Boltar gen X op-amp.

marko · 7th August 2010, 10:12 AM

Hi all, just fitted new rail caps in my Boltar project, they had literally failed through vibration! anyway i replaced them and on rebuild i noticed some issues with the pre-amp module, op amp 2068d for r/l in had disintigrated

it also took out a small cap which i have already replaced.

rest of amp seams ok and drawing 1.5amp on idle

any ideas where i may find a suitable replacement? ebay brings nothing up on the 2068d

Mark.

Perry Babin · 7th August 2010, 05:55 PM

It's an NJM2068D.

marko · 06:04 PM

any idea why it would fail?

would this be ok?

LINK

Perry Babin · 8th August 2010, 12:50 AM

It's virtually impossible to determine why it failed.

It appears to be the correct part but I've never seen one with a DD suffix.

marko · 17th August 2010, 04:03 PM

so i replaced the opamp, connected up and the small cap in the preamp module i replaced started to smoke immediately and went bang in a big way! no idea why this small cap would fail again? can inserting the POS card wrong do this?

mike49504 · 17th August 2010, 05:10 PM

Removed the bad cap first off.

have everything clamped tightly and everything soldered in place besides the cap that blew.

Power up the amp and set meter to volts and check the voltage across the pads for the cap.

what is the voltage across the pads??

what voltage rating does the cap have?

marko · 17th August 2010, 05:14 PM

Quote:

Originally Posted by mike49504

Removed the bad cap first off.

have everything clamped tightly and everything soldered in place besides the cap that blew.

Power up the amp and set meter to volts and check the voltage across the pads for the cap.

what is the voltage across the pads??

what voltage rating does the cap have?

good call, i'll go and do that and report back

think the cap is a 20v 47uf..

marko · 06:02 PM

i think i know why it went pop (again), it had 48v in there, i swapped the POS card around and 10ish volts appeared. there are 4 ways in which the POS card can fit and only 2 are the correct way!

EDIT- replaced the cap, no explosions but the amp is only pulling 0.14v on idle and has no output. think the amp is struggling to turn on

marko · 17th August 2010, 06:02 PM

Quote:

Originally Posted by marko

good call, i'll go and do that and report back

think the cap is a 25v 47uf..

Perry Babin · 17th August 2010, 09:36 PM

0.14v where?

POS card?

Can you post a few photos of the inside of the amp?

7th August 2010, 10:12 AM	#1
marko diyAudio Member Join Date: May 2004 Location: donnyuk	Boltar gen X op-amp. Hi all, just fitted new rail caps in my Boltar project, they had literally failed through vibration! anyway i replaced them and on rebuild i noticed some issues with the pre-amp module, op amp 2068d for r/l in had disintigrated it also took out a small cap which i have already replaced. rest of amp seams ok and drawing 1.5amp on idle any ideas where i may find a suitable replacement? ebay brings nothing up on the 2068d Mark.

7th August 2010, 05:55 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It's an NJM2068D. __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

7th August 2010, 06:00 PM	#3
marko diyAudio Member Join Date: May 2004 Location: donnyuk	any idea why it would fail? would this be ok? LINK Last edited by marko; 7th August 2010 at 06:04 PM.

8th August 2010, 12:50 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It's virtually impossible to determine why it failed. It appears to be the correct part but I've never seen one with a DD suffix. __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

17th August 2010, 05:33 PM	#8
marko diyAudio Member Join Date: May 2004 Location: donnyuk	i think i know why it went pop (again), it had 48v in there, i swapped the POS card around and 10ish volts appeared. there are 4 ways in which the POS card can fit and only 2 are the correct way! EDIT- replaced the cap, no explosions but the amp is only pulling 0.14v on idle and has no output. think the amp is struggling to turn on Last edited by marko; 17th August 2010 at 06:02 PM.


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17th August 2010, 04:03 PM	#5
marko diyAudio Member Join Date: May 2004 Location: donnyuk	so i replaced the opamp, connected up and the small cap in the preamp module i replaced started to smoke immediately and went bang in a big way! no idea why this small cap would fail again? can inserting the POS card wrong do this?

17th August 2010, 05:10 PM	#6
mike49504 diyAudio Member Join Date: Sep 2006	Removed the bad cap first off. have everything clamped tightly and everything soldered in place besides the cap that blew. Power up the amp and set meter to volts and check the voltage across the pads for the cap. what is the voltage across the pads?? what voltage rating does the cap have?

17th August 2010, 09:36 PM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	0.14v where? POS card? Can you post a few photos of the inside of the amp? __________________ Links >> Basic Car Audio Amp Repair * Basic Car Audio Electronics * New Site * Basic Switching Power Supply Design * Basic Computer Skills << Links

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