Electrical help please

[tonyidle]

The photo does show some pcb track missing, for peace of mind I'd build up the remaining track using wire and solder. Reduced track could result in overheating in that track area and therefore further problems. It would do no harm after all.

No - it would no harm as you suggest. IMO there's adequate copper left but more is good. For Figaro: the safest repair is to solder each end of a short piece of insulated wire between two component blobs either side of the damage.

 

[Figaro]

or @Figaro: the safest repair is to solder each end of a short piece of insulated wire between two component blobs either side of the damage.

I don`t think I have the skills for that so I`ll look for someone locally to do it.
I`m guessing it would be a fairly simple job for someone used to working on pcb`s.
I`ve a friend of a friend who repairs pcb`s on games consuls so I`d think he could do it ?

 

[Sandancers]

I don`t think I have the skills for that so I`ll look for someone locally to do it.
I`m guessing it would be a fairly simple job for someone used to working on pcb`s.
I`ve a friend of a friend who repairs pcb`s on games consuls so I`d think he could do it ?

Yes

 

[tonyidle]

Yes

What he said

 

[autorouter]

I may be missing something here, but I can't see any component soldered on the board at the site of the damage. It looks to me like a foreign object (an uninsulated spade terminal?) has got inside and somehow shorted the live to neutral. I think there is no connection at all between the two tracks, and also the track is wide enough for it not to matter too much about repairing the metal. Just so long as you scrape off any carbonisation.

Edit: just realised jezport already said this

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[jezport]

You mentioned ptfe spray, dont get that anywhere near where you want to solder, its a non stick spray!.
A bit unusual for a track to blow off like that, it would have been caused by excess current perhaps due to poor insulation ie damp between the tracks at that point
Keep your fingers crossed.
I still think it may be a seized compressor or lack of gas, did you follow the compressor resting instructions before switching on? Itll have a good rest, the right way up etc whislt you think about it.
Mike

NO TRACK HAS BLOWN OFF!!!

 

[jezport]

No - it would no harm as you suggest. IMO there's adequate copper left but more is good. For Figaro: the safest repair is to solder each end of a short piece of insulated wire between two component blobs either side of the damage.

As Tony has said there is enough copper left but if you want to apply the belt and braces policy do as Tony has said. Sounds like tony may have fixed a Philips G11 or 2?

 

[tonyidle]

As Tony has said there is enough copper left but if you want to apply the belt and braces policy do as Tony has said. Sounds like tony may have fixed a Philips G11 or 2?

He hasn't - but many other items with damaged PCB tracks. A very long time ago I repaired a fair number of CB radios for a market trader - what the average trucker could do to those had to be seen to be believed.

 

[Figaro]

Update : I've cleaned up the damaged track on the PCB as suggested above and bingo, works, well the blower fan does.
The unit cools to 16c but with ambient temperature about 8c the compressor and condenser fans are doing nothing !
Does anyone know how I can check for cooling function without waiting for summer ? The unit is still on my bench.
Thanks to all who helped on PCB problem

 

[Richard n Ann]

Update : I've cleaned up the damaged track on the PCB as suggested above and bingo, works, well the blower fan does.
The unit cools to 16c but with ambient temperature about 8c the compressor and condenser fans are doing nothing !
Does anyone know how I can check for cooling function without waiting for summer ? The unit is still on my bench.
Thanks to all who helped on PCB problem

Yes you need to warm the thermistor up so it runs. On house AC systems it's in the 'return air' flow which is where it sucks air in. It should be very similar for a habitation AC although I've never worked on one.
The thermistor will be a little bead with 2 tiny wires going into the circuit board.
Stick a hair dryer on it ??

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[Figaro]

Stick a hair dryer on it ??

That's what I did and now my air con unit thinks it's summer
Compressor kicked in and condenser fans started
Pipework started frosting up so all looks good.
On that basis I'm happy to fit it whenever it stops raining for more than 5 minutes.
It's so satisfying to have fixed a problem and learnt a bit about how the thing works.
Couldn't have done it without the helpful folk on here so many thanks.
It's also had a good clean up and I spray painted the cover that was a bit weathered and it's looking like new now.

 

[Richard n Ann]

That's what I did and now my air con unit thinks it's summer
Compressor kicked in and condenser fans started
Pipework started frosting up so all looks good.
On that basis I'm happy to fit it whenever it stops raining for more than 5 minutes.
It's so satisfying to have fixed a problem and learnt a bit about how the thing works.
Couldn't have done it without the helpful folk on here so many thanks.
It's also had a good clean up and I spray painted the cover that was a bit weathered and it's looking like new now.

Might be a bit short of refrigerant if the pipes stay frosted while running, sometimes they frost a bit when starting up as the pressure suddenly drops but the pipes on a healthy system should be cold, just above 0°c and condensating (if not insulated).
That goes for the evaporator too, should be no frost.

When a system starts to lose it's refrigerant the pressures in the system drops, therefore the evaporating temperature drops, causing frost ?

And I got through all that without mentioning Coronovirus once ?... ???? oh bugger.

 

[Figaro]

Might be a bit short of refrigerant if the pipes stay frosted while running, sometimes they frost a bit when starting up as the pressure suddenly drops but the pipes on a healthy system should be cold, just above 0°c and condensating (if not insulated).
That goes for the evaporator too, should be no frost.

You could be right, but I`ve not found anyone who is willing to top up the refridgerant gas as yet.
I watched a video on youtube of a guy in USA doing it on the same unit, he had all the kit to fit a tap valve onto the pipework and scales to weigh the gas and estimate quantity required.
Unfortunately nobody I speak to over here wants to know.
Mind you I`ve not tried fitting the unit either yet to test it properly.
The front pivot bolt on my drop down bed has dropped out and that`s causing me all the grief I can handle at the moment but that`s another story.

 

[Richard n Ann]

You could be right, but I`ve not found anyone who is willing to top up the refridgerant gas as yet.
I watched a video on youtube of a guy in USA doing it on the same unit, he had all the kit to fit a tap valve onto the pipework and scales to weigh the gas and estimate quantity required.
Unfortunately nobody I speak to over here wants to know.
Mind you I`ve not tried fitting the unit either yet to test it properly.
The front pivot bolt on my drop down bed has dropped out and that`s causing me all the grief I can handle at the moment but that`s another story.

To do it properly you have to reclaim the refrigerant and weigh it to see how short it is. There will be a label on the outdoor unit with the factory refrigerant charge in grams.
Then if it is short, braze in a 1/4" schraeder valve and pressure test up to 400psi with nitrogen. Fix the leak, then evacuate all the nitrogen/air and weigh in the correct charge of new refrigerant.

Or quick job, put a line tap on it, wang some in and see what happens ? problem with that is when the refrigerant leaks out it changes the composition of the blend, ie the lighter gas component escapes first, you can usually get away with it though.

If it uses R134a refrigerant you can usually buy that from motor factors as it's car AC refrigerant. Anyway if it's blowing cold out leave it ?

 

[Figaro]

If it uses R134a refrigerant you can usually buy that from motor factors as it's car AC refrigerant. Anyway if it's blowing cold out leave it ❄?

It`s R407c and I`m not certain yet it`s blowing cold as I`ve not fitted yet, it was just the frost appearing on the pipes during bench test that I took as a good sign, but maybe not ???

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[Richard n Ann]

R407c is being phased out, it's not banned yet but new refrigerant is no longer available, just recycled is available and will probably be expensive.

Try it, but I suppose you don't want to fit it if it's no good. How long did the pipes frost for? Did it stop frosting after 30 seconds? Was there plenty of airflow through the evaporator fins? If the airflow is blocked off that can lower the temperature and make it frost.
Was there warm air coming out of the condenser? Leave the hair dryer blowing into the evaporator to load it up and if it's working well you'll feel the heat coming out of the condenser as the system pressures (and temperatures) go up.

 

[Figaro]

It only ran for a few minutes with the hairdryer on the thermistor as it thought it was winter.
The polystyrene box enclosing the evaporator was off so air flow wasn`t properly directed.
At that point I was encouraged that the pipes were cooling / frosting and stopped testing.
Since then I`ve not done anything with it.
If I`m grounded I`ll fit it in the next week or two, but for the moment I`m more concerned about getting the bed fixed which is a pig of a job