Genelec 1031 Driver cards need repair/help

Hello everybody ,

a friend ask me help for check a non working Genelec 1031 monitor ,
after some test (as indicated in the service manual)
seem that the problem is on woofer driver card, fitted with smd components ,

any help about how to proceed for right test and repair the card is welcome ,
thanks in advance.
S.

Please post the picture of the card. Maybe I have some spares.
Without the schematic of the driver card (As I know, Genelec never published it in service manuals) your chance to fix it is very slim. You can only test driver transistors.
Did you check for cold joints on the card's connector?

moamps said:

Please post the picture of the card. Maybe I have some spares.
Without the schematic of the driver card (As I know, Genelec never published it in service manuals) your chance to fix it is very slim. You can only test driver transistors.
Did you check for cold joints on the card's connector?

Click to expand...

Hi , thanks so much for post ,

molex connectors - reworked .
driver card pins connection - reworked.

speaker same as before  :-[ :'(

attached an image about
any help really welcome

I.M.H.O.

the very baddest way to connect input for an active "professional" speaker ,
(cosidered all the types available at same or less cost !)

also very near to main power input cables  :-[

tweeter and woofer drivers cards overview

moamps said:

Please post the picture of the card. Maybe I have some spares.
Without the schematic of the driver card (As I know, Genelec never published it in service manuals) your chance to fix it is very slim. You can only test driver transistors.
Did you check for cold joints on the card's connector?

Click to expand...

do you mean the 2 transistors fitted in the back of driver card,
as in the attached image ?

how can i test them ?

main pcb overview

SIXTYNINER said:

I.M.H.O.

the very baddest way to connect input for an active "professional" speaker ,
(considered all the types available at same or less cost !)

Click to expand...

Given the mechanical constraints, I think they had little choice. Why is this little ribbon-cable assembly worse than discrete wires soldered to the board? I like that board-mount connector as it has a solid hold on the wires once connected.

also very near to main power input cables  :-[

Click to expand...

There's no crosstalk or other influence of the power wires on the line-level input, so as long as the wire dress is neat and doesn't violate what the TÜV and CE safety people demand for separation, what's the big deal?

And yes, I've had a pair of Genelec 1031As for 20 years.

-a

Thanks for post ,
unfortunately no helps inside .

Andy Peters said:

SIXTYNINER said:

I.M.H.O.

the very baddest way to connect input for an active "professional" speaker ,
(considered all the types available at same or less cost !)

Click to expand...

Given the mechanical constraints, I think they had little choice. Why is this little ribbon-cable assembly worse than discrete wires soldered to the board? I like that board-mount connector as it has a solid hold on the wires once connected.

also very near to main power input cables  :-[

Click to expand...

There's no crosstalk or other influence of the power wires on the line-level input, so as long as the wire dress is neat and doesn't violate what the TÜV and CE safety people demand for separation, what's the big deal?

And yes, I've had a pair of Genelec 1031As for 20 years.

-a

Click to expand...

So the Tweeter worked but the Woofer did not?  Are the fuses inside good?    These units also have a mute transistor to keep the amps from popping when turned on or off. 

I have had a pair of 1031's since 1995 and in that time the things that have happened is the ribbon cable has gotten intermittent on the input compression header.  The one you don't like.  I had to repair that a couple of times.    And The muting transistors will go bad and short out the signal to the amps so no  signal gets through.  In this case the amps fuses are good and power comes on but know audio from speakers. 

  I'm not saying your driver card is not bad but I am suggesting you look at the muting transisors to see if they are shorting out and need replaced.  Much simpler problem.

SIXTYNINER said:

moamps said:

Please post the picture of the card. Maybe I have some spares.

Click to expand...

speaker same as before  :-[ :'(

Click to expand...

Unfortunately, my cards doesn't look as yours. IIRC there was few version of boards used in 1031 and higher.
You can check driver transistors as diodes using DMM.
Also,  you can swap cards from twiter's amp and check if the bass amp works with twitter card to be sure that bass driver card is faulty. Did yo check output transistors?

hi,
some delay...... because so busy period.....
but finally back to the issue ......

as in the attached image ,
desoldered driver card and transistors "bar" too
now want to try to replace them with new ,
only need some help abpout the 2 "IC"...
that i do not know much about ,
and please any help about is so welcome,

as showed  in the image  on the transistors "front" there are the codes :

left IC code :  C4793    ,and as you can see on image also  : °7G , in the low corner (is this part of the code ? )
digikey have 2 type : 2W  , and 20W  , they can be a right replacement ?
https://www.digikey.com/product-search/en?keywords=C4793

right IC  code :  A1837  ,and as you can see on image also  : °7I , in the low corner (is this part of the code ? )
same here:
https://www.digikey.com/product-search/en/discrete-semiconductor-products/transistors-bipolar-bjt-single/1376376?k=A1837

thanks in advance for any help about !

ps
the tweetter drive card transistors do not have part code on the surface ,
....deleted with sandpaper.....

moamps said:

speaker same as before  :-[ :'(


Unfortunately, my cards doesn't look as yours. IIRC there was few version of boards used in 1031 and higher.
You can check driver transistors as diodes using DMM.
Also,  you can swap cards from twiter's amp and check if the bass amp works with twitter card to be sure that bass driver card is faulty. Did yo check output transistors?

Click to expand...

...another "shot"...

These are Toshiba driver transistors 2sa1837 and 2sc4793, first results from digikey  in your links are exact replacements.

Hey "moamps"
and thanks so much for post,

about the transistors  the new replacement it is not 100% like the  "original"
about  the - 1837
vce saturation
new - 1V , old 1,5V
max power
new - 2W , old 20W

are you shure that the replacement it is right ?
thanks in advance for any help about !

moamps said:

These are Toshiba driver transistors 2sa1837 and 2sc4793, first results from digikey  in your links are exact replacements.

Click to expand...

Hey guys,

I guess you got this already, but to be safe, here's the service manual for those:
http://www.mordpol.com/service_manual_1031.pdf

Best regards,
Mathias


EDIT: Just saw the driver PCBs missing there too, sry!

> max power new - 2W , old 20W

2W naked. 20W on a heatsink.

Get the FULL data-sheet, not a hasty sale-summary.

thanks "PRR" !!!
and
just to keep in life the thread , also  for who have same or similar issue and need/look help about,

replaced the 2 "Ic" (with same type) in the woofer driver card

but the woofer still do not work , no sound

any help about is welcome
thanks

Have you looked over here, for ideas?

https://groupdiy.com/index.php?topic=67169.0

Khron said:

Have you looked over here, for ideas?

https://groupdiy.com/index.php?topic=67169.0

Click to expand...

thanks for the link !!
i check about , not same issue , but as said any help is so welcome !