Memphis 16-mc1000d

mike49504 · 6th July 2010, 02:53 AM

I have this amp in for repair I opened it up and noticed the power supply is blown.

There are 8 power supply fets in this amp 4 of them are IRF3205"s

The other 4 have markings ive never seen.

500 12L4
1R 837D
59 40

Are theese 3205's as well or is there a part number for theese??

Perry Babin · 6th July 2010, 04:01 AM

It should have 8 3205s.

mike49504 · 7th July 2010, 04:37 AM

Ok i have yet another one of theese amps so now i have 4 total.

The next one has 13 volts DC on the outputs . All outputs test fine so i took out the driver boards and the board behind the rca jacks still measures that i have 13 volts on outputs.

Maybe a leaking output ?

Perry Babin · 7th July 2010, 04:59 AM

Do you read 0v on the secondary center tap and the RCA shields?

mike49504 · 7th July 2010, 05:05 AM

Yes 0 volts on rca shields and 0 volts on secondary center tap

Perry Babin · 7th July 2010, 05:29 AM

A leaking output is a likely suspect. If the voltage is positive, it's likely one of the 9640s.

mike49504 · 7th July 2010, 11:00 PM

I fixed the Dc on the outputs. Amp powers up and relay kicks on but no output.

I checked and its producing + - 63 volts on the outputs (rail voltage)

I have 15 volts on pin 4 of 2 op amps but not on pin 8

Other op-amp has no voltage + or - 15 volts

The op-amps i tested are the TLO72's

I swapped the board behind the rca jacks with another one .

Still same thing.

Wondering what controls the 15 volts on pin 8 of the op-amps and why doesnt one of the 3 op-amps have voltage on pin 4 or 8?

Perry Babin · 7th July 2010, 11:19 PM

The 15v regulator next to the 3205s produces the 15v. Confirm that it has supply voltage on pin 1, 0v on pin 2 and 15v on pin 3.

Which op-amp has no DC voltage on it?

mike49504 · 7th July 2010, 11:49 PM

Regulator
pin1: -1
Pin2:0
pin3:-.6

Q143 has no voltage on it

Perry Babin · 7th July 2010, 11:59 PM

There is a green inductor in front of the 7815 regulator. Do you have 15-20 volts on one end of the inductor?

6th July 2010, 02:53 AM	#1
mike49504 diyAudio Member Join Date: Sep 2006	Memphis 16-mc1000d I have this amp in for repair I opened it up and noticed the power supply is blown. There are 8 power supply fets in this amp 4 of them are IRF3205"s The other 4 have markings ive never seen. 500 12L4 1R 837D 59 40 Are theese 3205's as well or is there a part number for theese??

6th July 2010, 04:01 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	It should have 8 3205s. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

7th July 2010, 04:59 AM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Do you read 0v on the secondary center tap and the RCA shields? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

7th July 2010, 05:29 AM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	A leaking output is a likely suspect. If the voltage is positive, it's likely one of the 9640s. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

7th July 2010, 11:19 PM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	The 15v regulator next to the 3205s produces the 15v. Confirm that it has supply voltage on pin 1, 0v on pin 2 and 15v on pin 3. Which op-amp has no DC voltage on it? __________________ 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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7th July 2010, 04:37 AM	#3
mike49504 diyAudio Member Join Date: Sep 2006	Ok i have yet another one of theese amps so now i have 4 total. The next one has 13 volts DC on the outputs . All outputs test fine so i took out the driver boards and the board behind the rca jacks still measures that i have 13 volts on outputs. Maybe a leaking output ?

7th July 2010, 05:05 AM	#5
mike49504 diyAudio Member Join Date: Sep 2006	Yes 0 volts on rca shields and 0 volts on secondary center tap

7th July 2010, 11:00 PM	#7
mike49504 diyAudio Member Join Date: Sep 2006	I fixed the Dc on the outputs. Amp powers up and relay kicks on but no output. I checked and its producing + - 63 volts on the outputs (rail voltage) I have 15 volts on pin 4 of 2 op amps but not on pin 8 Other op-amp has no voltage + or - 15 volts The op-amps i tested are the TLO72's I swapped the board behind the rca jacks with another one . Still same thing. Wondering what controls the 15 volts on pin 8 of the op-amps and why doesnt one of the 3 op-amps have voltage on pin 4 or 8?

7th July 2010, 11:49 PM	#9
mike49504 diyAudio Member Join Date: Sep 2006	Regulator pin1: -1 Pin2:0 pin3:-.6 Q143 has no voltage on it

7th July 2010, 11:59 PM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	There is a green inductor in front of the 7815 regulator. Do you have 15-20 volts on one end of the inductor? __________________ 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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