The community repair thread

vasselmeyer

Danny1969 said:

So here's a great little cheap tool to help diagnose whether the problem of a typical tablet being dead is the charging port or the battery or both. This cost about £4 and can save you so much time. Plug in inline to the USB charger and it will give you the voltage and the current being drawn. So before you plug the cable into the tablet you should have 5V and 0 amps being drawn. 

They're incredibly useful little tools. There's a cracking YouTube channel called Tronicsfix where he uses these all the time when repairing Nintendo Switches.

Kittyfrisk

@Danny1969   is the Stanley knife blade near to the charger point to act as a heat sink, or for some other reason?

Danny1969

Kittyfrisk said:

@Danny1969   is the Stanley knife blade near to the charger point to act as a heat sink, or for some other reason?

I reflowed the socket with a hot air tool and that blade is just keeping the heat off some very small SM components which could have got moved in the heat 

Chris.B

Danny1969 said:

So here's a great little cheap tool to help diagnose whether the problem of a typical tablet being dead is the charging port or the battery or both. This cost about £4 and can save you so much time. Plug in inline to the USB charger and it will give you the voltage and the current being drawn. So before you plug the cable into the tablet you should have 5V and 0 amps being drawn. 
 


I didn't know such a device existed, let alone for such a small price. No place for an Avo 8 in a modern electronics workshop!

It's really interesting to read about your repairs - please keep posting. 

Danny1969

So this PCB is out of an expensive dishwasher .. not the first time I've seen one of these and a classic example of how a £4.60 component can put a 2K dishwasher out of action. The fault is it won't drain out after the wash cycle.  Look at the board and you can there's some logic going on and this ones even got some upgradable firmware in an EEPROM. As intelligent as it looks though it can't provide power to the drain pump because a relay, a device invented about a hundred years or more ago has broke, The reason it's broken is because ever time it makes or breaks the switch to the drain pump it sparks and a  small piece of metal is vaporized. Eventually the contacts won't make anymore and according to the manufacture you have to change the whole £330 PCB



So you can simply follow the drain pump motor connector to it's relay then here's an quick and easy way to test it in situ. Although these are 12V relays it will switch easy enough with 9V so put a meter on diode mode so you can hear the beep AND see the voltage drop across and then observing polarity touch a  9V battery on the relay coil. If your not sure which contact is which look at the part no of the relay and look up the pin out. Here you can I've drawn a ring around the relay coil. 



As suspected Relay coil switch's but contacts remain open circuit. All other relays tested good. New relay ordered at £4.60 and another PCB saved from scrap. 

Danny1969

So another quick job this morning, an iPad with the screen bulging up. Recently I've seen a few do this, all around 2018 models so I'm wondering if there was a bad batch of batteries ? 



So digi off and LCD out and see the battery has expanded and pushed the LCD up until the digi cracked ..



Replacing battery is easy enough, this is how it should look. Note the CD case giving me the correct height to install the digi without stressing the cables. 



Oh before you install the digi reuse the old home button, otherwise the fingerprint function won't work 



And we've back in business 



So is you buy a used 2017 to 2019 iPad look carefully around the edges . Is anything lifting at all ? look especially in the middle as there is less adhesive to hold it down in the middle. I've done about 4 of these with this fault in the last 4 weeks or so. Normally the batteries just go bad in terms of holding a charge not swelling so somethings amiss. 

boogieman

Danny1969 said:

So this PCB is out of an expensive dishwasher .. not the first time I've seen one of these and a classic example of how a £4.60 component can put a 2K dishwasher out of action. The fault is it won't drain out after the wash cycle.  Look at the board and you can there's some logic going on and this ones even got some upgradable firmware in an EEPROM. As intelligent as it looks though it can't provide power to the drain pump because a relay, a device invented about a hundred years or more ago has broke, The reason it's broken is because ever time it makes or breaks the switch to the drain pump it sparks and a  small piece of metal is vaporized. Eventually the contacts won't make anymore and according to the manufacture you have to change the whole £330 PCB



So you can simply follow the drain pump motor connector to it's relay then here's an quick and easy way to test it in situ. Although these are 12V relays it will switch easy enough with 9V so put a meter on diode mode so you can hear the beep AND see the voltage drop across and then observing polarity touch a  9V battery on the relay coil. If your not sure which contact is which look at the part no of the relay and look up the pin out. Here you can I've drawn a ring around the relay coil. 



As suspected Relay coil switch's but contacts remain open circuit. All other relays tested good. New relay ordered at £4.60 and another PCB saved from scrap. 

Nice job on sorting that one out. It’s stupid that they don’t make the relay a plug in part. But then of course they couldn’t rush you £300 + for a new board. 

We had a Bosch dishwasher go on the fritz a while back, again it wouldn’t pump out. A local white goods shop that has a repair section reckoned it’d need a new pump but as it was already an old model it’d probably be better to just replace the whole dishwasher. Bollocks to that. I googled the fault code and found a YouTube guide that said it could be a blocked impeller, so I fished around in the sump and sure enough I found a bit of broken glass that was jamming the pump. It’s still going strong to this day. 

Danny1969

boogieman said:

Nice job on sorting that one out. It’s stupid that they don’t make the relay a plug in part. But then of course they couldn’t rush you £300 + for a new board. 

We had a Bosch dishwasher go on the fritz a while back, again it wouldn’t pump out. A local white goods shop that has a repair section reckoned it’d need a new pump but as it was already an old model it’d probably be better to just replace the whole dishwasher. Bollocks to that. I googled the fault code and found a YouTube guide that said it could be a blocked impeller, so I fished around in the sump and sure enough I found a bit of broken glass that was jamming the pump. It’s still going strong to this day. 

Ha ha, nice one. In my experience most service centres do tend to quote you on the most expensive part in the hope you will buy another which really grinds me and I'm glad some people still have the will to get involved and help cut down the massive amount of perfectly repairable stuff we bin every year. 

Chris.B

I rescued our oven. A relay was refusing to provide supply to the relevant parts. Whilst looking for a manual to get the relay specification, I found a control panel for £20 - job done.

I've also replaced the thermal trip on the back of the oven a few times.  

Mrs Chris B looked a little disappointed last time I repaired it, she was already looking up shiny new ovens!

I blame my apprenticeship in the TV trade for giving me the "I can fix this" attitude - I do miss my old Avo 8.

crunchman

crunchman said:

Danny1969 said:

crunchman said:

I have a Shure mic with a dodgy XLR connector.  Anyone know where in the UK I can get one of these without paying £8 postage?

https://www.thomann.de/gb/shure_xlr_buchse_fuer_sm58.htm

Ebay item no 283896105676 £3.60 and £2.70 postage 

 
China but will probably get here before you need it 

Thanks

All fixed.  Thanks Danny.

Danny1969

Chris.B said:

I rescued our oven. A relay was refusing to provide supply to the relevant parts. Whilst looking for a manual to get the relay specification, I found a control panel for £20 - job done.

I've also replaced the thermal trip on the back of the oven a few times.  

Mrs Chris B looked a little disappointed last time I repaired it, she was already looking up shiny new ovens!

I blame my apprenticeship in the TV trade for giving me the "I can fix this" attitude - I do miss my old Avo 8.

Good work. 
Avo's are still used in calibration, especially for MOD stuff. If the procedure says you use an AVO XX to calibrate a radar position sensor or whatever that's what you have to use. A friend has a calibration company and keeps loads of old Avo's up and running purely for MOD work

Chris.B

Danny1969 said:Good work. 

Avo's are still used in calibration, especially for MOD stuff. If the procedure says you use an AVO XX to calibrate a radar position sensor or whatever that's what you have to use. A friend has a calibration company and keeps loads of old Avo's up and running purely for MOD work

I'm amazed to hear that the Avo is still in use commercially.  It was 1983 (I was very young) when I have to give mine back on leaving the TV business and joining the world of IT where they gave me a Fluke DMM - it just wasn't the same - but I still have it and it is still in use so it can't be that bad. 

Danny1969

@Chris_B ;
A Fluke 77 has been my DVM for the last 25 years, you can see the state of it in the pics. It's been dropped and got wet and had the internal current fuse blown many a time but it's still going strong and still remarkably accurate

crunchman

Cheaper meters these days can be pretty good.  I remember 15 or so years ago I was biasing an amp using my £20 meter and the plate voltage was noticeably higher than the nominal voltage.  There was a guy doing some work on our block of flats so I borrowed his Fluke.  It basically read the same as mine to within around 0.5%.  (It turned out the mains voltage was 246V, not the nominal 230V).

That same cheap meter is still working 15 or so years later.

It's nice to have high end tools and equipment, but you don't need to spend a fortune - especially if you aren't doing it every day.  Given how cheap they are, everyone should own a DMM these days.

Chris.B

One big advantage of a DMM over the old analogue meters is not having to watch the pointer try to wrap itself round the end stop when you measure mains voltage whilst set to a 3 volt range!  There was many a bent pointer amongst the collection in my Visionhire workshop

Danny1969

Yeah that's where the Fluke scores well, the autoranging is great from 200mV to 1000V, same setting . The touch hold is great too.
@crunchman the other meter in the pic above is a cheap Tenma from CPC .. bout £28 but it covers the basics well. The Flukes are expensive because you can calibrate them within a few mV and less than a tenth of an Ohm but in day to day repairs you don't need that accuracy. 

Kittyfrisk

Had my Fluke 75 for a bit longer that your 77. Great tools.
One of these days I'll really have to learn more, to do it justice 

Emp_Fab

As mentioned in another thread, I recently replaced the backlights in a 39" LED TV - only to crack the fucking screen refitting it!  Then I re-capped the board in another LED TV as 70% of them were bulging.  I was certain it would fix it.  Did it bollocks.

thermionic

Interesting to see an iPad with a bulging screen. At work we all have Microsoft Surface Pros and several people (including myself) have suffered bulging screens due to the battery swelling. Some have reportedly popped off quite dramatically as the glue can’t take it. I googled it and it’s very common, usually a couple of months after the warranty expires and sometimes even creating smoke and/or flames. Microsoft’s response is of course “not our problem, buy a new one”.

Danny1969

@thermonic ; Surface Pro's have a terrible board failure rate, I've seen 4 or 5 in for repair and all needed boards. They aren't the best built machines