Onkyo A10 - Power OK, relay click OK, no sound

[PTL-Pioneer]

Hi all
As the title, got me an a10, powers on, relay clicks, but no sound from unit, either via headphone socket or anything like that. However I did hear music very very low on right channel for a few seconds, barely audible.
So I turn system off immediately.
Looking for confirmation or criticisms of what I will do next
1. Deoxit all switches and inputs
2. Test output transistors - but if they were shorted would the protect circuit not kick in?
3. Connect pre out to another amp to check
4. Feed main in with external source.

After this it is time to start checking voltages.

Does this sound reasonable?
Thank you

 

[redk9258]

Main-In / Pre-Out jumpers installed?
Tape Monitor switch?
I would think if the outputs were shorted, there would be blown fuses.

 

[PTL-Pioneer]

Jumpers present and correct - Tape Monitor off (been caught out before).
I will have a look and see about those fuses!

 

[jheu02]

Hi all
As the title, got me an a10, powers on, relay clicks, but no sound from unit, either via headphone socket or anything like that. However I did hear music very very low on right channel for a few seconds, barely audible.
So I turn system off immediately.
Looking for confirmation or criticisms of what I will do next
1. Deoxit all switches and inputs
2. Test output transistors - but if they were shorted would the protect circuit not kick in?
3. Connect pre out to another amp to check
4. Feed main in with external source.

After this it is time to start checking voltages.

Does this sound reasonable?
Thank you

I'd make 3 and 4 above the first things you check. If you have a DBT, power it on that to check for shorted outputs really easily w/o having to pull and test. Plus, this will help protect the amp from further damage whilst troubleshooting.

 

[PTL-Pioneer]

Initial power on was done using dbt. No issue there bulb bright then barely lit. So outputs OK based on this?
Should i be keeping the unit on the DBT while performing any voltage testing?
I would have thought the DBT would knock these off a bit

 

[jheu02]

I just recommended that as a quick check of shorts in the system. If the outputs had gone to rail voltage, the bulb would stay bright. Depending on the bulb wattage, it will throw off voltage readings.

Try to isolate where the problem seems centered by the pre vs power amp check. even a walkman into the RCA power in and using the walkman's volume control can help you determine if the power amp section is ok. You can also do a visual inspection of the trace side of the board to see if there's any cracked solder joints or weak connections with the speaker binding posts and or RCA jacks.

 

[PTL-Pioneer]

I will be whipping off the cover of this shortly again, i will make sure and post pictures too, i do believe that this is a virgin system - nothing looks like it has been touch at all (famous last works i know) Wont be able to afford to shotgun this one, so ill be hoping to actual root cause the issue and fix, get some sound out of it.
Build quality is just unreal.

Off topic a bit, but how is modern Onkyo faring these days, are any of their modern offerings worthwhile?

 

[Kevin D]

Hope all goes well it's a great amp.

 

[petehall347]

have you tried this yet ?

4. Feed main in with external source.

 

[PTL-Pioneer]

No sorry i have not gotten the time to get to number 4 just yet, busy times, ill get to this asap.
Life is hectic at the minute - i wont be taking any action to shotgun this, want to try and locate issue first.|
Thanks

 

[fernarias]

I will be whipping off the cover of this shortly again, i will make sure and post pictures too, i do believe that this is a virgin system - nothing looks like it has been touch at all (famous last works i know) Wont be able to afford to shotgun this one, so ill be hoping to actual root cause the issue and fix, get some sound out of it.
Build quality is just unreal.

Off topic a bit, but how is modern Onkyo faring these days, are any of their modern offerings worthwhile?

Onkyo, one of the few companies that didn't leave the US hifi market in the late 80s and 90s. Yes, its new stuff is very nice but, pricing wise, can't compete with it's older gear. Yamaha and Technics are the only brands that are offering gear similar to what was offered in the 70s and early 80s(and the 90s in Japan until their economy crash, imagine a 30 plus year recession).

 

[sregor]

Make sure there are no shorting plugs in any outputs. Make sure jumpers go from in to out, not in to in and out to out. (FWI picture I found showed them going sideways, not up and down).

 

[PTL-Pioneer]

Okay so to update, i pulled the main in jumpers out and connected an mp3 player in at low volume , and i am getting sound but only on the right channel, so this points to an issue with the left amp board correct?
No point pulling the pre out jumpers as the mp3 provided that functionality in this scenario, Is this accurate?

 

[petehall347]

yes it appears that way .

 

[PTL-Pioneer]

Ok so is the next step top get multimeter out and start comparing the "good" side to the bad and looking for discrepancies in voltages??

I do apologise if that is not the correct method of diagnosis, i am learning (Snail pace) as i go

 

[petehall347]

first thing is a visual looking for burned components .

 

[jheu02]

I wouldn't do much with power on right now unless you're powering it thru a dim bulb tester. BUT, you can do basic testing of many components between channels with no power to find suspect components. Any that don't appear to match up on the bad channel with the good, desolder a leg or remove from the circuit and retest to confirm. I'd also give a good look at the boards...both sides...looking for heat stress, smoked components, poor or cracked solder joints, etc. You can remove the outputs and check them with the 6 way diode test, as is also the case with the drivers and other Qs.

Did you also check pre out to another amp for confirmation that the pre is functional.

 

[PTL-Pioneer]

I will investigate fully asap, and when I have the marantz finished, I'll use it as a preamp and see what happens. Thanks for the help, I'll be back asap with more questions, or if I am lucky, some answers!

 

[grey_beard]

I have one of these and had a "no sound" situation when I bought it from Goodwill. The issue with mine was no jumpers. Beyond that I have never had any issues and the general consensus seems to be that these are built like a tank inside and out.

My advice on this one is be very careful not to short your probe when checking voltages. You have an amazing amp there. Just go slow and be careful.

Congrats on the A-10 score!

 

[PTL-Pioneer]

So looks like there is an issue with the preamp of the onkyo. When I use a different pre, all seems to work well.

Now, visual check, then voltages to and from pre section?