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G8000 with no sound

7 pages of getting nowhere, must be time to start getting somewhere. Maybe some advice from someone who has actually worked on this particular model.

Is there no way you can trace the signal with a signal tracer, oscilloscope, or similar to find where the signal is getting lost?

I really feel this approach here measuring voltages and so forth is achieving nothing except going around in circles.

I have worked on a lot of G series receivers, and I have never found them to be this difficult, especially the higher end models like the 8000 9000...

The relay you were wondering about which is tucked away, this is the soft start relay, not an issue if the unit is powering up which it is.

Now, the driver boards in this particular amp are VERY easy to mount one pin off, this is because you dont really have a clear view when you plug them in. If you get them a pin off they will still plug in but you will have all sorts of weird issues.

You need to ascertain if you are actually getting signal to the input of the power amp driver boards.
There are a number of things this could be if it isnt.
One is the little green relay which everyone forgets about and overlooks on these amps.
Its on the F2804 board, I would get in there and jump it if you're not getting any signal to the power amp. Those relays are notoriously unreliable.

Let us know how you get on, ask questions.....
 
just to sum things up a little .
first off this manual i have is hard to follow as its scanned badly and no pages with a full schematic .
down to things . supply voltages appeared ok but no bias on the outputs of both channels . this is what i was starting to figure as to why . the reason behind this might well be the whole problem .even if not it needs sorting anyway . i failed to see a common point between the channels so maybe i am missing it in the schematics .
relays seem to be working . and some signal is passing although its very little .
now the supply has gone bad and needs to be back working first .
i must admit i haven't worked on one of these so it does make it a little harder when suggesting test points . pictures do help with this .
i was heading towards relay 1 after getting the bias sorted .
 
Ok, you are correct, those two fuses are DOA now, nothing like but moving forward. I have them, replace?

I, most of all, would like to see some forward progression, sorry if it's making some frustrated.
I have read up on this model a ton on AK before even posting. Most issues with this and the 9K are all fairly simple remedies, switches, connectors, relays, cleaning.

I am going along per all of your help at my ability.
 
thesaint said:
I have them, replace?
Click to expand...
Might be a little late to say, but if you do replace the fuses, power up with a DBT (if you have one), just in case the short that blew the fuses is still there. You might need to check the output from the regulator transistors TR09, (2SD438) and TR10 (2SB560) on the F-2809 AF PSU Board.

Good luck. ;)
 
it would be also best to pull out the driver boards again and look for anything burned . and leave them out for now .
 
DougBrewster, you were right
Somehow, the lower F-2806 board got put back 1 pin off. Idiot

Can I just replace the two fuses, put the board back in correctly, check it powered up on dim bulb and if all good, at least be back where I started.
Or is there now more broken.
 
thesaint said:
DougBrewster, you were right
Somehow, the lower F-2806 board got put back 1 pin off. Idiot

Can I just replace the two fuses, put the board back in correctly, check it powered up on dim bulb and if all good, at least be back where I started.
Or is there now more broken.
Click to expand...
No. now you need to test all the output transistors on that channel. If they are ok, test the drivers. If those are ok you can try to bring it up with the dim bulb tester.
 
Questions,
Once the heatsink is removed from the rear, can I pull the TO3's straight out to test them or do I have to do more disassembly than that to safely remove?

On the F-2806 board, I'm assuming you want me to test TR09/10.
Is there a way to test them with the board pulled out?
Continued thanks......
 
The TO3s come right out. Make careful note of which came from where. For testing the drivers it may be easier to isolate them by lifting one end of two of the resistors connected to them.
 
Understood!

Out of all the resto's done on here of 8k/9k's I have only managed to find a solid recap list, which is great. If I need or want to replace transistors or other parts is there a recommended list or thread that I missed that would have that.

I don't mind having/needing to replace but feel more confident with "expert" recommended subs.
 
Last edited:
raycarr00
Thanks for the pad link and the rebuild link, I'm going to pour through that tonight!

Working my way from the T03's.
Right and left channel both 2SC1403B's are good.
Right and left channel both 2SA745B's are not.

From preliminary readings the suggestion for replacement is On semi MJ21193G.
Will someone confirm that.

TR09/10 test good on both boards.
 
best to replace;as they're probably weak. those little Chinese do everything testers will tell you their HFE,etc...can look up data sheets-compare. I'd follow the rebuilt thread and begin to replace components,as they're likely worn out. 120w in the day,would mean lots of...parties! :rockon:
 
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