PL 400 II display problem

[AntMast]

[SIZE=+1]PL 400 II has a problem with both displays. [/SIZE][SIZE=+1][SIZE=+1]When I first powered up the amp the rite channel led's were not moving at all with a signal. Replacing the rc4558 got them moving again.[/SIZE] Now powering up(with no signal to inputs) the led's go to the left side as they should, then a second later both displays jump roughly[/SIZE][SIZE=+1][SIZE=+1] to the[/SIZE] -30db mark & stay there. Playing music they respond normally--except they never drop below the -30db mark. Last year [/SIZE][SIZE=+1][SIZE=+1]both[/SIZE] boards were recapped. Do both displays have a bad UAA170's??[/SIZE]

 

[laatsch55]

Have you adjusted them according to the service manual?

 

[AntMast]

Have you adjusted them according to the service manual?

Adjusting the pots has no effect.

 

[laatsch55]

Then the only thing you haven't replaced is the UAA's correct?

 

[AntMast]

Then the only thing you haven't replaced is the UAA's correct?

Yes..that's true. I did a in circuit check of the diodes..they checked OK. Looking for a source for the UAA170 & came across this link:
http://www.ebay.com/itm/Siemens-UAA...hash=item20d69fa06d:m:mD-ill6UBtEYFjwR15hahFw

 

[laatsch55]

Not bad....they look genuine, and they are not coming from Hong Kong.....

 

[AntMast]

Not bad....they look genuine, and they are not coming from Hong Kong.....

Yeah...I'd be leery of the Chinese listings!

 

[laatsch55]

I have been using some Chinese knockoffs of the 1237U that are needed in Don's DC protect boards, so far , so good.....

 

[grapplesaw]

I have been using some Chinese knockoffs of the 1237U that are needed in Don's DC protect boards, so far , so good.....

Have agree with you Lee. 90% of all electronics are coming from China. They reverse engineer it and they work or don't , not much in between. This chip is not rocket silence any way.

 

[laatsch55]

Yeah, rocket silence is a bitch.....so is typing on your phone.......

 

[AntMast]

I have been using some Chinese knockoffs of the 1237U that are needed in Don's DC protect boards, so far , so good.....

I bought & installed a couple of his protection boards. Actually emailed him earlier today, asking if he might have some UAA170 & LF351 for sale...no response yet.

 

[laatsch55]

He travels the country building uninterruptible power supplies so it may be a few days...

 

[AntMast]

He travels the country building uninterruptible power supplies so it may be a few days...

Good to know. Thanks

 

[laatsch55]

Welcome...

 

[grapplesaw]

Yeah, rocket silence is a bitch.....so is typing on your phone.......

I may correct that, then again manic not

 

[laatsch55]

Don't, you'd make me look petty....

 

[laatsch55]

Rocket Silence could be an instant classic....

 

[grapplesaw]

Rocket Silence could be an instant classic....