a JBL Eon 315.. Dead or Asleep?

[oc disorder]

Looking at a JBL Eon 315 which has the same boards as the smaller Eon 510.
The power amp and the SMPS are all on the one board.
The owner's complaint was "it doesn't switch on" and of course the fuse was the correct one and in mint condition as is the whole unit.

After seeing a post here about changing 2 surface mount IC's I started exploring the unit.
The circuit diagram calls for 2 x IRF 6644 "direct fet " SMD mosfets.
The parts list mentions "MOSFET N CH 100V 60A DIRECT FET"
The IRF6644 package is a SMD mounting arrangement under the board - and those tiny things put out nearly 300watts of audio.

Question 1. Where can I find the details for a NFO15 B30H100G ?

Well all the semi's measured ok no major shorts but I noticed that U608 supposed to be a LNK 304
was in fact a LNK 302 with about half the rating of a LNK 304!
The LNK series is made by Power Intergrations part of the Linkswitch TN family - Off-Line Switcher IC ..low cost buck converter solution.

Question 2. Could this be an assembly error or is the LNK 302 capable of managing whats required here ?

Showing my age when I say I'm still not comfortable connecting 240AC line voltage (Aust.) one end and getting 12 volts dc or whatever the other end.
I know it has other components to add... but when it's smaller than your little fingers fingernail !!...........................

The final question I have is .. are there any schematics or faultfinding schematics that detail the Test Points and how to use them?

I did see regarding another product on a "pay for advice" thread where the nice Indian man sent some troubleshooting advice manuals relating to a JBL product.


Thank You... (BTW changed both chips now the famous Blue Light power indicator comes on and stays on so I'm getting there....

Now to find the attachments.............

[MarkusBass]

Question 1. Where can I find the details for a NFO15 B30H100G ?

What kind of details you need? B30H100 is a dual Schotky diode - shown also on the schematic (D612 and D613). Datasheet is available here: (PDF) B30H100G Datasheet PDF Download - Switch-mode Power Rectifier and it can be purchased from e.g Mouser.

Mark

[oc disorder]

Whoops . thanks overlooked some stuff big time.. will edit out the rubbish.

[MarkusBass]

And the POWER LED lights up?

There are two test points on the schematic: T601 (+40V) and T603(-40V). Have you checked the voltages? If there are no voltages there, I would check voltages on C610, C611 - just after D601 bridge rectifier. But pay attention that this part of the circuit is not isolated and you cannot touch the circuit. Also, the transistors and diodes have to be attached to the heathsink.

Mark

[oc disorder]

Yes, after replacing U608 the LNK 302 with a LNK 304 and U603 the FAN7380MX and switching on, the back panel blue led illuminated.
Before I replaced them after turning on there was no indicator light but after working out some points to measure from the top side of the board I found the two main caps were charging up.
I switched it off and quickly measured both caps discharging so came to the conclusion either the start circuit was faulty or there was a problem somewhere telling the circuit not to start.
I do realise the lethal danger lurking on this board. I had also contacted the agent who sent me schematics and quoted a rather hi price for the complete module $AU$101 dollars less than the owner paid for the whole unit new!
The agent said that these were usually a board swap and after the owners unprintable comments I thought I had nothing to loose by trying a few inexpensive parts.
Thanks for the info re the test points must have had my blinkers on..

I haven't got back to it as yet , it seems too good to be true, shortly I'll check the voltages and try it into a dummy load and leave it running for a while.
Yes it's hard to measure under the board - well impossible with the unit operational with the board firmly bolted to the heatsink !
I intend to reply with the outcome one way or another.
Thanks again for your response to my dogs breakfast!

[oc disorder]

All good measured + & - 38volts approx tried it on an old "test" speaker then tried it temporarily with the speaker magnets on the floor facing up with the 315 still dismantled.
Apart from the horn sounding rather "barky" as no bass response from the unenclosed 15' speaker it's a goer !

Got some great clues from Telesis's solo post....

http://music-electronics-forum.com/t34038/

[MarkusBass]

So, is there any problem with the amp, or you are trying to fix an amp, which is already fixed?

[oc disorder]

It works now after changing those 2 chips U 608 and U 602 - just testing it for a while disassembled ... Surely you realise when you put the last screw in and turn it on, it will stop working or is that peculiar to us below the equator?

[MarkusBass]

You have several options:
1. Take a risk, assemble the amp and test it.
2. Check it with sound generator and oscilloscope.
3. Move above equator

[Telesis]

OC, I'd say you are good to go. As noted in my previous post, in mine, the one partially shorted IC lead to an overload of the LNK. If your blue led stays on, I'd put it back together, declare victory and treat yourself to an adult beverage!

Glad the info helped you out!

[sylmic]

Dear All,
I am new on the forum and a beginner in repairing electronic boards..but I must say that i wish i succeed this time (as the price of the board is really high..)
I have a pair of EON315 since 4 years and everything was working well until when one started to loose big part of the sound spectrum (high frequency mainly). I exchanged the loudspeaker and they are out of fault. Then i come to the amp. There is no visible sign of overheating or anything visible.
As I said, the system works but big part of the spectrum is missing and level is lower.
Would you have some ideas to start the board troubleshooting ?
Regards

[Enzo]

Hi sylmic, welcome to the forum.

And let us know where you are located.

Please start a new thread for your unit, otherwise we can get confused talking about more than one of them.

I don't know this unit, but if the high frequency driver is good, then your high frequency amp is problematic.