help to set dc offset to threshold s450

[Zen Mod]

dunno , maybe Papa will chime in

however , I believe 10uF/16V is adequate

can you pull one out and measure capacitance , if you have any sort of C meter?

 

[alfalf1]

i pull up one and it is 4,5 uF measurate with my c meter.

i purchase always 10uF /16 volt ?

 

[Zen Mod]

yup

again - check all solder joints

 

[alfalf1]

hi Zen 30 minutes ago i went to the eletronic shop to purchase the tantallio cup, but the shop tell me no more available.

so at home i have some oscon low esr 33uf 5v

can i connect two of these in serial so i have 15 uf 10v ?

i wait your answer

 

[Zen Mod]

yes , you can

what I wrote clearly - do not use Tantalum - use regular electrolytics

 

[alfalf1]

hi zen , i test it but the sistuations is almost the same -1,15 lef ch and 1,1 right ch

is lower of 0,1 volts for channel

what is the next step ?

the test is like before with no shorted input

 

[Zen Mod]

you must short inputs

 

[alfalf1]

other news

another people in internet send me the power supplat schema od s450 where is indicated that the nomial rail voltage shold be 74v dc

and i see that my s450 the vdc is 80 volts dc when i set to work to 220v ac

then i tried to set the s450 to work at 240v ac and vre s 73vdc

about the dc in otput with this operation ( set 240ac volts) is low anoher 0,1v dc

so i have 1.0 v dc on the right and -1.1v dc in the left

i wait yours comment

 

[alfalf1]

ok i now short the input and put the results

 

[alfalf1]

whit the input shor the situation is the following:

rihgt ch 1.13v
left ch -1.23v

respect the last measure is more higt of 0.1 v for channel

 

[Zen Mod]

clarify

what 0.1V?

 

[alfalf1]

wiht the input short respet no shorted there is an increment of 0,1 volts

now i am expain in a manner more cleary ?

just a considerations

 

[Zen Mod]

aha , clear now

will be back later

 

[alfalf1]

ok wait you

 

[alfalf1]

...alone I am at sea

 

[Zen Mod]

sorry

sometimes I need to sleep and work



besides that , I need to analyze schm and decide which route of checking things is easiest for you

 

[alfalf1]

oh yes

i am very impatient, but you keep your time.

thnkas a lot for your assistance.

i wait as long as you need

 

[alfalf1]

hello Zen

I did another test and would like your opinion.
precisely:
which is presents the DC component I have thought of to put a capacitor of electrolytic 6800UF in series with the loudspeakers to block the DC component so.
But as soon as I put the capacitor the sound is not coming out just croaked that if there were the final transistors burned.
as if for a moment I connected the speaker without consendatore the sound came.
I now wonder what the consensatore that causes abnormal operation so?
I did the same test with a s200 full working and all this did not happen.
so I assume that the problem is on the output transistors and not the card drivers.
waiting for your opinion.
I hope I was clear, conversely let me all appropriate questions.

 

[Zen Mod]

well , from your post #1 , I get that you have simple problem , regarding output offset , and that amp is otherwise functional ;

now , define all problems you have - is amp working at all and what are specific problems for each channel

 

[alfalf1]

chanell right + 1.1 dc volts
channel left - 1,2 dc volts

how strage left channel ninus voltage and right plus voltage offset.

about last mt test with cup in serial to speaker you thinks that is ok ?

how you think to proceed ?