Rockford T2500 - 1BD

[Perry Babin]

I don't know what's happening if the FETs are good and you're testing precisely the same way with the capacitors and the FETs.

 

[Albis2985]

Well I will try with other fet instead what replacement do you recommend?

 

[Perry Babin]

I don't think other FETs are going to make a difference if you read an open circuit (probes with both red/black placements) between the gate and both other legs for all of the FETs.

 

[Albis2985]

Good morning Perry, returned with this amplifier, when I install the output mosfet the signal is square wave becomes a noise in the gate of the mosfet, at some point I pressed the card and moved it from side to side and I got oscillation I've verified track by track and connection by connection and I do not find that it makes the amplifier not oscillate, definitely something is missing from the BD card but I can not find that it can be in the diagram that I sent you if you look at it you can tell me where to check the signal arrives well until the resistance before lm5110 the bd mute voltage drops to 0 and when it worked in a moment I had 7v, another thing is that the yellow LED also flashes quickly, for me it is something broken on the board but I can not find that it can be, give me ideas to review please

 

[Perry Babin]

The oscillator is on the driver board. The only things that come from the main board are power supply voltages and the audio signal.

 

[Albis2985]

Perry do you think the problem is the BD card? the strange thing is that I had oscillation in a moment and now only toggleA and B arrive until the resistances, if I disconnect B of the diode d2017 I have a square wave both at the entrance and exit of the lm5110, the only thing that I have not changed on the BD card is the HC74

 

[Perry Babin]

Are either of the transistors marked 702 on the lower left of the class D driver board shorted?

 

[Albis2985]

If you mean q201 and q 200 that are mosfet, both remove them and probe them out of the circuit and try them well, I exchanged them but nothing else the same problem that confuses me is that without the mosfet I have oscillation and with the capacitors that you indicated to me that I will also have oscillation I thought it was false contact but nothing I have solved and measured continuity and everything seems to be correct I have reviewed the welding in the entire bd card and in the area of ​​transistor drivers and diodes transformers but nothing I still suspect that there is something that is not and that was at the moment I moved the card

 

[Perry Babin]

This thread has dragged on so long that I'm not sure what you have at this point.

Are you testing without rail voltage and with the jumper in place on the driver board?

 

[Albis2985]

If you want to open a new one with what I currently have and the tests I have already done, because I already tested without rail voltage and closing the feedback cycle and I have a square wave in the output transistors, I introduced the rail voltage again without the bridge of the feedback and I get a wave signal with the 0.01 microfarad capacitors as soon as I put the mosfet the square wave does not reach the mosfet and is only clean before the resistances that are before 5110 and the yellow LED is constantly blinking

 

[Perry Babin]

The previous tests indicate that all of the drive circuit is OK.

The amp is going into protect.

Do you read 0 ohms from either the drain or source of 1/2 of the output FETs to the positive speaker terminals?

What is the resistance across the speaker terminals with no load connected?

 

[Albis2985]

ok I had to leave a moment when I return home again I try what you indicate and comment on the results

 

[Albis2985]

Good evening Perry from the positive terminal to the drain of q2014 and q2011 0 ohm and from the source of q2015 and q2013 to the positive terminal 0 ohm.
The resistance across the unloaded load terminals is 3.4 megaohm