rockford fosgate t30001bd

[dips1982]

Hi,

My amp stopped working the other week. I diagnosed the fault which was with the PSU. I found 3 mosfets had gone (75344G) which i replaced with 75345G. But yet there still is a fault. I have checked resistors, diodes, mosfets, caps and transisters but cant finder anything else. does anyone have any ideas? Does anyone have a schematic diagram? would very much appreciate it. I miss me bass

thanks in advance

 

[Perry Babin]

Email me for the schematic diagram.

babin_perry@yahoo.com

 

[dips1982]

Many thanks!

 

[dips1982]

do you think the 75345G instead of the 75344G would be ok? or would it be best sticking to the original ones?

 

[brandes.cm]

Why switch, the 75344 is readily available?

 

[dips1982]

i couldnt find any in the UK. Ive replaced the FET's with the 75345G, everything looks ok but when i power it on it make a buzzing sound. Gate resistors are reading ok. The location numbers to the fets that were gone are Q7, Q6 and Q25. Does anyone have any ideas?
Many thanks

 

[Perry Babin]

What are the symptoms (precisely)?

 

[dips1982]

the blue power light comes on but there is a very loud buzzing sound. Havent left it on too long, just incase it does too much damage. Im getting 120V on +HV and getting 4V on -HV, should i be getting -120V?

 

[Perry Babin]

How much current is it drawing?

Are you getting more than about 1v across the speaker terminals?

 

[dips1982]

ive not had chance to check these yet, but will do over the weekend and post the readings. It makes a buzzing sound when not even connected to the output stage board. Its somewhere on the PSU. Ive ordered the original mofets from the US (ordered them from work so it wont be costing me anything lol). Theres no swollen caps. Before this went on me, occasionally when I switched the head unit on it would make the sub sound a very loud humming sound. It would sometimes do it then go back to normal, then it just completley packed up on me.

 

[dips1982]

Right, ive put the 75344G's in instead of the 75345G, and when i powered it on, it smoked on me . Anyone have any ideas what would cause this? The gate resistors are reading 10ohm.

 

[Perry Babin]

Before reinstalling new power supply FETs, you need to check the drive signal. The PNP transistors generally fail. This can cause the new FETs to fail. Before you do anything else, read the basic amp repair page (link in sig line below).

 

[dips1982]

Thanks Perry, i dont access to a scope at the moment. Could i get away with using PMBTA56 instead of the MMBTA56L? Or should i stick with the same type?
Cheers

 

[Perry Babin]

They're essentially the same transistor (as far as I know).

 

[dips1982]

Thanks perry, i changed the npn and pnp and all is good. Many thanks for your help.

 

[Kantinho]

hello sir,
could you sent me schematic diagram? i have my t30001bd burn 3 years ago and cant solve the problem only change mosfets burned. im from Portugal and here doesnt have a Rockford dealer now :s

Sorry my poor english.
Best Regards
Best Regards,

 

[Perry Babin]

Can't send it without your email address. Email me if you want it.

babin_perry@yahoo.com

You can also contact Rockford's US tech support to get the diagram.

If you need help with the repair, start a new thread.

 

[siavmex]

Hi, I have the same model of this amplifier, and I looking for the Schematic diagram, because my amp worked out, I need the information for reapiar it, please!!!
Thanks, many thanks!!!