Philips HTS8100 , lower stand by.

[Moreno83]

Hey guys ,

I bought a defective soundbar which im trying to repair myself. I normally repair tv's and have repaired a Philips HTS7140 soundbar before but i have trouble fixing this one. Problem is , i don't know what the fault/problem is.

The set is stuck in "lower power standby". Plugging in the mains and standby light turns on and goes into "low power" standby. It won't respond to the remote or buttons on the device itself.

I already replaced :

- STRX6759 ( Fix for low audio )
- Elco 400V
- 4x 10uF

Nothing changed. Im not sure if its the psu or the mainboard?

Anyone of you ever repaired this unit?

I can post pictures if needed.

[Chungalin]

Re: Philips HTS8100 , lower stand by.

I’ve repaired 3 of these, but none of them is related to your problem and I can’t provide useful help.

From my notes I see that this sets have Panasonic MIP2C10MP as primary switcher. Then, what does STR-X6759? Fix for low volume? Actually, the last one had low volume problem and I was unable to fix it. I take note of this, thanks!

You can get SM at ElectroTanya.

[Moreno83]

Re: Philips HTS8100 , lower stand by.

Thanks for your help! What problem did you fix on this model?

Yes , that part + 400v capacitor + small caps on the board with the heatsink fixes low sound.

Already have the SM , cant find anything on this part. Not sure if its protection mode or something

[Khron]

Re: Philips HTS8100 , lower stand by.

Neither of the service manuals on ET contain any schematics of the power supply, unfortunately, it seems...

[Khron]

Re: Philips HTS8100 , lower stand by.

On page 30 of the SM there's a (low-res) photo of the power supply. The MIP2C10MP is on the bottom left, and i guess it controls that smallest transformer. The STR-X6759 is around the middle-bottom of the board, and most likely drives the biggest transformer.

But what's that other TO220-cased component, on the same heatsink as the STR-X6759? It looks like a FET driving that middle transformer, but is there some chip controlling it? Or is it somehow synchronously driven from the STR-X6759?

[Moreno83]

Re: Philips HTS8100 , lower stand by.

I will take some pictures of the board when i get home!

[Khron]

Re: Philips HTS8100 , lower stand by.

Also take note of the markings on that smaller FET(?), and whatever chips might be on the bottom of the board

[Chungalin]

Re: Philips HTS8100 , lower stand by.

Both MIP2C10MP and STR-X6759 are switching regulators (builtin mosfet), not controllers, so they don’t drive any external mosfet. It has sense that MIP is for standby PSU and STR is for working power.

Wow, 40MB service manual and they don’t provide PS schematics! Chapeau for Philips!

My two repairs were due to lightning surge. One had blown primary cap, varistor and a resistor. Second had primary cap, R151 (22Ω) and MIP2C10MP. Both sets had "dead" symptom, not what you say.

[Khron]

Re: Philips HTS8100 , lower stand by.

I know, i've looked into the datasheets, but like i said - what's with that FET(?) and medium-sized transformer, in the middle?

Well, in their defense, at least in the SM photo, the PSU *WAS* outsourced (says Mitsumi Elec Co on the board). I've seen similar things in "third party" plasma tv's, where the "big" PSU was from the panel manufacturer, together with the driver boards.

"Low sound" would be low volume, i'm guessing? Perhaps the power amps aren't receiving the full voltage they're supposed to? Or they're stuck in some sort of low-power mode?

I recall the TAS5630 evaluation boards having a nifty feature - the QFN-packaged version of the chip had a clip-indicator pin, and when that got asserted, it switched the power supply to put out the "full" 40-something volts, instead of the 20-something in normal / low-power mode.

[Moreno83]

Re: Philips HTS8100 , lower stand by.

Here are the pictures.

Diodes are all looking ok. Nothing short in circuit.
Maybe the psu is ok?

[Moreno83]

Re: Philips HTS8100 , lower stand by.

A 2A fuse on the mainboard is OL. First picture , behind the first connector. I'll replace that 1. So stupid i didnt see it. haha

[Moreno83]

Re: Philips HTS8100 , lower stand by.

Ps , STR-X6759 needs to be replaced if you have low volume. Most of the times the 120uf cap has to be replaced also.

[Khron]

Re: Philips HTS8100 , lower stand by.

In the words of Dave Jones (of EEVblog fame), the first commandment of troubleshooting is "Thou shalt measure voltages"

[Moreno83]

Re: Philips HTS8100 , lower stand by.

Haha true. I didnt notice that fuse. Replaced it and still same , its in lower standby.

[Khron]

Re: Philips HTS8100 , lower stand by.

Some photos of the bottom of the psu board would be welcome.

Other than that, though, you might consider checking the in / out voltages of those SOT223-cased regulators, on the subwoofer signal board.

On the block-diagram of the "power box" in the service manual, i see a cable with 4 signals (so a minimum of 5 wires) going to the "center unit". One is "Wake_UP, and another one is "CU_DET". Check to see if the 12v and 5v that are supposed to be going there, actually reach the center unit. The 5v should definitely be active; the 12v might only be there when the whole thing's out of stand-by.

[Moreno83]

Re: Philips HTS8100 , lower stand by.

I'll check! thanks for the help , appreciate it!!

[Moreno83]

Re: Philips HTS8100 , lower stand by.

Khron , did Dave Jones also say "If voltages are present , you might check the cable for damages" ? Main cable going to the soundbar is damaged. Its a very thick cable , and im honest ...i did not check the entire cable for cuts!

Going to fix the cable , will let you know the outcome

[Moreno83]

Re: Philips HTS8100 , lower stand by.

Fixed the cable. I now have a very faint image on the lcd screen "lower stand by"

I repaired a HTS7140 before and that one also had a faint image on the lcd. I fixed that with replacing caps on the lcd board. We are getting there...slowly!

[Khron]

Re: Philips HTS8100 , lower stand by.

As far as i know, no, he didn't

But hey, there's another old saying - "even a kick in the a*s is a step forward"

[Moreno83]

Re: Philips HTS8100 , lower stand by.

First picture , first connector ( 1201 ).

Voltages in DC

pin 1: 4.36v
pin2 : 5.5v
pin3 : 3.3v
pin4 : 0.16v
pin5 : 0.6v
pin6 : -27v
pin7 : 5.5v
pin8 : 12v
pin9 : 0v

Fan is not spinning , probably because its in standby mode. It reacts to the remote but only the power button. Either says "lower power standby or entering lower power standby"