transistor equivalents

[Andyuk]

Hello

Can somebody help me with two equivalents.

I have a board that I am trying to repair and due to my lack of electronic knowledge I have no option but to change the components one by one.

The first is PIP3210-R and the second is PIP3115-B. I have printed the data sheets of but I am struggling to find a like for like.

Any help would be much appreciated.

Andy

 

[(*steve*)]

Can you post the datasheets and indicate the purpose you're using these devices for.

 

[Herschel Peeler]

Can you post the datasheets and indicate the purpose you're using these devices for.

Data sheets

 

[Herschel Peeler]

Hello

Can somebody help me with two equivalents.

I have a board that I am trying to repair and due to my lack of electronic knowledge I have no option but to change the components one by one.

The first is PIP3210-R and the second is PIP3115-B. I have printed the data sheets of but I am struggling to find a like for like.

Any help would be much appreciated.

Andy

What does the board do? what is it doing or not doing? Is there any physical damage?

 

[(*steve*)]

These parts are now obsolete (try going to digikey and search for topfet).

Finding them may be tricky. You need to be sure they have failed, and if so, they won't fail again immediately you replace them.

 

[Andyuk]

The board if from a 24v air blown heater from a caravan. It consists of a main board within the heater and a thermostat. The thermostat is flashing an error code which indicates low voltage. I have the board at work plugged in to a power supply and upped the voltage up to 26V but it still shows the same error. I don't know whether the components in the thermostat control the error or the ones on the board.
Here are the pics.
One picture shows the components I have changed so far. In the thermostat I have changed the transistor and the LM2903n.

 

[(*steve*)]

It's probably better to troubleshoot than to just replace stuff until the fault is fixed.

Has the fault changed at all with all the replacements you've made?

 

[Andyuk]

No it is still the same. I know the heater was repeatedly switched on when the battery voltage was very low.
You can reset the fault by switching the thermostat on off on, It then takes a couple of seconds before it faults again if you don't reset it the fault shows as soon as you power up.
The first thing that happens as soon as power is supplied is the fan starts to run, this is correct, its a purge cycle but it wont go any further due to the low voltage fault.
This is the cycle.
Switch on Heater motor starts 15 second pre-purge to clear gases from heat exchanger Gas valve opens Spark generator operates Heater lights and runs on reduced motor speed for 30 seconds Motor speeds up to normal operating speed Heater switches off when thermostat temperature reached Post Purge –fan runs on its own for 2 minutes Temperature drops Cycle repeats.
Attached is a fault finding table.

Thanks

 

[Herschel Peeler]

No it is still the same. I know the heater was repeatedly switched on when the battery voltage was very low.
You can reset the fault by switching the thermostat on off on, It then takes a couple of seconds before it faults again if you don't reset it the fault shows as soon as you power up.
The first thing that happens as soon as power is supplied is the fan starts to run, this is correct, its a purge cycle but it wont go any further due to the low voltage fault.
This is the cycle.
Switch on Heater motor starts 15 second pre-purge to clear gases from heat exchanger Gas valve opens Spark generator operates Heater lights and runs on reduced motor speed for 30 seconds Motor speeds up to normal operating speed Heater switches off when thermostat temperature reached Post Purge –fan runs on its own for 2 minutes Temperature drops Cycle repeats.
Attached is a fault finding table.

Thanks

Well congats on your soldering skills.
But it still indicates low battery voltage even when running off of the power supply? The LM2903 would probably have been the main chip on that. Somewhere around the LM2903 you have a voltage reference a Zener diode or programmable voltage reference???

 

[Andyuk]

That's not soldering I call it welding.

 

[(*steve*)]

R8, R10, and R18 appear somewhat discoloured. Are any of them damaged?

 

[(*steve*)]

R29 and R36 are worth a look at too.

 

[(*steve*)]

Measure those resistors both ways around whilst in circuit. Replace them if the reading in either direction is more than 105% of the marked value.

The one right near the zener (if open) may be your problem.

But I bet you wont be that lucky.

 

[Andyuk]

Well congats on your soldering skills.
But it still indicates low battery voltage even when running off of the power supply? The LM2903 would probably have been the main chip on that. Somewhere around the LM2903 you have a voltage reference a Zener diode or programmable voltage reference???

yes it still indicates a low battery voltage while running on a power supply, even when I have upped the voltage to 26v.
around the LM2903 there are a number of Zener Diodes, Have a look at the picture.

 

[Andyuk]

Measure those resistors both ways around whilst in circuit. Replace them if the reading in either direction is more than 105% of the marked value.

The one right near the zener (if open) may be your problem.

But I bet you wont be that lucky.

Steve .
The resistors measure okay. The reason they look damaged is because the heater draws in, the fresh air across this board and I think moisture in the air has caused this. The front and back of the board is covered in varnish. This is why my soldering looks so bad. well that's my excuse anyway.

 

[Andyuk]

I have red on another web site that is discussing this problem, that the electronics that are responsible for detecting the correct voltage are on the thermostat board.

 

[Andyuk]

I measured the volts on the LM2903 while switched on.
Ground to pin 1 0v
Ground to pin 2 4.3v
Ground to pin 3 3.5v
Ground to pin 5 ov
Ground to pin 6 0v
Ground to pin 7 0v
Ground to pin 8 11.4 v

supply voltage to board is 24.5 volts

I used the attached pic as a reference.

 

[(*steve*)]

Measure the voltage across each zener diode with the power applied.

 

[Andyuk]

Steve

I have just replaced the diodes, I still have the same fault. I'm at a loss. If I new which components actually measure the voltage then I might have a chance.
I would really like to replace the two topfets but they are obsolete. I have tried searching on digikey but I cant make sense of the data.
If any one can find the alternatives I would be very great full.
PIP 3210-R and PIP 3115-B

Cheers

 

[(*steve*)]

Did you measure the voltage across the zener diodes?

I hope you didn't replace them...

What about the diodes you replaced? What did you replace them with and why?