DD Z2

[ultra]

This amp it totally blown.

In the power supply it uses A1275 and C3228 as totem poles to drive the fets.

Would BD139/140 work reliably ?

 

[Perry Babin]

I've never used them in that amp but they've worked for me in every other amp that used those drivers in the power supply.

 

[ultra]

I do carry some A1023 and C1027 as well.

I really dont know which pair to choose, but i think i am going to try 139/140 as

they can dissipate a bit more power.

 

[S Merlington]

Ive rebuilt One of theese amps from the ground up..

I used the BD139's and 140's in the one i rebuilt and it is still up and running 6 months later

 

[ultra]

Ive rebuilt One of theese amps from the ground up..

I used the BD139's and 140's in the one i rebuilt and it is still up and running 6 months later

Did you replace the 3S module, or you repaired the existing one?

Also, i dont know how much to ask for the repair, if you dont want to say on public how much you charged, please pm me.

Thanks

 

[Perry Babin]

Charge more than you think you should charge. Sometimes these amps have intermittent problems that cause them to repeatedly blow outputs and driver board components.

Generally, the only problems on the driver boards are the driver ICs which can easily be replaced, many times while the board is in the amp.

 

[S Merlington]

I rebuilt the Audio driverboard I replaced the Driver IC's ( IR21844's)

Also replaced the Ic's on the board and the surface mount transistors 1A 2A 1D and 2 D There is also a muting Transistor on that driverboard in Q10's spot


Check all the chokes on the main board..

Also the D1302's (muting transistors) may need to be replaced.

For the Z2 i rebuilt i charged $300.00 since its a large amp and alot can go wrong like Perry said..

If you rebuild the Audio driverboard be careful the pads under the driver IC's can damage easy

 

[ultra]

Thanks for the info, all these are in the tutorial.

I think of charging more, seems a lot of work to be done in this amp.

 

[Perry Babin]

Using ChipQuik allows you to use reduced temperatures when desoldering and virtually eliminates the chances of damaging the board.

 

[ultra]

I am using a similar product.

The 3S module is out of the board intact, with all ics removed.

Waiting for the parts to arrive any day now.

 

[ultra]

Finally i got all the parts.
Power supply seems to work OK
Installed a brand new 3S module (my client had already bought one)
and without the output fets on, when i power the amp, the relays click on and after a second, off.
During this time, i measured around 126VDC on the output. I guess thats not normal...

 

[Perry Babin]

Did you confirm that all rail and regulated voltages were present on the driver board pins after installing it?

 

[ultra]

Yes i did. I think there was some solder short between two fwt pins.
I am also going to replace the coresponding ic in the 3S module, just to be sure now.

 

[ultra]

Ok, amp powers up ok, the relays engage, and there is no DC on the output terminals.
I am going to put on the fets now.

 

[ultra]

Unfortunately, it blew two fets from the same bank.
Removed the 3S module replaced fet driver ics, as well as U3 U4 and i checked again for all auxiliary regulated voltages.
Replaced the entire fet bank of 3, and...the same thing happened.
What am i doing wrong?

 

[S Merlington]

Are the gate resistors within tolorance ?

 

[ultra]

Yes they are. In fact i lifted one end of them to be absolutely sure.

 

[S Merlington]

Are you touching any of the outputs or any components on the driverboad with the amp powerd up ?

 

[ultra]

i only touch 12v and rem in order to turn on the amp.

 

[S Merlington]

Remove the audio driverboard so you dont blow the new outputs..

Do you see any pulse of DC on the output filter inductors ?