Help needed with FM sound in Sony HB-F1XDJ

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By nanochess

Master (218)

nanochess's picture

01-10-2012, 18:45

Hi everybody.

Some months ago I bought a Sony HB-F1XDJ, but two days ago finally I've tested a game with FM sound, namely Sonyc.

The problem is that sounds like a dead duck (whir-pop-pop-whir-pop-pop), I've opened the case and checked that if I put my finger near/over C100 (a small cap), the sounds "revives" and it's great Smile but fails again after some seconds Sad. The PSG sounds works fine though.

I've dismounted the mainboard and resoldered the whole zone, but without results. Any suggestion?

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By nanochess

Master (218)

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03-10-2012, 03:07

Ok. I've downloaded the UPC4558 datasheet (double op-amp) and checked the voltages.

The 12V- read as -11.89V, looking fine.

The 12V+ read as 12.64V+ so I changed the regulator (78L12) and I got a nice 12.01V+.

Now the sound almost gets it right but still goes to the dead duck zone after some time. Fortunately my magical finger still works Tongue.

So now I'm doing a schematic of the zone.

By nanochess

Master (218)

nanochess's picture

03-10-2012, 19:04

After doing the schematic and checking the value of each resistor/capacitor (everything good), I got tired and showed the schematic to an electronics specialist, he gave a look and soldered a 47K resistor over R6 (22K) and the sound came out nicely! I'm still in awe! oO He said something about a bad amplifier design.

Anyway now can I return to my secret project with FM music Cool

By Manuel

Ascended (15441)

Manuel's picture

03-10-2012, 20:40

Thanks for keeping us updated!

By nanochess

Master (218)

nanochess's picture

19-10-2012, 00:17

The trick of the 47K resistor over R6 failed after half hour of power-on. Sad

So following my schematic I resorted to change C16 and C99 (1 µf polarized capacitors) one used for "connecting" the two amplifiers and the other for grounding, after measuring removed capacitors I discovered one had a leak (I couldn't detect it while it was in the PCB!), but I don't know if it was C16 or C99.

I was able to remove the 47K resistor. So next time you have a "dead duck sound" in your internal FM, just change C16 and C99. I used 63V capacitors as I didn't find the small 50V capacitors.

Now my MSX2+ works like new and so far eight hours playing the title screen melody of Sonyc without trouble Cool.

By nanochess

Master (218)

nanochess's picture

19-10-2012, 00:18

By the way I even bought an JRC4558 for replacing the UPC4558 double amplifier just in case. But I don't used it. Wink

By daniel683104

Paragon (1202)

daniel683104's picture

29-10-2014, 22:32

here is the picture of the capacitors positions on the motherboard

By Louthrax

Prophet (2051)

Louthrax's picture

12-03-2015, 19:35

I have the exact same "duck-sound" with my newly-bought HB-F1XDJ, so that looks like a common problem. The funny thing is that I bought this one to replace my Sony HB-F700F that needs "recap" too.
Anyway, thanks a lot to Nanochess and Daniel for sharing these informations and pictures Smile My HB-F1XDJ is just a few soldering points away from sounding perfect again !

By Louthrax

Prophet (2051)

Louthrax's picture

27-03-2015, 12:00

Worked perfectly, thanks again guys :-) That was a good little training before the full-recap of my HB-F700F !

By sd_snatcher

Prophet (3014)

sd_snatcher's picture

18-07-2015, 21:31

The culprit is the C99 capacitor. This article says that it's very common for it to fail on HB-F1XDJs. It can be replaced with a newer 1uF ceramic capacitor if you don't want to have this problem anymore.

By Louthrax

Prophet (2051)

Louthrax's picture

18-05-2016, 03:43

I had some sound problems again one year after I changed the C99 and C16 capacitors (not as bad as before though).

So I decided to replace all capacitors in the same area (delimited by a white rectangle on the PCB), even the ones I already replaced before. That fixed the sound again. I then decided to check all capacitors I unsoldered with my (basic) multimeter... and they all seem OK. That's strange? Anyway, Aleste sounds great again Smile

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