Philips HTS3100 home theatre no sound, not reading DVD

[slappala]

Got this set free from my sister.

Problem, doesn't start with sound. Especially when cold.
Does not read DVD, screen menu ok.


FIXEs were..

Sound:
Never found the real reason or the broken Caps, diodes etc. ..thought it might be a software timer .

Showed some fast digital spikes on my scope to earth on Digital amplifier processors wakeup line! So check that with scope. Find the digital amp signal processor datasheet and I found the info there.

wake up Signal goes from main board to power board and from there to the end amplifier boards signal processor. Somewhere between happened strange things and there was intermitted signals going to ground! REally like digital 0, so the wakeup time for amplifiers processor unit was never reached on the wakeup line..

I ended up adding a 100uf electrolyte to this line to take off /ditch the spikes. Worked fine since. If remember correctly did not work everytime with 47uf. Processor needs above 3.3V low logic level wakeup signal and there is a time limit for it.

If the thing some day does not play sound, I will probably find the intermitted annoying fault afterwards when the responsible component(processor?) has gone to electrical heaven 100%.

IF you know the real component that affects this, let me know. The wakeup circuitry was rather complex tho..
For now I think it's a software timer..(might be also a component timer )


DVD:

Cleaned laser head with Polypropylene alcohol..so safe for plastics. Never missed a beat since that day..

Hope this helps someone..this works for all DVD players that won' t read the disk and the laser head is ok.

PS: Cleaning with lens clotch etc. will not work. you have to use the real stuff for the laser head.

[tom66]

Re: Philips HTS3100 home theatre no sound, not reading DVD

Hmm, I had a problem with a DVD player once before. It would not turn on - turned out to be a shorted diode in the PSU secondary. But after that, it would not play DVDs, but would play CDs fine. I cleaned the lens with a soft, dry cloth - and it worked perfectly.

Is there a reason you couldn't just connect the wakeup line straight to 3.3V, through say a 1k resistor? Then cut the line coming from the MCU.

[slappala]

Re: Philips HTS3100 home theatre no sound, not reading DVD

This turned on ok, just not sound. I red from internet that it's the most common fault on these units.

Hmm, I had a problem with a DVD player once before. It would not turn on - turned out to be a shorted diode in the PSU secondary. But after that, it would not play DVDs, but would play CDs fine. I cleaned the lens with a soft, dry cloth - and it worked perfectly.

Is there a reason you couldn't just connect the wakeup line straight to 3.3V, through say a 1k resistor? Then cut the line coming from the MCU.

Yep, I wanted to keep the original functionality with the remote control standby/on/off functions. Now, it works as it's intented to work normally with the remote and sleep functions. Les the interference in the wakeup line off front board.

If I remember right there is 2 signals that need to be OK and TIMED OK + combined to wake up the Digital amplifier processor board. One from main CPU board straight to the amplifier CPU (signal 1) and one from main cpu --> front board(remote etc.) with the clock circuit.. --> back to the amplifier board (signal 2)

1 goes straight to amplifier CPU from main CPU, second signal is combined with wake up from Main CPU thru Remote/timer circuit on front board to amplifier board.

would have to get the schematics out, but it works now really nicely. I only modified the signal coming from front board.
Other words no remote control/sleep if the 2 signals came straight from the main board or the 3.3 signal. And no wake up/sleep without 2 signals timed right..

The wake up is 2 stage..Now I remember..good that you asked

There was no place to draw clean standby signal without the combined front board signal.--I did not find any other way to time them right.

Strange thing is that the original signals are not from 3.3 line, but from two mixed lines and the front board signal is a combined signal thru series of filters from Main CPU, front board clock, remote..this let me to think it is a software timer..It's so freaking complex for the purpose and includes several timers/IC:s.

the amplifier board also would take 5.v signal, but it must be above 3.3.V for some period to wake it up.

The modified(philips??) or broken component signal prevented the 2:nd signal for reaching the 3.3V level OR It cut it so fast that the amplifier board CPU started counting the dead/sleep time again..

....It looked like scrambled PWM signal on my scope that was alternating, but at the frequency that forced the amplifier be stuck to sleep mode since the main CPU signal was allright..but this combined signal from main CPU thru front board(+TIMER realtime clock etc..) kept the PWM so low that it did not get it's awaking voltage level..OR it just plainly zeroed the amplifier board sleep counter...

The signal inteference was also so random that I just did not have change to find it with my scope..also it looked like plain digital signal..sharp as knives. I have not seen any analog compnet to fail like causing it..

nice to find something coming from front (LCD,remote,real time clock)board that IS NOT GOING IN!! I checked every input from main board and could not find the source for this digital(inteference) signal..so it had to be coming thru front board.

If someone has the same problem and has time to fiddle little more I'm interested to hear it, but I got frustrated and just took care of the problem the hard way. OL'skool way..(I like it dirty , I'm not also not an electrical engineer, just a hobbyist, so I can do what I wan't if I'm not burning the house down )

So I filtered the second signal, Got over 3.3 volts nicely every start, timed right with the 1:st signal and away we go..functional but dirty..

Rise/fall time for the 2:nd signal altered a little bit, but stayed well below the timing limits found from the digital amp signal processor datasheet.


Maybe now you can see why I ended up filtering the 2:nd signal, I just could not see any real reason component wise other than a software timer in front board clock circuit/PIC/CPU.. Sorry if it's tru..for philips . Clever way of doing it tho'..taking scramble signal from other than main board..selling these cheap shit's and than selling some more..

I just think it's a waste..

Prove me wrong..I did not seriously have enought time to play more...
It's just my current view on this thing. And I'm by no means of an expert in electronic stuff so might be wrong. But it works now. Has been working 6months and that is a long time for any diode or cap misbehaving and not going out for sure..

For DVD/CD laser head:
Might be some cases ok to wipe it out with a cloth, but in this case my sisters girls DVD:s were so dirty that the normal cloth did nothing. It worked 5/10, but it hasn't had a hickup since the proper cleaning.

So I would advise that to everyone buy a Bottle off Polypropylene alcohol, is about 5-10$ at your local drug store and do clean it properly. Just use "topsy" ear cleaning sticks or whatever similar product with "pumpuli" or "nukkaamaton"

(Do a google trans. I do it all the time , finnish-english)

and take your time..the cleaning solution dryes quickly so don't rub or pressurizize it(the laser head)..just let the moisture do it's job gently.

i think 90% of broken laser disk readers go to junk yards because of dirty laserheads..

PS: Is there a forum that would be interested to play around with these new shit bag machines and make them better? Just a tought..like there are forums for old tube amps..(Hobby ). This new stuff Might have some market soon for tuning kits..