ads pq20

mike49504 · 3rd August 2007, 02:17 PM

im working on an older amp ads pq20 the amp does nothing i checked all diodes transistors and resistors in the power supply all check fine so im thinking it might be the op amp mn3102 wondering if anyone knows a good cross for that part number a more common used one and what else i might check out if thats not the cause of the problem thanks in advance

Perry Babin · 3rd August 2007, 08:06 PM

Generally if the amp does nothing, the best place to begin troubleshooting is the power supply driver IC. Post a list of the voltages on the pins of the IC.

1moreamp · 5th August 2007, 09:42 PM

The mn3102 is a integral pert of this very old school transistor power supply design. The chip was also used in very early kenwood amps, by early I mean the one ones with yellow and black cables coming out of the endplates and thats before the 820 & 920 & 1020 models numbers back in the late 80's < very old >

The part might be available from Kenwood still but I would doubt it, and ADS is now owned by Directed so not much hope there either. The ADS PH-15 has the same part in it also.

The mn3102 is a odd IC and was only used on these two brands of amps that I can remember < its been a long time>.

I see you posted that the board was baked badly

Shame the amp was not better cared for. Perhaps someone can help you with the schematic with that you can at least see what the mn3102 does for this supply, as it is a most important part and the supply will not function with out it.

Good luck

69CamaroSS396 · 8th August 2007, 01:11 AM

Is this the same chip?

http://www.visualsound.net/bbd.htm

http://parts.digikey.com/1/parts/606...os-mn3102.html

3rd August 2007, 02:17 PM	#1
mike49504 diyAudio Member Join Date: Sep 2006	ads pq20 im working on an older amp ads pq20 the amp does nothing i checked all diodes transistors and resistors in the power supply all check fine so im thinking it might be the op amp mn3102 wondering if anyone knows a good cross for that part number a more common used one and what else i might check out if thats not the cause of the problem thanks in advance

3rd August 2007, 08:06 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Generally if the amp does nothing, the best place to begin troubleshooting is the power supply driver IC. Post a list of the voltages on the pins of the IC. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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5th August 2007, 09:42 PM	#3
1moreamp diyAudio Member Join Date: Dec 2005 Location: Northern California	The mn3102 is a integral pert of this very old school transistor power supply design. The chip was also used in very early kenwood amps, by early I mean the one ones with yellow and black cables coming out of the endplates and thats before the 820 & 920 & 1020 models numbers back in the late 80's < very old > The part might be available from Kenwood still but I would doubt it, and ADS is now owned by Directed so not much hope there either. The ADS PH-15 has the same part in it also. The mn3102 is a odd IC and was only used on these two brands of amps that I can remember < its been a long time>. I see you posted that the board was baked badly Shame the amp was not better cared for. Perhaps someone can help you with the schematic with that you can at least see what the mn3102 does for this supply, as it is a most important part and the supply will not function with out it. Good luck

8th August 2007, 01:11 AM	#4
69CamaroSS396 diyAudio Member Join Date: Jan 2006 Location: Central Ohio	Is this the same chip? http://www.visualsound.net/bbd.htm http://parts.digikey.com/1/parts/606...os-mn3102.html

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