samsung ht z310 - FAN_CHK error

[Sadistic Taste]

Hi

Hoping someone can help me troubleshoot this, I'm still trying to learn. I found the schematics online, but i need some guidance

The system turns on a works, but after about 20-30 seconds I start getting FAN_CHK on the display, then it powers off. Obviously overheating.
Opened it up, and the fan isn't working. It doesn't seem to be getting power.

I have measured 12v up to QF3, then nothing. Can't find any shorted components, or any obvious blown caps.

If anyone is willing to take a look at the schematic, and help me out, I would really appreciate it. Thanks

[budm]

Re: samsung ht z310 - FAN_CHK error

What page is that QF3 at?
Pictures of the board and the model number of the fan?

[Sadistic Taste]

Re: samsung ht z310 - FAN_CHK error

Hi Budm, thanks for your replay.

My mistake, it's FQ3. I'm not home atm, I will upload a pic tomorrow.

Just a an update tho, I wasn't getting any voltage on the fan connector at first, but after about 20 seconds I was getting 3.3 on one pin, and 6.7 or so on the other pin.

The fan still would not spin, so I connected it to a 12v source and it spins fine. I connected it back up to the z310, and once the voltage kicked in, I manually turned the fan with my finger, and it starts spinning. However, once I power it off and back on, it stops working again.

[dick_barton]

Re: samsung ht z310 - FAN_CHK error

If you can start it with your finger then either the voltage is slightly low and unable to kick start it or most probably the fan bearings are worn and the fan needs to be replaced.

What DC voltage rating is on the fan. It also supplies feedback pulses when running to the mainboard.

[R_J]

Re: samsung ht z310 - FAN_CHK error

You should have +12v on the emiter of FQ3, once the unit is turned on the micro should tell FQ3 to turn on and supply +12 (aprox) on the collector, the current should flow through FR3, throught the FAN and through FR1 to D.ground. when the volume is turned up, audio is fed through fr8,9 fc5,6 and rectified by fd1,2 that turns on fq2 that turns on fq1 that connects fr12 accross fr3, this increases the voltage to the fan speeding it up. If the fan starts when you spin it do you still get the error? also if you spin the fan and it starts does the speed increase when you turn up the volume?
I suspect the fan is just bad enough to not start and run with the lower start voltage.
going by your voltages and assuming 12 volts at FQ3, it looks like there is about 100ma runnig through fr3, the fan and fr1

[dick_barton]

Re: samsung ht z310 - FAN_CHK error

I have never seen a circuit to drive a fan like this. Why so complicated?

[Sadistic Taste]

Re: samsung ht z310 - FAN_CHK error

First of all, thank you everyone for your help.

Pictures of the board and the model number of the fan?

I have attached some pics. Also, the fan model is Xfan: RDM5015S

If you can start it with your finger then either the voltage is slightly low and unable to kick start it or most probably the fan bearings are worn and the fan needs to be replaced.

I was thinking it could just be the fan..

If the fan starts when you spin it do you still get the error? also if you spin the fan and it starts does the speed increase when you turn up the volume? I suspect the fan is just bad enough to not start and run with the lower start voltage.

Thanks for explaining the circuit. Once I get the fan spinning, the error is gone, until the next time I turn it off/on, or stop the fan with my finger.

The fan isn't increasing when I adjust the volume, voltage is reading 4.12 on my meter with the fan running. I only have one speaker here.

[budm]

Re: samsung ht z310 - FAN_CHK error

So what DCV do you get between the two wires of the FAN?

[Sadistic Taste]

Re: samsung ht z310 - FAN_CHK error

I get 7v on the red, 3v on the black and 4v across the two pins.

[budm]

Re: samsung ht z310 - FAN_CHK error

So the fan is only getting 4VDC, min is 6V per spec for the Fan requirement.
Are you getting 12V on the Emitter of FQ1, and a little less on the Collector of FQ1.
Notes: FQ1 may not be turned on unless the circuit detects the Audio signal on the F-L speaker.

[Sadistic Taste]

Re: samsung ht z310 - FAN_CHK error

12v on the emitter, and 8v, on the collector. It's now decided to work normally. Tho I've had it on running for a while..

I'll leave it unplugged and try again shortly.

[Sadistic Taste]

Re: samsung ht z310 - FAN_CHK error

Ok, I've powered it on/off a few times now to test, and it has only gave the error once so far. I didn't get a chance to check the voltage, as it powered off.

I seem to be getting the 6VDC on the fan connector now, but I still feel that something is wrong, since I did get the error again once.

When I have the the error, the fan seems to be only getting 4VDC.. Strange

[R_J]

Re: samsung ht z310 - FAN_CHK error

When the unit is turned on you should get +12 on FQ3 emitter and aprox +12 on the collector, if not that transistor could be bad or its not being turned on enough by FQ4
Check the voltage on FG4 Base and collector (emitter is ground), the check the voltage at FQ3, base.
FQ3 is acting like an on/off switch for the circuit, if its not supplying +12 volts that circuit (and the audio driven speed control) will not work properly
It's possible FC3 (47uf/16V) could be bad (open)

[Sadistic Taste]

Re: samsung ht z310 - FAN_CHK error

Yes, I do get +12 at FQ3. It's FQ1 where I get +12 on the emitter, and +8 on the collector.

Strange thing is, its been working fine for the last few hours, powering on/off etc. Only thing I did, was replace R91, on the power supply board, as it was looking a bit burnt.

[toncsiking]

Re: samsung ht z310 - FAN_CHK error

Ok, old thread but could be helpful for newbies and for others too
I had the same problem (after 30 seconds the display shows fan-check, and ampilifier switches out in 30 seconds.)
For me I found a real solution:
there's a capacitor FC-2 (47microfarad, 16 V) at the output connector of the fan - it was short-circuited, zero ohm. Replaced, perfect...
Worth to check it!
Now, I can see after repairing, what happening:
at start the fan is out, but in 30 secs it starts to work, even if there's no real need for it - as the system gets shortcut respond/fan error stops the amplifier, switches out.
Hehe ))

[tom66]

Re: samsung ht z310 - FAN_CHK error

I think this fan circuit has to be one of the most complicated I have seen, a temperature sensor control circuit would have been so much easier but instead it is based off volume level. As a result it needs additional fault detection circuitry and many analogue components. Very odd!