PHILIPS HTS3100 Repair

[DzAnej]

Hello there.

So I am having some trouble finding a problem on my PHILIPS HTS... The device is actually working but only for a few minutes or until i change the source or power it off. After that it takes quite some time to start working again... Now I don't know the reason why it is working/not working. I have checked the power rails and the +5,+12 and +30V are there...

Here is a picture of the boards:

[DzAnej]

Also if i turn the volume up high it stops working quite quickly...

[MK14]

The service manual, almost a 20Mb download, may/should help.

They make it difficult to find the link. Click "Get Manual", approx middle of screen, in a tiny font.
It works, I got the download, and it includes schematics and many pages.

http://elektrotanya.com/philips_hts3100_ver1.1.pdf/download.html

[DzAnej]

The service manual, almost a 20Mb download, may/should help.

They make it difficult to find the link. Click "Get Manual", approx middle of screen, in a tiny font.
It works, I got the download, and it includes schematics and many pages.

http://elektrotanya.com/philips_hts3100_ver1.1.pdf/download.html

Yes, I have read the manuals, but I just can't figure it out... I have replaced the main and the amp board and nothing, so I am guessing that something is wrong with the power supply board. Maybe a faulty capacitor? but i can't see there being any caps that are "blown" or something like that...What are some other things that are wrong in a circuit that works and don't, a bad cap, overheating part??

[MK14]

Yes, I have read the manuals, but I just can't figure it out... I have replaced the main and the amp board and nothing, so I am guessing that something is wrong with the power supply board. Maybe a faulty capacitor? but i can't see there being any caps that are "blown" or something like that...What are some other things that are wrong in a circuit that works and don't, a bad cap, overheating part??

It seems to be a complicated switched mode power supply (PSU).

Using stuff like the
https://www.fairchildsemi.com/datasheets/UC/UC3844.pdf

They can have very difficult to diagnose problems/issues. Because they can be designed to shut down automatically, if it senses a number of different faults/problems, with the PSU. This is to avoid fire hazards, risk of further electrical problems, etc etc.

If someone asked me specifically about it. I would recommend they either replace the entire board, abandon the repair project (Since SMPS repair is known to be a potential nightmare) or get a specialist SMPS repair agent to fix it. Because it would either be a big time sink, with little/no success or even dangerous, such as a fire hazard or electric shock risk (probably more applicable to much larger, PC power supplies). But since this is an open forum and you are not asking me personally, opinions might vary.

[Gixy]

The PSU board is probably the root cause. Try to replace the regulator STR-W6759 and associated capacitors. I did that on my HTS6600 and it works now.
I found the regulator at Digikey only, with as much shipping cost as part price :-(

[PedroDaGr8]

The PSU board is probably the root cause. Try to replace the regulator STR-W6759 and associated capacitors. I did that on my HTS6600 and it works now.
I found the regulator at Digikey only, with as much shipping cost as part price :-(

If you pay by check, digikey will ship your order for free. Of course, that means the hassle of paying by check.

[Gixy]

Unfortunately paying by check from France should be difficult...