saved me from? At that time I read a book by John Bunyan called ´Visions of Heaven and Hell´. Some argue that John Bunyan couldn´t have written this. Nevertheless it made heaven and hell more real to me. I realised then what Jesus had saved me from. It was hell. I was hungry to know more and read ´A Divine Revelation of Hell´ by Mary Baxter. I also went to a website called ´divinerevelations.info´ and started listening to all sorts of testimonies from people claiming to have had out-of-body experiences in which they were taken to heaven and/or hell.

These testimonies were filled with accounts of dead people (souls) experiencing the most horrendous suffering in hell. Could it be true? For my part, I believed the testimonies and it spurred me on to evangelise more zealously than I had ever done before. Surely, I thought, there is no other message so important to a person than that they avoid this place called hell. I had to warn people about hell and tell them that the only way to escape it was to believe and trust in Jesus. And so now I had a passion! I must try to save as many as possible. The Bible says ´whosoever believes shall not perish´. Therefore the onus is surely on the people to believe. Correct? After all, isn´t this the basic gospel message?

Since this basic gospel message was not being proclaimed at the church I was currently attending, I decided to try another church. So I started attending a Baptist church nearby. Here the gospel message was preached faithfully and regularly. To my mind, perhaps too regularly given the fact that the whole congregation was undoubtedly Christian! This church didn´t have the contemporary style of worship I was accustomed to. Instead, we sang hymns accompanied by a piano. In place of the often wishy-washy lyrics of modern choruses, we had hymns with Bible-based lyrics which had stood the test of time and which often contained a sermon in and of themselves. And the preaching was strongly Bible-grounded. And it was here that I began to learn about something I had only ever heard about in passing. Calvinism.

Calvinism states, amongst other things that God has predestined us to be saved and that salvation is entirely of God. We are so utterly ´depraved´ that we are not even capable of responding to God´s invitation to believe in Jesus such that we might be saved. God has to first of all work in us to enable us to respond to his invitation. Without a doubt, such a statement is based squarely on what the Bible says. It means that a person cannot ever lose their salvation because it has already been predetermined that they will be saved. So it´s a comfort and an assurance to the Christian. But what if a person becomes a Christian but then years down the line, jettisons their faith and denies Jesus. If you ask a Calvinist about such a person they will tell you that the person never actually became a proper Christian and therefore wasn´t actually saved. But of course by the same token, that could equally apply to all of us who think we are Christians. How can we be sure that at some future date, we too might not fall away? What was meant to be assurance for us has become the opposite!

Furthermore, if a person´s eternal condition has already been determined by God, what is the point then in evangelising? I think the only real answer to this is that Jesus mandated us to evangelise. Nevertheless, it´s easier to be motivated to evangelise if you consider that there is no predetermination and that each person has to decide for themselves whether to believe in Jesus or not.

To muddy the waters even more, I continued to visit ´divinerevelations.info´ and read accounts of people who claim to have been taken to hell. Some accounts reveal that there are actually Christians in hell. These Christians believed in Jesus but did not obey him. They trusted in him as their Saviour but harboured bitterness in their hearts, told lies, committed adultery etc. Some accounts even show Christians in hell for not tithing or keeping the Sabbath holy. If these accounts are true (and perhaps they are not), how can any Christian then be certain of their salvation?

So, today I find myself alternating (1) between my previous church (where my wife goes) and the Baptist church (2) between Calvinism and Armenianism thinking and (3) between works-based and grace-based salvation thinking. One totally mixed up Christian! Perhaps this is what Paul was thinking when he wrote ´work out your own salvation with fear and trembling´.

The version debate

About 5 years ago I decided to seek out the 'best' translation of the myriad out there. At that time I had been looking into the Great Version Debate with a view to replacing my NIV (New International Version) for a more accurate translation. And this is what I learnt ...

There are two main types of translation of course: literal (aka 'word for word' or 'formal equivalence') and paraphrase (aka 'thought for thought' or 'dynamic equivalence'). Unfortunately there is no sharp dividing line between these types so what we have is a spectrum from the most literal at one end to the most paraphrased at the other end.

Literal translations not only attempt to translate the original Hebrew (Old Testament) and Greek (New Testament) words directly but also attempt to maintain the same word order. The advantage is that you get exactly what the original text says but the disadvantage is that you may not understand it! The most literal translations available today are for example the NASB (New American Standard Bible), ESV (English Standard Version), NKJV (New King James Version) and the KJV (King James Version).

Paraphrase translations attempt to render the meaning behind the original text rather than accurately translate each word. The advantage is that it is easy to read but the disadvantage is that you are relying on the translator's interpretation of the text. The most paraphrased versions available today are for example the GNB (Good News Bible) and TM (The Message).

In between the two extremes of most literal and most paraphrase, we have for example the NIV which tends to the literal end and the NLT (New Living Translation) which tends to the paraphrase end of the spectrum. I wanted a literal translation because I wanted to know that what I was reading was as close as possible to the very Word of God. The NASB is regarded as the most literal but because of this it can be quite hard to read. If it was hard to read I'd probably not persevere with it. So I decided that the NASB wasn't for me. So I was now down to three: the ESV, the NKJV and the KJV.

Now, many of the Christians that have influenced me the most, happen to read the KJV. I don’t know why this is the case. I thought that maybe I’d become a better Christian, just like them if I also read the KJV. I also began to find out that there are plenty of people who regard the KJV as the one and only "God's Word in English". These "KJV-Only" people will say that the KJV is the version that people were martyred for and it is the version of the great revivals of the past. They acknowledge that it's archaic but they argue that it's best to stick with the KJV and learn what the archaic words mean than to go with a modern "perversion" (their word, not mine!). And they are particularly dismissive of the NKJV because of its claims to be a modernised KJV. They say it is in fact a deception. They have many convincing arguments for their case. They convinced me and so I bought a KJV plus a little booklet explaining the meaning of all the archaic words. I still wasn't happy though because it was a struggle to comprehend the text in many places. I decided I should look into the other two versions. And so now it was 'NKJV versus the ESV'.

Now I already had a NKJV but one thing above all else put me off it and it was nothing to do with the text. It was the small dictionary/concordance in the back of the Bible which insisted in giving definitions for each of the word entries. Nothing wrong with that … until you get to words which actually don’t need defining and shouldn’t be defined! For instance: “dead” = not alive; deceased (and of course the ‘dead parrot’ sketch comes immediately to  mind!); “face” = the front of the head; “hand” = the end of the arm; “mother” = female parent; “night” = the period of darkness between sunset and sunrise. And there are more! It’s probably small-minded of me but unfortunately, this affected the credibility of the whole NKJV for me!

So, what is the difference between the NKJV and the ESV? (The ESV, I should say, is quite a recent translation, first appearing in 2001.) The difference comes down to a consideration of the original texts used in the translation of the NT (New Testament). The translation of the NKJV NT (apologies for all the acronyms which are now seeping in!) is based on something called the "Textus Receptus" (or Received Text). This is itself based on those Greek manuscripts which were around at the time that the KJV was translated. (It is also the basis for the KJV NT.) Since then, many more Greek manuscripts have been found which also support the Textus Receptus. However, in the late 19th and early 20th centuries 2 more manuscripts were found which pre-dated those which contributed to the Textus Receptus. The Greek text obtained from these 2 manuscripts became known as the Alexandrian Text. Bear with me!

This Alexandrian Text however differs in places with the Textus Receptus. Oh dear! So, the choice becomes 'minority of texts but oldest' (Alexandrian Text) versus 'majority of texts but youngest' (Textus Receptus). I'm probably over simplifying this. On the premise that 'oldest is best' most modern Bible scholars favour the Alexandrian Text and pretty much all contemporary translations of the NT have relied on this text in preference to the Textus Receptus (although footnotes often indicate differences). Incidentally, this is where the 'KJV-Only' people have their harshest criticism of the modern 'perversions'. They regard the Alexandrian text as a corrupt text. Most Bible scholars these days however consider the Alexandrian Text to be the better of the two. Now the ESV NT is based on the Alexandrian Text but the NKJV NT is based on the Textus Receptus.

One final consideration is that the NKJV is only available in Americanised English but the ESV is available in Anglicised English. After completing this research, I decided I had to get an ESV.

Fast forward to 2013. What am I reading now? "I don't care" I hear you say. But, if you've read this far, you clearly do care! Well I didn't actually stay with the ESV very long. I instead went onto the NKJV and in particular the 2002 'New Spirit-Filled Bible'. I'm not sure you can have a Bible which is Spirit-filled but at least it didn't have the silly dictionary/concordance at the back! (Incidentally, it does have at least one mistake in the text - Matthew 1:15 spells Eleazar wrongly as Elaazar.) But I didn't stay there. I now find myself reading mainly from the KJV with occasional dips into the Amplified Bible (AB) which, as a friend once said ... is the Bible for the hard-of-hearing!