BEB #96: Onkyo Grand Integra A-G10 / A-8990 Repair (Part 1) and Walkthrough

[@aegisofhonor]

it's almost a crime that this was relegated to a storage unit for so many years. This was one of the best integrated amplifiers of it's day with absurd build quality. The entire G10 line was a true feat of engineering by Onkyo and deserves to be played and enjoyed for years and never relegated to "storage".

[@cambridgemart2075]

If everything is floating at V+, I would guess you've lost the ground on that circuit board. The bodged wiring does go to an earth tag amongst other places, so that's what I would be looking at.

[@alancordwell9759]

I agree with that. Got to be an open ground.

[@MaxKoschuh]

Thank you! A good guess. Will check that ASAP.

[@MaxKoschuh]

@@alancordwell9759 Thank you Alan.

[@RTBNL]

I once had a problem with the voltages being way of spec in a amplifier which was caused by a missing ground.

[@belamezei8003]

At 4:20 on time the fuses you show, we'll one of them is blown I can see in the video that the right one from your finger the metal thread is split inside the fuse.

[@MaxKoschuh]

the fuse is fine. thanks anyway

[@karlramberg]

Nice to see you again :-)

[@MaxKoschuh]

Hi Karl. Thank you so much!

[@freshpat19]

Wann kommt part 2?

[@SoddingaboutSi]

Massive capacitor values for the power supply! Sounds like the transistors are not being biased. Has the drivers failed. Also check fusible resistors.

[@MaxKoschuh]

Hi Simon. Thanks, will check that!

[@uchu007]

I have already repaired several A-8990 the big problem on these amps are the power capacitors that are hs and that causes random ploq on the channels when its does not degage them outright

[@MaxKoschuh]

Hi Steven. Thank you for the hint with the large caps. What do you mean by "hs"?

[@uchu007]

Remplace les 2 transistors 2sc2229 dans les optocoupleurs sur les cartes d'amplificateur.....

[@rowangrigg2828]

Hi Max, did you ever get hold of a schematic? I also have an A-G10 which is in need of repair. I have the original remote control which motor drives the volume control and also offers phase inversion, regards Rowan

[@jesperdegerman]

Did you find the problem with the amplifier? I got the manual with full schematics.

[@MaxKoschuh]

I really need the schematics. Can you send them to me?

[@jesperdegerman]

@@MaxKoschuh Hello. Sorry for the late answer. Is it okay to take photos or scan the manual and e-mail it? If you are still interested..

[@blackwingmaster141]

Prehaps input stage failed, or maybe output stage driver?

[@blackwingmaster141]

I would disconnect every single wire coming to or from amplifier module, except for power supply(to make shure that output amplifier is failing, and not something in preamp section) Also, I would check every transistor and diode on board, perhaps even capacitors . I had similar failure on my amplifier, based around STK4048 hybrid module. Output just "stuck" to negative supply rail, however in my case negative rail output transistors shorted

[@MaxKoschuh]

It could very well be a broken input / driver stage, or one of the black, isolated amp blocks. Since there is DC on BOTH channels, I hope it can be tracked down quite easily.

[@MaxKoschuh]

@@blackwingmaster141 excellent hint with disconnecting all stuff. thank yxou so much!

[@mikeloeven]

Is there anyone who might possible have a spare or be able to mold a copy of the battery compartment cover for the A-G10 remote control. I have been using one of these for my home theater and the remote has had its batteries falling out since I inherited the thing from my grandparents XD

[@robomixdj]

netzteil hast du wohl gecheckt das beide schienen (positive und negative betriebsspanung der endstufe) da sind? hat da vielleicht jemand am massepotential gebastelt (mit den schwarzen, evtl. nicht originalen, kabeln?? sehr merkwürdig wenn an allen 3 pins exakt die gleiche spannung ist; oder gibt es minimale unterschiede?? ich hoffe du bekommst diesen sehr schönen verstärker wieder hin und er klingt dann auch gut (nicht so oft der fall bei japanischen meiner meinung nach :P ).

[@MaxKoschuh]

Ja, die symmetrische Hauptversorgung ist da, und stabil. Auch die übrigen Versorgungen sind ok. Ich denke auch dass an den kabeln etwas gebastelt wurde. Ich schaue wegen dem Schaltplan, dann messe ich alles gründlicher,... mit Kamera. Der kleinere A-8870 spielt ganz hervorragend. Ich erhoffe mir vom größeren Bruder einen anständigen Klang. Aber ja, wer weiß....

[@fabian6677]

Einfach aus Neugier: bist du weitergekommen und konntest das wunderbare Teil retten?

[@xtazzzi7033]

IT FOR SALE

[@kofikwakyeagyekum6487]

Correct I need this amp badly

[@SoddingaboutSi]

I want the luxman amp!

[@MaxKoschuh]

Hehehe, yes, it is wonderful! One has shorted transistors, and one has the typical leaked main caps. I don't sell them atm though :-|

[@SoddingaboutSi]

@@MaxKoschuh let me know if you do please Max.

[@Blowcrafter]

die fehler bei denen nix verbrannt oder explodiert ist, sind immer blöd zu finden :P

[@MaxKoschuh]

LOL, ja

[@Horst021]

Wie heißt es so schön: "Suched, so werdert ihr finden"...:-) Im Prinzip hat der Autor auch Recht..... Nur sagt Er nichts darüber wie lange zu suchen wäre. Tröstet euch mit dem Gedanken das der WEG das Ziel ist......:-) - Tzz, ich bin wieder gemein heute..... Aber denkt euch nix dabei, ich bin auch "auf der Suche" :-))) - BTW: Hat wer ne Idee wo ich ein SM von einem "FISHER RS-9010" herbekomme? - Grüße und ein schönes Wochenende! Horst

[@nordicstacker5706]

Can a person by items from you

[@msylvain59]

www.ebay.de/str/Max-Koschuh-Online-Shop

[@MrSITSERVICE]

Был в ремонте такой. была неисправна микросхема мотороловская в одном канале

[@tomislavgasparic8100]

Please don´t do anything on this amp if you don´t have skill and knowledge to repair it. Send it to someone who have a lost of experience before you do some more damage.

[@MaxKoschuh]

I will NOT do any harm to this amplifier :-) It will be repaired.