Question about Amplifiers & Preamps

1 Answer

Schematics for the Onkyo

Hi,

Just to let you know that FixYa has sent the diagram of the A-8190 and that am checking possibilities. Let you know ASAP.

Kind regards.

Benimur

Posted by on

  • 1 more comment 
  • Louie  Role
    Louie Role Oct 06, 2008

    Hi again,

    A question pls, at what point did you measure the -18VDC, speaker terminals?

    If
    yes, then most likely a problem with the output transistor pair as
    initially posted. Additionally, if it is only on one channel, then you
    can use the other channel as reference when doing voltage measurements
    or in passive/resistance checks.

    Good luck and pls postback updates.

  • Louie  Role
    Louie Role Oct 08, 2008

    Dan,

    Much appreciate the assist. I have to agree with you since this Onkyo is basically a DC amp. FixYa sent an email informing that the user asked that the schematic be forwarded to me. I did not post in the problem that I have a copy of the service manual/schematic but just mentioned that there are several models of the A-8190 (based on the primary of the main transformer). In any case, what I can not reconcile is where the user measured the -18V hence my question "at the speaker terminal?" Which is doubtful since this model uses (split PSU) +/- 60VDC. Assuming either the driver or the output is shorted, then the voltage across the speaker terminals would be greater than 18 closer to 60. The closest (but unlikely) possibility would be the +/- 22 Volts regulated supply of the NJM4558SE (Q519 or Q 520).

    Incidentally, here is the original post.





  • Louie  Role
    Louie Role Oct 09, 2008

    Thanks Dan for confirming my initial suggestion of checking Q701, and the 2SA1491 & 2SC3855 pairs as posted in the original Premium Problem.

×

1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points

    Superstar:

    An expert that got 20 achievements.

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

  • Master
  • 4,234 Answers

Benimur,

I don't have the info on the initial question/posting, but Onkyo systems I have worked on often have open driver transistors as well as shorted outputs. With one of the driver transistors open, the voltages tend to float to one side. The 18V you mention sounds like that is what is happening. have the initial asker replace the driver transistors (as a pair) just like the outputs.

Keep me posted.
Dan

Posted on Oct 08, 2008

  • ABRsvcs Oct 08, 2008

    Actually, if one of the drivers is open or one of the low voltage feeder resistors is open, this kind of offset is possible. Can you forward the schematic to me at dfleuryATverrents.com?



    I'll look into it a bit more and update this again.



    Thanks,

    Dan

  • ABRsvcs Oct 09, 2008

    After looking at the schematic, I see that this unit has a TA7317 chip. This is the "protection" chip and these are known for going bad. It is quite possible that the source of the 18V is this chip. have the asker change this IC. That may resolve the problem. Otherwise, lift the bases of each of the 4 output transistors and post the voltage readings on the 3 pads of each transistor here.



    Dan

×

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Hi I am looking for manual for my technics su-d7000 equalizer. Plz help


Hi,
try to use this manual which includes schematic diagram also:
TECHNICS SU C7000 SM Service Manual free download schematics eeprom repair...
If you could not use this please ask this question again.
Thanks

May 14, 2016 | Technics Amplifiers & Preamps

1 Answer

Transistors for Hitachi HMA 7500 amplifier


Hi,
you can download the service manual with this link:
HITACHI HMA 7500 MK II SM 1 Service Manual free download schematics...
In the document there is a schematic diagram also and you will see what type transistors are used by the device so you can find the replacement possibilities.
Thanks
gylacz

Mar 28, 2014 | Amplifiers & Preamps

1 Answer

I need the schematic for QSC RMX2450


HI,
if you can provide your email address the i will sent you the schematic diagram . Its not possible to upload PDF files here.
Ajin

Apr 30, 2013 | Amplifiers & Preamps

1 Answer

Onkyo pa-mc5500 service manual


http://www.eu.onkyo.com/dl/1463027/Manual_PA-MC5500_English.pdf
download here, i hope this helpfull, please rate very helpfull or helpfull if you think this helpfull
thanks for using fixya

Jan 20, 2011 | Onkyo Amplifiers & Preamps

1 Answer

Need Onkyo schematic diagram for TX-SV414PRO Tuner / Amp


hi...

try

www.stereomanuals.com

Rate my help if this helps

Thanks

Apr 20, 2010 | Amplifiers & Preamps

1 Answer

I need the schematics for a ONKYO Quartz Synthesized Tuner Amplifier, Model No. TX-903


I am not aware of that manual being available electronically. It was released as a paper manual. What is hte specific problem you are trying to solve? Perhaps we can help.

Dan

Nov 03, 2009 | Amplifiers & Preamps

1 Answer

Need ONKYO TX82 User Manuel


Hi and welcome to FixYa,

For the user's guide of an Onkyo TX-82, have you tried the link here?

Good luck and thank you for asking FixYa.

Oct 16, 2009 | Onkyo Amplifiers & Preamps

1 Answer

Marantz MA-7 schematics diagram needed


I am not aware of this beig available in PDF format. What is the problem you are trying to address? Perhaps we can resolve it without the schematic.

Dan

Apr 09, 2009 | Marantz Amplifiers & Preamps

1 Answer

Memory storage


posted this to the original problem, but here it is again for you :)

Hi hish

Sure mate... so long as you upgrade me to a FixYa... :)

It is a smallish part situated near the main processor, sometimes even on the front panel PCB. I cant recall exactly where on you model. But will look like one of these, and probably is one. 0,47F 5.5volt is the common value. Best place to get one may be from Farnel(the link i gave you). They are in many countries of the world, and generally have stock. Check it out and get let me know if you found it. :)

regards
robotek

May 07, 2008 | Amplifiers & Preamps

Not finding what you are looking for?
Amplifiers & Preamps Logo

Related Topics:

447 people viewed this question

Ask a Question

Usually answered in minutes!

Top Amplifiers & Preamps Experts

 Grubhead
Grubhead

Level 3 Expert

4567 Answers

Donald DCruz
Donald DCruz

Level 3 Expert

17129 Answers

The Knight
The Knight

Level 3 Expert

68153 Answers

Are you an Amplifier and Preamp Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...