Repairing a pair of digital scales

[HawkEye244]

I have a bit of experience soldering but not of testing circuitry, so can anyone tell me where the first places to start is?

The problem is that the scales are no longer switching on. The batteries have been changed to brand new ones and the LCD display is totally dead. It will not turn on.

Top view of the scales :

Bottom view of the scales :

Unscrewed the fascia:

Close up of the circuit board :

I'd like to have a go at repairing this before I toss it.

 

[mikeyd]

I think that's a "no user serviceable parts inside" product. There isn't even an on/off switch to check. Just googled Tanita and they don't look cheap/throw-away. Their website has plenty of contact options, customer support webchat, facebook etc. I'd ask them for advise, nothing to lose.

 

[HawkEye244]

It's well out of warranty so unlikely. I will contact them though. Just thought there's something I could try.

 

[Iggifer]

A better close up of the PCB (both sides) might help a bit more.

Have you checked to see if there's voltage at the first point from where the battery connects to the PCB? Could be a duff battery holder

 

[PrenticeBoyofDerry]

Yes would be best testing out contact first. But although expensive, power loss is a common issue with these. I binned mine. Sorry cannot help any further.

 

[HawkEye244]

Hi Igg.

anything obvious ? I'm getting a multimeter on wednesday. Never owned one.

 

[EFLImpudence]

This doesn't look too good ???

 

[ericmark]

I was required to repair a dumper mounted concrete mixer which was intended to mix an accurate batch of concrete, although much bigger it was same idea four strain gauges connected to a read out, found the faulty strain gauges and new ones ordered arrived and fitted. However the readings were wildly inaccurate, phoned manufacturer who offered to send their guy to calibrate it.

However when I explained that would tie him up for 2 months, 14 days to get to the Falklands and unless he completed in the hour it took to refuel he would need to wait for next boat 28 days latter then 14 days back, they decided they would fax me out the instructions, it was quite easy once given the step by step instructions, but without them it would be impossible.

So in real terms likely you just need to find a handy re-cycling centre.

 

[stillp]

Quite a few of the solder joints on the PCB look dry.

 

[HawkEye244]

This doesn't look too good ???

View attachment 119693

What do you think it is? Possibly related to moisture/corrosion? They sit in a bathroom

 

[HawkEye244]

I was required to repair a dumper mounted concrete mixer which was intended to mix an accurate batch of concrete, although much bigger it was same idea four strain gauges connected to a read out, found the faulty strain gauges and new ones ordered arrived and fitted. However the readings were wildly inaccurate, phoned manufacturer who offered to send their guy to calibrate it.

However when I explained that would tie him up for 2 months, 14 days to get to the Falklands and unless he completed in the hour it took to refuel he would need to wait for next boat 28 days latter then 14 days back, they decided they would fax me out the instructions, it was quite easy once given the step by step instructions, but without them it would be impossible.

So in real terms likely you just need to find a handy re-cycling centre.

It probably will come to that but because there's no impact damage as far as I know I'm going to give it a good go

 

[HawkEye244]

Quite a few of the solder joints on the PCB look dry.

Which ones and how does that affect the connection?

 

[EFLImpudence]

What do you think it is? Possibly related to moisture/corrosion? They sit in a bathroom

Doesn't look connected to me.

May be an optical delusion.

 

[HawkEye244]

It is connected but it's a bit corroded up, had another look.

 

[ban-all-sheds]

What do you think it is? Possibly related to moisture/corrosion?

Looks to me like corrosion from a leaking battery.