Philips D8734 problems

[Arbusto67]

Hi guys, I recently acquired a Philips D8734 in very good conditions that went for not a high price because it was sold as untested. It actually turns on, radio works and the sound is nice when loudness is engaged but unfortunately going further with testing I found a lot of problems. I almost immediately noticed that when the mono-stereo-spatial knob is used, if you want to listen in the stereo position the right channel is very low volume (in the other positions the level is Ok-ish), tried deoxidizing the pot but nothing changed. I then selected aux source position and a loud hiss is coming out off the speakers (I even tried with headphones but it's the same), incredibly the same happens even when moving to phono (only the hiss is a different frequency), already tried deoxidizing the source selector switch but to no avail. Another problem is with the deck B, in which the play-rec head was floating around since both plastic posts where it's secured with screws are broken (this will be a nightmare repair because the broken pieces are very small and there seem to be plastic fragments missing or impossible to glue back because you cannot even try to figure out how to handle them); obviously both cassette decks suffer from the usual "cheese gears" plague that affects Philips (but even Grundig or others) decks of that era but it's possible to buy very well made replacements from eBay, even if they are not cheap.
I really hope that some of you can help me trying to figure out the strange problem with phono and aux input, never seen something similar before, even the pot that changes the sound stepless from mono to spatial spereo (Philips name for wide stereo) is driving me crazy actually...
Many thanks in advance.

 

[hopey]

It's a process of elimination, all the pots and switches should be fully disassembled and reconditioned. Sometimes it better to start with a box that doesn't have these problems to start with.

 

[HaWe]

Hallo, bin neu in diesem Forum, eine meiner D8734 hat auch das Problem beim Umschalten. Hatte jedoch noch keine Zeit das Problem zu ergründen. Wie hoffe bereits erwähnt hat habe ich auch vor alle Regler und Schalter mit Kontaktreiniger zu reinigen, die Platinen möchte ich ebenfalls reinigen, hoffe, dass das Problem dann beseitigt ist. Kann ich ein Bild vom Kopf von Deck B haben ? Würde mich interessieren. Grüße

 

[Arbusto67]

Well guys, I did it! After a lot of thinking I was convinced to remove the source switch from the amplifier board, took it apart, clean it the best I could and then solder it back, so I started figuring out which solders I had to remove and I noticed what looked like a hair on the board, didn't notice it before, took my magnifiyng glass and it came out that it was a very fine but long crack! It was near the source switch and 9 or 10 copper tracks were broken, I repaired them with a tiny bit of solder and now the Philips is working as it should. I was about to give up after all this time...
Thank you very much for your support and to the next audio adventure!

 

[HaWe]

Thanks a lot for this information, do you have pictures of this ? Best regards

 

[Arbusto67]

Hi HaWe, unfortunately I didn"t take any picture but the crack was very subtle and I noticed it because I decided to inspect very carefully the area around the solders of the source switch (my idea was to remove it from the amplifier board) and I eventually saw the hairy crack.
Does your D8734 experience a very similar problem as mine?

 

[HaWe]

Hello, yes I have the same problem with one of my D8734, but at the Moment no time to repair this, because of other open things/projects. I inform you as soon as I found the problem @ my D8734. Thanks for sharing your outcome. BR