BSS DPR402 ledmeter trouble
« on: December 19, 2008, 07:49:00 PM »
My compressor has a problem with its led meter: the two or three first leds of the in/out level stay lit up all the time (on both channels) even with a perfectly quiet output. The audio works flawlessly. As I haven't seen any adjustment inside that could be for some ledmeter aligment, I guess I must have a bad cap somewhere (this dpr402 has seen hell, beaches, sand, mud etc before I bought it) and DC going somewhere it should'nt be.
The guy that does maintenance at the place I got it from (rental company) said it is a very common thing with those machines. Of course he won't help much further...

does someone here have a bss dpr402 service manual or an opinion on the matter at hand?

Please explain.


Re: BSS DPR402 ledmeter trouble
« Reply #1 on: December 20, 2008, 04:58:09 AM »
Inspect the PCB tracks very carefully - you will probably find that there is a disconnected copper track between the LED's and the drive IC (probably an LM339).
In meters of this type the LED's are normally connected in series and fed with a constant current - so normally all of them would be on. The IC simply shorts the LED's to turn them off - clearly this is not happening.
The LED's are obviously working OK - and the LM339's (or similar IC) are very reliable and seldom known to fail. In many designs the copper PCB track is VERY thin and can break easily where it joins the pad where the component is soldered.


Re: BSS DPR402 ledmeter trouble
« Reply #2 on: December 21, 2008, 07:50:35 PM »
Thank you for your answer AudioJohn,
I've checked and rechecked the copper tracks, nothing to do about the problem.

I guess I should say a little more about it. It' s an intermittent problem. The kind that drives you (me) mad.
Yesterday, (and actually now I can remember that exact same scene happening at least twice in the past two years), I plugged my dpr-402, and the problem was here: the two first diodes on the output level ledmeter (-40 and -30 or somehting like that) were lit up, the third one was sort of flickering. I then unplug and open the box, watch the board with a dumb look on my face for 2 hours, verify traces and connections, etc.
I then power up the unit.
...No problem. I let it sit and warm up for an hour. NOTHING. This unit begins to get on my nerves...

The only weird thing now is that the leds all light up for a split second when I power up the unit, and the 2 or 3 first leds stay on just a little longer than the other ones. The last diode (-3dB compression) for the GR meter lights up too for 2 or 3 seconds.

I'd like to get rid of this problem as I know very well it's gonna come back just as soon as the unit is racked back in my studio...

If anyone has a technical doc, it will be very very welcome, as of course it seems very hard to find on the internet... my email adress is just there on the left<<<<

<trying to stay calm and not hurt the FX)°DD}DX%% compressor>

Please explain.


Re: BSS DPR402 ledmeter trouble
« Reply #3 on: January 18, 2009, 07:47:14 PM »
I'm still looking for schematics, even just the meter board would be fine.
Please explain.


Re: BSS DPR402 ledmeter trouble
« Reply #4 on: January 21, 2009, 08:02:15 AM »

got quite a similar problem , but with me the compressor , won´t work .
it passes audio , shows compression , ( but with the similar problem described,but mine is dependent on the ratioknob, in off-mode no led´s are lit, but just a slight raise clockwise shows compression up to it´s maximum), but no compression on the output.

in deessing mode , pressing the MODE S.C. switch, one can hear the deesing effect , which shouldn´t be , cause this knob is to PFL  other equipment connected to dpr through the rear-barrier-strip´s sidechains. which now are factory set to standalone-usage.

so i´m also looking for the schematics.

doubleroger :the manuals and other downloads can be found on the bss- site. but won´t help in this case.
                  are both channels affected , or as with me , only one ? (at least i got a comparison possibility)
                  have you tried to contact bss support , or a distributor , for the schematic ? (don´t know how bss handles this , but i´m afraid as long as this   
                  product isn´t discontinued (which should be soon anyway  from what i heard,) they may not give away the docs,(as even then) but will want you       to send it to a
                  local service-partner . cash !! .

nice regards


Re: BSS DPR402 ledmeter trouble
« Reply #5 on: February 26, 2009, 09:45:09 AM »
just talked to tech at a bss-distributor.

he gave me the "hot" hint to check the ratio/attack 12pole pots.
they tend to give up their life very easily if pushed hard,etc.

have you checked them ?


Re: BSS DPR402 ledmeter trouble
« Reply #6 on: February 26, 2009, 11:48:27 AM »
Hi Nashkato,
really sorry, I didn't see your post from january...
I have this problem on both channels. Audio works perfectly, just some sort of offset in the led circuit I guess.
The compressor has been working ok for a month or so, then showed trouble again for a day last week, and is now back to normal...
I've kinda given up on it, to be honest... I will someday change the electrolytics on the vu board, as a shot in the dark, but that will be it.
Thanks for the tip on the attack/release pots, mine show no sign of wear (when i use them, at least).

Hope you find your answer there...
Please explain.


Re: BSS DPR402 ledmeter trouble New
« Reply #7 on: February 26, 2009, 04:14:19 PM »
hi doubleroger,
just checked those pots , and it was one of them.
what a fragile kind of thing.
me,too , i couldn´t have told that it was them. they seemed to work fine. but they´re kind of screwed quite tricky, only after removing the frontpanel,and screwing out those pots , it could be seen and checked properly.

all the best
« Last Edit: February 26, 2009, 04:27:30 PM by nashkato »


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