ZLX12P , Electro Voice monitor speaker schematic please

[zen]

Hi all

This is my next repair project .

There are a string of resistors connected in parallel that are visibly burnt . ( see picture )

I suspect they are all 1R in value , but would like conformation before proceeding .

[lotas]

Re: ZLX12P , Electro Voice monitor speaker schematic please

Yes, all resistors are 1 ohm

[zen]

Re: ZLX12P , Electro Voice monitor speaker schematic please

Thanks very much Lotas

[zen]

Re: ZLX12P , Electro Voice monitor speaker schematic please

Customer finally gave me the go ahead .

Replaced all the 1R resistors mentioned

Q1, ST Electronics 20N95K5 , S/C

Also replaced control chip , Texas Instrument 3845B , with one i hope is the ST Electronics equivalent UC3845BD1.

[zen]

Re: ZLX12P , Electro Voice monitor speaker schematic please

R26 ( 01A ) O/C

Replace with a 100R .

Can anyone confirm this is correct ? , as schematic showing as 150R , but assume that's a slightly different revision of the board .

[lotas]

Re: ZLX12P , Electro Voice monitor speaker schematic please

R26-101- 100 Om

[zen]

Re: ZLX12P , Electro Voice monitor speaker schematic please

Hi Lotas , thanks

The 101 is the one i used to replace the original 01A .

[lotas]

Re: ZLX12P , Electro Voice monitor speaker schematic please

01A - 101 = 100 Om, and about which one you wrote that it was at 150 Om.

[zen]

Re: ZLX12P , Electro Voice monitor speaker schematic please

Ok , thanks .

Now working & on test .

[zen]

Re: ZLX12P , Electro Voice monitor speaker schematic please

Also removed cheap glue on board indiscriminately used over the electronics ,plus replaced the 2 yellow looking thermal pads on same heat sink as FET replaced , as they seemed to have started to break down , which potentially may have been the root cause of failure .

[Ali.kh]

Re: ZLX12P , Electro Voice monitor speaker schematic please

hi , please post a photo of the input board ic3,4,5,6,7, unfortunately, the input signal has a problem, the op amps are burnt, if possible, send a pdf of the schematic of the input board, thank you